org.eclipse.paho.client.mqttv3.persist.MqttDefaultFilePersistence Maven / Gradle / Ivy

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/*******************************************************************************
 * Copyright (c) 2009, 2014 IBM Corp.
 *
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * and Eclipse Distribution License v1.0 which accompany this distribution. 
 *
 * The Eclipse Public License is available at 
 *    http://www.eclipse.org/legal/epl-v10.html
 * and the Eclipse Distribution License is available at 
 *   http://www.eclipse.org/org/documents/edl-v10.php.
 *
 * Contributors:
 *    Dave Locke - initial API and implementation and/or initial documentation
 */
package org.eclipse.paho.client.mqttv3.persist;

import java.io.File;
import java.io.FileFilter;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.FilenameFilter;
import java.io.IOException;
import java.util.Enumeration;
import java.util.Vector;

import org.eclipse.paho.client.mqttv3.MqttClientPersistence;
import org.eclipse.paho.client.mqttv3.MqttPersistable;
import org.eclipse.paho.client.mqttv3.MqttPersistenceException;
import org.eclipse.paho.client.mqttv3.internal.FileLock;
import org.eclipse.paho.client.mqttv3.internal.MqttPersistentData;

/**
 * An implementation of the {@link MqttClientPersistence} interface that provides
 * file based persistence.
 * 
 * A directory is specified when the Persistence object is created. When the persistence
 * is then opened (see {@link #open(String, String)}), a sub-directory is made beneath the base
 * for this client ID and connection key. This allows one persistence base directory
 * to be shared by multiple clients.
 * 
 * The sub-directory's name is created from a concatenation of the client ID and connection key
 * with any instance of '/', '\\', ':' or ' ' removed.
 */
public class MqttDefaultFilePersistence implements MqttClientPersistence {
	private static final String MESSAGE_FILE_EXTENSION = ".msg";
	private static final String MESSAGE_BACKUP_FILE_EXTENSION = ".bup";
	private static final String LOCK_FILENAME = ".lck"; 

	private File dataDir;
	private File clientDir = null;
	private FileLock fileLock = null;
	
	private static final FilenameFilter FILE_FILTER = new FilenameFilter() { 
		public boolean accept(File dir, String name) { return name.endsWith(MESSAGE_FILE_EXTENSION); }
		};
	
	public MqttDefaultFilePersistence()  { //throws MqttPersistenceException {
		this(System.getProperty("user.dir"));
	}
	
	/**
	 * Create an file-based persistent data store within the specified directory.
	 * @param directory the directory to use.
	 */
	public MqttDefaultFilePersistence(String directory) { //throws MqttPersistenceException {
		dataDir = new File(directory);
	}
	
	public void open(String clientId, String theConnection) throws MqttPersistenceException {
		
		if (dataDir.exists() && !dataDir.isDirectory()) {
			throw new MqttPersistenceException();
		} else if (!dataDir.exists() ) {
			if (!dataDir.mkdirs()) {
				throw new MqttPersistenceException();
			}
		} 
		if (!dataDir.canWrite()) {
			throw new MqttPersistenceException();
		}
		
		
		StringBuffer keyBuffer = new StringBuffer();
		for (int i=0;i