source: trunk/gsdl3/src/java/org/greenstone/gsdl3/service/GS2LuceneRetrieve.java@ 13916

/*
 *    GS2LuceneRetrieve.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.gsdl3.core.GSException;
import org.greenstone.gsdl3.util.GSFile;
import org.greenstone.gsdl3.util.GSXML;
import org.greenstone.gsdl3.util.GDBMWrapper;
import org.greenstone.gsdl3.util.DBInfo;
import org.greenstone.gsdl3.util.GSHTML;
import org.greenstone.gsdl3.util.OID;
// XML classes
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Text;

// General Java classes
import java.io.File;

import org.apache.log4j.Logger;

/** Retrieve documents from a gs2 lucene collection. Note that this doesn't 
    actually use lucene, as the documents are stored in XML files */
public class GS2LuceneRetrieve
    extends AbstractGS2DocumentRetrieve
{
    
    static Logger logger = Logger.getLogger(org.greenstone.gsdl3.service.GS2LuceneRetrieve.class.getName());
    
    
    protected static final String DOC_LEVEL="Doc";
    protected static final String SEC_LEVEL="Sec";
    protected static final String ID_ATT = "gs2:id";

    // Parameters used
    private static final String LEVEL_PARAM = "level";
    
    // Elements used in the config file that are specific to this class
    private static final String DEFAULT_LEVEL_ELEM = "defaultLevel";
    
    private String default_level = null;
    private String text_dir = null;

    private boolean text_available = true;
    
    public GS2LuceneRetrieve() {
    }
    
    public void cleanUp() {
    super.cleanUp();
    }
    
    /** configure this service */
    public boolean configure(Element info, Element extra_info)
    {
    if (!super.configure(info, extra_info)){
        return false;
    }
    
    // Do specific configuration
    logger.info("Configuring GS2LuceneRetrieve...");
    
    text_dir = GSFile.collectionIndexDir(this.site_home, this.cluster_name) + File.separatorChar+"text"+File.separatorChar;
    if (!(new File(text_dir).isDirectory())) {
        logger.error("Text directory "+text_dir+" does not exist, will be unable to retrieve text for "+cluster_name);
        text_available = false;
        return true; // return true so that we still get the other services for the collection
    }
    // Get the default level out of <defaultLevel> (buildConfig.xml)
    Element def = (Element) GSXML.getChildByTagName(info, DEFAULT_LEVEL_ELEM);
    if (def != null) {
        this.default_level = def.getAttribute(GSXML.SHORTNAME_ATT);
    }
    if (this.default_level == null || this.default_level.equals("")) {
        logger.error("Default level not specified for "+this.cluster_name+", assuming "+DOC_LEVEL);
        this.default_level = DOC_LEVEL;
    }
    
    return true;
    
    }
    
    /** returns the content of a node
     * should return a nodeContent element:
     * <nodeContent>text content or other elements</nodeContent>
     */
    protected Element getNodeContent(String doc_id, String lang) throws GSException {   
    String doc_content = getTextString("TextRetrievalError", lang);
    try {
        if (!text_available) {
        throw new Exception("No text directory available");
        }
        
        long doc_num = this.gdbm_src.OID2Docnum(doc_id);
        if (doc_num == -1) {
        throw new Exception("OID "+doc_id +" couldn't be converted to lucene doc num");
        }
    
        DBInfo info=this.gdbm_src.getInfo(OID.getTop(doc_id));
        if (info == null) {
        throw new Exception("Couldn't get GDBM database entry for "+OID.getTop(doc_id));
        }
        
        String archivedir=info.getInfo("archivedir");
        File doc_xml_file = new File(text_dir+archivedir+File.separatorChar+"doc.xml");
        if (!doc_xml_file.isFile()) {
        throw new Exception("Doc XML file "+doc_xml_file.getPath()+" does not exist");
        }
        Document doc_xml_doc = this.converter.getDOM(doc_xml_file);
        if (doc_xml_doc == null) {
        throw new Exception("Couldn't parse file "+doc_xml_file.getPath());
        }
        Element full_document = doc_xml_doc.getDocumentElement();
        if (full_document == null) {
        throw new Exception("Couldn't parse file "+doc_xml_file.getPath());
        }
        Element current_section = null;
        if (default_level.equals(DOC_LEVEL)) {
        current_section = full_document;
        } else {
        current_section = GSXML.getNamedElement(full_document, SEC_LEVEL, ID_ATT, String.valueOf(doc_num));
        }
        if (current_section == null) {
        throw new Exception("Couldn't find section "+ doc_num+" in file "+doc_xml_file.getPath());
        }
        doc_content = GSXML.getNodeText(current_section);
        if (doc_content == null) {
        doc_content = "";
        } else {
        doc_content = resolveTextMacros(doc_content, doc_id, lang);
        } 
    } catch (Exception e) {
        logger.error("Error trying to get document text for "+doc_id+" in collection "+this.cluster_name+": "+e);
    }
    
    Element content_node = this.doc.createElement(GSXML.NODE_CONTENT_ELEM);
    Text t = this.doc.createTextNode(doc_content);
    content_node.appendChild(t);
    return content_node;
    }
}