| 1 | <!doctype html public "-//w3c//dtd html 4.0 transitional//en">
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| 2 | <html>
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| 3 | <head>
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| 4 | <meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
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| 5 | <meta name="GENERATOR" content="Mozilla/4.76 [en] (X11; U; Linux 2.2.16-22 i686) [Netscape]">
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| 6 | <title>: Package org.nzdl.gsdl.service</title>
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| 7 | <!--NewPage-->
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| 8 | <!-- Generated by javadoc on Thu Mar 08 23:01:13 GMT+13:00 2001 -->
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| 9 | </head>
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| 10 | <body bgcolor="#FFFFFF">
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| 11 | Provides services for java client-side communication
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| 12 | to a Greenstone Digital Library via CORBA.
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| 13 | <br>
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| 14 | <h2>
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| 15 | Further Requirements</h2>
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| 16 |
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| 17 | <ul>
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| 18 | <li>
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| 19 | Sun Java 2 version 1.3 (or later)</li>
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| 20 |
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| 21 | <li>
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| 22 | Corbaserver, a server-side application for communicating to a Greenstone
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| 23 | Digital Library.</li>
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| 24 | </ul>
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| 25 |
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| 26 | <h2>
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| 27 | Java Interface Data Flows</h2>
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| 28 |
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| 29 | <center><img SRC="nzdl-service-package.png" ALT="NZDL Data Flow Diagram" height=280 width=637></center>
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| 30 |
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| 31 | <p><br>
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| 32 | <h2>
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| 33 | A Typical Query</h2>
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| 34 | From a users perspective, a typical query may work as follows:
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| 35 | <ul>
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| 36 | <li>
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| 37 | Create instances of the necessary NZDL Java-Client objects:</li>
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| 38 |
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| 39 | <ul>
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| 40 | <li>
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| 41 | a <b>NzdlQuery</b> object</li>
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| 42 |
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| 43 | <li>
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| 44 | a <b>NzdlRequest </b>object using your <b>NzdlQuery</b> object</li>
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| 45 |
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| 46 | <li>
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| 47 | a <b>NzdlResponse</b> object that will eventually hold response
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| 48 | data</li>
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| 49 |
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| 50 | <li>
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| 51 | a <b>NzdlService</b> object to service CORBA interface requests
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| 52 | to
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| 53 | a Greenstone collection</li>
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| 54 | </ul>
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| 55 |
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| 56 | <li>
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| 57 | Use the <b>NzdlService</b> object (with collection name and <b>NzdlRequest
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| 58 | </b>object)
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| 59 | to query the CORBA interface and place the reply into the <b>NzdlResponse</b>
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| 60 | object.</li>
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| 61 |
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| 62 | <li>
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| 63 | Create an instance of the <b>NzdlResultSet</b> object. Use <b>NzdlResponse.getResultSet()
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| 64 | </b>to
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| 65 | extract response data into the <b>NzdlResultSet</b> object.</li>
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| 66 |
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| 67 | <li>
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| 68 | Use the <b>NzdlResultSet</b> methods to view data such as document IDs</li>
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| 69 |
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| 70 | <br>Get documents using <b>NzdlService.getDocument()</b></ul>
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| 71 |
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| 72 | <h1>
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| 73 | Sample Code</h1>
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| 74 | Below is a trivial example of a client application. For a more elaborate
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| 75 | example, see <a href="../SimpleClient.html">SimpleClient</a>.
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| 76 | <p>In order to function, this app needs Corbaserver running on the same
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| 77 | machine.
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| 78 | <p><tt>/**</tt>
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| 79 | <br><tt>* TrivialDemo.java.</tt>
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| 80 | <br><tt>* A very simple client application that:</tt>
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| 81 | <br><tt>* - Creates a service object using an Interoperable</tt>
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| 82 | <br><tt>* Object Reference (IOR) from a file;</tt>
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| 83 | <br><tt>* - lists all available collections;</tt>
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| 84 | <br><tt>* - searches "demo" collection for "snail farming";</tt>
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| 85 | <br><tt>* - prints the number of hits;</tt>
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| 86 | <br><tt>* - lists first 10 titles found;</tt>
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| 87 | <br><tt>* - displays the unformatted text of first document found.</tt>
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| 88 | <br><tt>*/</tt>
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| 89 | <br><tt>import java.io.*;</tt>
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| 90 | <br><tt>import java.util.*;</tt>
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| 91 | <br><tt>import java.lang.*;</tt>
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| 92 | <br><tt>import org.nzdl.gsdl.service.*; //the java-client stuff</tt>
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| 93 | <br><tt>import org.nzdl.gsdl.util.NzdlIORs; //for obtaining the IOR</tt>
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| 94 | <p><tt>public class TrivialDemo {</tt>
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| 95 | <br><tt> public static void main( String [] args )</tt>
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| 96 | <br><tt> {</tt>
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| 97 | <br><tt> String myIorFile = "/tmp/localcorba.objid";</tt>
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| 98 | <br><tt> String myQueryString = "snail farming";</tt>
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| 99 | <br><tt> String myCollection = "demo";</tt>
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| 100 | <p><tt> // Create a Service Object</tt>
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| 101 | <br><tt> NzdlService myService = NzdlIORs.findIOR(null,
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| 102 | null,</tt>
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| 103 | <br><tt>
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| 104 | myIorFile, null);</tt>
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| 105 | <p><tt> // Use getCollectionSet to obtain List of Collections</tt>
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| 106 | <br><tt> Set myCollections = myService.getCollectionSet();</tt>
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| 107 | <p><tt> //Display List of Collections</tt>
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| 108 | <br><tt> System.out.println("\nThe available collections:");</tt>
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| 109 | <p><tt> for (Iterator i = myCollections.iterator(); i.hasNext();
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| 110 | )</tt>
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| 111 | <br><tt> {</tt>
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| 112 | <br><tt> String collName = (String)
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| 113 | i.next();</tt>
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| 114 | <br><tt> System.out.println("
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| 115 | "+ collName);</tt>
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| 116 | <br><tt> }</tt>
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| 117 | <p><tt> // Find The Number of documents in my collection</tt>
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| 118 | <br><tt> NzdlCollectionInfo myInfo = myService.getCollectionInfo(myCollection);</tt>
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| 119 | <br><tt> System.out.println("\nNum Of Collection docs
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| 120 | = "+myInfo.getNumOfDocs());</tt>
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| 121 | <p><tt> // Create query object</tt>
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| 122 | <br><tt> NzdlQuery query = new NzdlQuery( myQueryString
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| 123 | );</tt>
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| 124 | <p><tt> // Create request object</tt>
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| 125 | <br><tt> NzdlRequest request = new NzdlRequest( query
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| 126 | );</tt>
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| 127 | <p><tt> // create response object</tt>
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| 128 | <br><tt> NzdlResponse response = new NzdlResponse( );</tt>
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| 129 | <p><tt> // use service to get response from request to
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| 130 | myCollection</tt>
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| 131 | <br><tt> myService.service( myCollection, request, response
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| 132 | );</tt>
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| 133 | <p><tt> // use getResultSet to get results from response</tt>
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| 134 | <br><tt> NzdlResultSet results = response.getResultSet();</tt>
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| 135 | <p><tt> // getNumOfDocs</tt>
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| 136 | <br><tt> System.out.println("\nNumber of hits = "+results.getNumOfDocs());</tt>
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| 137 | <p><tt> // Use getDocumentIDs to build list of titles
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| 138 | (defaults: 1 - 10)</tt>
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| 139 | <br><tt> List docIDs = results.getDocumentIDs();</tt>
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| 140 | <br><tt> System.out.println("\nThe titles:");</tt>
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| 141 | <br><tt> for (ListIterator i = docIDs.listIterator();
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| 142 | i.hasNext(); )</tt>
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| 143 | <br><tt> {</tt>
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| 144 | <br><tt> Set metaData</tt>
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| 145 | <br><tt> = myService.getMetaData(
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| 146 | myCollection,(String)i.next(),"Title");</tt>
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| 147 | <br><tt> Iterator j = metaData.iterator();</tt>
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| 148 | <br><tt> System.out.println(j.next());
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| 149 | //print title metadata</tt>
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| 150 | <br><tt> }</tt>
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| 151 | <br><tt> System.out.println("\nThe first document returned
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| 152 | was:");</tt>
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| 153 | <p><tt> // Print first document returned</tt>
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| 154 | <br><tt> String myDoc</tt>
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| 155 | <br><tt> = myService.getDocument(myCollection,(String)docIDs.get(0));</tt>
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| 156 | <br><tt> System.out.println(myDoc);</tt>
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| 157 | <p><tt> } // end of main</tt>
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| 158 | <br><tt>} // end of demo class</tt>
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| 159 | <br>
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| 160 | </body>
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| 161 | </html>
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