Application: gvSIG desktop

/*

 * Created on 01-oct-2005

 */

package org.gvsig.remoteClient.taskplanning.retrieving;

import java.io.File;

import java.net.MalformedURLException;

import java.util.ArrayList;

import java.util.TreeMap;

import java.util.Vector;

import org.gvsig.remoteClient.taskplanning.IQueue;

/**

 * pa administrar les tasques (la hist?ria aquella

 *  de que hi haja una cola per a cada servidor)

 * @author Luis W. Sevilla (sevilla_lui@gva.es)

 */

public class RequestManager {

        private boolean debug = true;

        private static RequestManager instance;

        private TreeMap serversTable = new TreeMap();

        private RequestManager() {} // Avoid public instantiation

        public static RequestManager getInstance() {

                if (instance == null)

                        instance = new RequestManager();

                return instance;

        }

        public URLRequest addURLRequest(URLRequest request, RetrieveListener listener) {

                try {

                        if (downloadedFiles.contains(request)) {

                                for (int i = 0; i < downloadedFiles.size(); i++) {

                                        URLRequest r = (URLRequest) downloadedFiles.get(i);

                                        if (r.equals(request)) {

                                                System.out.println(request.getUrl()+" is cached at '"+r.getFileName()+"'");

                                                request.setFileName(r.getFileName()); /* Uaaah! 

                                                                                                                           * Si no pose a?? l'event es 

                                                                                                                           * dispara abans que haja 

                                                                                                                           * retornat el request 

                                                                                                                           * reasignat i confon el 

                                                                                                                           * sufixe.

                                                                                                                           */ 

                                                request = r;

                                                break;

                                        }

                                }

                                synchronized (this) {

                                        if (request.getStatus() == RetrieveEvent.REQUEST_CANCELLED ||

                                                request.getStatus() == RetrieveEvent.REQUEST_FAILED) {

                                                // The last requested URL was cancelled or it failed but now it is required again

                                                // so, I have to remove it and add again.

                                                removeURLRequest(request);

                                                return addURLRequest(request, listener);

                                        } else if (request.getStatus() == RetrieveEvent.REQUEST_FINISHED) {

                                                if (debug)

                                                        System.err.println("done job found ("+request.getFileName()+")");

                                                RetrieveEvent event = new RetrieveEvent();

                                                event.setType(RetrieveEvent.REQUEST_FINISHED);

                                                listener.transferEventReceived(event);

                                        } else {

                                                if (debug)

                                                        System.err.println("working job found ("+request.getFileName()+")");

                                                request.lock();

                                                request.addRetrieveListener(listener);

                                                request.unlock();

                                        }

                                }

                        } else {

                                // Pick an unrepeatable fileName

                                String host = request.getHost();

                                String fileName = request.getFileName();

                                File tempDir = new File(tempDirectoryPath);

                                if (!tempDir.exists())

                                        tempDir.mkdir();

                                String fileNamePrefix = tempDirectoryPath + 

                                                                                        File.separator + host + 

                                                                                        "-" ;

                                if (fileName.startsWith(fileNamePrefix))

                                        fileName = fileName.substring(fileNamePrefix.length(), fileName.length());

                                // get this server's task queue

                                RetrieveQueue serverQueue = (RetrieveQueue) getQueue(request.getHost());

                                fileName = fileNamePrefix + fileName;

                                request.setFileName(fileName);

                                synchronized (this) {

                                        addDownloadedURLRequest(request);

                                }

                                // TODO

                                // jo ac? comprovaria quin protocol, m?tode, host, etc... i crearia un

                                // objecte que tractara la desc?rrega segons el m?tode que li toca.

                                // algo en plan Strategy's

                                //

                                // per exemple si fem URLRetrieveTask una abstracta i tenim

                                // 

                                // GET de tota la vida

                                // serverQueue.put(new HTTPGetRetrieveTask(request, listener));

                                //

                                // POST

                                // serverQueue.put(new HTTPPostRetrieveTask(request, listener));

                                //

                                // FTP

                                // serverQueue.put(new FTPRetrieveTask(request, listener));

                                //

                                // ????Xarxa local?????

                                // serverQueue.put(new SMBRetrieveTask(request, listener));

                                // Enqueue the request and the listener will be notified when done.

                                request.addRetrieveListener(listener);

                                URLRetrieveTask task = new URLRetrieveTask(request);

                                serverQueue.put(task);

                        }

                } catch (MalformedURLException e) {

                        e.printStackTrace();

                }

                return request;

        }

        private IQueue getQueue(String hostName) {

                RetrieveQueue queue = null;

                if (serversTable.containsKey(hostName))

                        queue = (RetrieveQueue) serversTable.get(hostName);

                else {

                        // crea la cola

                        queue = new RetrieveQueue(hostName);

                        // pone la cola del server en marcha.

                }

                return queue;

        }

        private Vector downloadedFiles = new Vector();

        private final String tempDirectoryPath = System.getProperty("java.io.tmpdir")+"tmp-andami";

        /**

     * Remove an URL from the system cache. The file will remain in the file

     * system for further eventual uses.

     * @param request

     */

        public void removeURLRequest(URLRequest request) {

                if (downloadedFiles != null && downloadedFiles.contains(request))

                        downloadedFiles.remove(request);

        }

        /**

     * Adds an URL to the table of downloaded files for further uses. If the URL

     * already exists in the table its filePath value is updated to the new one and

     * the old file itself is removed from the file system.

     * 

     * @param url

     * @param filePath

     */

    private void addDownloadedURLRequest(URLRequest request){

        if (!downloadedFiles.contains(request)) {

                downloadedFiles.add(request);

        }

    }

}