net.dfs.server.filemapper.impl.FileLocationTrackerImpl.java Source code

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Here is the source code for net.dfs.server.filemapper.impl.FileLocationTrackerImpl.java

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/**
 * Copyright 2008 Rukshan Silva
 *  
 * Licensed under the Apache License, Version 2.0 (the "License"); 
 * you may not use this file except in compliance with the License. 
 * You may obtain a copy of the License at 
 * http://www.apache.org/licenses/LICENSE-2.0 
 * Unless required by applicable law or agreed to in writing, 
 * software distributed under the License is distributed on an "AS IS" BASIS, 
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 
 * See the License for the specific language governing permissions and limitations 
 * under the License.
 */

package net.dfs.server.filemapper.impl;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;

import net.dfs.server.filemapper.FileLocationTracker;
import net.dfs.server.filemodel.HashModel;
import net.dfs.user.connect.RetrievalConnectionHandler;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

/**
 * Implementation of the {@link FileLocationTracker} which will keep track of the 
 * File object Name and the remote storage machine. It will use a HashMap for the 
 * persistent storage of the associativities.
 * <p>
 * Each location of the File objects are being used in retrieving the File. So 
 * {@link RetrievalConnectionHandler} will use this Map to find the location of the 
 * each Files.
 * 
 * @author Rukshan Silva
 * @version 1.0
 */
public class FileLocationTrackerImpl implements FileLocationTracker {
    protected static final long DURATION = 50000;

    private Log log = LogFactory.getLog(FileLocationTrackerImpl.class);

    HashMap<String, String> hashMap = new HashMap<String, String>();

    @SuppressWarnings("unchecked")
    public void loadMap() {
        try {
            ObjectInputStream load = new ObjectInputStream(new FileInputStream(new File("locationMap")));
            hashMap = (HashMap<String, String>) load.readObject();
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        }
        log.info("Hash Map Loaded");

    }

    /**
     * createHashIndex will insert each and every File Name and Location tuples into
     * the newly created HashMap. It returns no value.
     * {@inheritDoc}
     */
    public void createHashIndex(String key, String value) {
        hashMap.put(key, value);
        log.debug("Key " + key + " and Value " + value + " Added to the HashMap");
    }

    public void deleteHashIndex(String key) {
        hashMap.remove(key);
        log.debug("Key " + key + " Removed from the HashMap");
    }

    /**
     * {@inheritDoc}
     */
    public void retrieveKeys() {

        Iterator<String> iterator = hashMap.keySet().iterator();
        while (iterator.hasNext()) {
            System.out.println(iterator.next());
        }
    }

    /**
     * getValues will add all the values which matches with the given key and 
     * insert the result into a ArrayList and will return it.
     * 
     * {@inheritDoc}
     */
    public HashModel[] getValues(String key, String ext) {

        List<HashModel> list = new ArrayList<HashModel>();

        for (int i = 1; i <= hashMap.size(); i++) {
            if (hashMap.containsKey(key + "_" + i + ext)) {
                HashModel hashModel = new HashModel();

                hashModel.setKey(key + "_" + i + ext);
                hashModel.setValue(hashMap.get(key + "_" + i + ext));
                list.add(hashModel);
                log.info("Hash Map contains : " + key + "_" + i + ext);
            } else
                log.info("The requested File " + key + "_" + i + ext + " Not Found");
        }

        return list.toArray(new HashModel[] {});
    }

    public void removeAll() {
        hashMap.clear();
    }

    public void saveMap() {
        new Thread(new Runnable() {
            public void run() {
                ObjectOutputStream save;
                while (true) {
                    try {
                        save = new ObjectOutputStream(new FileOutputStream(new File("locationMap")));
                        save.writeObject(hashMap);

                        Thread.sleep(DURATION);

                    } catch (FileNotFoundException e) {
                        e.printStackTrace();
                    } catch (IOException e) {
                        e.printStackTrace();
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                    log.info("Hash Map Saved");
                }
            }
        }).start();

    }

}