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Java example source code file (TestSpuriousWakeup.java)

This example source code file (TestSpuriousWakeup.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 tags/keywords

clientconnectionrequest, getconnthread, httphost, httpparams, httproute, override, routespecificpool, schemeregistry, target, testcase, testspuriouswakeup, waitingthread, xconnpoolbyroute, xtsccm

The TestSpuriousWakeup.java example 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.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 *
 */

package org.apache.http.impl.conn.tsccm;

import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.Condition;

import junit.framework.Test;
import junit.framework.TestCase;
import junit.framework.TestSuite;

import org.apache.http.HttpHost;
import org.apache.http.HttpVersion;
import org.apache.http.conn.ClientConnectionOperator;
import org.apache.http.conn.ClientConnectionRequest;
import org.apache.http.conn.ManagedClientConnection;
import org.apache.http.conn.routing.HttpRoute;
import org.apache.http.conn.scheme.PlainSocketFactory;
import org.apache.http.conn.scheme.Scheme;
import org.apache.http.conn.scheme.SchemeRegistry;
import org.apache.http.conn.scheme.SocketFactory;
import org.apache.http.conn.params.ConnPerRouteBean;
import org.apache.http.conn.params.ConnManagerParams;
import org.apache.http.params.BasicHttpParams;
import org.apache.http.params.HttpParams;
import org.apache.http.params.HttpProtocolParams;

// test imports
import org.apache.http.impl.conn.GetConnThread;



/**
 * Tests for spurious wakeups in <code>WaitingThread.
 * Requires some wrapping code to get at the lock and condition,
 * which is required to trigger a wakeup without actually
 * satisfying the condition.
 *
 */
public class TestSpuriousWakeup extends TestCase {

    public final static
        HttpHost TARGET = new HttpHost("target.test.invalid");
    public final static
        HttpRoute ROUTE = new HttpRoute(TARGET);


    public TestSpuriousWakeup(String testName) {
        super(testName);
    }

    public static void main(String args[]) {
        String[] testCaseName = { TestSpuriousWakeup.class.getName() };
        junit.textui.TestRunner.main(testCaseName);
    }

    public static Test suite() {
        return new TestSuite(TestSpuriousWakeup.class);
    }


    /**
     * An extended connection pool that gives access to some internals.
     */
    private static class XConnPoolByRoute extends ConnPoolByRoute {

        /** The last WaitingThread object created. */
        protected WaitingThread newestWT;


        public XConnPoolByRoute(ClientConnectionOperator operator, HttpParams params) {
            super(operator, params);
        }

        @Override
        protected synchronized
            WaitingThread newWaitingThread(Condition cond,
                                           RouteSpecificPool rospl) {
            WaitingThread wt = super.newWaitingThread(cond, rospl);
            newestWT = wt;
            return wt;
        }

    } // class XConnPoolByRoute


    /**
     * An extended TSCCM that uses XConnPoolByRoute.
     */
    private static class XTSCCM extends ThreadSafeClientConnManager {

        /** The extended connection pool. */
        protected XConnPoolByRoute extendedCPBR;


        public XTSCCM(HttpParams params, SchemeRegistry schreg) {
            super(params, schreg);
        }

        @Override
        protected AbstractConnPool createConnectionPool(HttpParams params) {
            extendedCPBR = new XConnPoolByRoute(connOperator, params);
            // no connection GC required
            return extendedCPBR;
        }

    } // class XTSCCM



    public void testSpuriousWakeup() throws Exception {

        // parameters with connection limit 1
        HttpParams params = new BasicHttpParams();
        HttpProtocolParams.setVersion(params, HttpVersion.HTTP_1_1);
        HttpProtocolParams.setUseExpectContinue(params, false);
        ConnManagerParams.setMaxConnectionsPerRoute(params, new ConnPerRouteBean(1));
        ConnManagerParams.setMaxTotalConnections(params, 1);

        SchemeRegistry schreg = new SchemeRegistry();
        SocketFactory sf = PlainSocketFactory.getSocketFactory();
        schreg.register(new Scheme("http", sf, 80));

        XTSCCM mgr = new XTSCCM(params, schreg);

        try {
            // take out the only connection
            ClientConnectionRequest connRequest = mgr.requestConnection(ROUTE, null);
            ManagedClientConnection conn = connRequest.getConnection(0, null);
            assertNotNull(conn);

            // send a thread waiting
            GetConnThread gct = new GetConnThread(mgr, ROUTE, 0L);
            gct.start();
            Thread.sleep(100); // give extra thread time to block

            assertEquals("thread not waiting",
                         Thread.State.WAITING, gct.getState());

            // get access to the objects we need
            Lock      lck = mgr.extendedCPBR.poolLock;
            Condition cnd = mgr.extendedCPBR.newestWT.getCondition();

            // Now trigger spurious wakeups. We'll do it several times
            // in a loop, just to be sure the connection manager has a
            // fair chance of misbehaving, and the gct to register it.

            for (int i=0; i<3; i++) {
                if (i > 0)
                    Thread.sleep(333); // don't go too fast

                try {
                    lck.lock();
                    cnd.signalAll(); // this is the spurious wakeup
                } finally {
                    lck.unlock();
                }

                // now give the waiting thread some time to register a wakeup
                Thread.sleep(100);

                assertEquals("thread no longer waiting, iteration " + i,
                             Thread.State.WAITING, gct.getState());
            }
        } finally {
            // don't worry about releasing the connection, just shut down
            mgr.shutdown();
        }
    } // testSpuriousWakeup


} // class TestSpuriousWakeup

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