| /* |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF licenses this file to You 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 org.apache.commons.jci2.monitor; |
| |
| import java.io.File; |
| import java.util.Collections; |
| import java.util.HashMap; |
| import java.util.Map; |
| |
| import org.apache.commons.logging.Log; |
| import org.apache.commons.logging.LogFactory; |
| |
| /** |
| * It's a runnable that spawns of a monitoring thread triggering the |
| * the observers and managing the their listeners. |
| * |
| * @author tcurdt |
| */ |
| public final class FilesystemAlterationMonitor implements Runnable { |
| |
| private final Log log = LogFactory.getLog(FilesystemAlterationMonitor.class); |
| |
| private final Object observersLock = new Object(); |
| private Map<File, FilesystemAlterationObserver> observers = Collections.unmodifiableMap(new HashMap<File, FilesystemAlterationObserver>()); |
| |
| /** delay between calls to {@link FilesystemAlterationObserver#checkAndNotify()}, default 3000 ms */ |
| private volatile long delay = 3000; // volatile because shared with daemon thread |
| private Thread thread = null; |
| |
| private volatile boolean running = true; |
| |
| public FilesystemAlterationMonitor() { |
| } |
| |
| |
| public void start() { |
| thread = new Thread(this); |
| thread.setName("Filesystem Alteration Monitor"); |
| thread.setDaemon(true); |
| thread.start(); |
| } |
| |
| |
| public void stop() { |
| running = false; |
| |
| if (thread != null) { |
| try { |
| thread.join(delay); |
| } catch (InterruptedException e) { |
| } |
| } |
| } |
| |
| |
| /** |
| * Set the delay between calls to the observers. |
| * |
| * @param pDelay the delay in milliseconds (default if not set 3000 ms) |
| */ |
| public void setInterval( final long pDelay ) { |
| delay = pDelay; |
| } |
| |
| |
| public void addListener( final File pRoot, final FilesystemAlterationListener pListener ) { |
| |
| FilesystemAlterationObserver observer; |
| |
| synchronized (observersLock) { |
| observer = observers.get(pRoot); |
| |
| if (observer == null) { |
| final Map<File, FilesystemAlterationObserver> newObservers = new HashMap<File, FilesystemAlterationObserver>(observers); |
| observer = new FilesystemAlterationObserverImpl(pRoot); |
| newObservers.put(pRoot, observer); |
| observers = Collections.unmodifiableMap(newObservers); |
| } |
| } |
| |
| observer.addListener(pListener); |
| } |
| |
| public void removeListener( final FilesystemAlterationListener pListener ) { |
| synchronized (observersLock) { |
| for (FilesystemAlterationObserver observer : observers.values()) { |
| observer.removeListener(pListener); |
| // FIXME: remove observer if there are no listeners? |
| } |
| } |
| } |
| |
| public FilesystemAlterationListener[] getListenersFor( final File pRoot ) { |
| final FilesystemAlterationObserver observer = observers.get(pRoot); |
| |
| if (observer == null) { |
| return new FilesystemAlterationListener[0]; |
| } |
| |
| return observer.getListeners(); |
| } |
| |
| |
| public void run() { |
| log.debug("fam running"); |
| |
| while (running) { |
| |
| for (FilesystemAlterationObserver observer : observers.values()) { |
| observer.checkAndNotify(); |
| } |
| |
| try { |
| Thread.sleep(delay); |
| } catch (final InterruptedException e) { |
| } |
| } |
| |
| log.debug("fam exiting"); |
| } |
| |
| } |