source: other-projects/gs3-webservices-java-client/trunk/src/GS3Fedora/org/greenstone/fedora/services/GSearchConnection.java@ 21573

/**
 *#########################################################################
 * GSearchConnection.java - works with the demo-client for Greenstone 3, 
 * of the Greenstone digital library suite from the New Zealand Digital 
 * Library Project at the  * University of Waikato, New Zealand.
 * <BR><BR>
 * Copyright (C) 2008 New Zealand Digital Library Project
 * <BR><BR>
 * 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.
 * <BR><BR>
 * 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.
 *########################################################################
 */

package org.greenstone.fedora.services;

import java.util.Vector;
import java.util.Iterator;
import java.util.Map;
import java.util.HashMap;

import java.net.URL;
import javax.xml.namespace.QName;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.rpc.ServiceException;
import java.net.MalformedURLException;

import org.apache.axis.client.Call;
import org.apache.axis.client.Service;
import org.apache.log4j.Logger;

import javax.xml.parsers.ParserConfigurationException;
import org.w3c.dom.Element;
import org.w3c.dom.NodeList;


/** 
 * Class GSearchConnection connects to FedoraGSearch's web services.
 * FedorGSearch offers indexing and full-text search functionality for 
 * Fedora repositories. Its search web service (method gFindObjects)
 * returns the response of a search as XML.
 * GSearchConnection offers more convenient methods that extract just 
 * the parts of search results that FedoraGS3Connection needs and returns
 * that.
 * @author ak19 
*/
public class GSearchConnection implements FedoraToGS3Interface.Constants {
    /** Logger for this class. */
    private static final Logger LOG = Logger.getLogger(
            GSearchConnection.class.getName());
    
    /* Accessing the web services of Fedora Generic Search */
    protected static String NAMESPACE_URI = "http://server.fedoragsearch.defxws.dk";
    protected static String SERVICE_NAME = "OperationsService"; 

    /** The names of the methods we use of Fedora Generic Search's web services
     * are declared here as static final Strings. */
    protected static final String G_FIND_OBJECTS = "gfindObjects";
    
    /* Some fixed string literals that will be encountered in the response XMLs
     * that FedoraGSearch's method gFindObjects() returns. */
    protected static final String PID = "PID";
    protected static final String HIT_TOTAL = "hitTotal";
    protected static final String OBJECT = "object";
    protected static final String FIELD = "field";
    protected static final String NAME = "name";
    protected static final String DC_TITLE_FIELD = "dc.title";
    protected static final String FULLTEXT_FIELD = "ds.fulltext";
    
    /** separator used internally to separate values of a search field */ 
    protected static final String SPACE = " ";

        /** The name of the Index wherein FedoraGSearch has indexed all the GS3 docs.
     * This final member is public here so that others may read the indexName  
     * that this GSearchConnection works with. */
    public final String indexName; 
    
    /** The Service object used to connect to the FedoraGSearch web services */
    protected final Service service;
    /** The Call object used to connect to the FedoraGSearch web services */
    protected final Call call;
    /** The portName object used when connecting to FedoraGSearch's web services */
    protected final QName portName;
    
    /** A DocumentBuilder object used to construct and parse XML */
    protected final DocumentBuilder builder;
    

    
    /** Constructor that takes a String representing the url of the WSDL
     * file for FedoraGSearch's web services, and tries to establish a 
     * connection to those web services. 
     * @param wsdlFileLocation is a String representing the url of the WSDL file
     * @param indexName is the name of the index that Fedora Generic Search
     * should work with (the index wherein the indexed GS3 documents have been
     * placed). 
    */
    public GSearchConnection(String wsdlFileLocation, String indexName) 
        throws MalformedURLException, ServiceException, 
            ParserConfigurationException
    { 
        this.indexName = indexName;
        
        URL wsdlURL = new URL(wsdlFileLocation);
        service = new Service(wsdlURL, new QName(NAMESPACE_URI, SERVICE_NAME));
        //call = (Call) service.createCall(new QName(NAMESPACE_URI, PORT_NAME));
        
        Iterator i = service.getPorts();
        // FIXME: can we just assume it's the first port of service SERVICE_NAME?
        // Do we need to work out which port to get??? Remember, the port names  
        // vary between wsdls though!
        if(i.hasNext()) {
            portName = (QName)i.next();
            call = (Call) service.createCall(portName);
        
            String endpointLocation = call.getTargetEndpointAddress();
            LOG.debug("Wsdl file url: " + wsdlURL 
                    + "\nEndpoint location is: " + endpointLocation);
        } else { // should never happen: a service without a port
            // portName = null;
            call = (Call)service.createCall(); 
                // FIXME: possibly manually get the ports and choose
                // one containing "FEDORA" and "API-A" in its name?
            throw new ServiceException(this.getClass() + ": No port in wsdl file");
        }
        
        // we can set the portName which remains constant for the various methods
        // call.setPortName(portName);
        
        DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
        builder = factory.newDocumentBuilder(); // to create XML docs
    }
        
    
    /**
     * Method to invoke gfindObjects operation of Fedora Generic Search
     * web services.
     * 
     * Parameter types, parameter order and return type of gFindObjects are as  
     * obtained from the wsdl file for the Fedora Generic Search web services 
     * located at:
     * http://localhost:8080/fedoragsearch/services/FgsOperations?wsdl
     *  &lt;wsdl:message name="gfindObjectsRequest"&gt;
     *  &lt;wsdl:part name="query" type="xsd:string"/&gt;
     *  &lt;wsdl:part name="sort" type="xsd:string"/&gt;
     *  &lt;wsdl:part name="hitPageStart" type="xsd:int"/&gt;
     *  &lt;wsdl:part name="hitPageSize" type="xsd:int"/&gt;
     *  &lt;wsdl:part name="snippetsMax" type="xsd:int"/&gt;
     *  &lt;wsdl:part name="fieldMaxLength" type="xsd:int"/&gt;
     *  &lt;wsdl:part name="indexName" type="xsd:string"/&gt;
     *  &lt;wsdl:part name="resultPageXslt" type="xsd:string"/&gt;
     *  &lt;/wsdl:message&gt;
     * 
     * &lt;wsdl:message name="gfindObjectsResponse"&gt;
     * &lt;wsdl:part name="gfindObjectsReturn" type="xsd:string"/&gt;
     * &lt;/wsdl:message&gt;
     * 
     * &lt;wsdl:operation name="gfindObjects" 
     * parameterOrder="query sort hitPageStart hitPageSize snippetsMax 
     * fieldMaxLength indexName resultPageXslt"&gt;
     *  
     * This method works: it searches the dc.title field of our FedoraIndex 
     * for the term (e.g. "interview") and the result returned is an XML String.
     *
     * There's no example on how to call gFindObjects with parameters. In 
     * particular, I don't know what values the parameter <b>sort</b> can take.
     * But topazproject has an example on how to call updateIndex(). 
     * @see <a href="http://www.topazproject.org/trac/wiki/FedoraSearch?format=txt">An example on how to call updateIndex() with parameters</a>
     * @see <a href="http://ws.apache.org/axis/java/apiDocs/org/apache/axis/client/Service.html">Axis Service class</a>
     * @see <a href="http://ws.apache.org/axis/java/apiDocs/javax/xml/rpc/Call.html">Axis RPC Call, for specification of interface Call</a>
     * @see <a href="http://ws.apache.org/axis/java/apiDocs/org/apache/axis/client/Call.html">Axis client Call class, for implementation of interface Call</a> 
    */
    protected String gFindObjects(String searchFieldedTerms, String sort, 
            int hitPageStart, int hitPageSize, int snippetsMax,
            /*int fieldMaxLength,*/ String indexName, String resultPageXslt) throws Exception
    {
        // "Prefills as much info from the WSDL as it can. Right now it's SOAPAction, 
        // operation qname, parameter types and return type of the Web Service. 
        // This method considers that port name and target endpoint address have 
        // already been set. This is useful when you want to use the same Call instance
        // for several calls on the same Port. NOTE: Not part of JAX-RPC specification."
        
        //call.removeAllParameters(); // no need for this when using setOpName below
        call.setOperationName(G_FIND_OBJECTS);
        
        // Max num of chars in field vals returned. Since return values exceeding 
        // maxlength will be truncated, ensure length suffices for long PIDs returned.
        // The only element of the response XML we'll be using is the PID of the document
        // in which the searchTerm occurred.
        final int fieldMaxLength = 100; // NOT TRUE: max length in words of field values
              // returned. E.g. snippet sizes will be reduced to fieldMaxLength words too.

        // This is the method call for Fedora 2's GSearch
        //String valueFound =(String)call.invoke( new Object[] {
        //  searchFieldedTerms, sort, hitPageStart, hitPageSize, snippetsMax,
        //  fieldMaxLength, indexName, resultPageXslt} );

        // The method call for GSearch 2.2 of Fedora 3 takes the args in a different order:
        String valueFound =(String)call.invoke( new Object[] {
            searchFieldedTerms, hitPageStart, hitPageSize, snippetsMax,
            fieldMaxLength, indexName, sort, resultPageXslt} );
        
        // for debugging
        //javax.swing.JOptionPane.showMessageDialog(null, "GSearchConnection.gFindObjects:" + valueFound);
            
        return valueFound;
    }
    
    /**
     * Method that performs a search for the given searchTerm inside the given
     * indexed field.
     * @param searchFieldName is the name of the indexed field within which the
     * given searchTerm is to be searched for.
     * @param searchTerm is the term to be searched for.
     * @param hitPageStart is the page of search results to start returning.
     * @param hitPageSize is the number of search result pages to return, 
     * starting from hitPageStart.
     * @param snippetsMax is the maximum number of separate snippets containing  
     * the searchTerm that are to be returned. (snippetsMax or a fewer number of 
     * occurrences of the word in the text will be returned)
    */
    public String search(String searchFieldName, String searchTerm, 
            int hitPageStart, int hitPageSize, int snippetsMax) throws Exception
    {
        final String sort = ""; // returns results from highest to lowest rank
        final String resultPageXslt = "";       
        
        // when a fieldname is given to search in (ds.fulltext, dc.title)
        // then prepend that followed by a COLON to the searchTerm.
        final String fullSearchTerm = searchFieldName.equals("") ?
                searchTerm : (searchFieldName+":"+searchTerm); 
        
        return gFindObjects(fullSearchTerm, sort, 
            hitPageStart, hitPageSize, snippetsMax, 
            indexName, resultPageXslt);
    }
    
    /** 
     * FedoraGSearch accepts a query of the form: 
     * <code>&lt;"cyclone val" "Gender Inequalities" ds.fulltext:"cyclone val"
     * ds.fulltext:"worst storm"&gt;</code>
     * where the first two phrases are searched for in all indexed fields,
     * (in this case dc.title and ds.fulltext), while the last two are 
     * searched for in the ds.fulltext field.
     * Another example: 
     * <code>&lt;gender dc.title:interview ds.fulltext:"cyclone val"&gt;
     * titles and fulltexts are searched for "gender", while title index
     * is searched for "interview" and fulltexts are searched for the phrase
     * "cyclone val"</code>
     * @param fieldsToSearchTerms is a Hashmap of searchfields and 
     * associated search terms (words or phrases). The terms are in a 
     * comma-separated list. fieldsToSearchTerms is a Hashmap of 
     * (Searchfields, associated-searchTerms) pairs. It can contain 3 
     * searchfields: allfields, titles, text. The value for each is a 
     * comma-separated list of search terms in that field.
     * Internally the field names get converted to what FedoraGSearch's
     * gfindObjects understands: titles becomes dc.title:, text becomes 
     * ds.fulltext and allfields becomes nothing.
     * @param hitPageStart is the page of search results to start returning.
     * @param hitPageSize is the number of search result pages to return, 
     * starting from hitPageStart.
     * @return the XML (in string format) returned from Fedora Generic Search's
     * gfindObjects method
     * 
    */
    public String search(Map fieldsToSearchTerms,
            int hitPageStart, int hitPageSize) 
        throws Exception
    {
        LOG.debug("In FedoraGS3's GSearchConnection.search(Map,...)");
        
        // HashMap consists of several (key, value) entries, 3 of
        // which will be dealt with here:
        // - allfields, <comma separated list of search terms/phrases>
        // - titles, <comma separated list of search terms/phrases>
        // - (full)text, <comma separated list of search terms/phrases>
        // We need to obtain each value and change the separator to space:
        String allfields = (String)fieldsToSearchTerms.get(ALL_FIELDS);
        String titles = (String)fieldsToSearchTerms.get(ALL_TITLES);
        String fulltexts = (String)fieldsToSearchTerms.get(FULLTEXT);
        
        // Each field is a comma separated list of terms that may be 
        // either a word OR a phrase.
        // We're going to separate each term from the list,
        // and put quotes around phrases, then combine all the terms
        // together again with spaces to separate them.
        allfields = formatSearchTermsInField(allfields, ALL_FIELDS); 
            // ALL_FIELDS has no field name
        titles = formatSearchTermsInField(titles, DC_TITLE_FIELD);
        fulltexts = formatSearchTermsInField(fulltexts, FULLTEXT_FIELD);
    
        String fullSearchTerm = allfields + titles + fulltexts;
        if(fullSearchTerm.trim().equals("")) { // nothing to search on
            return "";
        }
        
        // Finally, restrict the search to the Greenstone digital objects 
        // stored in Fedora
        final String greenstonePID 
            = PID + FedoraGS3DL.COLON + FedoraGS3DL.GREENSTONE; 
                //"PID:\"greenstone\""; 
        fullSearchTerm += greenstonePID;
            //! Everything after the colon in the pid is ignored by FedoraGSearch:
                // "PID:\"greenstone:gs2mgdemo\""; // ignores "gs2mgdemo"
        
        // <snippet> tags interfere when PID field is searched on, set it to 0
        return search(fullSearchTerm, hitPageStart, hitPageSize, 0);
        // return search(fullSearchTerm, hitPageStart, hitPageSize, snippetsMax);
    }
    
    /** Each field is a comma separated list of terms that may be either a word  
     * OR a phrase. We're going to separate each term from the list, and put 
     * quotes around phrases, then combine all the terms together again with 
     * spaces to separate them. Examples: 
     * <pre>dc.title:"a phrase" word
     * dc.fulltext: "cyclone val"
     * (ALL_FIELDS) interview gender</pre>
     * This is required to facilitate fielded searching with fedoraGSearch.
     * @param field is a comma separated list of search terms (corresponding 
     * to one fieldName) to be reorganised
     * @param fieldName is the name of the field to prepend to the reorganised
     * field value. FieldName ALL_FIELDS is ignored.
     * @return parameter field reorganised such that terms that are phrases 
     * are in quotes and each term is separated by a space from the previous one.
    */
    protected String formatSearchTermsInField(String field, String fieldName) 
    {   
        if(field != null) { // check that the field isn't empty
            //LOG.debug("field: " + field);
            String[] terms = field.split(",");
            field = ""; // we'll build it up again
            for(int i = 0; i < terms.length; i++) {
                // if it contains a space, then the term's a phrase,
                // put it in quotes
                if(terms[i].indexOf(SPACE) != -1) { 
                    terms[i] = "\"" + terms[i] + "\"";
                }
                field = field + terms[i] + SPACE;
            }
            
            // Prefix it with the name of the field we want to search for 
            // the term in. Every field other than allfields has a prefix
            if(!fieldName.equals(ALL_FIELDS)) { 
                field = fieldName + ":" + field;
            }
            
        } else field = "";
        return field;
    }
    
    /** 
     * Uses FedoraGSearch to perform a search where the query is embedded in
     * fieldedSearchTerms, which not only provides the terms to search on, but
     * also the fields to search the (various) given terms in.
     * @param fieldedSearchTerms is the String specifying all the search terms
     * with their fields (or no field if it should search for the terms in 
     * all fields). The terms with no associated search-fields should come first.
     * Search terms may be in quotes.
     * @param snippetsMax is the maximum number of separate snippets containing  
     * the searchTerm (snippetsMax number of occurrences of the word in the text) 
     * returned.
     * @param hitPageStart is the page of search results to start returning.
     * @param hitPageSize is the number of search result pages to return, 
     * starting from hitPageStart.
     * @return the XML (in string format) returned from Fedora Generic Search's
     * gfindObjects method
    */
    public String search(String fieldedSearchTerms,
            int hitPageStart, int hitPageSize, int snippetsMax) throws Exception
    {
        LOG.debug("In method search(String fieldedSearchTerms,...). "
                + "Query is:\n" + fieldedSearchTerms);
        
        final String sort = ""; // returns results from highest to lowest rank
        final String resultPageXslt = "";       
        return gFindObjects(fieldedSearchTerms, sort, 
                hitPageStart, hitPageSize, snippetsMax, 
                indexName, resultPageXslt);
    }
    
    /** Call this method with the return value of calling search(). 
     * Search results are returned in GSearch's XML response format, 
     * containing information that includes the PIDs of the documents that 
     * matched the search. These PIDs are returned in the array. 
     * @param collectionName is the name of the collection to restrict the 
     * search results by. If it's "", then results from all collections are
     * returned. Generally, don't want to pass "", because, theoretically, 
     * all indexed collections in the repository could be considered and 
     * not all of them may be Greenstone collections. If all Greenstone 
     * collections should be searched for, pass "greenstone" as the 
     * collection name instead.
     * @param searchResult is the Fedora Generic Search XML response returned 
     * from performing a gfindObjects() operations. 
     * @return an array of the pids of documents found for the search. */
    public String[] getPIDsFromSearchResult(String collectionName,
            String searchResult) 
        throws Exception 
    {
        final String[] empty = {};
        if(searchResult.equals("")) {
            return empty;
        }
        
        //  <?xml version="1.0" encoding="UTF-8"?>
        //  <resultPage xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:foxml="info:fedora/fedora-system:def/foxml#" xmlns:zs="http://www.loc.gov/zing/srw/" indexName="FedoraIndex" dateTime="Sat Feb 09 16:43:04 NZDT 2008">
        //  <gfindObjects hitTotal="1" resultPageXslt="" hitPageSize="10" hitPageStart="1" query="ds.fulltext:Cyclone">
        //  <objects>
        //  <object no="1" score="0.24639596">
        //  <field name="PID">greenstone:gs2mgdemo-HASH01d667303fe98545f03c14ae</field>
        //  <field name="repositoryName">Fedora</field>
        //  <field name="object.type">FedoraObject</field>
        //  <field name="object.state">Active</field>
        //  <field name="object.label">The Courier - N°159 - Sept- Oct 1996 Dossier Inves ... </field>
        //  <field name="object.createdDate">2007-11-23T04:23:15.363Z</field>
        //  <field name="object.lastModifiedDate">2008-01-15T04:37:49.518Z</field>
        //  <field name="dc.title">some title</field>
        //  <field name="dc.title">some title2</field>
        //  ...
        //  <field name="ds.fulltext" snippet="yes">(The 1993 <span class="highlight">cyclone</span>, although</field>
        //  <field name="ds.label">Metadata</field>
        //  ...
        //  </object>
        //  </objects>
        //  </gfindObjects>
        // 1. Get documentElement, which is <resultPage>
        Element resultPage = FedoraCommons.getResponseAsDOM(builder, searchResult);
        // 2. find the hitTotal value which is the number of results 
        // it's an attribute of the sole compulsory <gFindObjects> element
        int hitTotal = 0;
        Element gfindObjectsEl
            = (Element)resultPage.getElementsByTagName(G_FIND_OBJECTS).item(0);
        String value = gfindObjectsEl.getAttribute(HIT_TOTAL);
        hitTotal = Integer.parseInt(value);
        if(hitTotal == 0) {
            return new String[]{};
        }
        
        // Our resulting list of pids will be no more than hitTotal,
        // but may be fewer if we constrain the results to a collection
        Vector pidsInCollection = new Vector(hitTotal);
        
        // Returns a NodeList of all descendant Elements with object tagname
        NodeList objects = gfindObjectsEl.getElementsByTagName(OBJECT);
        for(int i = 0; i < objects.getLength(); i++) {
            // should be the case that pids.length == (digital)objects.getLength()
            // get the PID of each object
            Element object = (Element)objects.item(i);
            NodeList fields = object.getElementsByTagName(FIELD);
            
            for(int j = 0; j < fields.getLength(); j++) { 
                // find the sole <field> of <object> where NAME attribute == PID
                Element field = (Element)fields.item(j);
                if(field.getAttribute(NAME).equals(PID)) {
                    String pid = FedoraCommons.getValue(field);
                    // Either store only the pids which are part of the collection,
                    // or, if no collection is specified (=""),then store the pid too
                    if(collectionName.equals("") || pid.contains(collectionName)) {
                        pidsInCollection.add(pid);
                    }
                    break; // found pid field, meaning that we have
                        // finished for loop on <field>s of this <object>, 
                        // consider next <object>
                }
            }
        }
        String[] pids = new String[pidsInCollection.size()];
        pidsInCollection.toArray(pids);
        return pids;
    }
    
    public static void main(String[] args) {
        try { 
            GSearchConnection searcher = new GSearchConnection(
                "http://localhost:8080/fedoragsearch/services/FgsOperations?wsdl", "FedoraIndex");
            
            
            HashMap map = new HashMap();
            map.put(GSearchConnection.ALL_FIELDS, "gender inequalities");
            map.put(GSearchConnection.FULLTEXT, "cyclone val,worst storm");
            //map.put(GSearchConnection.ALL_FIELDS, "\"gender inequalities\"");
            //map.put(GSearchConnection.FULLTEXT, "\"cyclone val\",\"worst storm\"");
            String searchResult = searcher.search(map, 1, 10); //snippetsMax: 3);
            System.out.println(searchResult);
            
            String[] pids = searcher.getPIDsFromSearchResult("gs2mgdemo", searchResult);
            System.err.println("Found pids for search:\n"); 
            for(int i = 0; i < pids.length; i++) {
                System.out.println(pids[i]);
            }
            
            //searchResult = searcher.search("", "minh", 0, 50, 50);
            //System.err.println(searchResult);
            
            //String searchTerms = "cyclone dc.title:interview dc.title:gender";
            String searchTerms="\"gender inequalities\" ds.fulltext:\"cyclone val\" ds.fulltext:\"worst storm\"";
            searchResult = searcher.search(searchTerms, 1, 10, 3);
            System.out.println(searchResult);
            
            // Not restricting results to any collection (search results from 
            // all collections)
            pids = searcher.getPIDsFromSearchResult("", searchResult);
            System.err.println("Found pids for search: "); 
            for(int i = 0; i < pids.length; i++) {
                System.out.println(pids[i]);
            } 
            
            searchResult = searcher.search("ds.fulltext", "cyclone", 1, 10, 3);
            //String searchResult = searcher.search("ds.label", "hierarchical", 1, 10, 3);
            // System.out.println(searcher.search("ds.fulltext", "Pinky", 1, 10, 3));
            System.out.println(searchResult);
            
            pids = null;
            pids = searcher.getPIDsFromSearchResult("", searchResult);
            System.err.println("Found pids for search: "); 
            for(int i = 0; i < pids.length; i++) {
                System.out.println(pids[i]);
            }
            
        }catch(Exception e) {
            System.err.println(e.getMessage());
        }
        
    }

}