source: trunk/gsdl3/src/java/org/greenstone/gsdl3/action/QueryAction.java@ 3645

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));

    // query type is the subaction
    String query_type = request.getAttribute(GSXML.SUBACTION_ATT) + "Query";
    
    // for now assume all queries can be handled by basic query
    return basicQuery(page, request, query_type);
    
    }
    
    /** 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, String service_name) {

    // 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;
    }

    // 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);

    String collection = (String)params.get(GSCGI.COLLECTION_ARG);
    if (collection == null || collection.equals("")) {
        System.err.println("QueryAction Error: no collection was specified!");
        return null; 
    }

    // get the service info from the MR - this will probably need to be cached somehow later on. and add the service node to the page 
    Element mr_info_message = doc_.createElement(GSXML.MESSAGE_ELEM);
    Element mr_info_request = doc_.createElement(GSXML.REQUEST_ELEM);
    mr_info_message.appendChild(mr_info_request);
    mr_info_request.setAttribute(GSXML.TYPE_ATT, GSXML.REQUEST_TYPE_DESCRIBE);
    mr_info_request.setAttribute(GSXML.LANG_ATT, page.getAttribute(GSXML.LANG_ATT));

    String to = collection;
    to = GSPath.appendLink(to, service_name);
    mr_info_request.setAttribute(GSXML.TO_ATT, to);

    Element mr_info_response = (Element) mr_.process(mr_info_message);
    String path = GSXML.RESPONSE_ELEM;
    path = GSPath.appendLink(path, GSXML.SERVICE_ELEM);
    Element description = (Element)doc_.importNode(GSXML.getNodeByPath(mr_info_response, path), true);
    Element pl = (Element)GSXML.getChildByTagName(description, GSXML.PARAM_ELEM+GSXML.LIST_MODIFIER);
    
    if (pl !=null) {
        System.out.println("adding shortnames");
        // 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();
        }
    }
    
    // part of the data for the description is the cgi-params
    // if we have this here, do we need to do the previous step?
    Element cgi_request = (Element)doc_.importNode(request, true);
    page.appendChild(cgi_request);

    page.appendChild(description);

    // now we always do the query - we have no way of knowing whether 
    // a query was specified or not cos we cant assume that q is the 
    // query string - maybe we could check that any required params have
    // a value??
    
    Element mr_query_message = doc_.createElement(GSXML.MESSAGE_ELEM);
    Element mr_query_request = doc_.createElement(GSXML.REQUEST_ELEM);
    mr_query_message.appendChild(mr_query_request);
    
    mr_query_request.setAttribute(GSXML.TYPE_ATT, GSXML.REQUEST_TYPE_QUERY);
    mr_query_request.setAttribute(GSXML.TO_ATT, to);
    mr_query_request.setAttribute(GSXML.LANG_ATT, page.getAttribute(GSXML.LANG_ATT));
    // 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);
        
    // 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 = GSXML.RESPONSE_ELEM;
    path = GSPath.appendLink(path, GSXML.CONTENT_ELEM);
    path = GSPath.appendLink(path, GSXML.DOCUMENT_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));
        
        Document style_doc = converter_.getDOM(new File(stylesheet));
        GSXSLT.absoluteIncludePaths(style_doc, config_);
        return (Element)transformer_.transform(style_doc, page);    
        
    }
    
    // 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_QUERY);
    mr_metadata_request.setAttribute(GSXML.LANG_ATT, page.getAttribute(GSXML.LANG_ATT));
    to = GSPath.appendLink(collection, "MetadataRetrieve");
    mr_metadata_request.setAttribute(GSXML.TO_ATT, to);
    
    Element meta_content = doc_.createElement(GSXML.CONTENT_ELEM);
    mr_metadata_request.appendChild(meta_content);
    
    // the first part of the content is the doc list
    meta_content.appendChild(doc_.importNode(document_list, true));
    
    // the second part of the content is the metadata list
    Element metadata_list = doc_.createElement(GSXML.METADATA_ELEM+GSXML.LIST_MODIFIER);
    Element title = doc_.createElement(GSXML.METADATA_ELEM);
    title.setAttribute(GSXML.NAME_ATT, "Title");
    metadata_list.appendChild(title);
    meta_content.appendChild(metadata_list);
    
    Element mr_metadata_response = (Element)mr_.process(mr_metadata_message);
    
    Element result_response = (Element)GSXML.getChildByTagName(mr_metadata_response, GSXML.RESPONSE_ELEM);
    
    page.appendChild(doc_.importNode(result_response, true));
    
    
    // output the page
    // process using the stylesheet
    Document style_doc = converter_.getDOM(new File(stylesheet));
    GSXSLT.absoluteIncludePaths(style_doc, config_);
    return (Element)transformer_.transform(style_doc, page);    
    
    }


}