| /* |
| * 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.zest.library.locking; |
| |
| import java.lang.reflect.InvocationHandler; |
| import java.lang.reflect.Method; |
| import java.util.concurrent.TimeUnit; |
| import java.util.concurrent.locks.Lock; |
| import java.util.concurrent.locks.ReadWriteLock; |
| import org.apache.zest.api.common.AppliesTo; |
| import org.apache.zest.api.concern.ConcernOf; |
| import org.apache.zest.api.injection.scope.This; |
| |
| /** |
| * Applies write-lock to Composite |
| */ |
| @AppliesTo( WriteLock.class ) |
| public class WriteLockConcern |
| extends ConcernOf<InvocationHandler> |
| implements InvocationHandler |
| { |
| private |
| @This |
| ReadWriteLock lock; |
| |
| @Override |
| public Object invoke( Object o, Method method, Object[] objects ) |
| throws Throwable |
| { |
| Lock writeLock = lock.writeLock(); |
| lock(writeLock); |
| try |
| { |
| return next.invoke( o, method, objects ); |
| } |
| finally |
| { |
| writeLock.unlock(); |
| } |
| } |
| |
| /** |
| * Fix for this bug: |
| * http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6822370 |
| */ |
| protected void lock(Lock lock) |
| { |
| while(true) |
| { |
| try |
| { |
| //noinspection StatementWithEmptyBody |
| while( !lock.tryLock( 1000, TimeUnit.MILLISECONDS ) ) |
| { |
| // On timeout, try again |
| } |
| return; // Finally got a lock |
| } |
| catch( InterruptedException e ) |
| { |
| // Try again |
| } |
| } |
| } |
| } |