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Apache CXF example source code file (AutomaticWorkQueueImpl.java)

This example Apache CXF source code file (AutomaticWorkQueueImpl.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Java - Apache CXF tags/keywords

annotation, automaticworkqueueimpl, automaticworkqueueimpl, awqthreadfactory, awqthreadfactory, classloader, log, logging, runnable, security, string, string, stringbuilder, thread, threadfactory, threadgroup, threadgroup, threading, threads, workqueuemanagerimpl

The Apache CXF AutomaticWorkQueueImpl.java source code

/**
 * 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.cxf.workqueue;

import java.security.AccessController;
import java.security.PrivilegedAction;
import java.util.concurrent.LinkedBlockingQueue;
import java.util.concurrent.RejectedExecutionException;
import java.util.concurrent.ThreadFactory;
import java.util.concurrent.ThreadPoolExecutor;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.logging.Level;
import java.util.logging.Logger;

import javax.annotation.PostConstruct;
import javax.annotation.Resource;
import javax.management.JMException;

import org.apache.cxf.common.logging.LogUtils;
import org.apache.cxf.management.InstrumentationManager;

public class AutomaticWorkQueueImpl extends ThreadPoolExecutor implements AutomaticWorkQueue {

    static final int DEFAULT_MAX_QUEUE_SIZE = 256;
    private static final Logger LOG =
        LogUtils.getL7dLogger(AutomaticWorkQueueImpl.class);
    
    int maxQueueSize;
    
    WorkQueueManagerImpl manager;
    String name = "default";

    public AutomaticWorkQueueImpl() {
        this(DEFAULT_MAX_QUEUE_SIZE);
    }    
    public AutomaticWorkQueueImpl(String name) {
        this(DEFAULT_MAX_QUEUE_SIZE, name);
    }    
    public AutomaticWorkQueueImpl(int max) {
        this(max, "default");
    }
    public AutomaticWorkQueueImpl(int max, String name) {
        this(max,
             0,
             25,
             5,
             2 * 60 * 1000L,
             name);
    }
    public AutomaticWorkQueueImpl(int mqs, 
                                  int initialThreads, 
                                  int highWaterMark, 
                                  int lowWaterMark,
                                  long dequeueTimeout) {
        this(mqs, initialThreads, highWaterMark, lowWaterMark, dequeueTimeout, "default");
    }    
    public AutomaticWorkQueueImpl(int mqs, 
                                  int initialThreads, 
                                  int highWaterMark, 
                                  int lowWaterMark,
                                  long dequeueTimeout,
                                  String name) {
        
        super(-1 == lowWaterMark ? Integer.MAX_VALUE : lowWaterMark, 
            -1 == highWaterMark ? Integer.MAX_VALUE : highWaterMark,
                TimeUnit.MILLISECONDS.toMillis(dequeueTimeout), TimeUnit.MILLISECONDS, 
                mqs == -1 ? new LinkedBlockingQueue<Runnable>(DEFAULT_MAX_QUEUE_SIZE)
                    : new LinkedBlockingQueue<Runnable>(mqs),
            createThreadFactory(name));
        
        maxQueueSize = mqs == -1 ? DEFAULT_MAX_QUEUE_SIZE : mqs;
        
        
        lowWaterMark = -1 == lowWaterMark ? Integer.MAX_VALUE : lowWaterMark;
        highWaterMark = -1 == highWaterMark ? Integer.MAX_VALUE : highWaterMark;
                
        StringBuilder buf = new StringBuilder();
        buf.append("Constructing automatic work queue with:\n");
        buf.append("max queue size: " + maxQueueSize + "\n");
        buf.append("initialThreads: " + initialThreads + "\n");
        buf.append("lowWaterMark: " + lowWaterMark + "\n");
        buf.append("highWaterMark: " + highWaterMark + "\n");
        LOG.fine(buf.toString());

        if (initialThreads > highWaterMark) {
            initialThreads = highWaterMark;
        }

        // as we cannot prestart more core than corePoolSize initial threads, we temporarily
        // change the corePoolSize to the number of initial threads
        // this is important as otherwise these threads will be created only when the queue has filled up, 
        // potentially causing problems with starting up under heavy load
        if (initialThreads < Integer.MAX_VALUE && initialThreads > 0) {
            setCorePoolSize(initialThreads);
            int started = prestartAllCoreThreads();
            if (started < initialThreads) {
                LOG.log(Level.WARNING, "THREAD_START_FAILURE_MSG", new Object[] {started, initialThreads});
            }
            setCorePoolSize(lowWaterMark);
        }
    }
    private static ThreadFactory createThreadFactory(final String name) {
        ThreadGroup group;
        try { 
            //Try and find the highest level ThreadGroup that we're allowed to use.
            //That SHOULD allow the default classloader and thread locals and such 
            //to be the least likely to cause issues down the road.
            group = AccessController.doPrivileged(
                new PrivilegedAction<ThreadGroup>() { 
                    public ThreadGroup run() { 
                        ThreadGroup group = Thread.currentThread().getThreadGroup(); 
                        ThreadGroup parent = group;
                        try { 
                            while (parent != null) { 
                                group = parent;  
                                parent = parent.getParent(); 
                            } 
                        } catch (SecurityException se) {
                            //ignore - if we get here, the "group" is as high as 
                            //the security manager will allow us to go.   Use that one.
                        }
                        return new ThreadGroup(group, name + "-workqueue");
                    } 
                }
            );
        } catch (SecurityException e) { 
            group = new ThreadGroup(name + "-workqueue");
        }
        return new AWQThreadFactory(group, name);
    }
    static class AWQThreadFactory implements ThreadFactory {
        final AtomicInteger threadNumber = new AtomicInteger(1);
        ThreadGroup group;
        String name;
        ClassLoader loader;
        AWQThreadFactory(ThreadGroup gp, String nm) {
            group = gp;
            name = nm;
            //force the loader to be the loader of CXF, not the application loader
            loader = AutomaticWorkQueueImpl.class.getClassLoader();
        }
        public Thread newThread(Runnable r) {
            if (group.isDestroyed()) {
                group = new ThreadGroup(group.getParent(), name + "-workqueue");
            }
            Thread t = new Thread(group, 
                                  r, 
                                  name + "-workqueue-" + threadNumber.getAndIncrement(),
                                  0);
            t.setContextClassLoader(loader);
            t.setDaemon(true);
            if (t.getPriority() != Thread.NORM_PRIORITY) {
                t.setPriority(Thread.NORM_PRIORITY);
            }
            return t;
        }
        public void setName(String s) {
            name = s;
        }
        public void shutdown() {
            if (!group.isDestroyed()) {
                try {
                    group.destroy();
                    group.setDaemon(true);
                } catch (Throwable t) {
                    //ignore
                }
            }            
        }
    }
    
    @Resource(name = "org.apache.cxf.workqueue.WorkQueueManager")
    public void setManager(WorkQueueManager mgr) {
        manager = (WorkQueueManagerImpl)mgr;
    }
    public WorkQueueManager getManager() {
        return manager;
    }

    public void setName(String s) {
        name = s;
        ThreadFactory factory = this.getThreadFactory();
        if (factory instanceof AWQThreadFactory) {
            ((AWQThreadFactory)factory).setName(s);
        }
    }
    public String getName() {
        return name;
    }
    
    @PostConstruct
    public void register() {
        if (manager != null) {
            manager.addNamedWorkQueue(name, this);
            InstrumentationManager imanager = manager.getBus().getExtension(InstrumentationManager.class);
            if (null != imanager) {
                try {
                    imanager.register(new WorkQueueImplMBeanWrapper(this));
                } catch (JMException jmex) {
                    LOG.log(Level.WARNING , jmex.getMessage(), jmex);
                }
            }
        }
    }
    
    public String toString() {
        StringBuilder buf = new StringBuilder();
        buf.append(super.toString());
        buf.append(" [queue size: ");
        buf.append(getSize());
        buf.append(", max size: ");
        buf.append(maxQueueSize);
        buf.append(", threads: ");
        buf.append(getPoolSize());
        buf.append(", active threads: ");
        buf.append(getActiveCount());
        buf.append(", low water mark: ");
        buf.append(getLowWaterMark());
        buf.append(", high water mark: ");
        buf.append(getHighWaterMark());
        buf.append("]");
        return buf.toString();
    }
    
    public void execute(final Runnable command) {
        //Grab the context classloader of this thread.   We'll make sure we use that 
        //on the thread the runnable actually runs on.
        
        final ClassLoader loader = Thread.currentThread().getContextClassLoader();
        Runnable r = new Runnable() {
            public void run() {
                ClassLoader orig = Thread.currentThread().getContextClassLoader();
                try {
                    Thread.currentThread().setContextClassLoader(loader);
                    command.run();
                } finally {
                    Thread.currentThread().setContextClassLoader(orig);
                }
            }
        };
        super.execute(r);
    }
    
    // WorkQueue interface
    public void execute(Runnable work, long timeout) {
        try {
            execute(work);
        } catch (RejectedExecutionException ree) {
            try {
                getQueue().offer(work, timeout, TimeUnit.MILLISECONDS);
            } catch (InterruptedException ie) {
                throw new RejectedExecutionException(ie);
            }
        }    
    }

    public void schedule(final Runnable work, final long delay) {
        // temporary implementation, replace with shared long-lived scheduler
        // task
        execute(new Runnable() {
            public void run() {
                try {
                    Thread.sleep(delay);
                } catch (InterruptedException ie) {
                    // ignore
                }
                work.run();
            }
        });
    }
    
    // AutomaticWorkQueue interface
    
    public void shutdown(boolean processRemainingWorkItems) {
        if (!processRemainingWorkItems) {
            getQueue().clear();
        }
        shutdown();
    }
    @Override
    protected void terminated() {
        ThreadFactory f = this.getThreadFactory();
        if (f instanceof AWQThreadFactory) {
            ((AWQThreadFactory)f).shutdown();
        }
    }

    /**
     * Gets the maximum size (capacity) of the backing queue.
     * @return the maximum size (capacity) of the backing queue.
     */
    public long getMaxSize() {
        return maxQueueSize;
    }

    /**
     * Gets the current size of the backing queue.
     * @return the current size of the backing queue.
     */
    public long getSize() {
        return getQueue().size();
    }


    public boolean isEmpty() {
        return getQueue().size() == 0;
    }

    boolean isFull() {
        return getQueue().remainingCapacity() == 0;
    }

    public int getHighWaterMark() {
        int hwm = getMaximumPoolSize();
        return hwm == Integer.MAX_VALUE ? -1 : hwm;
    }

    public int getLowWaterMark() {
        int lwm = getCorePoolSize();
        return lwm == Integer.MAX_VALUE ? -1 : lwm;
    }

    public void setHighWaterMark(int hwm) {
        setMaximumPoolSize(hwm < 0 ? Integer.MAX_VALUE : hwm);
    }

    public void setLowWaterMark(int lwm) {
        setCorePoolSize(lwm < 0 ? 0 : lwm);
    }
}

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