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Changeset 4892

Timestamp:

2003-07-10T16:44:56+12:00 (21 years ago)

Author:

kjdon

Message:

updated some more, but stil not finished going through it

File:

: 1 edited

trunk/gsdl3/docs/manual/manual.tex (modified) (44 diffs)

Legend:

: Unmodified
: Added
: Removed

trunk/gsdl3/docs/manual/manual.tex

-              r4236
+              r4892
 {\end{tt}\end{footnotesize}}
 \newcommand{\gst}[1]{{\footnotesize \tt #1} }
+\newcommand{\gst}[1]{{\footnotesize \tt #1}}
 \begin{document}
 …
 {\em Communicator/Server}: these facilitate communication between remote modules. For example, if you want MR1 to talk to MR2, you need a Communicator-Server pair. The Server sits on top of MR2, and MR1 talks to the Communicator. Each communication type needs a new pair. So far we have only been using SOAP, so we have a SOAPCommunicator and a SOAPServer.
 {\em Receptionist}: this is the point of contact for the 'front end'. It is pretty much a router to Actions, but it also handles anything that is common to all pages, such as creating some XML data for the pages.
 {\em Actions}: these do the job of creating the 'pages'. There is a different action for each type of page, for example PageAction handles semi-static pages, QueryAction handles queries, DocumentAction displays documents. They know a little bit about specific service types. Based on the 'cgi' arguments passed in to them, they construct requests for the system, and put together the responses into data for the page. This data is transformed (currently into HTML) using XSLT. The various actions are described in  more detail in Section~\ref{sec:pagegen}.
+{\em Receptionist}: this is the point of contact for the 'front end'. Its core functionality involves routing requests to the Actions, but it may do more than that. For example, a Receptionist may: modify the request in some way before sending it to teh appropriate Action; add some data to the page responses that is common to all pages; transform the response into another form using XSLT for example. There is a hierarchy of different REceptionist types, which is described in Section~\ref{sec:recepts}.
+{\em Actions}: these do the job of creating the 'pages'. There is a different action for each type of page, for example PageAction handles semi-static pages, QueryAction handles queries, DocumentAction displays documents. They know a little bit about specific service types. Based on the 'cgi' arguments passed in to them, they construct requests for the system, and put together the responses into data for the page. This data is returned to the Receptionist, which may transform it to HTML. The various actions are described in  more detail in Section~\ref{sec:pagegen}.
 \section{Configuration}\label{sec:config}
+Initial Greenstone3 system configuration  is determined by a set of configuration files, all expressed in XML. Each site has a configuration file that binds parameters for
+the site, \gst{siteConfig.xml}.  Each collection has two configuration files, \gst{collectionConfig.xml} and \gst{buildConfig.xml}, that give metadata and other information for the
+collection.\footnote{\gst{siteConfig.xml} is new for Greenstone3, while \gst{collectionConfig.xml} and \gst{buildConfig.xml} replace \gst{collect.cfg} and \gst{build.cfg} in
+Greenstone2.}  The first includes user-defined metadata for the collection,
+such as its name and the {\em About this collection} text; and also gives
+Initial Greenstone3 system configuration is determined by a set of configuration files, all expressed in XML. Each site has a configuration file that binds parameters for the site, \gst{siteConfig.xml}. Each interface has a config file, \gst{interfaceConfig.xml}, that specifies Actions for the interface. Each collection has two configuration files, \gst{collectionConfig.xml} and \gst{buildConfig.xml}, that give metadata, display and other information for the
+collection.\footnote{\gst{siteConfig.xml} and \gst{interfaceConfig.xml} is new for Greenstone3, while \gst{collectionConfig.xml} and \gst{buildConfig.xml} replace \gst{collect.cfg} and \gst{build.cfg} in
+Greenstone2.}  The first includes user-defined presentation metadata for the collection,
+such as its name and the {\em About this collection} text; gives formatting information for the collection display; and also gives
 instructions on how the collection is to be built.  The second is produced by
 the build-time process and includes any metadata that can be determined
 …
 The HTTP address is used for retrieving resources from a site outside the XML protocol. Because a site is HTTP accessible, any files (e.g. images) belonging to that site or to its collections can be specified in the HTML of a page by a URL. This avoids having to retrieve these files from a remote site via the XML protocol\footnote{Currently, sites live inside the Tomcat gsdl3 root context, and therefore all their content is accessible over HTTP via the Tomcat address. We need to see if parts can be restricted. Also, if we use a different protocol, then resources from remote sites may need to come through the XML. Also, if we are running locally without using Tomcat, we may want to get them via file:// rather than http://.}.
 The first example in Figure~\ref{fig:siteconfig} shows a site configuration file for a rudimentary site with no site-wide services,
+Figure~\ref{fig:siteconfig} shows two example site configuration files. The first example is for a rudimentary site with no site-wide services,
 which does not connect to any external sites. The second example is for a site with one site-wide service cluster - a collection building cluster.  It also connects to the first site using SOAP.
 These two sites are running on the same machine. For site gsdl1 to talk to site localsite, a SOAP server must be run for localsite. The address of the SOAP server, in this case, is \gst{http://localhost:8090/soap/servlet/rpcrouter}.
+These two sites are running on the same machine. For site \gst{gsdl1} to talk to site \gst{localsite}, a SOAP server must be run for \gst{localsite}. The address of the SOAP server, in this case, is \gst{http://localhost:8090/soap/servlet/rpcrouter}.
 …
 </siteConfig>
 \end{verbatim}\end{gsc}
 \caption{Two sample site config files}
+\caption{Two sample site configuration files}
 \label{fig:siteconfig}
 \end{figure}
+\subsection{Interface configuration file}\label{sec:interfaceconfig}
+The interface config file \gst{interfaceConfig.xml} lists all the actions that the interface knows about at the start (but other ones can be loaded dynamically). If the interface uses servlets, it specifies what short name each action should use for the action cgi parameter eg QueryAction should use a=q. If the interface uses xslt, it specifies what xslt file should be used for each action and subaction.
+\begin{figure}
+\begin{gsc}\begin{verbatim}
+<interfaceConfig>
+  <actionList>
+    <action name='p' class='PageAction'>
+      <subaction name='home' xslt='home.xsl'/>
+      <subaction name='about' xslt='about.xsl'/>
+    </action>
+    <action name='q' class='QueryAction' xslt='basicquery.xsl'/>
+    <action name='b' class='BrowseAction' xslt='classifier.xsl'/>
+    <action name='a' class='AppletAction' xslt='applet.xsl'/>
+    <action name='d' class='DocumentAction' xslt='document.xsl'/>
+    <action name='pr' class='ProcessAction' xslt='process.xsl'/>
+    <action name='s' class='SystemAction' xslt='system.xsl'/>
+  </actionList>
+</interfaceConfig>
+\end{verbatim}\end{gsc}
+\caption{A sample interface config file}
+\label{fig:ifaceconfig}
+\end{figure}
+This makes it easy for developers to implement and use different actions and/or xslt files without recompilation. The server must be restarted, however.
 \subsection{Collection configuration file}\label{sec:collconfig}
 The collection configuration file is where the collection designer (eg a librarian) decides what form the collection should take. This includes the collection metadata such as title and description, and also includes what indexes and browsing structures should be built. The format of \gst{collectionConfig.xml} is still under consideration. However, Figure~\ref{fig:collconfig}
+here is an example as it is at present.
+The collection configuration file is where the collection designer (eg a librarian) decides what form the collection should take. This includes the collection metadata such as title and description, and also includes what indexes and browsing structures should be built. The format of \gst{collectionConfig.xml} is still under consideration. However, Figure~\ref{fig:collconfig} shows the parts of it that have been defined so far. (Since collection building at this stage is still done using Greenstone2 perl scripts and the old \gst{collect.cfg} file, we have only defined the format for the parts of \gst{collectionConfig.xml} that are used by the runtime-system.)
 \begin{figure}
 …
 \caption{Sample collectionConfig.xml file}
 \label{fig:collconfig}
+***** REDO *****
 \end{figure}
+****REDO****
 The \gst{<metadataList>} element specifies some collection metadata, such as name and description. These metadata elements can be specified in different languages. The configuration file should be encoded in utf-8.
 The \gst{<search>} element specifies what type of indexer to use, and what indexes to build. A \gst{<format>} element is used to customize what each document entry in a results list should look like.
 The \gst{<browse>} element specifies what browsing structures should be created over the documents. Again, \gst{<format>} elements are used to customize items in the hierarchy, both classifier nodes, and document entries. Section~\ref{sec:colldesign} looks at the collection configuration file in more detail.
 There is also a need for a description of how documents should be displayed. For example, whether a table of contents is needed, what metadata to display, and whether or not the text should be displayed. This will probably be in an element such as \gst{<documentDisplay>}.
+The \gst{<display>} element contains optional formatting information for the display of documents. Templates that can be specified here include \gst{documentHeading}, \gst{DocumentContent}, and other information that could be specified (in a yet to be decided format) are things such as  whether or not to display the cover image, table of contents etc.
 \subsection{Building configuration file}\label{sec:buildconfig}
 …
 collection.  The serviceRack names are Java classes that are loaded
 dynamically at runtime. Any information inside the serviceRack element is
 specific to that service---there is no set format. Figure~\ref{fig:buildconfig} shows an example. This config file specifies that the collection should load up 3 ServiceRacks: GS2MGPPRetrieve,  GS2MGPPSearch, and PhindPhraseBrowse. The contents of each \gst{<serviceRack>} element are passed to the appropriate ServiceRack objects for configuration.
+specific to that service---there is no set format. Figure~\ref{fig:buildconfig} shows an example. This config file specifies that the collection should load up 3 ServiceRacks: GS2MGPPRetrieve,  GS2MGPPSearch, and PhindPhraseBrowse. The contents of each \gst{<serviceRack>} element are passed to the appropriate ServiceRack objects for configuration. The collectionConfig.xml file is also passed ot the ServiceRack objects at configure time---the \gst{format} and \gst{displayItem} information is used directly from the \gst{collectionConfig.xml} file rather than added into \gst{buildConfig.xml} during building. This enables changes in \gst{collectionConfig.xml} to take effect in the collection without rebuilding being necessary.
 …
 The \gst{init()} method creates a new Receptionist and a new
 MessageRouter. By default, the base Receptionist and MessageRouter classes are used, but subclasses can be used if they are specified in the servlet init params (see Section~\ref{sec:tomcat}). The appropriate system variables are set in each (interface
 name, site name, etc.) and then \gst{configure()} is called. The MessageRouter
+MessageRouter. Default classes (DefaultReceptionist, MessageRouter) are used unless subclasses have been specified  in the servlet initiation parameters (see Section~\ref{sec:tomcat}). The appropriate system variables are set for each object (interface
+name, site name, etc.) and then \gst{configure()} is called on both. The MessageRouter
 is passed to the Receptionist. The servlet then communicates only with
 the Receptionist, not with the MessageRouter.
+The Receptionist loads up all the different Action classes. A
+static list is used initially, and other Actions may be loaded on the fly as needed. Actions are added to a map, with shortnames for keys. Eg the QueryAction is added with key 'q'. The Actions are passed the MessageRouter reference too.
+The MessageRouter reads in its site configuration file \gst{siteConfig.xml}. This
+lists the ServiceRack and ServiceCluster classes that need to be loaded and  any sites that need
+to be connected to.
+It has a module map that maps names to objects. This is used for routing the messages. It also keeps small chunks of XML---serviceList, collectionList, clusterList and siteList. These are what get returned in response to a describe request (see Section~\ref{sec:describe}.).
+The Receptionist reads in the \gst{interfaceConfig.xml} file, and loads up all the different Action classes. Other Actions may be loaded on the fly as needed. Actions are added to a map, with shortnames for keys. Eg the QueryAction is added with key 'q'. The Actions are passed the MessageRouter reference too.
+If the Receptionist is a Transforming receptionist, a mapping between shortnames  and xslt files is also created.
+The MessageRouter reads in its site configuration file \gst{siteConfig.xml}. It creates a module map that maps names to objects. This is used for routing the messages. It also keeps small chunks of XML---serviceList, collectionList, clusterList and siteList. These are what get returned in response to a describe request (see Section~\ref{sec:describe}.).
 Each ServiceRack specified in the config file is created, then queried for its list of services. Each service name is added to the map, pointing to the ServiceRack object. Each service is also added to the serviceList. After this stage, ServiceRacks are transparent to the system, and each service is treated as a separate module.
 ServiceClusters are created and passed the \gst{<serviceCluster>} element for configuration. They are added to the map as is, with the cluster name as a key. A serviceCluster is also added to the serviceClusterList.
 For each site specified, the MessageRouter creates an appropriate type Communicator object. Then is tries to get the site description. If the server for the remote site is up and running, this should  be successful. The site will be added to the map with its site name as a key. The sites collections, services and clusters will also be added into the static xml lists. If the server for the remote site is not running, the site will not be included in the siteList or module map. To try again to access the site, either Tomcat must be restarted, or a run-time reconfigure sites commands must be sent (see next section).
+For each site specified, the MessageRouter creates an appropriate type Communicator object. Then it tries to get the site description. If the server for the remote site is up and running, this should  be successful. The site will be added to the map with its site name as a key. The sites collections, services and clusters will also be added into the static xml lists. If the server for the remote site is not running, the site will not be included in the siteList or module map. To try again to access the site, either Tomcat must be restarted, or a run-time reconfigure sites commands must be sent (see next section).
 The MessageRouter also looks inside the site's \gst{collect} directory, and  loads up a Collection object for each valid collection found.
 …
 The Collection object reads its \gst{buildConfig.xml} and \gst{collectionConfig.xml}
 files, determines the metadata, and loads ServiceRack classes based on the
 names specified in \gst{buildConfig.xml\/}. The \gst{<ServiceRack>} XML element is passed to the object to be used in configuration. The collectionConfig.xml contents are also passed in to the ServiceRacks. Any format or display information that the services need must be extracted from the collection config file.
+names specified in \gst{buildConfig.xml\/}. The \gst{<serviceRack>} XML element is passed to the object to be used in configuration. The \gst{collectionConfig.xml} contents are also passed in to the ServiceRacks. Any format or display information that the services need must be extracted from the collection config file.
 Collection objects are added to the module map with their name as a key, and also a collection element is added into the collectionList xml.
 …
 The startup configuration reads in the various config files and loads up quite a lot of XML into memory. This avoids having to read in files all the time. However, this means that any changes to these files will have no effect in the system. So some run-time reconfiguration options are provided. Currently, these can only be accessed by typing in cgi-arguments into the URL, there is no nice web form yet to do this. SystemAction converts these arguments into system requests, which are described in Section~\ref{sec:system}.
+The cgi arguments are entered after the \gst{library?} part of the URL. There are three types of commands: configure, activate, deactivate. These are specified by \gst{a=s\&sa=c}, \gst{a=s\&sa=a}, and \gst{a=s\&sa=d}, respectively (a is action, sa is subaction). By default, the requests are sent to the MessageRouter, but they can be sent to a collection/cluster by the addition of \gst{c=xxx}, where \gst{xxx} is the name of the collection or cluster.
+The cgi arguments are entered after the \gst{library?} part of the URL. There are three types of commands: configure, activate, deactivate. These are specified by \gst{a=s\&sa=c}, \gst{a=s\&sa=a}, and \gst{a=s\&sa=d}, respectively (\gst{a} is action, \gst{sa} is subaction). By default, the requests are sent to the MessageRouter, but they can be sent to a collection/cluster by the addition of \gst{sc=xxx}, where \gst{xxx} is the name of the collection or cluster. Table~\ref{tab:run-time config} describes the arguments in abit more detail.
+\begin{table}
+\caption{Example run-time configuration arguments.}
+\label{tab:run-time config}
 \begin{tabular}{lp{8cm}}
 a=s\&sa=c & reconfigures the whole site, reads in siteConfig.xml, reloads all the collections. Just part of this can be specified with another argument ss (system subset). The valid values are collectionList, siteList, serviceList, clusterList. \\
 a=s\&sa=c\&c=demo & reconfigures a collection or cluster. ss can also be used here, valid values are metadataList and serviceList. \\
 a=s\&sa=a & activate a specific module. Modules are specified using two arguments, st (system module type) and sn (system module name). Valid types are collection, cluster site.\\
 a=s\&sa=d & deactivate a module. st and sn can be used here too. Valid types are collection, cluster, site, service. \\
 a=s\&sa=d\&c=demo & deactivate a module belonging to a collection or cluster. Valid types are service. \\
+\gst{a=s\&sa=c} & reconfigures the whole site, reads in siteConfig.xml, reloads all the collections. Just part of this can be specified with another argument \gst{ss} (system subset). The valid values are \gst{collectionList}, \gst{siteList}, \gst{serviceList}, \gst{clusterList}. \\
+\gst{a=s\&sa=c\&sc=XXX} & reconfigures the XXX collection or cluster. \gst{ss} can also be used here, valid values are \gst{metadataList} and \gst{serviceList}. \\
+\gst{a=s\&sa=a} & activate a specific module. Modules are specified using two arguments, \gst{st} (system module type) and \gst{sn} (system module name). Valid types are \gst{collection}, \gst{cluster} \gst{site}.\\
+\gst{a=s\&sa=d} & deactivate a module. \gst{st} and \gst{sn} can be used here too. Valid types are \gst{collection}, \gst{cluster}, \gst{site}, \gst{service}. \\
+\gst{a=s\&sa=d\&sc=XXX} & deactivate a module belonging to the XXX collection or cluster. \gst{st} and \gst{sn} can be used here too. Valid types are \gst{service}. \\
 \end{tabular}
+\end{table}
 \section{System messages}\label{sec:messages}
 …
 process described in Section~\ref{sec:startup-config} has been carried out), it is passing messages back and forth. All modules communicate via message passing.
+There are two different styles of messaging.  The first style of messaging is the internal Greenstone communication. Requests and responses follow a basic format, and both are in XML.Each individual  communication is contained in a \gst{<message>} element\footnote{all sample requests and responses shown here  are assumed to have \gst{<message>} elements}.
+They contain either \gst{<request>} or \gst{<response>} elements--- a single message may contain multiple requests/responses. Each \gst{<request>} (and \gst{<response>}?) has a language attribute, of the form \gst{lang='...'}.
+The language attribute is used by the XSLT to determine the language currently
+being used by the user interface.  Virtually all messages contain text strings,
+and services use this attribute to return strings in the appropriate language. Element and attribute names are formated in lower case with the first letter of internal words capitalized, like 'matchDocs'. Each request typically specifies one service or one action, and the response contains either the data requested, or a status message.
+Lists must only have the same elements in them.(put this here??)
+Requests have
+a \gst{to} attribute and responses have \gst{from}.  These are addresses used
+There are two different styles of messaging.  The first style of messaging is the internal Greenstone communication. Requests and responses follow a basic format, and both are in XML. Each individual  communication is contained in a \gst{<message>} element\footnote{all sample requests and responses shown are assumed to have \gst{<message>} elements}.
+They contain either \gst{<request>} or \gst{<response>} elements--- a single message may contain multiple requests/responses. Each \gst{<request>} (and \gst{<response>}?) has a language attribute, of the form \gst{lang='...'}. Virtually all responses contain text strings, and this attribute specifies the preferred language for these strings.  Element and attribute names are formated in lower case with the first letter of internal words capitalized, like 'matchDocs'. Each request typically specifies one service or one action, and the response contains either the data requested, or a status message.
+Requests have a \gst{to} attribute and responses have \gst{from}.  These are addresses used
 by routing modules.  For example \gst{to='site1/demo/TextQuery'} routes a
 message to modules named site1, demo then TextQuery. These modules happen to be a MessageRouter for a remote site (site1), a Collection (demo), and a Service (TextQuery).
 There are several types of request: 'describe', 'system', 'process', 'status', 'format'. These requests can ask for any functionality available in the system.
+The second messaging style is the communication between the servlet (or other external agent) and the Greenstone system (via the Receptionist). The request contains a simple representation of the arguments in a Greenstone URL, and has a request type of 'cgi'. It has the same format as any other request in the system.  The response, however, is a page of data, typically in HTML.
+These cgi-type messages come into the Receptionist and are passed to the appropriate action. The actions generate appropriate internal messages which are sent to the MessageRouter. The responses are put together into a single piece of XML and transformed, using XSLT, into a 'page' of HTML.
+\subsection{cgi-type messages}\label{sec:cgi}
+These are the special 'external'-style messages. Servlet to Receptionist messages are requests for a 'page' of data---for example, the home page for a site; the query page for a collection; the text of a document. They contain, in XML, a representation of the arguments in a
 Greenstone URL.  The two main arguments are \gst{a} (action) and \gst{sa}
+message to modules named \gst{site1}, \gst{demo} then \gst{TextQuery}. These modules happen to be a MessageRouter for a remote site (\gst{site1}), a Collection (\gst{demo}), and a Service (\gst{TextQuery}).
+There are several types of request, specified by the \gst{type} attribute: \gst{describe}, \gst{system}, \gst{process}, \gst{status}, \gst{format}. These requests can ask for any functionality available in the system. They are described in more detail in Sections~\ref{sec:describe}, \ref{sec:system}, \ref{sec:process}, \ref{sec:status}, and \ref{sec:format}, respectively.
+The second messaging style is the communication between the servlet (or other external agent) and the Greenstone system (via the Receptionist). The request contains a simple representation of the arguments in a Greenstone URL, and has a request type of 'page', as it is a request for a page of data. It has the same format as any other request in the system.  The response, however, does not follow the same format as other responses, and may given in different formats, such as XML, HTML etc.
+These page-type messages come into the Receptionist and are passed to the appropriate action. The actions generate appropriate internal messages which are sent to the MessageRouter. The responses are put together into a single page of XML. This may be returned as XML, or transformed into some other form, eg HTML using XSLT. This type of message is described in Section~\ref{sec:page}.
+\subsection{page-type messages}\label{sec:page}
+These are the special 'external'-style messages. Requests originate from outside Greenstone, for example from a servlet, or java application. They are requests for a 'page' of data---for example, the home page for a site; the query page for a collection; the text of a document. They contain, in XML, a list of arguments specifiying what type of page is required. If the external context is a servlet, the arguments represent the 'cgi' arguments in a Greenstone URL.  The two main arguments are \gst{a} (action) and \gst{sa}
 (subaction).\footnote{The \gst{sa} replaces Greenstone's old \gst{p} arg for
 the page action, and is new for other actions.  For example, a text query could
 be encoded as \gst{a=q \& sa=text\/}.}  All other arguments are treated as
+be encoded as \gst{a=q \& sa=text\/}.}  All other arguments are encoded as
 parameters.
 Here is the XML representation of the arguments:
 \begin{quote}\begin{gsc}\begin{verbatim}
 <request type='cgi' action='a-arg-value' subaction='sa-arg-value'
          lang='en' output='html'>
+Here is some examples of  requests\footnote{In a servlet context, these correspond to the URLs \gst{a=p\&sa=about\&c=demo\&l=fr}, and \gst{a=q\&l=en\&s=TextQuery\&c=demo\&rt=r\&ca=0\&st=1\&m=10\&q=snail}.}:
+\begin{quote}\begin{gsc}\begin{verbatim}
+<request type='page' action='p' subaction='about'
+         lang='fr' output='html'>
   <paramList>
+    <param name='xx' value='yyy'/>
+    <param name=...
+    <param name='c' value='demo'/>
   </paramList>
 </request>
 \end{verbatim}\end{gsc}\end{quote}
+The receptionist routes the message to the appropriate action.  The output
+field is used to indicate what type of output to return. The actions do not
+return responses in the normal format; instead they return a page of
+information, expressed by default in HTML. Alternative formats could be XML or WML. The basic structure of the XML data (before transformation to HTML or other) is described in Section~\ref{sec:pagegen}. What the HTML looks like depends on the XSLT used to transform the data, and will not be shown here.
+\begin{quote}\begin{gsc}\begin{verbatim}
+<request  lang='en' type='page' action='q'  output='html'>
+  <paramList>
+    <param name='s' value='TextQuery'/>
+    <param name='c' value='demo'/>
+    <param name='rt' value='r'/>
+    <!-- the rest are the service specific params -->
+    <param name='ca' value='0'/> <!-- casefold -->
+    <param name='st' value='1'/> <!-- stem -->
+    <param name='m' value='10'/> <!-- maxdocs -->
+    <param name='q' value='snail'/> <!-- query string -->
+  </paramList>
+</request>
+\end{verbatim}\end{gsc}\end{quote}
+The Receptionist routes the message to the appropriate Action (determined by looking up its shortname$->$Action object map). The actions determine what information is needed from the server and retrieves it, making one or more internal requests to the MessageRouter. This information is gathered together into a single response, and returned to the Receptionist. The Receptionist may process the result further, depending on what type of Receptionist is it, and returns the page to the external entity. Section~\ref{sec:pagegen} describes the different types of Receptionist, and details the structure of the 'pages' they produce.
 The LibraryServlet class communicates with the Receptionist, which is the entry
 point into the system.  Future GUIs could communicate either with the
 Receptionist or directly with the MessageRouter. If they communicate with the Receptionist they must use the cgi-args type of request, asking for predefined pages of information. However, the Receptionist will pass other types of request directly to the MessageRouter. If they communicate with the MessageRouter directly, they must use the internal message format described in the next section---this is more powerful, but involves more work by the client. Individual services are requested---the results need to be put together by the client.
 The cgi arguments used currently are shown in Table~\ref{tab:args}.
 Other arguments can be specified by  particular actions. For example, when the query action receives a list of parameters from the TextQuery service, it creates short names for them and adds them to the global list of cgi-args.
+Receptionist or directly with the MessageRouter. If they communicate with the Receptionist they may use the either page type requests, asking for predefined pages of information, or they can use any of the other internal type requests--- these requests will be passed directly to the MessageRouter. If they communicate with the MessageRouter directly, they must use the internal message format described in the next sections---this is more powerful, but involves more work by the client. Individual services are requested---the results need to be put together by the client.
+The main  arguments/parameters used currently are shown in Table~\ref{tab:args}.
+Other arguments can be specified by  particular actions. These include any parameters needed to access services.  For example, the TextQuery service has a set of parameters including stem and case etc, that are only used by the query action.
 \begin{table}
 …
 \end{table}
+Here is an example request that retrieves the home page in French:
+\begin{quote}\begin{gsc}\begin{verbatim}
+a=p&sa=home&l=fr
+<request lang='fr' type='cgi' action='p' subaction='home'
+    output='html'/>
+\end{verbatim}\end{gsc}\end{quote}
+This request represents a text query:
+\begin{quote}\begin{gsc}\begin{verbatim}
+a=q&l=en&s=TextQuery&c=demo&rt=r&ca=0&st=1&m=10&q=snail
+<request  lang='en' type='cgi' action='q'  output='html'>
+  <paramList>
+    <param name='s' value='TextQuery'/>
+    <param name='c' value='demo'/>
+    <param name='rt' value='r'/>
+    <!-- the rest are the service specific params -->
+    <param name='ca' value='0'/> <!-- casefold -->
+    <param name='st' value='1'/> <!-- stem -->
+    <param name='m' value='10'/> <!-- maxdocs -->
+    <param name='q' value='snail'/> <!-- query string -->
+  </paramList>
+</request>
+\end{verbatim}\end{gsc}\end{quote}
+These cgi requests get passed to the appropriate action, which determines what data is required for the page, and what internal requests to send off. The page generation process for the different actions is described in Section~\ref{sec:pagegen}.
 \subsection{'describe'-type messages}\label{sec:describe}
+This is the first of the internal messages.
+The most basic message is ``describe-yourself'', which can be sent to any module in the system. The module responds with a semi-predefined piece of XML, making these requests very efficient. The info is predefined apart from any language specific text strings, which are put together as each request comes in.
+**** REDO (the responses may now contain display information which is not shown here) ****
+This is the first of the standard internal messages.
+The most basic message is ``describe-yourself'', which can be sent to any module in the system. The module responds with a semi-predefined piece of XML, making these requests very efficient. The response is predefined apart from any language-specific text strings, which are put together as each request comes in.
 \begin{quote}\begin{gsc}\begin{verbatim}
 <request lang='en' type='describe' to=''/>
 …
 </param>
 \end{verbatim}\end{gsc}\end{quote}
-****describe the various types, what the type means - display purposes- etc.
 If no default is specified, the parameter is assumed to be mandatory.
 Here are some examples of parameters:
 \begin{quote}\begin{gsc}\begin{verbatim}
 <param name='Case' type='boolean' default='0'/>
 <param name='MaxDocs' type='integer' default='50'/>
 <param name='Index' type='enum' default='dtx'>
+<param name='case' type='boolean' default='0'/>
+<param name='maxDocs' type='integer' default='50'/>
+<param name='index' type='enum' default='dtx'>
   <option name='dtx'/>
   <option name='stt'/>
 …
 <!-- this one is for the text box and field list for the
 simple field query-->
 <param name='simple' type='multi' occurs='4'>
+<param name='simpleField' type='multi' occurs='4'>
   <param name='fqv' type='string'/>
   <param name='fqf' type='enum_single'>
 …
 \end{verbatim}\end{gsc}\end{quote}
 The type attribute is used to determine how to display the parameters on a web page or interface. For example, a string parameter may result in   a text entry box, a boolean an on/off button, enum\_single/enum\_multi a drop-down menu, where one or more items, respectively, can be selected.
+The type attribute is used to determine how to display the parameters on a web page or interface. For example, a string parameter may result in   a text entry box, a boolean an on/off button, enum\_single/enum\_multi a drop-down menu, where one or many items, respectively, can be selected.
 A multi-type parameter indicates that two or more parameters are associated, and should be displayed appropriately. For example, in a field query, the text box and field list should be associated. The occurs attribute specifies how many times the parameter should be displayed on the page.
 Parameters also come with display information...
+Parameters also come with display information: all the text strings needed to present them to teh user. These include the name of the parameter and the display values for any options.
 A service description also contains a display element - this contains all the language dependent text strings - put together on the fly. These strings are name of the service, what to use for the submit button, and text strings for all the parameters: name, what each value is called, etc.
+Here is a request, along with a sample response.
+\begin{quote}\begin{gsc}\begin{verbatim}
+<request lang='en'  type='describe' to='demo/TextQuery'/>
+<response lang='en' type='describe' from='demo/TextQuery' >
+  <service name='TextQuery' type='query'>
+  <paramList>
+    <param name='matchDocs' type='integer' default='50/>
+    <param name='case' type='boolean' default='1'/>
+    <param name='index' type='enum' default='tt'>
+      <option name='tt'/>
+      <option name='t0'/>
+    </param>
+  </paramList>
+</response>
+\end{verbatim}\end{gsc}\end{quote}
+\begin{figure}
+Here is a sample describe request to the FieldQuery service of collection mgppdemo, along with its response. Figure~\ref{fig:query-display} gives an example html search form that may be generated from this describe response.
 \begin{quote}\begin{gsc}\begin{verbatim}
 <request lang="en" to="mgppdemo/FieldQuery" type="describe" />
 …
 </response>
 \end{verbatim}\end{gsc}\end{quote}
-\end{figure}
 \begin{figure}[t]
   \centering
   \includegraphics[width=3.5in]{query2.ps}
   \caption{Sample query form.}
   \label{fig:query}
+  \caption{The previous query service describe response as displayed on the search page.}
+  \label{fig:query-display}
 \end{figure}
+describe request to an applet type service: returns ...
+A describe request to an applet type service returns the applet html element: this will be embedded into a web page to run the applet.
 \begin{quote}\begin{gsc}\begin{verbatim}
 <request type='describe' to='mgppdemo/PhindApplet'/>
 …
 \end{verbatim}\end{gsc}\end{quote}
+Note that the library parameter has been left blank. This is because library refers to the current servlet that is running and the name is not necessarily known in advance. So either the applet action or the receptionist must fill in this parameter before displaying the html.
 \subsection{'system'-type messages}\label{sec:system}
+``System'' requests are used to tell a MessageRouter, Collection or ServiceCluster to update its cached information and activate or deactivate other modules. For example, the MessageRouter has a set of Collection modules that it can talk to. It also holds some XML information about those collections---this is returned when a request for a collection list comes in. If a collection is deleted or modified, or a new one created, this information may need to change, and the list of available modules may also change.
+``System'' requests are used to tell a MessageRouter, Collection or ServiceCluster to update its cached information and activate or deactivate other modules. For example, the MessageRouter has a set of Collection modules that it can talk to. It also holds some XML information about those collections---this is returned when a request for a collection list comes in. If a collection is deleted or modified, or a new one created, this information may need to change, and the list of available modules may also change. Currenlty they are initiated by particular cgi parameters (see Section~\ref{sec:runtime-config}).
 The basic format of a system request is as follows:
 …
 \end{verbatim}\end{gsc}\end{quote}
 Each system request is specified in a system element. The following are examples:
+One or more actual requests are specified in  system elements. The following are examples:
 \begin{quote}\begin{gsc}\begin{verbatim}
 <system type='configure' subset=''/>
 …
 \end{verbatim}\end{gsc}\end{quote}
+At some stage, an error or status code should be included.
 System requests are mainly answered by the MessageRouter. However, Collections and ServiceClusters will respond to a subset of these requests.
+\subsection{'process'-type messages} ***** TODO ****
+divide this up into service types: query, retrieve (metadata, structure, content), process, applet, enrich, browse...
+show basic structure, then more detailed format for each subtype
+The main type of requests in the system are for services. There are different types of services: query, browse, retrieve, process, applet. Query services do some kind of search and return a list of documents. Retrieve services can return those documents, metadata about the documents, or other resources. Browse is for browsing lists or hierarchies of documents. process type services are those where the request is for a command to be run. A status code will be returned immediately, and then if the command has not finished, an update of the status can be requested. Applet services are those that run an applet.
+  Other possibilities include  transform, enrich, extract, accrete. These types of service generally enhance the functionality of the first set. They may be used during collection formation: 'accrete' documents by adding them to a collection, 'transform' the documents into a different format, 'extract' information or acronyms from the documents, 'enrich' those documents with the information extracted or by adding new information. They may also be used during querying: 'transform' a query before using it to query a collection, or 'transform' the documents you get back into an appropriate form.
+The basic structure of a service request is as follows:
+\begin{quote}\begin{gsc}\begin{verbatim}
+<message>
+  <request lang='en'  type='query' to='demo/TextQuery'>
+    <paramList/>
+    other elements...
+  </request>
+</message>
+\end{verbatim}\end{gsc}\end{quote}
+The parameters are name value pairs corresponding to parameters that were specified in the service description sent in response to a describe request.
+\subsection{'process'-type messages}
+The main type of requests in the system are for services. There are different types of services, currently: \gst{query}, \gst{browse}, \gst{retrieve}, \gst{process}, \gst{applet}, \gst{enrich}. Query services do some kind of search and return a list of document identifiers. Retrieve services can return the content of those documents, metadata about the documents, or other resources. Browse is for browsing lists or hierarchies of documents. Process type services are those where the request is for a command to be run. A status code will be returned immediately, and then if the command has not finished, an update of the status can be requested. Applet services are those that run an applet. Enrich services take a document and return the document with some extra markup added.
+  Other possibilities include transform, extract, accrete. These types of service generally enhance the functionality of the first set. They may be used during collection formation: 'accrete' documents by adding them to a collection, 'transform' the documents into a different format, 'extract' information or acronyms from the documents, 'enrich' those documents with the information extracted or by adding new information. They may also be used during querying: 'transform' a query before using it to query a collection, or 'transform' the documents you get back into an appropriate form.
+The basic structure of a service 'process' request is as follows:
+\begin{quote}\begin{gsc}\begin{verbatim}
+<request lang='en'  type='process' to='demo/TextQuery'>
+  <paramList/>
+  other elements...
+</request>
+\end{verbatim}\end{gsc}\end{quote}
+The parameters are name-value pairs corresponding to parameters that were specified in the service description sent in response to a describe request.
 \begin{quote}\begin{gsc}\begin{verbatim}
 …
 \end{verbatim}\end{gsc}\end{quote}
 Some requests have other content---for document retrieval, this would be a list of documents to retrieve. For metadata retrieval, the content is the list of documents, and a list of metadata to retrieve for each document.
 Responses vary depending on the type of request.
+Some requests have other content---for document retrieval, this would be a list of document identifiers to retrieve. For metadata retrieval, the content is the list of documents to retrieve metadata for.
+Responses vary depending on the type of request. The following sections look at hte process type requests and responses for each type of service.
 \subsubsection{'query'-type services}
+Responses to query requests contain a content, which is the actual result, along with some metadata about the query\footnote{is this called metadata or something else?}. For instance, a text query on 'snail farming', with the parameter 'maxDocs=10' might return the first 10 documents, and one of the query metadata items would be the total number of documents that matched the query.\footnote{no metadata about the query result is returned yet.}
+The following shows some example query requests and their responses.
+Find at most 10 Sections containing the word snail (stemmed), returning the results in unsorted order:
+\begin{quote}\begin{gsc}\begin{verbatim}
+<message>
+  <request lang='en'  to="mgppdemo/TextQuery" type="process">
+    <paramList>
+      <param name="maxDocs" value="10"/>
+      <param name="queryLevel" value="Section"/>
+      <param name="stem" value="1"/>
+      <param name="matchMode" value="some"/>
+      <param name="sortBy" value="natural"/>
+      <param name="index" value="t0"/>
+      <param name="case" value="0"/>
+      <param name="query" value="snail"/>
+    </paramList>
+  </request>
+</message>
+\end{verbatim}\end{gsc}\end{quote}
+\begin{quote}\begin{gsc}\begin{verbatim}
+<message>
+  <response lang='en' from="mgppdemo/TextQuery" type="query">
+    <documentList>
+      <document name="HASH010f073f22033181e206d3b7"/>
+      <document name="HASH010f073f22033181e206d3b7.2"/>
+      <document name="HASHac0a04dd14571c60d7fbfd"/>
+    </documentList>
+  </response>
+</message>
+\end{verbatim}\end{gsc}\end{quote}
+Responses to query requests contain a list of document identifiers, along with some other information, dependent on the query type. For a text query, this includes term frequency information, and some metadata about the result. For instance, a text query on 'snail farming', with the parameter 'maxDocs=10' might return the first 10 documents, and one of the query metadata items would be the total number of documents that matched the query.\footnote{no metadata about the query result is returned yet.}
+The following shows an example query request and its response.
+Find at most 10 Sections in the mgppdemo collection, containing the word snail (stemmed), returning the results in ranked order:
+\begin{quote}\begin{gsc}\begin{verbatim}
+<request lang='en'  to="mgppdemo/TextQuery" type="process">
+  <paramList>
+    <param name="maxDocs" value="10"/>
+    <param name="queryLevel" value="Section"/>
+    <param name="stem" value="1"/>
+    <param name="matchMode" value="some"/>
+    <param name="sortBy" value="1"/>
+    <param name="index" value="t0"/>
+    <param name="case" value="0"/>
+    <param name="query" value="snail"/>
+  </paramList>
+</request>
+<response from="mgppdemo/TextQuery" type="process">
+  <metadataList>
+    <metadata name="numDocsMatched" value="59" />
+  </metadataList>
+  <documentNodeList>
+    <documentNode nodeID="HASHac0a04dd14571c60d7fbfd.4.2"
+    docType='hierarchy' nodeType="leaf" />
+    <documentNode nodeID="HASH010f073f22033181e206d3b7.2.12"
+    docType='hierarchy' nodeType="leaf" />
+    <documentNode nodeID="HASH010f073f22033181e206d3b7.1"
+    docType='hierarchy' nodeType="interior" />
+    <documentNode nodeID="HASHac0a04dd14571c60d7fbfd.2.2"
+    docType='hierarchy' nodeType="leaf" />
+    ...
+  </documentNodeList>
+  <termList>
+    <term field="" freq="454" name="snail" numDocsMatch="58" stem="3">
+      <equivTermList>
+        <term freq="" name="Snail" numDocsMatch="" />
+        <term freq="" name="snail" numDocsMatch="" />
+        <term freq="" name="Snails" numDocsMatch="" />
+        <term freq="" name="snails" numDocsMatch="" />
+      </equivTermList>
+    </term>
+  </termList>
+</response>
+\end{verbatim}\end{gsc}\end{quote}
+The list of document identifiers includes some information about document type and node type. Currently, document types include \gst{simple}, \gst{paged} and \gst{hierarchy}. \gst{simple} is for single section documents, i.e. ones with no sub-structure. \gst{paged} is documents that have a single list of sections, while \gst{hierarchy} type documents have a hierarchy of nested sections. For \gst{paged} and \gst{hierarchy} type documents, the node type identifies whather a section is the root of the document, an internal section, or a leaf.
+The term list identifies, for each term in teh query, what its frequency in the collection is, how many documents contained that term, and a list of its equivalent terms (if stemming or casefolding was used).
+\subsubsection{'browse'-type services}
+Browse type services are used for classification browsing. The request consists of a list of classifier identifiers, and some structure parameters listing what structure to retrieve.
+\begin{quote}\begin{gsc}\begin{verbatim}
+<request lang="en" to="mgppdemo/ClassifierBrowse" type="process">
+  <paramList>
+    <param name="structure" value="ancestors" />
+    <param name="structure" value="children" />
+  </paramList>
+  <classifierNodeList>
+    <classifierNode nodeID="CL1.2" />
+  </classifierNodeList>
+</request>
+<response from="mgppdemo/ClassifierBrowse" type="process">
+  <classifierNodeList>
+    <classifierNode nodeID="CL1">
+      <nodeStructure>
+    <classifierNode nodeID="CL1">
+          <classifierNode nodeID="CL1.2">
+        <classifierNode nodeID="CL1.2.1" />
+        <classifierNode nodeID="CL1.2.2" />
+        <classifierNode nodeID="CL1.2.3" />
+        <classifierNode nodeID="CL1.2.4" />
+        <classifierNode nodeID="CL1.2.5" />
+          </classifierNode>
+    </classifierNode>
+      </nodeStructure>
+    </classifierNode>
+  </classifierNodeList>
+</response>
+\end{verbatim}\end{gsc}\end{quote}
+Possible values for structure parameters are \gst{ancestors}, \gst{parent}, \gst{siblings}, \gst{children}, \gst{descendents}. The response gives, for each identifier in the request, a \gst{<nodeStructure>} element with all the requested structure put together into a hierarchy. The structure may include classifier and document nodes.
 \subsubsection{'retrieve'-type services}
+Retrieval services are special in that requests are not explicilty initiated by a user from a form on a web page, but are called from actions in response to other things. This means that their names are hard-coded into the Actions. DocumentContentRetrieve, DocumentStructureRetrieve and DocumentMetadataRetrieve are the standard names for retrieval services for content, structure, and metadata of documents. Requests to each of these include a list of document identifiers. Because these generally refer to parts of documents, the elements are called \gst{<documentNode>}. For the content, that is all that is required. For the metadata retrieval service, the request also needs parameters specifying what metadata is required. For structure retrieval services, requests need parameters specifying what structure or structural info is required.
+Some example requests and responses follow.
 Give me the Title metadata for these documents:
 \begin{quote}\begin{gsc}\begin{verbatim}
+<message>
+  <request lang='en'  to="mgppdemo/MetadataRetrieve"
+    type="retrieve">
+      <documentList>
+        <document name="HASH010f073f22033181e206d3b7"/>
+        <document name="HASH010f073f22033181e206d3b7.2"/>
+        <document name="HASHac0a04dd14571c60d7fbfd"/>
+      </documentList>
+<request lang="en" to="mgppdemo/DocumentMetadataRetrieve" type="process">
+  <paramList>
+    <param name="metadata" value="Title" />
+  </paramList>
+  <documentNodeList>
+    <documentNode nodeID="HASHac0a04dd14571c60d7fbfd.4.2"/>
+    <documentNode nodeID="HASH010f073f22033181e206d3b7.2.12"/>
+    <documentNode nodeID="HASH010f073f22033181e206d3b7.1"/>
+    ...
+  </documentNodeList>
+</request>
+<response from="mgppdemo/DocumentMetadataRetrieve" type="process">
+  <documentNodeList>
+    <documentNode nodeID="HASHac0a04dd14571c60d7fbfd.4.2">
       <metadataList>
         <metadata name="Title"/>
+        <metadata name="Title">Putting snails in your second pen</metadata>
       </metadataList>
+    </content>
+  </request>
+</message>
+\end{verbatim}\end{gsc}\end{quote}
+\begin{quote}\begin{gsc}\begin{verbatim}
+<message>
+  <response lang='en' from="mgppdemo/MetadataRetrieve"
+    type="retrieve">
+    <content>
+      <documentList>
+        <document name="HASH010f073f22033181e206d3b7">
+          <metadataList>
+            <metadata name="Title">Farming snails 1:
+Learning about snails; Building a pen; Food and shelter plants
+            </metadata>
+          </metadataList>
+        </document>
+        <document name="HASH010f073f22033181e206d3b7.2">
+          <metadataList>
+            <metadata name="Title">Learning about snails
+        </metadata>
+          </metadataList>
+        </document>
+        <document name="HASHac0a04dd14571c60d7fbfd">
+          <metadataList>
+            <metadata name="Title">Farming snails 2:
+Choosing snails; Care and harvesting; Further improvement
+            </metadata>
+          </metadataList>
+        </document>
+      </documentList>
+    </content>
+  </response>
+</message>
+\end{verbatim}\end{gsc}\end{quote}
+Give me the text for this document:
+\begin{quote}\begin{gsc}\begin{verbatim}
+<message>
+  <request lang='en'   to="mgppdemo/DocumentRetrieve"
+    type="retrieve">
+    <content>
+      <documentList>
+        <document name="HASH010f073f22033181e206d3b7.2"/>
+      </documentList>
+    </content>
+  </request>
+</message>
+\end{verbatim}\end{gsc}\end{quote}
+\begin{quote}\begin{gsc}\begin{verbatim}
+<message>
+  <response lang='en' from="mgppdemo/DocumentRetrieve"
+    type="retrieve">
+    <content>
+      <document name="HASH010f073f22033181e206d3b7.2">
+        <content>
+    </documentNode>
+    <documentNode nodeID="HASH010f073f22033181e206d3b7.2.12">
+      <metadataList>
+        <metadata name="Title">Now you must decide</metadata>
+      </metadataList>
+    </documentNode>
+    <documentNode nodeID="HASH010f073f22033181e206d3b7.1">
+      <metadataList>
+        <metadata name="Title">Introduction</metadata>
+      </metadataList>
+    </documentNode>
+  </documentNodeList>
+</response>
+\end{verbatim}\end{gsc}\end{quote}
+One or more parameters specifying metadata may be included in a request. Also, a value of \gst{all} will retrieve all the metadata for each document.
+Any browse-type service must also implement a metadata retrieval service to provide metadata for the nodes in the classification hierarchy. The name of it is the brose service name plus \gst{MetadataRetrieve}. For example, the ClassifierBrowse service described in the previous section should also have a ClassifierBrowseMetadataRetrieve service. The request and response format is exactly the same as for the DocumentMetadataREtrieve service, except that \gst{<documentNode>} elements are replaced by \gst{<classifierNode>} elements (and the corresponding list element is also changed).
+Give me the text (content) of this document:
+\begin{quote}\begin{gsc}\begin{verbatim}
+<request lang="en" to="mgppdemo/DocumentContentRetrieve" type="process">
+  <paramList />
+  <documentNodeList>
+    <documentNode nodeID="HASHac0a04dd14571c60d7fbfd.4.2" />
+  </documentNodeList>
+</request>
+<response from="mgppdemo/DocumentContentRetrieve" type="process">
+  <documentNodeList>
+    <documentNode nodeID="HASHac0a04dd14571c60d7fbfd.4.2">
+      <nodeContent>&lt;Section&gt;
 &lt;/B&gt;&lt;P ALIGN=&quot;JUSTIFY&quot;&gt;&lt;/P&gt;
+&lt;P ALIGN=&quot;JUSTIFY&quot;&gt;11. To farm snails is not hard; however,
+it is quite different from keeping chickens or ducks or from growing crops
+such as maize, rice, cassava or groundnuts.&lt;/P&gt;
+&lt;P ALIGN=&quot;JUSTIFY&quot;&gt;&lt;/P&gt;
+&lt;P ALIGN=&quot;JUSTIFY&quot;&gt;12. Since farming snails is so different
+from other kinds of farming, you will have to learn a lot of new things.
+&lt;/P&gt;....
+        </content>
+      </document>
+    </content>
+  </response>
+</message>
+\end{verbatim}\end{gsc}\end{quote}
+\subsubsection{'browse'-type services}
+\subsubsection{'process'-type services}
+Build requests are not a request for data---they are a request for some action to be carried out, for example, create or import or build or activate a collection. The response is a status or an error message. The import and build commands may take a long time to complete, so a message is sent back after a successful start of the command. The status may be polled by the requester to see how the process is going.
+Build requests generally do not need a content, they just have a parameter list.\footnote{or is the collection the content?} Like any service, the parameters used by the service can be obtained by a describe request to that service.
+Some example requests (note that the build services are grouped into a service cluster called 'build', hence the addresses all begin with 'build/'):
+\begin{quote}\begin{gsc}\begin{verbatim}
+<message>
+  <request lang='en'  type='process' to='build/NewCollection'>
+    <paramList>
+      <param name='creator' value='[email protected]'/>
+      <param name='collName' value='the demo collection'/>
+      <param name='collShortName' value='demo'/>
+    </paramlist>
+  </request>
+</message>
+<message>
+  <request lang='en'  type='process' to='build/ImportCollection'>
+    <paramList>
+      <param name='collection' value='demo'/>
+    </paramlist>
+  </request>
+</message>
+\end{verbatim}\end{gsc}\end{quote}
+\subsubsection{'enrich]-type services}
+&lt;P ALIGN=&quot;JUSTIFY&quot;&gt;190. When the plants in your second pen have
+grown big enough to provide food and shelter, you can put in the snails.&lt;/P&gt;
+      </nodeContent>
+    </documentNode>
+  </documentNodeList>
+</response>
+\end{verbatim}\end{gsc}\end{quote}
+The content of a node is returned in a \gst{<nodeContent>} element.
+Give me the ancestors and children of the specified node, along with the number of siblings it has:
+\begin{quote}\begin{gsc}\begin{verbatim}
+<request lang="en" to="mgppdemo/DocumentStructureRetrieve" type="process">
+  <paramList>
+    <param name="structure" value="ancestors" />
+    <param name="structure" value="children" />
+    <param name="info" value="numSiblings" />
+  </paramList>
+  <documentNodeList>
+    <documentNode nodeID="HASHac0a04dd14571c60d7fbfd.4.2" />
+  </documentNodeList>
+</request>
+<response from="mgppdemo/DocumentStructureRetrieve" type="process">
+  <documentNodeList>
+    <documentNode nodeID="HASHac0a04dd14571c60d7fbfd.4.2">
+      <nodeStructureInfo>
+        <info name="numSiblings" value="2" />
+      </nodeStructureInfo>
+      <nodeStructure>
+        <documentNode nodeID="HASHac0a04dd14571c60d7fbfd"
+                docType='hierarchy' nodeType="root">
+          <documentNode nodeID="HASHac0a04dd14571c60d7fbfd.4"
+                  docType='hierarchy' nodeType="interior">
+            <documentNode nodeID="HASHac0a04dd14571c60d7fbfd.4.2"
+                   docType='hierarchy' nodeType="leaf" />
+          </documentNode>
+        </documentNode>
+      </nodeStructure>
+    </documentNode>
+  </documentNodeList>
+</response>
+\end{verbatim}\end{gsc}\end{quote}
+Structure is returned inside a nodeStructure element, while structural info is returned in a nodeStructureInfo element. Possible values for strcuture parameters are as for browse services: \gst{ancestors}, \gst{parent}, \gst{siblings}, \gst{children}, \gst{descendents}. Possible values for info parameters are \gst{numSiblings}, \gst{siblingPosition}, \gst{numChildren}.
+\subsubsection{'process'-type services}\label{sec:process}
+Process requests are not a request for data---they are a request for some action to be carried out, for example, create a new collection, or import a collection. The response is a status or an error message. The import and build commands may take a long time to complete, so a response is sent back after a successful start to the command. The status may be polled by the requester to see how the process is going.
+Process requests generally contain just a parameter list. Like for any service, the parameters used by a process-type service can be obtained by a describe request to that service.
+Here are two example requests for process-services that are part of the build service cluster (hence the addresses all begin with 'build/'), followed by an example response:
+\begin{quote}\begin{gsc}\begin{verbatim}
+<request lang='en'  type='process' to='build/NewCollection'>
+  <paramList>
+    <param name='creator' value='[email protected]'/>
+    <param name='collName' value='the demo collection'/>
+    <param name='collShortName' value='demo'/>
+  </paramlist>
+</request>
+<request lang='en'  type='process' to='build/ImportCollection'>
+  <paramList>
+    <param name='collection' value='demo'/>
+  </paramlist>
+</request>
+<response from="build/ImportCollection">
+  <status code="2" pid="2">Starting process...</status>
+</response>
+\end{verbatim}\end{gsc}\end{quote}
+The \gst{code} attribute in the response specifies whether the command has been successfully stated, whether its still going, etc (see Table~\ref{tab:status codes} for a list of currently used codes). The pid attribute specifies a process id number that can be used when querying the status of this process. The content of teh status element is (currenlty) just the output from the process so far. Status messages, which are described in Section~\ref{sec:status}, are used to find out how the process is going, and whether it has finished or not.
 \subsubsection{'applet'-type services}
+\begin{quote}\begin{gsc}\begin{verbatim}
+<message>
+Applet-type services are those that process the data for an applet. A request consists only of a list of parameters, and the response contains an \gst{<appletData>} element that contains the XML data to be returned to tehe applet. The format of this is entirely specific to the applet---there is no set format to the applet data.
+Here is an example request and response, used by the Phind applet:
+\begin{quote}\begin{gsc}\begin{verbatim}
   <request type='query' to='mgppdemo/PhindApplet'>
     <paramList>
 …
     </paramList>
   </request>
+</message>
+<message>
   <response type='query' from='mgppdemo/PhindApplet'>
     <appletData>
 …
     </appletData>
   </response>
+</message>
+\end{verbatim}\end{gsc}\end{quote}
+\subsection{'status'-type messages}
+\subsection{'format'-type messages}
+\end{verbatim}\end{gsc}\end{quote}
+\subsubsection{'enrich'-type services}
+*** TODO ****
+\subsection{'status'-type messages}\label{sec:status}
+These are only used with process-type services, which are those where a request is sent to start some type of process (see Section~\ref{sec:process}). The initial response states whether the process had successfully started, and whether its still continuing. If the process is not finished, status requests can be sent repeatedly to the service to poll the status, using the pid to identify the  process.  Status codes are used to identify the state of a process. The values used at the moment are listed in Table~\ref{tab:status codes}\footnote{A more standard set of codes should probably be used, for example, the HTTP codes}.
+\begin{table}
+\caption{Status codes currently used in Greenstone 3}
+\label{tab:status codes}
+\begin{tabular}{llp{8cm}}
+\bf code name & \bf code  & \bf meaning \\
+& \bf value & \\
+SUCCESS &  1 & the request was accepted, and the process was  completed \\
+ACCEPTED & 2 & the request was accepted, and the process has been started, but it is not completed yet \\
+ERROR & 3 & there was an error and the process was stopped \\
+CONTINUING & 10 & the process is still continuing \\
+COMPLETED & 11 & the process has  finished \\
+HALTED & 12 & the process has stopped  \\
+INFO & 20 & just an info message that doesnt imply anything \\
+\end{tabular}
+\end{table}
+ The following shows an example status request, along with two responses, the first a 'ok but continuing' response, and the second a 'successfully completed' response. The content of the status elements in the two responses is the output from the process since the last status update was sent back.
+\begin{quote}\begin{gsc}\begin{verbatim}
+<request lang="en" to="build/ImportCollection" type="status">
+  <paramList>
+    <param name="pid" value="2" />
+  </paramList>
+</request>
+<response from="build/ImportCollection">
+  <status code="2" pid="2">Collection construction: import collection.
+command = import.pl -collectdir /research/kjdon/home/gsdl3/web/sites/
+    localsite/collect test1
+starting
+  </status>
+</response>
+<response from="build/ImportCollection">
+  <status code="11" pid="2">RecPlug: getting directory
+/research/kjdon/home/gsdl3/web/sites/localsite/collect/test1/import
+WARNING - no plugin could process /.keepme
+*********************************************
+Import Complete
+*********************************************
+* 1 document was considered for processing
+* 0 were processed and included in the collection
+* 1 was rejected. See /research/kjdon/home/gsdl3/web/sites/
+    localsite/collect/test1/etc/fail.log for a list of rejected documents
+Success
+  </status>
+</response>
+\end{verbatim}\end{gsc}\end{quote}
+\subsection{'format'-type messages}\label{sec:format}
+Collection designers are able to specify how their collection looks to a certain degree. They can specify format statements for display that will apply to the results of a search, the display of a document, entries in a classification hierarchy, for example. This info is generally service specific. All services respond to a format request, where they return any service specific formatting information. A typical request and response looks like this:
 \begin{quote}\begin{gsc}\begin{verbatim}
 <request lang="en" to="mgppdemo/FieldQuery" type="format" />
 …
 <response from="mgppdemo/FieldQuery" type="format">
   <format>
+    <gsf:template match="documentNode"><td><gsf:link><gsf:metadata name="Title" />(<gsf:metadata name="Source" />)</gsf:link></td></gsf:template>
+    <gsf:template match="documentNode"><td><gsf:link>
+      <gsf:metadata name="Title" />(<gsf:metadata name="Source" />)
+      </gsf:link></td>
+    </gsf:template>
   </format>
 </response>
 \end{verbatim}\end{gsc}\end{quote}
+\section{Page generation}\label{sec:pagegen}
+URL-style requests are received by the Receptionist. Based on the arguments, a page of data must be returned to the servlet. As described in Section~\ref{sec:cgi}, the requests are XML representations of Greenstone URLs. One of the arguments is action (a). This tells the Receptionist which Action module to pass the request to. Action modules decode the rest of the cgi-arguments to determine what requests need to be made to the system.
+The actual format statements are described further in Section~\ref{sec:colldesign}. They are templates written directly in XSLT, or in GSF, which  stands for Greenstone Format, and is a simple XML representation of the more complicated XSLT templates.
+GSF style format statements need to be converted to proper XSLT. This is currently done by the Receptionist (but may be moved to an ActionHelper): the format xml is transformed to xslt using xslt with the config\_format.xsl stylesheet.
+\section{Page generation}\label{sec:pagegen} **** REDO ********
+\subsection{Receptionists}\label{sec:recepts}
+The receptionist is the controlling module for the page generation part of greenstone. It has the job of loading up all the actions, and it knows about the message router it and the actions are supposed to talk to. It routes messages received to the appropriate action (page-type messages) or directly to the message router (all other types). Receptionists also do other things, for example, adding to the page received back from the action any information that is common to all pages.
+There are different ways of providing an interface to greenstone, from web based cgi style (using servlets) to Java GUI applications. These different interfaces require slightly different responses from a receptionist, so we provide several standard types of receptionist.
+Receptionist: This is the most basic receptionist. The page it returns consists of the original request, and the response from the action it was sent to. Methods preProcessRequest, and postProcessPage are called on the request and page, respectively, but in this basic receptionist, they dont do anything.
+TransformingReceptionist: This extends Receptionist, and overwrites postProcessPage to transform the page using xslt. An xslt is listed for each action in the receptionists config file, and this is used to transform the page. First, some display information, and config information is added to the page. Then it is transformed using the specified xslt for the action, and returned.
+WebReceptionist: The WebReceptionist extends TransformingREceptionist. It doesn't do much else except some argument conversion. To keep the url's short, parameters from the services are given shortnames, and these are used in the web pages.
+DefaultReceptionist: This extends WebReceptionist, and is the default one for greenstone 3 servlets. Due to the page design, some extra information is needed for each page: some metadata about the current collection. THe receptionist sends a describe request to teh collection to get this, and appends it to teh page before transformation using xslt.
+NZDLReceptionist: (do we want to talk about this?) This is an example of a custom receptionist. For a look-alike nzdl.org system, even more information is needed for each page, namely the list of classifiers available from teh ClassifierBrowse service.
+By default, the LibraryServlet uses DefaultReceptionist. However, there is an init-param called receptionist which can be set to make the servlet use a different one.
+* talk general first: get data, get format info, transform gsf->xsl. transfrom xml->html
+URL-style requests are received by the Receptionist. Based on the arguments, a page of data must be returned to the servlet. As described in Section~\ref{sec:page}, the requests are XML representations of Greenstone URLs. One of the arguments is action (a). This tells the Receptionist which Action module to pass the request to. Action modules decode the rest of the cgi-arguments to determine what requests need to be made to the system.
 System requests are received by the MessageRouter, which answers them one by one, either itself or by passing them on to the appropriate module.
 …
 \end{verbatim}\end{gsc}\end{quote}
+* show config and describe whats its used for
 There are four main elements in the page: config, translate, request, response. The request is the original request that came into the Receptionist---this is included so that any parameters  can be preset to their previous values, for example, the query options on the query form.\footnote{this should be saved instead in some sort of state saving - if you leave a page and go back you want your parameters to be the same as well}. The response contains all the data that has been gathered from the system by the action. The other two elements contain extra information needed by XSLT. Config contains run-time variables such as the location of the gsdl home directory, the current site name, the name of the executable that is running (eg library)---these are needed to allow the XSLT to generate correct HTML URLs. Display contains some of the text strings needed in the interface---these are separate from the XSLT to allow for internationalization.
 …
 files. New interfaces have their own directory inside interfaces/. Sites and collections can have a transform directory containing XSLT files. The order in which the XSLT files are looked for is collection, site, current
 interface, default interface.\footnote{this currently breaks down for remote sites - need to rethink it a bit.}
 ***TODO*** describe a bit more??
+***TODO*** describe a bit more?? currently only can get this locally
 \subsection{Internationalization}
 …
 The interface ones are treated differently from the other ones. The action doesn't know which text strings are needed by a particular transform, so it gets them all out of the properties file, and puts them into an xml \gst{<display>} element - the xslt can get the ones it needs from there.
 xslt could perhaps get the stuff from the properties bundle on the fly using java extension elements - would this be better?
+xslt could perhaps get the stuff from the properties bundle on the fly using java extension elements - would this be better? but we dont want to re-load teh properties file every time a new text string is needed.
 All other class specific text strings are just retrieved one by one as they are needed and added into the xml - for example, the names for query params are retrieved when the service description is created.
+* for each page type, show a typical request (cgi or xml??) and a sample response
 \subsection{Page action}
+* kind of info pages. other actions are associated with specific services.
+* uses describe requests to modules
 Depending on the subaction argument, different pages can be generated. For the 'home' page, a 'describe' request is sent to the MessageRouter---this returns a list of all the collections, services, serviceClusters and sites known about. For each collection, its metadata is retrieved via a 'describe' request. This metadata is added into the previous result, which is then added into the page.  The page is
 transformed using \gst{home.xsl}.  For the 'about' page, a \gst{describe} request is sent to the module that the about page is about: this may be a collection or a service cluster.  This returns a list of metadata
 …
 \subsection{Query action}
+THe basic url is \gst{a=q\&s=TextQuery\&c=demo\&rt=d/r}.
 There are three query services which have been implemented: TextQuery, FieldQuery, and AdvancedFieldQuery. These are all handled in the same way by query action.
 For each page, the service description is requested from the  service  of the current collection (via a describe request).  This is done every time the query page is
 displayed.\footnote{This information should be cached.} The description includes a list of the parameters available for the query, such as case/stem, max num docs to return, etc. If the request type (rt) parameter is set to d for display, the action only needs to display the form, and this is the only request to the service. Otherwise, the submit button has been pressed, and a query request to the TextQuery service is sent. This has  all the parameters from the URL put into the parameter list. A list of document identifiers
+For each page, the service description is requested from the  service  of the current collection (via a describe request).  This is currently done every time the query page is
+displayed, but should be cached. The description includes a list of the parameters available for the query, such as case/stem, max num docs to return, etc. If the request type (rt) parameter is set to d for display, the action only needs to display the form, and this is the only request to the service. Otherwise, the submit button has been pressed, and a query request to the TextQuery service is sent. This has  all the parameters from the URL put into the parameter list. A list of document identifiers
 is returned. A followup query is sent to the MetadataRetrieve service of the collection: the content includes the list of
 documents, with a request for their \gst{Title} metadata.  The service description and query result are combined into a page of xml, which is
+documents, with a request for some of their metadata. Which metadata to retrieve is determined by looking through the xslt that wil be used to transform the page (Formatter object??). The service description and query result are combined into a page of xml, which is
 transformed using \gst{basicquery.xsl} to produce the html page.
 \subsection{Applet action}
 There are two types of request to the applet action: \gst{a=a \& sa=d\/} and
 \gst{a=a \& sa=r\/}.  The value \gst{sa=d\/} means ``display the applet.'' A
+There are two types of request to the applet action: \gst{a=a \& rt=d\/} and
+\gst{a=a \& rt=r\/}.  The value \gst{rt=d\/} means ``display the applet.'' A
 \gst{describe} request is sent to the service, which returns the \gst{<applet>} HTML element.  The transformation file \gst{applet.xsl} embeds this
 into the page, and the servlet returns the HTML.
 The value \gst{sa=r} signals a request from the applet.  The result is returned
+The value \gst{rt=r} signals a request from the applet.  The result is returned
 directly to the applet code, in XML.  The other parameters are sent to the
 service untransformed, and the result is passed directly back to the applet.
 …
 The first request corresponds to the URL arguments \gst{a=a \&
 sa=d \& sn=Phind \& c=mgppdemo\/}, which translate to ``display the Phind
+rt=d \& sn=Phind \& c=mgppdemo\/}, which translate to ``display the Phind
 applet for the mgppdemo collection''.
 The second request corresponds to the  arguments \gst{a=a \& sa=r \& sn=Phind \& c=mgppdemo \& pc=1 \& pptext=health \& pfe=0 \& ple=10 \& pfd=0 \& pld=10 \& pfl=0 \& pll=10}---this
+The second request corresponds to the  arguments \gst{a=a \& rt=r \& sn=Phind \& c=mgppdemo \& pc=1 \& pptext=health \& pfe=0 \& ple=10 \& pfd=0 \& pld=10 \& pfl=0 \& pll=10}---this
 indicates a request to the service itself. The extra arguments (not a, sa, sn, c)  are simply copied into the
 request as parameters. The response is in a form suitable for the applet, placed inside
 …
 \bf arg & \bf description\\
 a=s & system action\\
 sa=c|a|d & type of system request: c (configure), a (add/activate), \\
+sa=c$|$a$|$d & type of system request: c (configure), a (add/activate), \\
 & d (delete/deactivate) \\
 c=demo &  the request will go to this collection/servicecluster \\
 …
 & collectionList, siteList.\\
 &  For a collection/cluster, can be metadataList or serviceList.\\
 sn= & \\
 st & \\
+sn=demo & \\
+st=collection& \\
 \hline
 \end{tabular}
 …
 \subsection{Importing gs2 collections}
 Collections built in a Greenstone2 system can be used in Greenstone3. Just copy across the collection's directory into the appropriate collect directory, and run \gst{convert\_coll\_from\_gs3.pl}. You need to specify the collect directory and the collection name. Eg.
 \gst{convert\_coll\_from\_gs2.pl -collectdir /research/kjdon/gsdl3/web/sites/localsite/collect demo}
 This creates the appropriate Greenstone3 XML configuration files. If you restart Tomcat, or give an add command (\gst{a=s\&sa=a\&st=collection\&sn=demo}), you should be able to see your new collection.
+Collections built in a Greenstone2 system can be used in Greenstone3. Just copy across the collection's directory into the appropriate collect directory, and run \gst{convert\_coll\_from\_gs2.pl}. You need to specify the collect directory and the collection name. Eg.
+\gst{convert\_coll\_from\_gs2.pl -collectdir /research/kjdon/gsdl3/web/\-sites/\-localsite/collect demo}
+This creates the appropriate Greenstone3 XML configuration files. If you restart Tomcat, or give an add command (\gst{a=s\&sa=a\&st=collection\&sn=demo}), you should be able to see your new collection. You may need to edit some of the format stuff by hand.
 \subsection{Building new collections through the web interface}
 Collection construction can be done through the web, using the build ServiceCluster in localsite. Just sequence through the steps needed. There is no automatic sequence taking you to the next page, you have to go back to the build 'about' page, and select the next service manually. So far, AddDocument does not work, so documents need to be manually added to the import directory. And there is no ConfigureCollection service yet, so if you want anything other than the default configuration, you need to edit the config files by hand. Editing collect.cfg will change the way building is done (by Greenstone2), and editing collectionConfig.xml will change the way the collection is used (by Greenstone3).
+Collection construction can be done through the web, using the build ServiceCluster in localsite. Just sequence through the steps needed. There is no automatic sequence taking you to the next page, you have to go back to the build 'about' page, and select the next service manually. So far, AddDocument does not work, so documents need to be manually added to the import directory. And there is no ConfigureCollection service yet, so if you want anything other than the default configuration, you need to edit the collect.cfg config file by hand.
 You need to carry out the following steps:
 …
 NewCollection\\
 - add docs to import directory\\
 - optionally edit collect.cfg and/or collectionConfig.cfg\\
+- optionally edit collect.cfg
 ImportCollection\\
 BuildCollection\\
 …
 \end{quote}
+Note, activate uses \gst{activate\_gs2\_style\_coll.pl} which is similar to \gst{convert\_coll\_from\_gs2.pl} but assumes that collectionConfig.xml already exists.
 \subsection{Command line building}
 …
 \end{verbatim}\end{gsc}
+the options get passed to the underlying script, - there is no good help message yet.
+The options get passed to the underlying script, - there is no good help message yet.
 import and build use gs2 import.pl and buildcol.pl so you can specify any of their options if you like.
+The sequence of steps is the same as for building via the web interface: new, manually add documents to the import directory, and edit collect.cfg if needed, import, build, activate.
 Building stuff is in src/java/org/greenstone/gsdl3/build.
+CollectionConstructor is the base class for building control. GS2PerlConstructor is the implementation that uses Greenstone 2 Perl scripts. The building process sends events (ConstructionEvent) to any listeners (ConstructionListener) as important stages happen. You can add one or more listeners to the constructor which will get notified of events.
+CollectionConstructor is the base class for building control. GS2PerlConstructor is the implementation that uses Greenstone 2 Perl scripts. The building process sends events (ConstructionEvent) to any listeners (ConstructionListener) as important stages happen. You can add one or more listeners to the constructor which will get notified of events. The perl stuff just passes any messages on---should be more informative in  future.
 \subsection{Collection design}\label{sec:colldesign}
+\section{Installation details}
+Part of collection design involves deciding how the collection should look. Greenstone has a default 'look' for a collection, so this is optional. However, the default may not suit the purposes of some collections, so many parts to the look of a collection can be determined by the collection designer.
+In standard greenstone, the library is served to a web browser by a servlet, and the html is generated using XSLT. XSLT templates are used to format all the parts of the pages. Some commonly overwritten templates are those for formatting lists: search results list, classifier browsing hierarchies, and for parts of the document display.
+Real XSL templates for formatting search results or classifier  lists are quite complicated, and not at all easy for a new user to write. For example, the following is a sample template for formatting a classifier list, to show Keyword metadata as a link to the document.
+\begin{gsc}\begin{verbatim}
+<xsl:template match="documentNode" priority="2"
+     xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
+  <xsl:param name="collName"/>
+    <td><a href="{\$library_name}?a=d&amp;c={\$collName}&amp;
+           d={@nodeID}&amp;dt={@docType}"><xsl:value-of
+           select="metadataList/metadata[@name='Keyword']"/></a>
+    </td>
+</xsl:template>
+ \end{verbatim}\end{gsc}
+To write this, the user would need to know that:
+\begin{bulletedlist}
+\item the variable \$library\_name exists,
+\item the collection name is passed in as a parameter called collName
+\item metadata for a document is found in a metadataList and that its form is \gst{<metadata name="Keyword">the value</metadata>}
+\item the arguments needed for the link to the document are a, sa, c, d and dt.
+\end{bulletedlist}
+Since XSLT is written in XML, we can use XSLT to transform XML into XSLT. GSF uses a simple set of XML elements to represent the old (Greenstone2) format statement elements, and we use XSLT to transform it into a proper XSLT template.
+\begin{tabular}{ll}
+\bf Greenstone 2        & \bf Greenstone 3 \\
+\gst{[Text]} & \gst{<gsf:text/>} \\
+\gst{[num]} & \gst{<gsf:num/>}\\
+\gst{[link][/link]} & \gst{<gsf:link></gsf:link>} or \\
+& \gst{<gsf:link type='document'></gsf:link>}\\
+\gst{[srclink][/srclink]} & \gst{<gsf:link type='source'></gsf:link>}\\
+\gst{[icon]} & \gst{<gsf:icon/>} or \\
+& \gst{<gsf:icon type='document'/>}\\
+\gst{[srcicon]} & \gst{<gsf:icon type='source'/>}\\
+\gst{[Title]} (metadata) & \gst{<gsf:metadata name='Title'/>} or \\
+& \gst{<gsf:metadata name='Title' select='current'/>}\\
+\gst{[parent:Title]} & \gst{<gsf:metadata name='Title' select='parent' />}\\
+\gst{[parent(All):Title]} & \gst{<gsf:metadata name='Title' select='ancestors'/>}\\
+\gst{[parent(Top):Title]} & \gst{<gsf:metadata name='Title' select='root' />}\\
+\gst{[parent(All': '):Title]} & \gst{<gsf:metadata name='Title' select='ancestors'}\\
+& \gst{separator=': ' />}\\
+\end{tabular}
+ Other select values for gsf:metadata are \gst{children} and \gst{descendents}. How you would actually use these is unclear.
+The user specifies a \gst{<gsf:template>} for what they want to format---these can match \gst{documentNode} or \gst{classifierNode} (for node in a classification hierarchy).
+The template above is now represented as:
+\begin{gsc}\begin{verbatim}
+<gsf:template match='documentNode'>
+  <td><gsf:link><gsf:metadata name='Keyword'/></gsf:link></td>
+</gsf:template>
+\end{verbatim}\end{gsc}
+I am not sure how the \{If\} and \{Or\} stuff will go yet. Any ideas????
+\section{Greenstone Installation}
 This section describes the directory structure of the Greenstone source, and provides an installation guide to installing Greenstone from CVS.
 \subsection{Directory structure}
 The first part of Table~\ref{tab:dirs} shows the common stuff which can be shared between
 Greenstone users---the src, libraries etc. These will eventually be installed into appropriate system directories. The second part shows
+Table~\ref{tab:dirs} shows the file hierarchy for Greenstone3.
+The first part  shows the common stuff which can be shared between
+Greenstone users---the src, libraries etc. Under linux, these will eventually be installed into appropriate system directories. The second part shows
 stuff used by one person/group---their sites and interface setup
 etc. There can be several sites/interfaces per installation.
 …
 To shutdown or startup Tomcat, the commands are:
 \begin{quote}\begin{gsc}
 \gsdlhome/comms/tomcat/jakarta/bin/shutdown.sh\\
 \gsdlhome/comms/tomcat/jakarta/bin/startup.sh\\
+\gsdlhome/comms/jakarta/tomcat/bin/shutdown.sh\\
+\gsdlhome/comms/jakarta/tomcat/bin/startup.sh\\
 \end{gsc}\end{quote}
 …
 The initialisation parameters used by the library servlets are as follows:
 \begin{tabular}{lll}
+\begin{tabular}{llp{5cm}}
 \bf name & \bf sample value & \bf description \\
 \hline
 …
 It is possible to run several servlets at once, with different combinations of sites and/or interfaces.
 The file \gst{\gsdlhome/comms/tomcat/jakarta/conf/server.xml} is the Tomcat configuration file. The installation process adds a context for Greenstone3 servlets (\gst{\gsdlhome/web})---this tells Tomcat where to find the web.xml file, and what URL (\gst{/gsdl3}) to give it. Anything inside the context directory is accessible via Tomcat\footnote{can we use .htaccess files to restrict access??}. For example, the index.html file that lives in \gst{\gsdlhome/web} can be accessed through the URL \gst{localhost:8080/gsdl3/index.html}. The demo collection's images can be accessed through \gst{localhost:8080/gsdl3/sites/localsite/collect/demo/images/}~.
+The file \gst{\gsdlhome/comms/jakarta/tomcat/conf/server.xml} is the Tomcat configuration file. The installation process adds a context for Greenstone3 servlets (\gst{\gsdlhome/web})---this tells Tomcat where to find the web.xml file, and what URL (\gst{/gsdl3}) to give it. Anything inside the context directory is accessible via Tomcat\footnote{can we use .htaccess files to restrict access??}. For example, the index.html file that lives in \gst{\gsdlhome/web} can be accessed through the URL \gst{localhost:8080/gsdl3/index.html}. The demo collection's images can be accessed through \gst{localhost:8080/gsdl3/sites/localsite/collect/demo/images/}~.
 …
 \begin{gsc}\begin{tt}
 \noindent cd \gsdlhome/comms/tomcat/jakarta/bin\\
+\noindent cd \gsdlhome/comms/jakarta/tomcat/bin\\
 ./startup.sh
 \end{tt}\end{gsc}
 …
 \begin{gsc}
 \item \gsdlhome/web/WEB-INF/web.xml
 \item \gsdlhome/comms/tomcat/jakarta-tomcat-4.0.1/conf/server.xml
+\item \gsdlhome/comms/jakarta/tomcat-tomcat-4.0.1/conf/server.xml
 \end{gsc}
 \item any classes or jar files used by the servlets
 \end{bulletedlist}
 \noindent Note: stdin and stdout for the servlets both go to\\
 \gst{\gsdlhome/comms/tomcat/jakarta/logs/catalina.out}
+\gst{\gsdlhome/comms/jakarta/tomcat/logs/catalina.out}
 On startup, the servlet loads in its collections and services. If the site or collection configuration files are changed, these changes will not take effect until the site/collection is reloaded. This can be done through the reconfiguration messages (see Section~\ref{sec:runtime-config}, or by restarting Tomcat.
 …
 address for talking to the Tomcat SOAP servlet services.
+\section{Developer's notes}
+\section{Greenstone Customization}
+\subsection{How to define a new interface}
+Most of an interface is defined by XSLT files, which are stored in web/interfaces/interface-name/transform.
+\subsection{Adding a new language}
+Adding a new interface language to Greenstone 3 is easy. All of the language-dependent text strings are contained in Java resource bundle properties files. These are plain text files consisting of key-value pairs, located in resources/java. Each interface has one named interface\_name.properties (where name is the interface name). Each service class has one with the same name as the class (eg GS2Search.properties). To add another language these files must be translated. The translated files keep the same names, but with a language extension added. For example, a French version of interface\_default.properties would be named interface\_default\_fr.properties.
+Keys will be looked up in the properties file closest to the specified language. For example, if language fr\_CA was specified (french language, country Canada), and the default locale was en\_GB,  java would look at properties files in the following order, until it found the key: XXX\_fr\_CA.properties, XXX\_fr.properties,  XXX\_en\_GB.properties, then XXX\_en.properties, and finally the default XXX.properties.
+\section{Greenstone Development}
 Here are some random notes for developers who want to modify the source code.
 …
 \subsection{Creating new services}
+a browse type service must also implement servicenameMetadataRetrieve service.
+*inherit from service rack
+* what methods are expected
+*service type responses expected
+*a browse type service must also implement servicenameMetadataRetrieve service.
+* should a metadata retrieval service advertise what metadata is available??
+\subsection{creating new actions/pages}
 \subsection{Working with XML}
 …
 Document style = converter.getDOM(stylesheet);\\
 String message = ``<message><request type='cgi'/></message>'';\\
+String message = ``<message><request type='page'/></message>'';\\
 Document m = converter.getDOM(message);\\
 \end{gsc}\end{quote}
 …
 xmlns:gsf="http://www.greenstone.org/configformat"
+(xslt namespace: xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
 no DTDs or Schema defined yet. Until there are, try and keep to the following rules:
 …
 \end{verbatim}\end{footnotesize}\end{quote}
+\item{\em using Java extension elements:}
+Declare the namespace for your java extensions using one of the following
+three formats.
+class format: \gst{xmlns:my-class="xalan://FQCN"} where FQCN is the fully qualified class name. Examples: \gst{xmlns:my-class="xalan://java.util.Hashtable"},  \gst{xmlns:my-class="xalan://mypackage.myclass"}
+package format: \gst{xmlns:my-class="xalan://PJPN"} where PJPN is a partial java package name. That is, it is the beginning of or the complete name of a java  package. Examples: \gst{xmlns:my-package="xalan://java.util"}, \gst{xmlns:my-package="xalan://mypackage"}
+Java format: \gst{xmlns:java="http://xml.apache.org/xalan/java"}
+Then, how you use the java classes and methods depends on which format you declared you namespace.
+class format:
+To create an instance of an object: \gst{prefix:new (args)}. Example: \gst{<xsl:variable name="myType" select="my-class:new()">}
+To invoke an instance method on a specified object: \gst{prefix:methodName (object, args)} where methodName is the name of the method to invoke on object with the args arguments. object must be an object of the class indicated by the namespace declaration. Example: \gst{<xsl:variable name="new-pop" select="my-class:valueOf(\$myType, string(@population))">}
+To invoke an instance method on a default object: \gst{prefix:methodName (args)}  where  methodName is the name of the method to invoke with the args arguments. If a matching method is found, a default instance of the class will be created if it does not already exist. Example: \gst{<xsl:variable name="new-pop" select="my-class:valueOf(string(@population))">}
+To invoke a static method: \gst{prefix:methodName (args)} where methodName is the name of the method to invoke with the args arguments. Example: \gst{<xsl:variable name="new-pop" select="my-class:printit(string(@population))">}
+package format:
+o create an instance of an object:
+                   prefix:subpackage.class.new (args)
+                   where prefix is the extension namespace prefix, subpackage is the rest of the package name (the
+                   beginning of the package name was in the namespace declaration), and class is the name of the class.
+                   A new instance is to be created with the args constructor arguments (if any). All constructor methods
+                   are qualified for method selection.
+                   Example: <xsl:variable name="myType"
+                          select="my-package:extclass.new()">
+                   To invoke an instance method on a specified instance:
+                   prefix:methodName (object, args)
+                   where prefix is the extension namespace prefix and methodName is the name of the method to invoke
+                   on object with the args arguments. Only instance methods of the object with the name methodName
+                   are qualified methods. If a matching method is found, object will be used to identify the object instance
+                   and args will be passed to the invoked method.
+                   Example: <xsl:variable name="new-pop"
+                        select="my-package:valueOf(\$myType, string(@population))">
+                   To invoke a static method:
+                   prefix:subpackage.class.methodName (args)
+                   where prefix is the extension namespace prefix, subpackage is the rest of the package name (the
+                   beginning of the package name was in the namespace declaration), class is the name of the class, and
+                   methodName is the name of the method to invoke with the args arguments. Only static methods with
+                   the name methodName are qualified methods. If a matching method is found, args will be passed to the
+                   invoked static method.
+                   Example: <xsl:variable name="new-pop"
+                        select="my-package:extclass.printit(string(@population))">
+                       Unlike the class format namespace, there is no concept of a default object since the namespace
+                       declaration does not identify a unique class.
+java format:
+                   To create an instance of an object:
+                   prefix:FQCN.new (args)
+                   where prefix is the extension namespace prefix for the Java namespace and FQCN is the fully qualified
+                   class name of the class whose constructor is to be called. A new instance is to be created with the
+                   args constructor arguments (if any). All constructor methods are qualified for method selection.
+                   Example: <xsl:variable name="myHash"
+                          select="java:java.util.Hashtable.new()">
+                   To invoke an instance method on a specified instance:
+                   prefix:methodName (object, args)
+                   where prefix is the extension namespace prefix and methodName is the name of the method to invoke
+                   on object with the args arguments. Only instance methods of the object with the name methodName
+                   are qualified methods. If a matching method is found, object will be used to identify the object instance
+                   and args will be passed to the invoked method.
+                   Example: <xsl:variable name="new-pop"
+                        select="java:put(\$myHash, string(@region), \$newpop)">
+                   To invoke a static method:
+                   prefix:FQCN.methodName (args)
+                   where prefix is the extension namespace prefix, FQCN is the fully qualified class name of the class
+                   whose static method is to be called, and methodName is the name of the method to invoke with the
+                   args arguments. Only static methods with the name methodName are qualified methods. If a matching
+                   method is found, args will be passed to the invoked static method.
+                   Example: <xsl:variable name="new-pop"
+                        select="java:java.lang.Integer.valueOf(string(@population))">
+                       Unlike the class format namespace, there is no concept of a default object since the namespace
+                       declaration does not identify a unique class.
 \end{bulletedlist}
 …
 \item xsl:for-each is fast because it does not require pattern matching.
+\item avoid recursion
 \item Keep in mind that xsl:sort prevents incremental processing.

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