source: trunk/gsdl3/src/java/org/greenstone/gsdl3/action/QueryAction.java@ 3999

package org.greenstone.gsdl3.action;

import org.greenstone.gsdl3.core.ModuleInterface;
import org.greenstone.gsdl3.util.*;
// XML classes
import org.w3c.dom.Node; 
import org.w3c.dom.NodeList; 
import org.w3c.dom.Text; 
import org.w3c.dom.Document; 
import org.w3c.dom.Element; 

import java.util.HashMap;
import java.util.Map;
import java.util.Iterator;
import java.io.File;

/** action class for queries */
public class QueryAction extends Action {
    
    /** process - processes a request.
     */ 
    public Element process (Element message) {

    // get the request - assume there is only one
    Element request = (Element)GSXML.getChildByTagName(message, GSXML.REQUEST_ELEM);

    // create the return page tree
    Element page = doc_.createElement(GSXML.PAGE_ELEM);
    page.setAttribute(GSXML.LANG_ATT, request.getAttribute(GSXML.LANG_ATT));
    // add the lang stuff from message
    page.appendChild(doc_.importNode(GSXML.getChildByTagName(message, GSXML.DISPLAY_ELEM), true));
    // add the system stuff from message
       page.appendChild(doc_.importNode(GSXML.getChildByTagName(message, GSXML.CONFIGURATION_ELEM), true));

       // if want to have a different type of query here, check the subaction att of request

       // for now assume all queries can be handled by basic query
       return basicQuery(page, request);
       
    }
    
    /** a generic query handler 
     * this gets the service description, does the query (just passes all teh 
     * params to the service, then gets the titles for any results 
     */
    protected Element basicQuery(Element page, Element request) {

    // check that the stylesheet is present - cant output the page without one. 
    String stylesheet = GSFile.stylesheetFile(config_, "basicquery.xsl");
    if (stylesheet==null) {
        System.err.println("QueryAction Error: basicquery stylesheet not found!");
        return null;
    }
    Document style_doc = converter_.getDOM(new File(stylesheet));

    // part of the data for the page is the cgi-params
    // if we have this here, do we need to overwrite default values in the 
    // param list down below??
    Element page_request = GSXML.duplicateWithNewName(doc_, request, "pageRequest", true);
    page.appendChild(page_request);

    // extract the params from the cgi-request, and check that we have a coll specified
    Element cgi_param_list = (Element)GSXML.getChildByTagName(request, GSXML.PARAM_ELEM+GSXML.LIST_MODIFIER);
    HashMap params = GSXML.extractParams(cgi_param_list, false);
    
    String request_type = (String)params.get(GSCGI.REQUEST_TYPE_ARG);
    String service_name = (String)params.get(GSCGI.SERVICE_ARG);
    String collection = (String)params.get(GSCGI.COLLECTION_ARG);
    if (collection == null || collection.equals("")) {
        System.err.println("QueryAction Error: no collection was specified!");
        return null; 
    }
    
    String lang = request.getAttribute(GSXML.LANG_ATT);
    String to = GSPath.appendLink(collection, service_name);

    //create teh pageREsponse
    Element page_response = doc_.createElement(GSXML.PAGE_RESPONSE_ELEM);
    page.appendChild(page_response);
    
    // the second part of the page is the service description 
    // for now get this again from the service. 
    // this will probably need to be cached somehow later on. 
    Element mr_info_message = doc_.createElement(GSXML.MESSAGE_ELEM);
    Element mr_info_request = GSXML.createBasicRequest(doc_, GSXML.REQUEST_TYPE_DESCRIBE,  to, lang);
    mr_info_message.appendChild(mr_info_request);

    // also get the format stuff now if there is some
    Element format_request = GSXML.createBasicRequest(doc_, GSXML.REQUEST_TYPE_FORMAT, to, lang);
    mr_info_message.appendChild(format_request);

    // also get the coll description
    Element coll_about_request = GSXML.createBasicRequest(doc_, GSXML.REQUEST_TYPE_DESCRIBE,  collection, lang);
    mr_info_message.appendChild(coll_about_request);

    // process the messages
    Element mr_info_response = (Element) mr_.process(mr_info_message);
    
    // the three responses
    NodeList responses = mr_info_response.getElementsByTagName(GSXML.RESPONSE_ELEM);
    Element service_response = (Element)responses.item(0);
    Element format_response = (Element)responses.item(1);
    Element coll_response = (Element)responses.item(2);
    
    Element service_description = (Element)doc_.importNode(GSXML.getChildByTagName(service_response, GSXML.SERVICE_ELEM), true);
    page_response.appendChild(service_description);
    
    Element pl = (Element)GSXML.getChildByTagName(service_description, GSXML.PARAM_ELEM+GSXML.LIST_MODIFIER);
    
    if (pl !=null) {
        // add short names to the params in the param list
        cgi_.paramListAddShortNames(pl);
        // for each param in the description, overwrite teh default value with the currently set value if present 
        Element param = (Element)pl.getFirstChild();
        while (param !=null) {
        if (param.getNodeName().equals(GSXML.PARAM_ELEM)) { // just in case
            if (param.getAttribute(GSXML.TYPE_ATT).equals(GSXML.PARAM_TYPE_MULTI)) {
            // get the values for each sub param
            NodeList subparams = param.getElementsByTagName(GSXML.PARAM_ELEM);
            for (int i=0; i<subparams.getLength(); i++) {
                String name = ((Element)subparams.item(i)).getAttribute(GSXML.NAME_ATT);
                String current = (String)params.get(name);
                if (current !=null && !current.equals("")) {
                Element e = GSXML.createTextElement(pl.getOwnerDocument(), GSXML.DEFAULT_ELEM, current);
                e.setAttribute(GSXML.NAME_ATT, name);
                param.appendChild(e);
                }
            }
            } else {
            
            String name = param.getAttribute(GSXML.NAME_ATT);
            String current = (String)params.get(name);
            if (current !=null && !current.equals("")) {
                param.setAttribute(GSXML.DEFAULT_ATT, current);
            }
            }
        }
        param = (Element)param.getNextSibling();
        }
    }

    
    // add the coll-response to the page 
    Element coll_description = (Element)GSXML.getChildByTagName(coll_response, GSXML.COLLECTION_ELEM);
    page_response.appendChild(doc_.importNode(coll_description, true));


    // just a display request
    if (request_type.equals("d")) {
        System.out.println("(QueryAction) Finished page:\n" + converter_.getPrettyString(page));
        // output the page
        // process using the stylesheet
        GSXSLT.absoluteIncludePaths(style_doc, config_);
        return (Element)transformer_.transform(style_doc, page);    
    }
    
    // do the query
    Element mr_query_message = doc_.createElement(GSXML.MESSAGE_ELEM);
    Element mr_query_request = GSXML.createBasicRequest(doc_, GSXML.REQUEST_TYPE_PROCESS, to, page.getAttribute(GSXML.LANG_ATT));
    mr_query_message.appendChild(mr_query_request);
    
    // paramList
    Element query_param_list = (Element)doc_.importNode(cgi_param_list, true);
    mr_query_request.appendChild(query_param_list);
        Element mr_query_response = (Element)mr_.process(mr_query_message);

    String path = GSPath.appendLink(GSXML.RESPONSE_ELEM, GSXML.METADATA_ELEM+GSXML.LIST_MODIFIER);
    Element query_result_metadata_list = (Element) GSXML.getNodeByPath(mr_query_response, path);
    if (query_result_metadata_list == null) {
        System.err.println("QueryAction: Warning: No query result metadata.\n");
    }
    path = GSPath.appendLink(GSXML.RESPONSE_ELEM, GSXML.TERM_ELEM+GSXML.LIST_MODIFIER);
    Element query_term_info_list = (Element) GSXML.getNodeByPath(mr_query_response, path);
    if (query_term_info_list == null) {
        System.err.println("QueryAction: Warning: No query term information.\n");
    }

    // this result is the list of docs.
    // now take that list, and get the Titles
    // for now, just create a whole new request
    
    // check that there are some documents - for now check the list, but later should use a numdocs metadata elem
    path = GSPath.appendLink(GSXML.RESPONSE_ELEM, GSXML.DOC_NODE_ELEM+GSXML.LIST_MODIFIER);
    
    Element document_list = (Element)GSXML.getNodeByPath(mr_query_response,
                                 path); 
    // documentList not present if no docs found
    if (document_list == null) {
        
        //Element result_response = (Element)GSXML.getChildByTagName(mr_query_response, GSXML.RESPONSE_ELEM);

        //page.appendChild(doc_.importNode(result_response, true));
        GSXSLT.absoluteIncludePaths(style_doc, config_);
        return (Element)transformer_.transform(style_doc, page);    
        
    }
    
    // add in the format info
    Element format_elem = getAndTransformFormat(format_response);
    if (format_elem != null) {
        GSXSLT.mergeStylesheets(style_doc, format_elem);
    }

    // we have a doc list, so get the metadata - for now, get title.
    // can we dynamically decide what metadata to get?
    Element mr_metadata_message = doc_.createElement(GSXML.MESSAGE_ELEM);
    Element mr_metadata_request = doc_.createElement(GSXML.REQUEST_ELEM);
    mr_metadata_message.appendChild(mr_metadata_request);
    
    mr_metadata_request.setAttribute(GSXML.TYPE_ATT, GSXML.REQUEST_TYPE_PROCESS);
    mr_metadata_request.setAttribute(GSXML.LANG_ATT, page.getAttribute(GSXML.LANG_ATT));
    to = GSPath.appendLink(collection, "DocumentMetadataRetrieve"); // Hard-wired?
    mr_metadata_request.setAttribute(GSXML.TO_ATT, to);

    // Create a parameter list to specify the required metadata information
    Element dm_param_list = doc_.createElement(GSXML.PARAM_ELEM+GSXML.LIST_MODIFIER);
    mr_metadata_request.appendChild(dm_param_list);
    Element dm_param = doc_.createElement(GSXML.PARAM_ELEM);
    dm_param_list.appendChild(dm_param);
    dm_param.setAttribute(GSXML.NAME_ATT, "metadata");
    dm_param.setAttribute(GSXML.VALUE_ATT, "Title");

    mr_metadata_request.appendChild(doc_.importNode(document_list, true));
    Element mr_metadata_response = (Element) mr_.process(mr_metadata_message);  

    path = GSPath.appendLink(GSXML.RESPONSE_ELEM, GSXML.DOC_NODE_ELEM+GSXML.LIST_MODIFIER);
    Element query_result_document_list = (Element) GSXML.getNodeByPath(mr_metadata_response, path);

    if (query_result_document_list != null) {
        page_response.appendChild(doc_.importNode(query_result_document_list, true));
    }
    // If there is some metadata about the query results, add it in
    if (query_result_metadata_list != null) {
        page_response.appendChild(doc_.importNode(query_result_metadata_list, true));
    }
    // If there is some metadata about the query results, add it in
    if (query_term_info_list != null) {
        page_response.appendChild(doc_.importNode(query_term_info_list, true));
    }

    // System.out.println("Query page:\n" + converter_.getPrettyString(page));

    // output the page
    // process using the stylesheet
    GSXSLT.absoluteIncludePaths(style_doc, config_);
    return (Element)transformer_.transform(style_doc, page);
    }
}