source: trunk/gsdl3/src/java/org/greenstone/gsdl3/collection/Collection.java@ 3441

/*
 *    Collection.java
 *    Copyright (C) 2002 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.collection;

import org.greenstone.gsdl3.util.*;
import org.greenstone.gsdl3.core.*;
import org.greenstone.gsdl3.service.*;


// java XML classes we're using
import org.w3c.dom.Document; 
import org.w3c.dom.Node; 
import org.w3c.dom.Element; 
import org.w3c.dom.NodeList; 

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

/**
 * Represents a collection in Greenstone.
 *
 * Implements ModuleInterface. Contains a list of services supported by the collection, as well as collection metadata
 *
 * @author <a href="mailto:[email protected]">Katherine Don</a>
 * @version $Revision: 3441 $
 * @see ModuleInterface
 */
public class Collection 
    implements ModuleInterface {

    /** base directory for the site */
    protected String site_home_ = null;

    /** The name of the collection - this must be the name of the collection 
     * directory inside collect */
    protected String collection_name_ = null;

    /** The map of services.
     *
     * Maps Services to ServiceModule objects
     * @see ServiceModule
     *
     */
    protected HashMap service_map_=null;

    /** XML converter for String to DOM and vice versa */
    protected XMLConverter converter_=null;

    /** container doc for description elements */
    protected Document doc_ = null;
    /** list of services */
    protected Element service_info_ = null;
    /** list of Metadata */
    protected Element meta_info_ = null;
    /** full description */
    protected Element description_ = null;

    public void setSiteHome(String home) {
    site_home_ = home;
    }

    public void setCollectionName(String name) {
    collection_name_ = name;
    description_.setAttribute("name", name);
    }

    public Collection() {
    service_map_ = new HashMap();
    converter_ = new XMLConverter();
    doc_ = converter_.newDOM();
    description_ = doc_.createElement("collection");
    service_info_ = doc_.createElement("serviceList");
    meta_info_ = doc_.createElement("metadataList");
    
    
    }
    
    /**
     * Configures the collection.
     *
     * gsdlHome and collectionName must be set before configure is called.
     *
     * the file buildcfg.xml is located in gsdlHome/collect/collectionName
     * collection metadata is obtained, and services loaded.
     *
     * @return true/false on success/fail
     */
    public boolean configure() {
    
    if (site_home_ == null || collection_name_== null) {
        System.err.println("site_home_ and collection_name_ must be set before configure called!");
        return false;
    }
    // read the collection build configuration file
    File config_file_ = new File(GSFile.collectionBuildConfigFile(site_home_, collection_name_));

    if (!config_file_.exists()) {
        System.err.println(config_file_+" does not exist");
        System.err.println("couldn't configure collection: "+collection_name_);
        return false;
    }

    try {
        
        Document doc = converter_.getDOM(config_file_);
        
        // create all the services
        NodeList nodes = doc.getElementsByTagName("serviceModule");

        // the xml request to send to each serviceModule to query what
        // services it provides
        Element request = doc_.createElement("request");
        request.setAttribute("type", "describe");
        request.setAttribute("info", "serviceList");

        if (nodes.getLength()==0) {
        System.err.println("Collection configuration error: collection "+collection_name_+" has no services!");
        return false;
        }

        for(int i=0; i<nodes.getLength(); i++) {
        Element n = (Element)nodes.item(i);
        String servicetype = n.getAttribute("name");
        
        ServiceModule s = (ServiceModule)Class.forName("org.greenstone.gsdl3.service."+servicetype).newInstance();
        s.setSiteHome(site_home_);
        s.setCollectionName(collection_name_);
        // pass the xml node to the service for configuration
        s.configure(n);

        // find out the supported service types for this service module
        Node types = s.process(request);
        NodeList typenodes = ((Element)types).getElementsByTagName("service");     

        for (int j=0; j<typenodes.getLength();j++) {
            String service = ((Element) typenodes.item(j)).getAttribute("name");        
            service_map_.put(service, s);

            // also add info to the ServiceInfo XML element
            service_info_.appendChild(doc_.importNode(typenodes.item(j), true));
        }
        
        }

        // get the metadata - for now just add it to the list
        NodeList metanodes = doc.getElementsByTagName("metadata");

        if (metanodes.getLength()>0) {  
        for(int k=0; k<metanodes.getLength(); k++) {
            meta_info_.appendChild(doc_.importNode(metanodes.item(k),true));
        }
        }        

    } catch (Exception e) {
        System.out.println("Collection configure exception: "+e.getMessage() + e.getClass() );
        e.printStackTrace();
        return false;
    }

    // add elements to description
    description_.appendChild(service_info_);
    description_.appendChild(meta_info_);
    return true;
    }


    /**
     * Process an XML document - uses Strings 
     *  just calls process(Node).
     *
     * @param in the Document to process - a string
     * @return the resultant document as a string - contains any error messages
     * @see String
     */
    public String process(String in) {

    Document doc = converter_.getDOM(in);
    Element e = doc.getDocumentElement();
    
    Node res = process(e);
    return converter_.getString(res);
    
    }
    
    /** process XML as Node
     *
     */
    public Node process(Node xml_in) {

    // xml_in should always be an Element - should check this
    Element xml = (Element)xml_in;
    String to = xml.getAttribute("to");

    // the collection name should be first, check, then remove
    String col = GSPath.getFirstLink(to);
    if (col.equals(collection_name_)){
        to = GSPath.removeFirstLink(to);
        xml.setAttribute("to", to);
    } else {
        System.out.println("Collection error: collection name wrong! was "+col+" should have been "+collection_name_);
        return null;
    }

    if (to.equals("")) { // this command is for me
        String type = xml.getAttribute("type");
        if (type.equals("describe")) {
        // create a response with the description inside it
        Element response = doc_.createElement("response");
        response.setAttribute("from", collection_name_);
        response.setAttribute("type", "describe");
        response.appendChild(description_);
        return response;
        } else {
        System.out.println("Collection: error, cant handle request:");
        System.out.println(converter_.getString(xml));
        return null;
        }
        
    } else { // the request is for one of my services
        String service = GSPath.getFirstLink(to);
        
        if (service_map_.containsKey(service)) {
        return ((ServiceModule)service_map_.get(service)).process(xml);
        } else {
        System.err.println("Collection "+collection_name_+": non-existant service in:\n"+converter_.getString(xml));
        return null;
        }

    }
    }
     
}