Java tutorial
/* * $Id$ * -------------------------------------------------------------------------------------- * Copyright (c) MuleSoft, Inc. All rights reserved. http://www.mulesoft.com * * The software in this package is published under the terms of the CPAL v1.0 * license, a copy of which has been included with this distribution in the * LICENSE.txt file. */ package org.mule.module.launcher; import java.io.File; import java.util.Arrays; import java.util.Collection; import java.util.HashMap; import java.util.Map; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; public abstract class AbstractFileWatcher implements Runnable { protected Log logger = LogFactory.getLog(getClass()); private Collection<File> files; private Map<File, Long> timestamps = new HashMap<File, Long>(); public AbstractFileWatcher(File file) { this(Arrays.asList(file)); } public AbstractFileWatcher(Collection<File> files) { this.files = files; for (File file : files) { timestamps.put(file, file.lastModified()); } } @Override public final void run() { File latestFile = null; for (File file : files) { long originalTimestamp = timestamps.get(file); long currentTimestamp = file.lastModified(); if (originalTimestamp != currentTimestamp) { timestamps.put(file, currentTimestamp); latestFile = file; } } if (latestFile != null) { try { onChange(latestFile); } catch (Throwable t) { logger.error(String.format("Monitor for %s threw an exception", latestFile), t); } } } protected abstract void onChange(File file); }