source: branches/ant-install-branch/gsdl3/src/java/org/greenstone/gsdl3/service/AbstractMGSearch.java@ 9815

/*
 *    AbstractMGSearch.java
 *    Copyright (C) 2005 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.
 */
package org.greenstone.gsdl3.service;

// Greenstone classes
import org.greenstone.mg.*;
import org.greenstone.gsdl3.util.GSXML;
import org.greenstone.gsdl3.util.GSFile;
// XML classes
import org.w3c.dom.Document;
import org.w3c.dom.Element; 
import org.w3c.dom.NodeList;

// java
import java.util.Vector;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Map;
import java.util.Set;
import java.util.Iterator;
import java.io.File;

/** Partially implements a generic MG search service
 *
 * @author <a href="mailto:[email protected]">Katherine Don</a>
 */

abstract public class AbstractMGSearch
    extends AbstractSearch
{
    protected static final String CASE_PARAM = "case";
    protected static final String STEM_PARAM = "stem";
    protected static final String MATCH_PARAM = "matchMode";
    protected static final String MATCH_PARAM_ALL = "all";
    protected static final String MATCH_PARAM_SOME = "some";

    protected static final String BOOLEAN_PARAM_ON = "1";
    protected static final String BOOLEAN_PARAM_OFF = "0";

    protected static final String EQUIV_TERM_ELEM = "equivTerm";

    protected static final String STEM_ATT = "stem";
    protected static final String NUM_DOCS_MATCH_ATT = "numDocsMatch";
    protected static final String FREQ_ATT = "freq";

    // Elements used in the config file that are specific to this class
    protected static final String DEFAULT_INDEX_ELEM = "defaultIndex";
    protected static final String INDEX_STEM_ELEM = "indexStem";
    protected static final String INDEX_ELEM = "index";

    /** the default index */
    protected String default_index = null;
    /** the stem used for the index files */
    protected String index_stem = null;
    protected MGWrapper mg_src = null;

    
    public AbstractMGSearch()
    {
    this.mg_src = new MGWrapper();
    }

    public boolean configure(Element info, Element extra_info)
    {
    if (!super.configure(info, extra_info)) {
        return false;
    }
    // do we support any of the extended features?
    does_chunking = true;

    // Get the default index out of <defaultIndex> (buildConfig.xml)
    Element def = (Element) GSXML.getChildByTagName(info, DEFAULT_INDEX_ELEM);
    if (def != null) {
        this.default_index = def.getAttribute(GSXML.NAME_ATT);
    }
    if (this.default_index == null || this.default_index.equals("")) {
        System.err.println("Error: default index not specified!");
        return false;
    }

    // the index stem is either the collection name or is specified in the config file
    Element index_stem_elem = (Element) GSXML.getChildByTagName(info, INDEX_STEM_ELEM);
    if (index_stem_elem != null) {
        this.index_stem = index_stem_elem.getAttribute(GSXML.NAME_ATT);
    }
    if (this.index_stem == null || this.index_stem.equals("")) {
        System.err.println("AbstractMGSearch.configure(): indexStem element not found, stem will default to collection name");
        this.index_stem = this.cluster_name;
    }
    
    // get display info from extra info
    if (extra_info !=null) {
        Document owner = info.getOwnerDocument();
        // so far we have index specific display elements, and global format elements 
        NodeList indexes = info.getElementsByTagName(GSXML.INDEX_ELEM);
        Element config_search = (Element)GSXML.getChildByTagName(extra_info, GSXML.SEARCH_ELEM);
        
        for (int i=0; i<indexes.getLength();i++) {
        Element ind = (Element)indexes.item(i);
        String name = ind.getAttribute(GSXML.NAME_ATT);
        Element node_extra = GSXML.getNamedElement(config_search,
                               GSXML.INDEX_ELEM,
                               GSXML.NAME_ATT,
                               name);
        if (node_extra == null) {
            System.err.println("GS2Search: haven't found extra info for index named "+name);
            continue;
        }
        
        // get the display elements if any - displayName
        NodeList display_names = node_extra.getElementsByTagName(GSXML.DISPLAY_TEXT_ELEM);
        if (display_names !=null) {
            for (int j=0; j<display_names.getLength(); j++) {
            Element e = (Element)display_names.item(j);
            ind.appendChild(owner.importNode(e, true));
            }
        }
        } // for each index
    }
    return true;
    }

    protected void addCustomQueryParams(Element param_list, String lang) 
    {
    createParameter(CASE_PARAM, param_list, lang);
    createParameter(STEM_PARAM, param_list, lang);
    createParameter(MATCH_PARAM, param_list, lang); 
    }

    protected void getIndexData(ArrayList index_ids, ArrayList index_names, String lang) 
    {
    // the index info - read from config file - cache it??
    Element index_list = (Element)GSXML.getChildByTagName(this.config_info, INDEX_ELEM+GSXML.LIST_MODIFIER);
    NodeList indexes = index_list.getElementsByTagName(INDEX_ELEM);
    int len = indexes.getLength();
    // now add even if there is only one
    for (int i=0; i<len; i++) {
        Element index = (Element)indexes.item(i);
        index_ids.add(index.getAttribute(GSXML.NAME_ATT));
        index_names.add(GSXML.getDisplayText(index, GSXML.DISPLAY_TEXT_NAME, lang, "en"));
        
    }

    }

    /** do the actual query */
    protected Element processTextQuery(Element request) 
    {

    // Create a new (empty) result message
    Element result = this.doc.createElement(GSXML.RESPONSE_ELEM);
    result.setAttribute(GSXML.FROM_ATT, TEXT_QUERY_SERVICE);
    result.setAttribute(GSXML.TYPE_ATT, GSXML.REQUEST_TYPE_PROCESS);

    // Get the parameters of the request
    Element param_list = (Element) GSXML.getChildByTagName(request, GSXML.PARAM_ELEM+GSXML.LIST_MODIFIER);
    if (param_list == null) {
        System.err.println("Error: TextQuery request had no paramList.");
        return result;  // Return the empty result
    }

    // Process the request parameters
    HashMap params = GSXML.extractParams(param_list, false);
    
    // Make sure a query has been specified
    String query = (String) params.get(QUERY_PARAM);
    if (query == null || query.equals("")) {
        return result;  // Return the empty result
    }

    // If an index hasn't been specified, use the default
    String index = (String) params.get(INDEX_PARAM); 
    if (index == null) {
        index = this.default_index;
    }

    // The location of the MG index and text files
    String basedir = GSFile.collectionBaseDir(this.site_home, this.cluster_name) +  File.separatorChar;  // Needed for MG
    String textdir = GSFile.collectionTextPath(this.index_stem);
    String indexpath = GSFile.collectionIndexPath(this.index_stem, index);
    this.mg_src.setIndex(indexpath);
    
    // set the mg query parameters to the values the user has specified
    setStandardQueryParams(params);
    this.mg_src.runQuery(basedir, textdir, query);
    MGQueryResult mqr = this.mg_src.getQueryResult();
    if (mqr.isClear()) {
        // something has gone wrong
        GSXML.addError(this.doc, result, "Couldn't query the mg database", GSXML.ERROR_TYPE_SYSTEM);
        return result;
    }
    long totalDocs = mqr.getTotalDocs();

    // Get the docnums out, and convert to HASH ids
    Vector docs = mqr.getDocs();
    if (docs.size() == 0) {
        System.err.println("GS2MGSearch: Warning: No results found...\n");
    }

    // Create a metadata list to store information about the query results
    Element metadata_list = this.doc.createElement(GSXML.METADATA_ELEM+GSXML.LIST_MODIFIER); 
    result.appendChild(metadata_list);

    // Add a metadata element specifying the number of matching documents
    // because teh total number is just the number returned, use numDocsReturned, not numDocsMatched
    GSXML.addMetadata(this.doc, metadata_list, "numDocsReturned", ""+totalDocs);
    // add a metadata item to specify what actual query was done - eg if stuff was stripped out etc. and then we can use the query later, cos we don't know which parameter was the query
    GSXML.addMetadata(this.doc, metadata_list, "query", query);

    // Create a document list to store the matching documents, and add them
    Element document_list = this.doc.createElement(GSXML.DOC_NODE_ELEM+GSXML.LIST_MODIFIER);
    result.appendChild(document_list);
    for (int d = 0; d < docs.size(); d++) {
        long docnum = ((MGDocInfo) docs.elementAt(d)).num_;
        float rank = ((MGDocInfo) docs.elementAt(d)).rank_;
        String doc_id = MGNum2OID(docnum);
        Element doc_node = createDocNode(doc_id, Float.toString(rank));
        document_list.appendChild(doc_node);
    }

    // Create a term list to store the term information, and add it
    Element term_list = this.doc.createElement(GSXML.TERM_ELEM+GSXML.LIST_MODIFIER);
    result.appendChild(term_list);
    Vector terms = mqr.getTerms();
    for (int t = 0; t < terms.size(); t++) {
        MGTermInfo term_info = (MGTermInfo) terms.get(t);

        String term = term_info.term_;
        int stem_method = term_info.stem_method_;
        Vector equiv_terms = term_info.equiv_terms_;

        Element term_elem = this.doc.createElement(GSXML.TERM_ELEM);
        term_elem.setAttribute(GSXML.NAME_ATT, term);
        term_elem.setAttribute(STEM_ATT, "" + stem_method);

        Element equiv_term_list = this.doc.createElement(EQUIV_TERM_ELEM+GSXML.LIST_MODIFIER);
        term_elem.appendChild(equiv_term_list);

        long total_term_freq = 0;
        for (int et = 0; et < equiv_terms.size(); et++) {
        MGEquivTermInfo equiv_term_info = (MGEquivTermInfo) equiv_terms.get(et);

        Element equiv_term_elem = this.doc.createElement(GSXML.TERM_ELEM);
        equiv_term_elem.setAttribute(GSXML.NAME_ATT, equiv_term_info.term_);
        equiv_term_elem.setAttribute(NUM_DOCS_MATCH_ATT, "" + equiv_term_info.match_docs_);
        equiv_term_elem.setAttribute(FREQ_ATT, "" + equiv_term_info.term_freq_);
        equiv_term_list.appendChild(equiv_term_elem);

        total_term_freq += equiv_term_info.term_freq_;
        }

        term_elem.setAttribute(FREQ_ATT, "" + total_term_freq);
        term_list.appendChild(term_elem);
    }
    return result;
    }

    // should probably use a list rather than map
    protected boolean setStandardQueryParams(HashMap params)
    {
    // set the default ones
    this.mg_src.setReturnTerms(true);
    this.mg_src.setCase(true); // turn casefolding on by default
    Set entries = params.entrySet();
    Iterator i = entries.iterator();
    while (i.hasNext()) {
        Map.Entry m = (Map.Entry)i.next();
        String name = (String)m.getKey();
        String value = (String)m.getValue();

        if (name.equals(CASE_PARAM)) {
        boolean val = (value.equals(BOOLEAN_PARAM_ON) ? true : false);
        this.mg_src.setCase(val);
        }
        else if (name.equals(STEM_PARAM)) {
        boolean val = (value.equals(BOOLEAN_PARAM_ON) ? true : false);
        this.mg_src.setStem(val);
        }
        else if (name.equals(MATCH_PARAM)) {
        int mode = (value.equals(MATCH_PARAM_ALL) ? 1 : 0);
        this.mg_src.setMatchMode(mode);
        }
        else if (name.equals(MAXDOCS_PARAM)) {
        int docs = Integer.parseInt(value);
        this.mg_src.setMaxDocs(docs);
        } // ignore any others
    }
    return true;
    }

    /** convert MG internal id to Greenstone oid */
    abstract protected String MGNum2OID(long docnum);
}