| /* |
| * 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.ode.bpel.engine; |
| |
| import org.apache.commons.logging.Log; |
| import org.apache.commons.logging.LogFactory; |
| import org.apache.ode.bpel.clapi.ClusterLock; |
| |
| import java.util.HashMap; |
| import java.util.Map; |
| import java.util.concurrent.TimeUnit; |
| import java.util.concurrent.locks.Condition; |
| import java.util.concurrent.locks.Lock; |
| |
| /** |
| * |
| * WARNING --- EXPERIMENTAL |
| * |
| * Mechanism for obtaining instance-level locks. Very simple implementation at the moment, that is only valid |
| * for a single processing node. To move to multi-processor setup we'll need to implement this lock in the database. |
| * |
| * @author Maciej Szefler - m s z e f l e r @ g m a i l . c o m |
| */ |
| public class InstanceLockManager implements ClusterLock<Long> { |
| private static final Log __log = LogFactory.getLog(InstanceLockManager.class); |
| |
| private final Lock _mutex = new java.util.concurrent.locks.ReentrantLock(); |
| private final Map<Long, InstanceInfo> _locks = new HashMap<Long,InstanceInfo>(); |
| |
| public void lock(Long key) { |
| // Noting to do here. |
| } |
| |
| public void lock(Long iid, int time, TimeUnit tu) throws InterruptedException, TimeoutException { |
| if (iid == null) return; |
| |
| String thrd = Thread.currentThread().toString(); |
| if (__log.isDebugEnabled()) |
| __log.debug(thrd + ": lock(iid=" + iid + ", time=" + time + tu+")"); |
| |
| InstanceInfo li; |
| |
| _mutex.lock(); |
| try { |
| |
| while (true) { |
| li = _locks.get(iid); |
| if (li == null) { |
| li = new InstanceInfo(iid, Thread.currentThread()); |
| _locks.put(iid, li); |
| if (__log.isDebugEnabled()) |
| __log.debug(thrd + ": lock(iid=" + iid + ", time=" + time + tu+")-->GRANTED"); |
| return; |
| } else { |
| if (__log.isDebugEnabled()) |
| __log.debug(thrd + ": lock(iid=" + iid + ", time=" + time + tu+")-->WAITING(held by " + li.acquierer + ")"); |
| |
| if (!li.available.await(time, tu)) { |
| if (__log.isDebugEnabled()) |
| __log.debug(thrd + ": lock(iid=" + iid + ", time=" + time + tu+")-->TIMEOUT (held by " + li.acquierer + ")"); |
| throw new TimeoutException(); |
| } |
| } |
| } |
| |
| } finally { |
| _mutex.unlock(); |
| } |
| |
| } |
| |
| public void unlock(Long iid) { |
| if (iid == null) return; |
| |
| String thrd = Thread.currentThread().toString(); |
| if (__log.isDebugEnabled()) |
| __log.debug(thrd + ": unlock(iid=" + iid + ")"); |
| |
| _mutex.lock(); |
| try { |
| InstanceInfo li = _locks.get(iid); |
| if (li == null) |
| throw new IllegalStateException("Instance not locked, cannot unlock!"); |
| |
| _locks.remove(iid); |
| |
| // Note, that we have to signall all threads, because new holder will create a new |
| // instance of "available" condition variable, so all the waiters need to try again |
| li.available.signalAll(); |
| |
| } finally { |
| _mutex.unlock(); |
| } |
| |
| } |
| |
| public boolean tryLock(Long key) { |
| // Noting to do here. |
| return false; |
| } |
| |
| public boolean tryLock(Long key, int time, TimeUnit tu) { |
| // Noting to do here. |
| return false; |
| } |
| |
| public void putIfAbsent(Long key, Long keyVal) { |
| // Noting to do here. |
| } |
| |
| |
| @Override |
| public String toString() { |
| return "{InstanceLockManager: " + _locks + "}"; |
| } |
| |
| /** |
| * Information about the lock state for a particular instance. |
| * @author Maciej Szefler - m s z e f l e r @ g m a i l . c o m |
| */ |
| private class InstanceInfo { |
| final long iid; |
| |
| /** Thread that acquired the lock. */ |
| final Thread acquierer; |
| |
| /** Condition-Variable indicating that the lock has become available. */ |
| Condition available = _mutex.newCondition(); |
| |
| |
| InstanceInfo(long iid, Thread t) { |
| this.iid = iid; |
| this.acquierer = t; |
| } |
| |
| @Override |
| public String toString() { |
| return "{Lock for Instance #" + iid +", acquired by " + acquierer + "}"; |
| } |
| } |
| } |
| |
| |