001    //  Copyright 2008, 2009, 2011 The Apache Software Foundation
002    //
003    // Licensed under the Apache License, Version 2.0 (the "License");
004    // you may not use this file except in compliance with the License.
005    // You may obtain a copy of the License at
006    //
007    //     http://www.apache.org/licenses/LICENSE-2.0
008    //
009    // Unless required by applicable law or agreed to in writing, software
010    // distributed under the License is distributed on an "AS IS" BASIS,
011    // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
012    // See the License for the specific language governing permissions and
013    // limitations under the License.
014    
015    package org.apache.tapestry5.ioc.internal;
016    
017    import org.apache.tapestry5.ioc.Invokable;
018    import org.apache.tapestry5.ioc.OperationTracker;
019    import org.apache.tapestry5.ioc.internal.util.JDKUtils;
020    import org.slf4j.Logger;
021    
022    import java.util.concurrent.locks.Lock;
023    
024    /**
025     * Manages a per-thread OperationTracker using a ThreadLocal.
026     */
027    public class PerThreadOperationTracker implements OperationTracker
028    {
029        private final Logger logger;
030    
031        private final Lock lock = JDKUtils.createLockForThreadLocalCreation();
032    
033        private final ThreadLocal<OperationTrackerImpl> perThread = new ThreadLocal<OperationTrackerImpl>()
034        {
035            @Override
036            protected OperationTrackerImpl initialValue()
037            {
038                return new OperationTrackerImpl(logger);
039            }
040        };
041    
042        public PerThreadOperationTracker(Logger logger)
043        {
044            this.logger = logger;
045        }
046    
047        OperationTracker get()
048        {
049            lock.lock();
050    
051            try
052            {
053                return perThread.get();
054            } finally
055            {
056                lock.unlock();
057            }
058        }
059    
060        void cleanup()
061        {
062            try
063            {
064                lock.lock();
065                if (perThread.get().isEmpty()) perThread.remove();
066            } finally
067            {
068                lock.unlock();
069            }
070        }
071    
072        public void run(String description, Runnable operation)
073        {
074            try
075            {
076                get().run(description, operation);
077            } finally
078            {
079                cleanup();
080            }
081        }
082    
083        public <T> T invoke(String description, Invokable<T> operation)
084        {
085            try
086            {
087                return get().invoke(description, operation);
088            } finally
089            {
090                cleanup();
091            }
092        }
093    }