source: main/trunk/greenstone3/src/java/org/greenstone/gsdl3/service/AbstractSearch.java@ 24394

/*
 *    AbstractSearch.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.util.GSXML;
import org.greenstone.gsdl3.util.GSPath;
import org.greenstone.gsdl3.util.AbstractSimpleDocument;
import org.greenstone.gsdl3.util.SimpleDocument;

// XML classes
import org.w3c.dom.Document;
import org.w3c.dom.Element; 
import org.w3c.dom.NodeList;

// java classes
import java.util.ArrayList;
import java.util.HashMap;

import org.apache.log4j.*;

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

public abstract class AbstractSearch
    extends ServiceRack 
{

    static Logger logger = Logger.getLogger(org.greenstone.gsdl3.service.AbstractSearch.class.getName());

    // the search service
    protected String QUERY_SERVICE = null; // set by subclass 
    
    // compulsory params
    protected static final String INDEX_PARAM = "index";
    protected static final String QUERY_PARAM = "query";

    // optional standard params - some of these have to be implemented
    protected static final String MAXDOCS_PARAM = "maxDocs";
    protected static final String HITS_PER_PAGE_PARAM = "hitsPerPage";
    protected static final String START_PAGE_PARAM = "startPage";

    protected AbstractSimpleDocument gs_doc = null;

    /** can more than one index be searched at the same time? */
    protected boolean does_multi_index_search = false;
    /** does this service support paging of results? */
    protected boolean does_paging = false;
    /** does this service support asking for a subset of results? */
    protected boolean does_chunking = false;
    /** the default document type - use if all documents are the same type
     */
    protected String default_document_type = null;
    /** the default index, or comma separated list if more than one is 
     * the default (with start and end commas, eg ,TI,SU,). 
     * Should be set by configure()
     */
    protected String default_index = "";

    protected String default_max_docs = "100";
    
    protected String default_hits_per_page = "10";
 
    public AbstractSearch()
    {
    }

    /** Sets up the short service info for service by QUERY_SERVICE 
     *    (e.g. TextQuery or AudioQuery)
     *  If other services will be provided, should be added in the
     *  subclass configure also looks for search format info, and
     *  document format info
     */
    public boolean configure(Element info, Element extra_info)
    {
    if (!super.configure(info, extra_info)){
        return false;
    }

    logger.info("Configuring AbstractSearch...");
    
    this.config_info = info;

    // set up short_service_info_ 
    // => for now just has id and type. the name (lang dependent)
    //    will be added in if the list is requested.

    Element tq_service = this.doc.createElement(GSXML.SERVICE_ELEM);
    tq_service.setAttribute(GSXML.TYPE_ATT, GSXML.SERVICE_TYPE_QUERY);
    tq_service.setAttribute(GSXML.NAME_ATT, QUERY_SERVICE);
    this.short_service_info.appendChild(tq_service);

    // add some format info to service map if there is any 
    // => lookin extra info first look in buildConfig

    Element format = (Element)GSXML.getChildByTagName(info, GSXML.FORMAT_ELEM);

    if (format==null) {
        String path = GSPath.appendLink(GSXML.SEARCH_ELEM, GSXML.FORMAT_ELEM);

        // Note by xiao: instead of retrieving the first 'format'
        //   element inside the 'search' element, we are trying to
        //   find the real format element which has at least one
        //   'gsf:template' child element. (extra_info is
        //   collectionConfig.xml)

        //format = (Element) GSXML.getNodeByPath(extra_info, path);
      
        Element search_elem = (Element) GSXML.getChildByTagName(extra_info, GSXML.SEARCH_ELEM);
        NodeList format_elems = null;
        if (search_elem != null) {
        format_elems = search_elem.getElementsByTagName(GSXML.FORMAT_ELEM);
        }
        for(int i=0; i<format_elems.getLength(); i++) {
        format = (Element)format_elems.item(i);
        if (format.getElementsByTagName("gsf:template").getLength() != 0) {
            break;
        }
        }
    }//end of if(format==null)
    //
    if (format != null) {
        this.format_info_map.put(QUERY_SERVICE, this.doc.importNode(format, true));
    }
    
    // look for document display format - for documentType
    String path = GSPath.appendLink(GSXML.DISPLAY_ELEM, GSXML.FORMAT_ELEM);
    Element display_format = (Element)GSXML.getNodeByPath(extra_info, path);
    if (display_format != null) {
        // check for docType option.
        Element doc_type_opt = GSXML.getNamedElement(display_format, "gsf:option", GSXML.NAME_ATT, "documentType");
        if (doc_type_opt != null) {
        String value = doc_type_opt.getAttribute(GSXML.VALUE_ATT);
        if (!value.equals("")) {
            this.default_document_type = value;
        }
        }
    }

    // Base line for document (might be overriden by sub-classes)
    gs_doc = new SimpleDocument(this.doc,this.default_document_type);

    return true;
    }
    
    /** returns a basic description for QUERY_SERVICE. If a subclass 
     * provides other services they need to provide their own descriptions */
    protected Element getServiceDescription(String service, String lang, String subset) 
    {
    if (!service.equals(QUERY_SERVICE)) {
        return null;
    }

    Element tq_service = this.doc.createElement(GSXML.SERVICE_ELEM);
    tq_service.setAttribute(GSXML.TYPE_ATT, GSXML.SERVICE_TYPE_QUERY);
    tq_service.setAttribute(GSXML.NAME_ATT, QUERY_SERVICE);
    if (subset==null || subset.equals(GSXML.DISPLAY_TEXT_ELEM+GSXML.LIST_MODIFIER)) {
        tq_service.appendChild(GSXML.createDisplayTextElement(this.doc, GSXML.DISPLAY_TEXT_NAME, getServiceName(QUERY_SERVICE, lang) ));
        tq_service.appendChild(GSXML.createDisplayTextElement(this.doc, GSXML.DISPLAY_TEXT_SUBMIT, getServiceSubmit(QUERY_SERVICE, lang) ));
        tq_service.appendChild(GSXML.createDisplayTextElement(this.doc, GSXML.DISPLAY_TEXT_DESCRIPTION, getServiceDescription(QUERY_SERVICE, lang)));
    }
    if (subset==null || subset.equals(GSXML.PARAM_ELEM+GSXML.LIST_MODIFIER)) {
        Element param_list = this.doc.createElement(GSXML.PARAM_ELEM+GSXML.LIST_MODIFIER);
        addCustomQueryParams(param_list, lang);
        addStandardQueryParams(param_list, lang);
        tq_service.appendChild(param_list);
    }
    return tq_service;
    
    }

    // perhaps these should be changed to search down the class hierarchy for 
    // values - do can just put the info in the resource bundle to use it
    /** returns the default name for the TextQuery service */
    protected String getServiceName(String service_id, String lang) {
    return getTextString(service_id+".name", lang);
    }
    
    /** returns the default description for the TextQuery service */
    protected String getServiceDescription(String service_id, String lang) {
    return getTextString(service_id+".description", lang);
    }

    /** returns the default submit button text for the TextQuery service */
    protected String getServiceSubmit(String service_id, String lang) {
    return getTextString(service_id+".submit", lang);

    }
    /** adds the standard query params into the service description */
    protected void addStandardQueryParams(Element param_list, String lang) 
    {
      // this test is not so good. here we are using absence of default index
      // to determine whether we have indexes or not. But in other places,
      // absence of default index just means to use the first one as default.
    if (!default_index.equals("")){
        createParameter(INDEX_PARAM, param_list, lang);
    }
    if (does_chunking) {
        createParameter(MAXDOCS_PARAM, param_list, lang);
    }
    if (does_paging) {
        createParameter(HITS_PER_PAGE_PARAM, param_list, lang);
        createParameter(START_PAGE_PARAM, param_list, lang);
    }
    createParameter(QUERY_PARAM, param_list, lang);
    }

    /** adds any service specific query params into the service
     *  default implementation: add nothing. subclasses may need to 
     * override this to add in their specific parameters
     */
    protected void addCustomQueryParams(Element param_list, String lang) 
    {
    // default behaviour, do nothing
    }
    
    protected void createParameter(String name, Element param_list, String lang) 
    {
    createParameter(name, param_list, lang, null);
    }

     protected void createParameter(String name, Element param_list, String lang, String default_value) 
    {
    // at this level, not interested in boolean return type
    createParameterChain(name,param_list,lang,default_value);
    }


    /** default implementations for the standard parameters plus some
     * other common ones index, maxDocs, hitsPerPage, startPage
    */

     protected boolean createParameterChain(String name, Element param_list, String lang, String default_value) 
    {
    Element param = null;
    String param_default = default_value;

    if (name.equals(QUERY_PARAM)) {
        param = GSXML.createParameterDescription(this.doc, QUERY_PARAM, getTextString("param."+QUERY_PARAM, lang), GSXML.PARAM_TYPE_STRING, param_default, null, null);
        param_list.appendChild(param);
        return true;
    } else if (name.equals(INDEX_PARAM)) {

        // should we make these class fields?
        ArrayList index_ids = new ArrayList();
        ArrayList index_names = new ArrayList();
        getIndexData(index_ids, index_names, lang);
        String param_type = GSXML.PARAM_TYPE_ENUM_SINGLE;
        if (does_multi_index_search) {
        param_type = GSXML.PARAM_TYPE_ENUM_MULTI;
        }
        if (param_default == null) {
          param_default = this.default_index;
        }
        param = GSXML.createParameterDescription2(this.doc, INDEX_PARAM, getTextString("param."+INDEX_PARAM, lang), param_type, param_default, index_ids, index_names);
        param_list.appendChild(param);
        return true;
    }
        else if (name.equals(MAXDOCS_PARAM)) {
        if (param_default == null) {
        param_default = this.default_max_docs;
        }
      
        param = GSXML.createParameterDescription(this.doc, name, getTextString("param."+name, lang), GSXML.PARAM_TYPE_INTEGER, param_default, null, null);
        param_list.appendChild(param);
        return true;
    }
    else if(name.equals(HITS_PER_PAGE_PARAM)){
        if (param_default == null) {
        param_default = this.default_hits_per_page;
        }
      
        param = GSXML.createParameterDescription(this.doc, name, getTextString("param."+name, lang), GSXML.PARAM_TYPE_INTEGER, param_default, null, null);
        param_list.appendChild(param);
        return true;
    } else if (name.equals(START_PAGE_PARAM)) {
        if (param_default == null) {
        param_default = "1";
        }
        
        // start page - set to 1 for the search page
        param = GSXML.createParameterDescription(this.doc, START_PAGE_PARAM, "", GSXML.PARAM_TYPE_INVISIBLE, param_default, null, null);
        param_list.appendChild(param);
        return true;
    }

    // Get to there then none of the above params matched
    // => return false so the chain can continue
    return false;
    }


    /** create an element to go into the search results list. A node element
     * has the form
     * <docNode nodeId='xxx' nodeType='leaf' docType='hierarchy' rank='0.23'/>
     */
    protected Element createDocNode(String node_id, String rank) 
    {
    return this.gs_doc.createDocNode(node_id,rank);
    }

    /** returns the document type of the doc that the specified node 
    belongs to. should be one of 
    GSXML.DOC_TYPE_SIMPLE, 
    GSXML.DOC_TYPE_PAGED, 
    GSXML.DOC_TYPE_HIERARCHY
    */
    protected String getDocType(String node_id){
    return this.gs_doc.getDocType(node_id);
    }

    /** returns the node type of the specified node.
    should be one of 
    GSXML.NODE_TYPE_LEAF, 
    GSXML.NODE_TYPE_INTERNAL, 
    GSXML.NODE_TYPE_ROOT
    */
    protected String getNodeType(String node_id, String doc_type) 
    {
    return this.gs_doc.getNodeType(node_id,doc_type);
    }
    
    /** returns true if the node has child nodes */
    protected boolean hasChildren(String node_id)
    {
    return this.gs_doc.hasChildren(node_id);
    }
    
    /** returns true if the node has a parent */
    protected boolean hasParent(String node_id)
    {
    return this.gs_doc.hasParent(node_id);
    }


    /** get the details about the indexes available
     * must be implemented by subclass
     * there must be at least one index */
    abstract protected void getIndexData(ArrayList index_ids, ArrayList index_names, String lang);

}