source: main/trunk/greenstone3/src/java/org/greenstone/gsdl3/core/DefaultReceptionist.java@ 32549

package org.greenstone.gsdl3.core;

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

// other java classes
import java.io.File;
import java.util.HashMap;
import java.util.Enumeration;

import org.apache.log4j.*;

/** The default greenstone receptionist - needs some extra info for each page */
public class DefaultReceptionist extends TransformingReceptionist
{

    static Logger logger = Logger.getLogger(org.greenstone.gsdl3.core.DefaultReceptionist.class.getName());

    /**
     * add in the collection description to the page, then for each service, add
     * in the service description
     */
    protected void addExtraInfo(Element page)
    {
        super.addExtraInfo(page);
        // the document for the page
        Document doc = page.getOwnerDocument();
        // a new document to create messages to send to MR
        Document msg_doc = XMLConverter.newDOM();
        Element page_request = (Element) GSXML.getChildByTagName(page, GSXML.PAGE_REQUEST_ELEM);
        // if it is a system request, then we don't bother with this.
        String action = page_request.getAttribute(GSXML.ACTION_ATT);
        if (action.equals("s"))
        {
            logger.error("HACK: don't ask for coll info if system action");
            return;
        }
        logger.debug("add extra info, page request=" + this.converter.getString(page_request));
        // is a collection defined?
        Element param_list = (Element) GSXML.getChildByTagName(page_request, GSXML.PARAM_ELEM + GSXML.LIST_MODIFIER);
        if (param_list == null)
        { // must be the original home page
            logger.debug(" no param list, assuming home page");
            return;
        }
        Element coll_param = GSXML.getNamedElement(param_list, GSXML.PARAM_ELEM, GSXML.NAME_ATT, GSParams.COLLECTION);
        if (coll_param == null)
        {
            logger.debug(" coll param is null, returning");
            return;
        }

        // see if the collection/cluster element is already there
        String coll_name = coll_param.getAttribute(GSXML.VALUE_ATT);
        UserContext userContext = new UserContext(page_request);

        if (coll_name.equals(""))
        {
            Element pc_param = GSXML.getNamedElement(param_list, GSXML.PARAM_ELEM, GSXML.NAME_ATT, "p.c");
            if (pc_param != null)
            {
                coll_name = pc_param.getAttribute(GSXML.VALUE_ATT);
            }
        }

        boolean get_service_description = false;
        Element page_response = (Element) GSXML.getChildByTagName(page, GSXML.PAGE_RESPONSE_ELEM);

        Element coll_description = (Element) GSXML.getChildByTagName(page_response, GSXML.COLLECTION_ELEM);
        if (coll_description == null)
        {
            // try cluster
            coll_description = (Element) GSXML.getChildByTagName(page_response, GSXML.CLUSTER_ELEM);
        }
        if (coll_description == null)
        {
          logger.debug("getting the coll description");
            // we dont have one yet - get it

            Element coll_about_message = msg_doc.createElement(GSXML.MESSAGE_ELEM);
            Element coll_about_request = GSXML.createBasicRequest(msg_doc, GSXML.REQUEST_TYPE_DESCRIBE, coll_name, userContext);
            coll_about_message.appendChild(coll_about_request);

            Node coll_about_response_message = this.mr.process(coll_about_message);
            Element coll_about_response = (Element) GSXML.getChildByTagName(coll_about_response_message, GSXML.RESPONSE_ELEM);
            if (coll_about_response == null)
            {
                return;
            }
            coll_description = (Element) GSXML.getChildByTagName(coll_about_response, GSXML.COLLECTION_ELEM);
            if (coll_description == null)
            { // may be a cluster
                coll_description = (Element) GSXML.getChildByTagName(coll_about_response, GSXML.CLUSTER_ELEM);
            }

            if (coll_description == null)
            {
                logger.error(" no collection description, returning");
                return;
            }
            // have found one, append it to the page response
            coll_description = (Element) doc.importNode(coll_description, true);
            page_response.appendChild(coll_description);
            get_service_description = true;
        }
        

        // have got a coll description
        // now get the dispay info for the services
        Element service_list = (Element) GSXML.getChildByTagName(coll_description, GSXML.SERVICE_ELEM + GSXML.LIST_MODIFIER);
        if (service_list == null)
        {
            logger.error(" no service list, returning");
            // something weird has gone wrong
            return;
        }

        NodeList services = service_list.getElementsByTagName(GSXML.SERVICE_ELEM);
        if (services.getLength() == 0)
        {
            logger.error("DefaultReceoptionist: no services found for colllection/cluster " + coll_name);
            return;
        }
        // check one service for display items
        if (!get_service_description)
        {
            // we dont know yet if we need to get these
            int i = 1;
            Element test_s = (Element) services.item(0);
            while (i < services.getLength() && (test_s.getAttribute(GSXML.TYPE_ATT).equals(GSXML.SERVICE_TYPE_RETRIEVE) || test_s.getAttribute(GSXML.TYPE_ATT).equals(GSXML.SERVICE_TYPE_OAI)))
            {
                test_s = (Element) services.item(i);
                i++;
            }
            if (i == services.getLength())
            {
                // we have only found retrieve or oai services, so dont need descripitons anyway
                return;
            }
            if (GSXML.getChildByTagName(test_s, GSXML.DISPLAY_TEXT_ELEM) != null)
            {
                // have got descriptions already, 
                return;
            }
        }

        // if get here, we need to get the service descriptions

        // we will send all the requests in a single message
        Element info_message = msg_doc.createElement(GSXML.MESSAGE_ELEM);
        for (int i = 0; i < services.getLength(); i++)
        {
            Element c = (Element) services.item(i);
            String name = c.getAttribute(GSXML.NAME_ATT);
            String address = GSPath.appendLink(coll_name, name);
            Element info_request = GSXML.createBasicRequest(msg_doc, GSXML.REQUEST_TYPE_DESCRIBE, address, userContext);
            //Element req_param_list = this.doc.createElement(GSXML.PARAM_ELEM+GSXML.LIST_MODIFIER);
            //req_param_list.appendChild(GSXML.createParameter(this.doc, GSXML.SUBSET_PARAM, GSXML.DISPLAY_TEXT_ELEM+GSXML.LIST_MODIFIER));
            //info_request.appendChild(req_param_list);
            info_message.appendChild(info_request);

        }

        Element info_response = (Element) this.mr.process(info_message);

        NodeList service_responses = info_response.getElementsByTagName(GSXML.RESPONSE_ELEM);
        // check that have same number of responses as collections
        if (services.getLength() != service_responses.getLength())
        {
            logger.error(" didn't get a response for each service - somethings gone wrong!");
            // for now, dont use the metadata
        }
        else
        {
            for (int i = 0; i < services.getLength(); i++)
            {
                Element c1 = (Element) services.item(i);
                Element c2 = (Element) GSXML.getChildByTagName((Element) service_responses.item(i), GSXML.SERVICE_ELEM);
                if (c1 != null && c2 != null && c1.getAttribute(GSXML.NAME_ATT).equals(c2.getAttribute(GSXML.NAME_ATT)))
                {
                    //add the service data into the original response
                    GSXML.mergeElements(c1, c2);
                }
                else
                {
                    logger.debug(" response does not correspond to request!");
                }

            }
        }
    }
}