ActiveMQ example source code file (HttpClientTransport.java)

This example ActiveMQ source code file (HttpClientTransport.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 - ActiveMQ tags/keywords

exception, failed, failed, get, get, http, httpclient, httpclient, idgenerator, io, ioexception, ioexception, max_client_timeout, net, network, object, uri

The ActiveMQ HttpClientTransport.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.activemq.transport.http;

import java.io.DataInputStream;
import java.io.IOException;
import java.io.InterruptedIOException;
import java.net.URI;

import org.apache.activemq.command.ShutdownInfo;
import org.apache.activemq.transport.FutureResponse;
import org.apache.activemq.transport.util.TextWireFormat;
import org.apache.activemq.util.ByteArrayInputStream;
import org.apache.activemq.util.IOExceptionSupport;
import org.apache.activemq.util.IdGenerator;
import org.apache.activemq.util.ServiceStopper;
import org.apache.commons.httpclient.HttpClient;
import org.apache.commons.httpclient.HttpMethod;
import org.apache.commons.httpclient.HttpStatus;
import org.apache.commons.httpclient.methods.GetMethod;
import org.apache.commons.httpclient.methods.HeadMethod;
import org.apache.commons.httpclient.methods.InputStreamRequestEntity;
import org.apache.commons.httpclient.methods.PostMethod;
import org.apache.commons.httpclient.params.HttpClientParams;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * A HTTP {@link org.apache.activemq.transport.TransportChannel} which uses the
 * <a href="http://jakarta.apache.org/commons/httpclient/">commons-httpclient
 * library
 * 
 * 
 */
public class HttpClientTransport extends HttpTransportSupport {

    public static final int MAX_CLIENT_TIMEOUT = 30000;
    private static final Logger LOG = LoggerFactory.getLogger(HttpClientTransport.class);
    private static final IdGenerator CLIENT_ID_GENERATOR = new IdGenerator();

    private HttpClient sendHttpClient;
    private HttpClient receiveHttpClient;

    private final String clientID = CLIENT_ID_GENERATOR.generateId();
    private boolean trace;
    private GetMethod httpMethod;
    private volatile int receiveCounter;

    private int soTimeout = MAX_CLIENT_TIMEOUT;
    
    public HttpClientTransport(TextWireFormat wireFormat, URI remoteUrl) {
        super(wireFormat, remoteUrl);
    }

    public FutureResponse asyncRequest(Object command) throws IOException {
        return null;
    }

    public void oneway(Object command) throws IOException {

        if (isStopped()) {
            throw new IOException("stopped.");
        }
        PostMethod httpMethod = new PostMethod(getRemoteUrl().toString());
        configureMethod(httpMethod);
        String data = getTextWireFormat().marshalText(command);
        byte[] bytes = data.getBytes("UTF-8");
        InputStreamRequestEntity entity = new InputStreamRequestEntity(new ByteArrayInputStream(bytes));
        httpMethod.setRequestEntity(entity);

        try {

            HttpClient client = getSendHttpClient();
            HttpClientParams params = new HttpClientParams();
            params.setSoTimeout(soTimeout);
            client.setParams(params);
            int answer = client.executeMethod(httpMethod);
            if (answer != HttpStatus.SC_OK) {
                throw new IOException("Failed to post command: " + command + " as response was: " + answer);
            }
            if (command instanceof ShutdownInfo) {
            	try {
            		stop();
            	} catch (Exception e) {
            		LOG.warn("Error trying to stop HTTP client: "+ e, e);
            	}
            }
        } catch (IOException e) {
            throw IOExceptionSupport.create("Could not post command: " + command + " due to: " + e, e);
        } finally {
            httpMethod.getResponseBody();
            httpMethod.releaseConnection();
        }
    }

    public Object request(Object command) throws IOException {
        return null;
    }

    public void run() {

        LOG.trace("HTTP GET consumer thread starting: " + this);
        HttpClient httpClient = getReceiveHttpClient();
        URI remoteUrl = getRemoteUrl();

        while (!isStopped() && !isStopping()) {

            httpMethod = new GetMethod(remoteUrl.toString());
            configureMethod(httpMethod);

            try {
                int answer = httpClient.executeMethod(httpMethod);
                if (answer != HttpStatus.SC_OK) {
                    if (answer == HttpStatus.SC_REQUEST_TIMEOUT) {
                        LOG.debug("GET timed out");
                        try {
                            Thread.sleep(1000);
                        } catch (InterruptedException e) {
                            onException(new InterruptedIOException());
                            break;
                        }
                    } else {
                        onException(new IOException("Failed to perform GET on: " + remoteUrl + " as response was: " + answer));
                        break;
                    }
                } else {
                    receiveCounter++;
                    DataInputStream stream = new DataInputStream(httpMethod.getResponseBodyAsStream());
                    Object command = (Object)getTextWireFormat().unmarshal(stream);
                    if (command == null) {
                        LOG.debug("Received null command from url: " + remoteUrl);
                    } else {
                        doConsume(command);
                    }
                }
            } catch (IOException e) {
                onException(IOExceptionSupport.create("Failed to perform GET on: " + remoteUrl + " Reason: " + e.getMessage(), e));
                break;
            } finally {
                httpMethod.releaseConnection();
            }
        }
    }

    // Properties
    // -------------------------------------------------------------------------
    public HttpClient getSendHttpClient() {
        if (sendHttpClient == null) {
            sendHttpClient = createHttpClient();
        }
        return sendHttpClient;
    }

    public void setSendHttpClient(HttpClient sendHttpClient) {
        this.sendHttpClient = sendHttpClient;
    }

    public HttpClient getReceiveHttpClient() {
        if (receiveHttpClient == null) {
            receiveHttpClient = createHttpClient();
        }
        return receiveHttpClient;
    }

    public void setReceiveHttpClient(HttpClient receiveHttpClient) {
        this.receiveHttpClient = receiveHttpClient;
    }

    // Implementation methods
    // -------------------------------------------------------------------------
    protected void doStart() throws Exception {

        LOG.trace("HTTP GET consumer thread starting: " + this);
        HttpClient httpClient = getReceiveHttpClient();
        URI remoteUrl = getRemoteUrl();

        HeadMethod httpMethod = new HeadMethod(remoteUrl.toString());
        configureMethod(httpMethod);

        int answer = httpClient.executeMethod(httpMethod);
        if (answer != HttpStatus.SC_OK) {
            throw new IOException("Failed to perform GET on: " + remoteUrl + " as response was: " + answer);
        }

        super.doStart();
    }

    protected void doStop(ServiceStopper stopper) throws Exception {
        if (httpMethod != null) {
            httpMethod.abort();
        }
    }

    protected HttpClient createHttpClient() {
        HttpClient client = new HttpClient();
        if (getProxyHost() != null) {
            client.getHostConfiguration().setProxy(getProxyHost(), getProxyPort());
        }
        return client;
    }

    protected void configureMethod(HttpMethod method) {
        method.setRequestHeader("clientID", clientID);
    }

    public boolean isTrace() {
        return trace;
    }

    public void setTrace(boolean trace) {
        this.trace = trace;
    }

    public int getReceiveCounter() {
        return receiveCounter;
    }

    public int getSoTimeout() {
        return soTimeout;
    }

    public void setSoTimeout(int soTimeout) {
        this.soTimeout = soTimeout;
    }
}