source: main/trunk/greenstone3/src/java/org/greenstone/gsdl3/collection/ServiceCluster.java@ 26446

/*
 *    ServiceCluster.java
 *    Copyright (C) 2002 New Zealand Digital Library, http://www.nzdl.org
 *
 *    This program is free software; you can redistribute it and/or modify
 *    it under the terms of the GNU General Public License as published by
 *    the Free Software Foundation; either version 2 of the License, or
 *    (at your option) any later version.
 *
 *    This program is distributed in the hope that it will be useful,
 *    but WITHOUT ANY WARRANTY; without even the implied warranty of
 *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *    GNU General Public License for more details.
 *
 *    You should have received a copy of the GNU General Public License
 *    along with this program; if not, write to the Free Software
 *    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */
// leave the package name as is for now - should be changed to something better
// cluster? groups?
package org.greenstone.gsdl3.collection;

import java.io.File;
import java.util.HashMap;
import java.util.Iterator;

import org.apache.log4j.Logger;
import org.greenstone.gsdl3.core.MessageRouter;
import org.greenstone.gsdl3.core.ModuleInterface;
import org.greenstone.gsdl3.service.ServiceRack;
import org.greenstone.gsdl3.util.GSFile;
import org.greenstone.gsdl3.util.GSPath;
import org.greenstone.gsdl3.util.GSXML;
import org.greenstone.gsdl3.util.SimpleMacroResolver;
import org.greenstone.gsdl3.util.UserContext;
import org.greenstone.gsdl3.util.XMLConverter;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;

/* ServiceCluster - a groups of services that are related in some way
 * Implements ModuleInterface. Contains a list of services provided by the cluster, along with metadata about the cluster itself.
 * a collection is a special type of cluster
 *  @see ModuleInterface
 */
public class ServiceCluster implements ModuleInterface
{

    static Logger logger = Logger.getLogger(org.greenstone.gsdl3.collection.ServiceCluster.class.getName());

    protected static final String CONFIG_ENCODING = "utf-8";

    protected static final String DEFAULT_LANG = "en"; // hack for now, should be read from the coll cfg file? or site cfg file for cluster

    /** base directory for the site that this cluster belongs to */
    protected String site_home = null;
    /** http address of the site that this cluster belongs to */
    protected String site_http_address = null;
    /** The name of the cluster - for a collection, this is the collection name */
    protected String cluster_name = null;
 
    /** a reference to the message router */
    protected MessageRouter router = null;
    /**
     * The map of services.
     * 
     * Maps Services to ServiceRack objects
     * 
     * @see ServiceRack
     * 
     */
    protected HashMap<String, ServiceRack> service_map = null;
    /**
     * maps pseudo service names to real service names - needed if we have two
     * services with the same name for one collection
     */
    protected HashMap<String, String> service_name_map = null;

    /** XML converter for String to DOM and vice versa */
    protected XMLConverter converter = null;
  /** a MacroResolver for resolving macros in displayItems */
  protected SimpleMacroResolver macro_resolver = null;

    /** container doc for description elements */
    protected Document doc = null;
    /** list of services */
    protected Element service_list = null;
    /** list of metadata - all metadata, regardless of language goes in here */
    protected Element metadata_list = null;
  /** language specific display items */

    protected Element display_item_list = null;
  /** default values for servlet params */
  protected Element library_param_list = null;
    /** the element that will have any descriptions passed back in */
    protected Element description = null;

    /** list of plugin */
    //protected Element plugin_item_list = null;

    protected Element _globalFormat = null;

    public void setSiteHome(String home)
    {
        this.site_home = home;
    }

    public void setSiteAddress(String address)
    {
        this.site_http_address = address;
    }

    public void cleanUp()
    {
        Iterator<ServiceRack> i = this.service_map.values().iterator();
        while (i.hasNext())
        {
            ServiceRack s = i.next();
            s.cleanUp();
        }
    }

    public void setClusterName(String name)
    {
        this.cluster_name = name;
        this.description.setAttribute(GSXML.NAME_ATT, name);
    }

    public void setMessageRouter(MessageRouter m)
    {
        this.router = m;
    }

    public ServiceCluster()
    {
        this.service_map = new HashMap<String, ServiceRack>();
        this.service_name_map = new HashMap<String, String>();
        this.converter = new XMLConverter();
        this.macro_resolver = new SimpleMacroResolver();
        this.doc = this.converter.newDOM();
        this.description = this.doc.createElement(GSXML.CLUSTER_ELEM);
        this.display_item_list = this.doc.createElement(GSXML.DISPLAY_TEXT_ELEM + GSXML.LIST_MODIFIER);
        this.metadata_list = this.doc.createElement(GSXML.METADATA_ELEM + GSXML.LIST_MODIFIER);
        this.library_param_list = this.doc.createElement("libraryParamList");
        this.service_list = this.doc.createElement(GSXML.SERVICE_ELEM + GSXML.LIST_MODIFIER);
        //this.plugin_item_list = this.doc.createElement(GSXML.PLUGIN_ELEM + GSXML.LIST_MODIFIER);
    }

    /**
     * Configures the cluster.
     * 
     * gsdlHome and clusterName must be set before configure is called.
     * 
     * reads the site configuration file, and configures itself this calls
     * configure(Element) with the XML element node from the config file.
     * configure(Element) should be used if the config file has already been
     * parsed. This method will work with any subclass.
     * 
     * This is called by ServiceCluster itself when asked to do a reconfigure
     * @return true if configure successful, false otherwise.
     */
    public boolean configure()
    {

        if (this.site_home == null || this.cluster_name == null)
        {
            logger.error("site_home and cluster_name must be set before configure called!");
            return false;
        }
        logger.info("configuring service cluster");
        macro_resolver.addMacro("_httpsite_", this.site_http_address);
        // read the site configuration file
        File config_file = new File(GSFile.siteConfigFile(this.site_home));

        if (!config_file.exists())
        {
            logger.error("couldn't configure cluster: " + this.cluster_name + ", " + config_file + " does not exist");
            return false;
        }

        Document doc = this.converter.getDOM(config_file, CONFIG_ENCODING);
        if (doc == null)
        {
            logger.error("couldn't parse config file " + config_file.getPath());
            return false;
        }

        // get the appropriate service cluster element
        Element cluster_list = (Element) GSXML.getChildByTagName(doc.getDocumentElement(), GSXML.CLUSTER_ELEM + GSXML.LIST_MODIFIER);
        Element sc = GSXML.getNamedElement(cluster_list, GSXML.CLUSTER_ELEM, GSXML.NAME_ATT, this.cluster_name);

        // this is probably a reconfigure, so clear all previous info
        clearServices();
        clearLocalData();
        return this.configure(sc);
    }

  /** this is called by configure(), but also by MR when it is loading up all the service clusters */
    public boolean configure(Element service_cluster_info)
    {
      configureLocalData(service_cluster_info);
        // //get the plugin info
        // Element import_list = (Element) GSXML.getChildByTagName(service_cluster_info, GSXML.IMPORT_ELEM);
        // if (import_list != null)
        // {
        //  Element plugin_list = (Element) GSXML.getChildByTagName(service_cluster_info, GSXML.PLUGIN_ELEM + GSXML.LIST_MODIFIER);
        //  if (plugin_list != null)
        //  {
        //      if (!addPlugins(plugin_list))
        //      {

        //          logger.error("couldn't configure the plugins");
        //      }
        //  }
        // }

        // do the service racks
        // empty the service map in case this is a reconfigure
        //clearServices();
        Element service_rack_list = (Element) GSXML.getChildByTagName(service_cluster_info, GSXML.SERVICE_CLASS_ELEM + GSXML.LIST_MODIFIER);
        logger.error("cluster service rack list =");
        logger.error(GSXML.xmlNodeToString(service_rack_list));
        if (service_rack_list == null)
        {
            // is this an error? could you ever have a service cluster
            // without service racks???
            logger.error(cluster_name+" has no service racks!!");
        }
        else
        {

            if (!configureServiceRackList(service_rack_list, null))
            {
                logger.error("couldn't configure "+cluster_name+" service racks!!");
                return false;
            }
        }

        return true;
    }

    protected void configureLocalData(Element service_cluster_info) {
        // get the metadata - for now just add it to the list
        Element meta_list = (Element) GSXML.getChildByTagName(service_cluster_info, GSXML.METADATA_ELEM + GSXML.LIST_MODIFIER);
        if (meta_list != null)
        {
            if (!addMetadata(meta_list))
            {

                logger.error(" couldn't configure the metadata");
            }
        }

        // get the display info
        Element display_list = (Element) GSXML.getChildByTagName(service_cluster_info, GSXML.DISPLAY_TEXT_ELEM + GSXML.LIST_MODIFIER);
        if (display_list != null)
        {
          resolveMacros(display_list);
            if (!addDisplayItems(display_list))
            {

                logger.error("couldn't configure the display items");
            }
        }

        // get the servlet params
        Element param_list = (Element) GSXML.getChildByTagName(service_cluster_info, "libraryParamList");
        if (param_list != null) {
          if (!addLibraryParams(param_list)) {
            logger.error("couldn't configure the library param list");
          }
        }

  }
    /**
     * adds metadata from a metadataList into the metadata_list xml
     */
    protected boolean addMetadata(Element metadata_list)
    {
        if (metadata_list == null)
            return false;
        NodeList metanodes = metadata_list.getElementsByTagName(GSXML.METADATA_ELEM);
        if (metanodes.getLength() > 0)
        {
            for (int k = 0; k < metanodes.getLength(); k++)
            {
                this.metadata_list.appendChild(this.doc.importNode(metanodes.item(k), true));
            }
        }

        return true;
    }
  /** adds an individual metadata element into the list */
  protected boolean addMetadata(String name, String value) {
    return GSXML.addMetadata(this.doc, this.metadata_list, name, value);
  }
  
  /** in displayItemList, end up with the following for each named displayItem
      <displayItem name="">
        <displayItem name="" lang="">value</displayItem>
        <displayItem name="" lang="">value</displayItem>
      </displayItem>
  */
    protected boolean addDisplayItems(Element display_list)
    {

        if (display_list == null)
            return false;
        NodeList displaynodes = display_list.getElementsByTagName(GSXML.DISPLAY_TEXT_ELEM);
        if (displaynodes.getLength() > 0)
        {
            for (int k = 0; k < displaynodes.getLength(); k++)
            {
                Element d = (Element) displaynodes.item(k);
                String lang = d.getAttribute(GSXML.LANG_ATT);
                if (lang == null || lang.equals(""))
                {
                    //set the lang to teh default
                    d.setAttribute(GSXML.LANG_ATT, DEFAULT_LANG);
                }
                String name = d.getAttribute(GSXML.NAME_ATT);
                Element this_item = GSXML.getNamedElement(this.display_item_list, GSXML.DISPLAY_TEXT_ELEM, GSXML.NAME_ATT, name);
                if (this_item == null)
                {
                    this_item = this.doc.createElement(GSXML.DISPLAY_TEXT_ELEM);
                    this_item.setAttribute(GSXML.NAME_ATT, name);
                    this.display_item_list.appendChild(this_item);
                }

                this_item.appendChild(this.doc.importNode(d, true));
            }
        }

        return true;
    }

    // protected boolean addPlugins(Element plugin_list)
    // {
    //  if (plugin_list == null)
    //      return false;
    //  NodeList pluginNodes = plugin_list.getElementsByTagName(GSXML.PLUGIN_ELEM);
    //  if (pluginNodes.getLength() > 0)
    //  {
    //      for (int k = 0; k < pluginNodes.getLength(); k++)
    //      {
    //          this.plugin_item_list.appendChild(this.doc.importNode(pluginNodes.item(k), true));
    //      }
    //  }

    //  return true;
    // }
    protected boolean resolveMacros(Element display_list)
    {
        if (display_list == null)
            return false;
        NodeList displaynodes = display_list.getElementsByTagName(GSXML.DISPLAY_TEXT_ELEM);
        if (displaynodes.getLength() > 0)
        {
          //String http_site = this.site_http_address;
          //String http_collection = this.site_http_address + "/collect/" + this.cluster_name;
            for (int k = 0; k < displaynodes.getLength(); k++)
            {
                Element d = (Element) displaynodes.item(k);
                String text = GSXML.getNodeText(d);
                text= macro_resolver.resolve(text);
                //text = StringUtils.replace(text, "_httpsite_", http_site);
                //text = StringUtils.replace(text, "_httpcollection_", http_collection);
                GSXML.setNodeText(d, text);
            }
        }
        return true;
    }

    /**
     * adds library params from libraryParamList into library_param_list xml
     */
    protected boolean addLibraryParams(Element param_list)
    {
        if (param_list == null)
            return false;
        NodeList paramnodes = param_list.getElementsByTagName(GSXML.PARAM_ELEM);
        if (paramnodes.getLength() > 0)
        {
            for (int k = 0; k < paramnodes.getLength(); k++)
            {
                this.library_param_list.appendChild(this.doc.importNode(paramnodes.item(k), true));
            }
        }

        return true;
    }
    protected void clearServices()
    {
      cleanUp();
        service_map.clear();
        service_name_map.clear();
        this.service_list = this.doc.createElement(GSXML.SERVICE_ELEM + GSXML.LIST_MODIFIER);
    }

  protected void clearLocalData() {
    this.description = this.doc.createElement(GSXML.CLUSTER_ELEM);
    this.display_item_list = this.doc.createElement(GSXML.DISPLAY_TEXT_ELEM + GSXML.LIST_MODIFIER);
    this.metadata_list = this.doc.createElement(GSXML.METADATA_ELEM + GSXML.LIST_MODIFIER);
    this.library_param_list = this.doc.createElement("libraryParamList");
 
  }
    /**
     * creates and configures all the services - extra_info is some more xml
     * that is passed to teh service - eg used for coll config files for
     * Collection
     */
    protected boolean configureServiceRackList(Element service_rack_list, Element extra_info)
    {

        // create all the services
        NodeList nodes = service_rack_list.getElementsByTagName(GSXML.SERVICE_CLASS_ELEM);
        if (nodes.getLength() == 0)
        {
            logger.error("ServiceCluster configuration error: cluster " + this.cluster_name + " has no service modules!");
            return false;
        }

        for (int i = 0; i < nodes.getLength(); i++)
        {

            // the xml request to send to the serviceRack to query what
            // services it provides
            Element message = this.doc.createElement(GSXML.MESSAGE_ELEM);
            Element request = GSXML.createBasicRequest(this.doc, GSXML.REQUEST_TYPE_DESCRIBE, "", new UserContext());
            message.appendChild(request);

            Element n = (Element) nodes.item(i);
            String servicetype = n.getAttribute(GSXML.NAME_ATT);

            ServiceRack s = null;

            try
            {
                // try for a default service in standard package
                s = (ServiceRack) Class.forName("org.greenstone.gsdl3.service." + servicetype).newInstance();
            }
            catch (Exception e)
            {
            }
            if (s == null)
            {
                try
                {
                    // name as is, in case package is already specified
                    s = (ServiceRack) Class.forName(servicetype).newInstance();
                }
                catch (Exception e)
                {
                }
            }

            if (s == null)
            {
                logger.error("Couldn't get an instance of class " + servicetype + ", or org.greenstone.gsdl3.service." + servicetype);
                continue;
            }

            if (_globalFormat != null)
            {
                s.setGlobalFormat(_globalFormat);
            }

            s.setSiteHome(this.site_home);
            s.setSiteAddress(this.site_http_address);
            s.setClusterName(this.cluster_name);
            s.setMessageRouter(this.router);
            // pass the xml node to the service for configuration
            if (s.configure(n, extra_info))
            {
                // find out the supported service types for this service module
                Node types = s.process(message);
                NodeList typenodes = ((Element) types).getElementsByTagName(GSXML.SERVICE_ELEM);

                for (int j = 0; j < typenodes.getLength(); j++)
                {
                    String service = ((Element) typenodes.item(j)).getAttribute(GSXML.NAME_ATT);

                    if (service_map.get(service) != null)
                    {
                        char extra = '0';
                        String new_service = service + extra;

                        while (service_map.get(new_service) != null)
                        {
                            extra++;
                            new_service = service + extra;
                        }
                        this.service_name_map.put(new_service, service);
                        service = new_service;
                        ((Element) typenodes.item(j)).setAttribute(GSXML.NAME_ATT, service);
                    }
                    this.service_map.put(service, s);
                    // also add info to the ServiceInfo XML element
                    this.service_list.appendChild(this.doc.importNode(typenodes.item(j), true));
                }
            }
        }

        return true;

    }

    /**
     * Process an XML document - uses Strings just calls process(Node).
     * 
     * @param in
     *            the Document to process - a string
     * @return the resultant document as a string - contains any error messages
     * @see String
     */
    public String process(String in)
    {

        Document doc = this.converter.getDOM(in);

        Node res = process(doc);
        return this.converter.getString(res);

    }

    /**
     * process XML as Node
     * 
     */
    public Node process(Node message_node)
    {
        Element message = this.converter.nodeToElement(message_node);

        NodeList requests = message.getElementsByTagName(GSXML.REQUEST_ELEM);
        Document mess_doc = message.getOwnerDocument();
        Element mainResult = this.doc.createElement(GSXML.MESSAGE_ELEM);
        if (requests.getLength() == 0)
        {
            logger.error("no requests for cluster:" + this.cluster_name);
            // no requests
            return mainResult; // for now
        }
        for (int i = 0; i < requests.getLength(); i++)
        {
            Element request = (Element) requests.item(i);
            String to = request.getAttribute(GSXML.TO_ATT);

            // the cluster name should be first, check, then remove
            String clustername = GSPath.getFirstLink(to);
            if (!clustername.equals(this.cluster_name))
            {
                logger.error("cluster name wrong! was " + clustername + " should have been " + this.cluster_name);
                continue; // ignore this request
            }
            to = GSPath.removeFirstLink(to);
            request.setAttribute(GSXML.TO_ATT, to);

            if (to.equals(""))
            { // this command is for me
                Element response = processMessage(request);
                mainResult.appendChild(response);

            }
            else
            { // the request is for one of my services
                String service = GSPath.getFirstLink(to);

                if (!this.service_map.containsKey(service))
                {
                    logger.error("non-existant service, " + service + ", specified!");
                    continue;
                }
                String real_service = service;
                if (this.service_name_map.containsKey(service))
                {
                    real_service = this.service_name_map.get(service);
                    // need to change the to att in the request - give the real service name
                    to = request.getAttribute(GSXML.TO_ATT);
                    String old_to = to;
                    to = GSPath.replaceFirstLink(to, real_service);
                    request.setAttribute(GSXML.TO_ATT, to);
                }
                // have to pass the request to the service
                Element single_message = mess_doc.createElement(GSXML.MESSAGE_ELEM);
                single_message.appendChild(request);

                Node response_message = this.service_map.get(service).process(single_message);
                if (response_message != null)
                {
                    Element response = (Element) GSXML.getChildByTagName(response_message, GSXML.RESPONSE_ELEM);
                    String from = response.getAttribute(GSXML.FROM_ATT);
                    if (!real_service.equals(service))
                    {
                        // replace the real service name with the pseudo service name
                        from = GSPath.replaceFirstLink(from, service);
                        // also need to do it in the service itself
                        // shoudl this be done here??
                        Element service_elem = (Element) GSXML.getChildByTagName(response, GSXML.SERVICE_ELEM);
                        if (service_elem != null)
                        {
                            service_elem.setAttribute(GSXML.NAME_ATT, service);
                        }
                    }
                    from = GSPath.prependLink(from, this.cluster_name);
                    response.setAttribute(GSXML.FROM_ATT, from);
                    mainResult.appendChild(this.doc.importNode(response, true));
                }

            } // else

        } // for each request
        return mainResult;
    }

    /**
     * handles requests made to the ServiceCluster itself
     * 
     * @param req
     *            - the request Element- <request>
     * @return the result Element - should be <response>
     */
    protected Element processMessage(Element request)
    {
        Element response = this.doc.createElement(GSXML.RESPONSE_ELEM);
        response.setAttribute(GSXML.FROM_ATT, this.cluster_name);
        String type = request.getAttribute(GSXML.TYPE_ATT);
        String lang = request.getAttribute(GSXML.LANG_ATT);
        response.setAttribute(GSXML.TYPE_ATT, type);

        if (type.equals(GSXML.REQUEST_TYPE_DESCRIBE))
        {
            // create the collection element
            Element description = (Element) this.description.cloneNode(false);
            // set collection type : mg, mgpp, lucene or solr
            //description.setAttribute(GSXML.TYPE_ATT, col_type);
            //description.setAttribute(GSXML.DB_TYPE_ATT, db_type);

            response.appendChild(description);
            // check the param list
            Element param_list = (Element) GSXML.getChildByTagName(request, GSXML.PARAM_ELEM + GSXML.LIST_MODIFIER);
            if (param_list == null)
            {
                addAllDisplayInfo(description, lang);
                description.appendChild(this.service_list);
                description.appendChild(this.metadata_list);
                description.appendChild(this.library_param_list);
                //description.appendChild(this.plugin_item_list);
                return response;
            }

            // go through the param list and see what components are wanted
            NodeList params = param_list.getElementsByTagName(GSXML.PARAM_ELEM);
            for (int i = 0; i < params.getLength(); i++)
            {

                Element param = (Element) params.item(i);
                // Identify the structure information desired
                if (param.getAttribute(GSXML.NAME_ATT).equals(GSXML.SUBSET_PARAM))
                {
                    String info = param.getAttribute(GSXML.VALUE_ATT);
                    if (info.equals(GSXML.SERVICE_ELEM + GSXML.LIST_MODIFIER))
                    {
                        description.appendChild(this.service_list);
                    }
                    else if (info.equals(GSXML.METADATA_ELEM + GSXML.LIST_MODIFIER))
                    {
                        description.appendChild(this.metadata_list);
                    }
                    else if (info.equals(GSXML.DISPLAY_TEXT_ELEM + GSXML.LIST_MODIFIER))
                    {
                        addAllDisplayInfo(description, lang);
                    }
                    else if (info.equals("libraryParamlist"))
                    {
                      description.appendChild(this.library_param_list);
                    }
                }
            }
            return response;
        }
        /*
         * if (type.equals(GSXML.REQUEST_TYPE_FORMAT_STRING)) {
         * logger.error("Received format string request"); String service =
         * request.getAttribute("service"); logger.error("Service is " +
         * service); String classifier = null;
         * if(service.equals("ClassifierBrowse")) { classifier =
         * request.getAttribute("classifier"); logger.error("Classifier is " +
         * classifier); } Element format_element = (Element)
         * GSXML.getChildByTagName(request, GSXML.FORMAT_STRING_ELEM); String
         * format_string = GSXML.getNodeText(format_element);
         * logger.error("Format string: " + format_string);
         * logger.error("Config file location = " +
         * GSFile.collectionConfigFile(this.site_home, this.cluster_name));
         * 
         * // check for version file
         * 
         * String directory = new
         * File(GSFile.collectionConfigFile(this.site_home,
         * this.cluster_name)).getParent() + File.pathSeparator;
         * logger.error("Directory is " + directory);
         * 
         * String version_filename = "";
         * 
         * if(service.equals("ClassifierBrowse")) version_filename = directory +
         * "browse_"+classifier+"_format_statement_version.txt"; else
         * version_filename = directory + "query_format_statement_version.txt";
         * 
         * File version_file = new File(version_filename);
         * logger.error("Version filename is " + version_filename);
         * 
         * String version_number = "1"; BufferedWriter writer; // = new
         * BufferedWriter(new FileWriter(version_filename)); //RandomAccessFile
         * version_file_random_access;
         * 
         * try{
         * 
         * if(version_file.exists()) { // Read version BufferedReader reader =
         * new BufferedReader(new FileReader(version_filename));
         * //version_file_random_access = new RandomAccessFile(version_file,
         * "r"); //logger.error(" //version_number =
         * version_file_random_access.readInt(); version_number =
         * reader.readLine(); int aInt = Integer.parseInt(version_number) + 1;
         * version_number = Integer.toString(aInt); reader.close();
         * //version_file_random_access.close(); } else{ // Create
         * version_file.createNewFile(); // write 1 to file writer = new
         * BufferedWriter(new FileWriter(version_filename));
         * //version_file_random_access = new RandomAccessFile(version_file,
         * "w"); //version_file_random_access.writeInt(version_number);
         * writer.write(version_number); writer.close();
         * //version_file_random_access.close(); }
         * 
         * // Write version file String format_statement_filename = "";
         * 
         * if(service.equals("ClassifierBrowse")) format_statement_filename =
         * directory + "browse_"+classifier+"_format_statement_v" +
         * version_number + ".txt"; else format_statement_filename = directory +
         * "query_format_statement_v" + version_number + ".txt";
         * 
         * logger.error("Format statement filename is " +
         * format_statement_filename);
         * 
         * writer = new BufferedWriter(new
         * FileWriter(format_statement_filename)); writer.write(format_string);
         * writer.close();
         * 
         * // Update version number //version_file_random_access = new
         * RandomAccessFile(version_file, "w");
         * //version_file_random_access.writeInt(version_number);
         * //version_file_random_access.close();
         * 
         * writer = new BufferedWriter(new FileWriter(version_filename));
         * //version_file_random_access = new RandomAccessFile(version_file,
         * "w"); //version_file_random_access.writeInt(version_number);
         * writer.write(version_number); writer.close();
         * 
         * 
         * 
         * } catch (IOException e) { logger.error("IO Exception "+e);
         * //System.exit(1); }
         * 
         * 
         * }
         */
        if (type.equals(GSXML.REQUEST_TYPE_SYSTEM))
        {
            response = processSystemRequest(request);
        }
        else
        { // unknown type
            logger.error("cant handle request of type " + type);

        }
        return response;
    }

    protected Element processSystemRequest(Element request)
    {

        Element response = this.doc.createElement(GSXML.RESPONSE_ELEM);
        response.setAttribute(GSXML.FROM_ATT, this.cluster_name);
        response.setAttribute(GSXML.TYPE_ATT, GSXML.REQUEST_TYPE_SYSTEM);

        // a list of system requests - should put any error messages
        // or success messages into response
        NodeList commands = request.getElementsByTagName(GSXML.SYSTEM_ELEM);
        String message = null;
        for (int i = 0; i < commands.getLength(); i++)
        {
            // all the commands should be Elements
            Element elem = (Element) commands.item(i);
            String action = elem.getAttribute(GSXML.TYPE_ATT);
            if (action.equals(GSXML.SYSTEM_TYPE_CONFIGURE))
            {
                String subset = elem.getAttribute(GSXML.SYSTEM_SUBSET_ATT);
                if (subset.equals(""))
                {
                    // need to reconfigure the service cluster

                    if (this.configure())
                    {
                        Element s = GSXML.createTextElement(this.doc, GSXML.STATUS_ELEM, this.cluster_name + " reconfigured");
                        response.appendChild(s);

                    }
                    else
                    {
                        Element s = GSXML.createTextElement(this.doc, GSXML.STATUS_ELEM, this.cluster_name + " could not be reconfigured");
                        response.appendChild(s);
                    }
                }
                else if (this.configureSubset(subset))
                {
                    Element s = GSXML.createTextElement(this.doc, GSXML.STATUS_ELEM, this.cluster_name + " " + subset + " reconfigured");
                    response.appendChild(s);
                }
                else
                {
                    Element s = GSXML.createTextElement(this.doc, GSXML.STATUS_ELEM, this.cluster_name + " " + subset + " could not be reconfigured");
                    response.appendChild(s);
                }
                continue;
            } // configure action

            String module_name = elem.getAttribute(GSXML.SYSTEM_MODULE_NAME_ATT);
            String module_type = elem.getAttribute(GSXML.SYSTEM_MODULE_TYPE_ATT);
            if (action.equals(GSXML.SYSTEM_TYPE_ACTIVATE))
            {
                Element s = GSXML.createTextElement(this.doc, GSXML.STATUS_ELEM, "activate action not yet implemented - does it even make sense in this context??");
                response.appendChild(s);
            }
            else if (action.equals(GSXML.SYSTEM_TYPE_DEACTIVATE))
            {
                if (module_type.equals(GSXML.SERVICE_ELEM))
                {
                    // deactivate the service
                    // remove from service_map
                    this.service_map.remove(module_name);
                    Element service_elem = GSXML.getNamedElement(this.service_list, GSXML.SERVICE_ELEM, GSXML.NAME_ATT, module_name);
                    service_list.removeChild(service_elem);
                    message = module_type + ": " + module_name + " deactivated";
                }
                else
                {
                    message = "can't deactivate " + module_type + " type modules!";
                }
                Element s = GSXML.createTextElement(this.doc, GSXML.STATUS_ELEM, message);
                response.appendChild(s);
            }
            else
            {
                logger.error("cant process system request, action " + action);
                continue;
            }
        } // for each command
        return response;
    }

    /**
     * do a configure on only part of the collection
     */
    protected boolean configureSubset(String subset)
    {

        File configFile = new File(GSFile.siteConfigFile(this.site_home));
        if (!configFile.exists())
        {
            logger.error("site config file: " + configFile.getPath() + " not found!");
            // wont be able to do any of the requests
            return false;

        }

        Document site_config_doc = this.converter.getDOM(configFile);
        if (site_config_doc == null)
        {
            logger.error("could not read in site config file: " + configFile.getPath());
            return false;
        }

        Element site_config_elem = site_config_doc.getDocumentElement();
        Element cluster_config_elem = GSXML.getNamedElement((Element) GSXML.getChildByTagName(site_config_elem, GSXML.CLUSTER_ELEM + GSXML.LIST_MODIFIER), GSXML.CLUSTER_ELEM, GSXML.NAME_ATT, this.cluster_name);
        if (cluster_config_elem == null)
        {
            logger.error("site config file: " + configFile.getPath() + " has no element for cluster " + this.cluster_name);
            // wont be able to do any of teh requests
            return false;

        }
        if (subset.equals(GSXML.SERVICE_ELEM + GSXML.LIST_MODIFIER))
        {
            Element service_rack_list = (Element) GSXML.getChildByTagName(cluster_config_elem, GSXML.SERVICE_CLASS_ELEM + GSXML.LIST_MODIFIER);
            clearServices();
            return configureServiceRackList(service_rack_list, null);
        }
        else if (subset.equals(GSXML.METADATA_ELEM + GSXML.LIST_MODIFIER))
        {
            this.metadata_list = this.doc.createElement(GSXML.METADATA_ELEM + GSXML.LIST_MODIFIER);
            Element metadata_list = (Element) GSXML.getChildByTagName(cluster_config_elem, GSXML.METADATA_ELEM + GSXML.LIST_MODIFIER);
            return addMetadata(metadata_list);
        }
        // else if (subset.equals(GSXML.PLUGIN_ELEM + GSXML.LIST_MODIFIER))
        // {
        //  this.plugin_item_list = this.doc.createElement(GSXML.PLUGIN_ELEM + GSXML.LIST_MODIFIER);
        //  Element import_list = (Element) GSXML.getChildByTagName(cluster_config_elem, GSXML.IMPORT_ELEM);
        //  if (import_list != null)
        //  {
        //      Element plugin_item_list = (Element) GSXML.getChildByTagName(cluster_config_elem, GSXML.PLUGIN_ELEM + GSXML.LIST_MODIFIER);
        //      return addPlugins(plugin_item_list);
        //  }
        //  else
        //      return false;
        // }
        else
        {
            logger.error("cannot process system request, configure " + subset);
            return false;
        }

    }

    protected boolean addAllDisplayInfo(Element description, String lang)
    {

        NodeList items = this.display_item_list.getChildNodes();
        for (int i = 0; i < items.getLength(); i++)
        { // for each key
            Element m = (Element) items.item(i);
            // findthe child with the correct language
            Element new_m = GSXML.getNamedElement(m, GSXML.DISPLAY_TEXT_ELEM, GSXML.LANG_ATT, lang);
            if (new_m == null && lang != DEFAULT_LANG)
            {
                // use the default lang
                new_m = GSXML.getNamedElement(m, GSXML.DISPLAY_TEXT_ELEM, GSXML.LANG_ATT, DEFAULT_LANG);
            }
            if (new_m == null)
            {
                // just get the first one
                new_m = (Element) GSXML.getChildByTagName(m, GSXML.DISPLAY_TEXT_ELEM);
            }
            description.appendChild(new_m.cloneNode(true));
        }
        return true;

    }

    protected Element getDisplayTextElement(String key, String lang)
    {

        Element this_item = GSXML.getNamedElement(this.display_item_list, GSXML.DISPLAY_TEXT_ELEM, GSXML.NAME_ATT, key);
        if (this_item == null)
        {
            return null;
        }

        Element this_lang = GSXML.getNamedElement(this_item, GSXML.DISPLAY_TEXT_ELEM, GSXML.LANG_ATT, lang);
        if (this_lang == null && lang != DEFAULT_LANG)
        {
            // try the default
            this_lang = GSXML.getNamedElement(this_item, GSXML.DISPLAY_TEXT_ELEM, GSXML.LANG_ATT, DEFAULT_LANG);
        }
        if (this_lang == null)
        {
            // just return the first one
            return GSXML.getFirstElementChild(this_item);//(Element)this_item.getFirstChild().cloneNode(true);
        }
        return (Element) this_lang.cloneNode(true);

    }

    public HashMap<String, ServiceRack> getServiceMap()
    {
        return service_map;
    }
}