source: main/trunk/greenstone3/src/java/org/greenstone/gsdl3/action/NoCollQueryAction.java@ 28964

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.HashSet;
import java.util.Vector;
import java.util.Map;
import java.util.Iterator;
import java.io.File;
import java.io.Serializable;

import org.apache.log4j.*;

/**
 * action class for queries this is used when querying isn't collection
 * specific, but it occurs across all collections in the site. The service
 * description is assumed to be known by the xslt so we dont ask for it. we just
 * pass all the service params to the TextQuery service of all the collections
 */
public class NoCollQueryAction extends Action
{

    static Logger logger = Logger.getLogger(org.greenstone.gsdl3.action.NoCollQueryAction.class.getName());

    /**
     * process - processes a request.
     */
    public Node process(Node message_node)
    {

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

        // create the return message
        Element result = doc.createElement(GSXML.MESSAGE_ELEM);
        // for now we only have one type of query - subaction not used
        Element response = basicQuery(request);
        result.appendChild(doc.importNode(response, true));
        return result;
    }

    /**
     * a generic query handler this gets the service description, does the query
     * (just passes all the params to the service, then gets the titles for any
     * results
     */
    protected Element basicQuery(Element request)
    {
        // the result
        Document doc = request.getOwnerDocument();
        
        Element page_response = doc.createElement(GSXML.RESPONSE_ELEM);

        // 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<String, Serializable> params = GSXML.extractParams(cgi_param_list, false);

        String request_type = (String) params.get(GSParams.REQUEST_TYPE);
        UserContext userContext = new UserContext(request);
        if (request_type.equals("d"))
        {
            // display the query page
            // the only info we need to return is the collection list cos the xslt does teh rest

            Element coll_list = getCollectionList(doc, userContext);
            page_response.appendChild(doc.importNode(coll_list, true));
            return page_response;

        }

        // else we have a query
        String service_name = (String) params.get(GSParams.SERVICE);
        if (service_name == null || service_name.equals(""))
        {
            service_name = "TextQuery";
        }
        String query_coll_list = (String) params.get(GSParams.COLLECTION);

        if (query_coll_list == null || query_coll_list.equals(""))
        {
            logger.error("no collections were specified!");
            Element coll_list = getCollectionList(doc,userContext);
            page_response.appendChild(doc.importNode(coll_list, true));
            return page_response;
        }

        // service paramList
        HashMap service_params = (HashMap) params.get("s1");
        if (service_params == null)
        { // no query
            return page_response;
        }
        Element query_param_list = doc.createElement(GSXML.PARAM_ELEM + GSXML.LIST_MODIFIER);
        GSXML.addParametersToList(query_param_list, service_params);

        // we will do a query for each coll
        String[] colls = query_coll_list.split(",");

        Element mr_query_message = doc.createElement(GSXML.MESSAGE_ELEM);

        for (int i = 0; i < colls.length; i++)
        {
            String to = GSPath.appendLink(colls[i], service_name);
            Element mr_query_request = GSXML.createBasicRequest(doc, GSXML.REQUEST_TYPE_PROCESS, to, userContext);
            mr_query_message.appendChild(mr_query_request);
            mr_query_request.appendChild(query_param_list.cloneNode(true));

        }

        // do the query
        Element mr_query_response = (Element) this.mr.process(mr_query_message);

        // get the Title metadata for each node - need Node title and root title
        Element mr_meta_message = doc.createElement(GSXML.MESSAGE_ELEM);
        NodeList responses = mr_query_response.getElementsByTagName(GSXML.RESPONSE_ELEM);
        for (int j = 0; j < responses.getLength(); j++)
        {
            Element document_list = (Element) GSXML.getChildByTagName((Element) responses.item(j), GSXML.DOC_NODE_ELEM + GSXML.LIST_MODIFIER);
            if (document_list != null)
            {
                String coll_name = extractCollName(((Element) responses.item(j)).getAttribute(GSXML.FROM_ATT));
                String path = GSPath.appendLink(coll_name, "DocumentMetadataRetrieve");
                Element mr_meta_request = GSXML.createBasicRequest(doc, GSXML.REQUEST_TYPE_PROCESS, path, userContext);
                mr_meta_message.appendChild(mr_meta_request);
                mr_meta_request.appendChild(doc.importNode(document_list, true));
                // metadata params 
                Element param_list = doc.createElement(GSXML.PARAM_ELEM + GSXML.LIST_MODIFIER);
                Element param = GSXML.createParameter(doc, "metadata", "Title");
                param_list.appendChild(param);
                param = GSXML.createParameter(doc, "metadata", "root_Title");
                param_list.appendChild(param);
                mr_meta_request.appendChild(param_list);

            }
        }

        // do the request
        Element mr_meta_response = (Element) this.mr.process(mr_meta_message);

        // the result 
        Element result_doc_list = doc.createElement(GSXML.DOC_NODE_ELEM + GSXML.LIST_MODIFIER);
        page_response.appendChild(result_doc_list);

        responses = mr_meta_response.getElementsByTagName(GSXML.RESPONSE_ELEM);
        for (int j = 0; j < responses.getLength(); j++)
        {
            Element document_list = (Element) GSXML.getChildByTagName((Element) responses.item(j), GSXML.DOC_NODE_ELEM + GSXML.LIST_MODIFIER);
            String coll_name = extractCollName(((Element) responses.item(j)).getAttribute(GSXML.FROM_ATT));

            mergeDocLists(result_doc_list, document_list, coll_name);
        }

        return page_response;
    }

    protected String extractCollName(String path)
    {
        return GSPath.removeLastLink(path);
    }

    protected void mergeDocLists(Element result_list, Element from_list, String collection)
    {

        Document owner = result_list.getOwnerDocument();
        Node child = from_list.getFirstChild();
        while (child != null && child.getNodeType() == Node.ELEMENT_NODE)
        {
            ((Element) child).setAttribute("collection", collection);
            result_list.appendChild(owner.importNode(child, true));
            child = child.getNextSibling();
        }

    }

    protected Element getCollectionList(Document doc, UserContext userContext)
    {

        // first, get the message router info
        Element coll_list_message = doc.createElement(GSXML.MESSAGE_ELEM);
        Element coll_list_request = GSXML.createBasicRequest(doc, GSXML.REQUEST_TYPE_DESCRIBE, "", userContext);
        coll_list_message.appendChild(coll_list_request);
        Element coll_list_response = (Element) this.mr.process(coll_list_message);
        if (coll_list_response == null)
        {
            logger.error("couldn't query the message router!");
            return null;
        }

        // second, get the display info for each collection 
        NodeList colls = coll_list_response.getElementsByTagName(GSXML.COLLECTION_ELEM);

        Element coll_param_list = doc.createElement(GSXML.PARAM_ELEM + GSXML.LIST_MODIFIER);
        Element param = GSXML.createParameter(doc, GSXML.SUBSET_PARAM, GSXML.DISPLAY_TEXT_ELEM + GSXML.LIST_MODIFIER);
        coll_param_list.appendChild(param);
        // we will send all the requests in a single message
        Element metadata_message = doc.createElement(GSXML.MESSAGE_ELEM);
        for (int i = 0; i < colls.getLength(); i++)
        {
            Element c = (Element) colls.item(i);
            String name = c.getAttribute(GSXML.NAME_ATT);

            Element metadata_request = GSXML.createBasicRequest(doc, GSXML.REQUEST_TYPE_DESCRIBE, name, userContext);
            metadata_request.appendChild(coll_param_list.cloneNode(true));
            metadata_message.appendChild(metadata_request);
        }

        Element metadata_response = (Element) this.mr.process(metadata_message);

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

            }
        }

        String path = GSPath.appendLink(GSXML.RESPONSE_ELEM, GSXML.COLLECTION_ELEM + GSXML.LIST_MODIFIER);
        Element response = (Element) GSXML.getNodeByPath(coll_list_response, path);
        return response;

    }
}