ClientEvictExpiredConnections.java

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 *
 *  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.
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 *
 * 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/>.
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package org.apache.http.examples.client;

import java.util.concurrent.TimeUnit;

import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.HttpVersion;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.conn.ClientConnectionManager;
import org.apache.http.conn.params.ConnManagerParams;
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.impl.client.DefaultHttpClient;
import org.apache.http.impl.conn.tsccm.ThreadSafeClientConnManager;
import org.apache.http.params.BasicHttpParams;
import org.apache.http.params.HttpParams;
import org.apache.http.params.HttpProtocolParams;

/**
 * Example demonstrating how to evict expired and idle connections
 * from the connection pool.
 */
public class ClientEvictExpiredConnections {

    public static void main(String[] args) throws Exception {
        // Create and initialize HTTP parameters
        HttpParams params = new BasicHttpParams();
        ConnManagerParams.setMaxTotalConnections(params, 100);
        HttpProtocolParams.setVersion(params, HttpVersion.HTTP_1_1);
        
        // Create and initialize scheme registry 
        SchemeRegistry schemeRegistry = new SchemeRegistry();
        schemeRegistry.register(
                new Scheme("http", PlainSocketFactory.getSocketFactory(), 80));
        
        ClientConnectionManager cm = new ThreadSafeClientConnManager(params, schemeRegistry);
        HttpClient httpclient = new DefaultHttpClient(cm, params);
        
        // create an array of URIs to perform GETs on
        String[] urisToGet = {
            "http://jakarta.apache.org/",
            "http://jakarta.apache.org/commons/",
            "http://jakarta.apache.org/commons/httpclient/",
            "http://svn.apache.org/viewvc/jakarta/httpcomponents/"
        };
        
        IdleConnectionEvictor connEvictor = new IdleConnectionEvictor(cm);
        connEvictor.start();
        
        for (int i = 0; i < urisToGet.length; i++) {
            String requestURI = urisToGet[i];
            HttpGet req = new HttpGet(requestURI);

            System.out.println("executing request " + requestURI);

            HttpResponse rsp = httpclient.execute(req);
            HttpEntity entity = rsp.getEntity();

            System.out.println("----------------------------------------");
            System.out.println(rsp.getStatusLine());
            if (entity != null) {
                System.out.println("Response content length: " + entity.getContentLength());
            }
            System.out.println("----------------------------------------");

            if (entity != null) {
                entity.consumeContent();
            }
        }
        
        // Sleep 10 sec and let the connection evictor do its job
        Thread.sleep(20000);
        
        // Shut down the evictor thread
        connEvictor.shutdown();
        connEvictor.join();

        // When HttpClient instance is no longer needed, 
        // shut down the connection manager to ensure
        // immediate deallocation of all system resources
        httpclient.getConnectionManager().shutdown();        
    }
    
    public static class IdleConnectionEvictor extends Thread {
        
        private final ClientConnectionManager connMgr;
        
        private volatile boolean shutdown;
        
        public IdleConnectionEvictor(ClientConnectionManager connMgr) {
            super();
            this.connMgr = connMgr;
        }

        @Override
        public void run() {
            try {
                while (!shutdown) {
                    synchronized (this) {
                        wait(5000);
                        // Close expired connections
                        connMgr.closeExpiredConnections();
                        // Optionally, close connections
                        // that have been idle longer than 5 sec
                        connMgr.closeIdleConnections(5, TimeUnit.SECONDS);
                    }
                }
            } catch (InterruptedException ex) {
                // terminate
            }
        }
        
        public void shutdown() {
            shutdown = true;
            synchronized (this) {
                notifyAll();
            }
        }
        
    }
    
}