| /* |
| * 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.felix.eventadmin.impl.tasks; |
| |
| import java.util.ArrayList; |
| import java.util.Iterator; |
| import java.util.List; |
| import java.util.concurrent.Semaphore; |
| import java.util.concurrent.TimeUnit; |
| |
| import org.apache.felix.eventadmin.impl.util.LogWrapper; |
| |
| /** |
| * |
| * A latch that checks handlers for blacklisting on an interval. |
| * |
| */ |
| public class BlacklistLatch { |
| |
| private final Semaphore internalSemaphore; |
| |
| private final int count; |
| |
| private final long timeout; |
| |
| private final List<HandlerTask> handlerTasks; |
| |
| /** |
| * @param count Number of handlers that must call countdown |
| * @param timeout Timeout in Milliseconds to check for blacklisting handlers |
| */ |
| public BlacklistLatch(final int count, final long timeout) |
| { |
| this.handlerTasks = new ArrayList<HandlerTask>(count); |
| this.count = count; |
| this.timeout = timeout; |
| internalSemaphore = new Semaphore(count); |
| internalSemaphore.drainPermits(); |
| } |
| |
| /** |
| * |
| * Count down the number of handlers blocking event completion. |
| * |
| */ |
| public void countDown() |
| { |
| internalSemaphore.release(); |
| } |
| |
| /** |
| * |
| * Adds a handler task to the timeout based blackout checking. |
| * |
| * @param task |
| */ |
| public void addToBlacklistCheck(final HandlerTask task) |
| { |
| this.handlerTasks.add(task); |
| } |
| |
| /** |
| * |
| * Causes current thread to wait until each handler has called countDown. |
| * Checks on timeout interval to determine if a handler needs blacklisting. |
| * |
| */ |
| public void awaitAndBlacklistCheck() |
| { |
| try |
| { |
| while(!internalSemaphore.tryAcquire(this.count, this.timeout, TimeUnit.MILLISECONDS)) |
| { |
| final Iterator<HandlerTask> handlerTaskIt = handlerTasks.iterator(); |
| while(handlerTaskIt.hasNext()) |
| { |
| HandlerTask currentTask = handlerTaskIt.next(); |
| currentTask.checkForBlacklist(); |
| } |
| } |
| } |
| catch (final InterruptedException e) |
| { |
| LogWrapper.getLogger().log( |
| LogWrapper.LOG_WARNING, |
| "Event Task Processing Interrupted. Events may not be received in proper order."); |
| } |
| } |
| |
| |
| } |