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Java example source code file (ManagerConnectDirect.java)

This example source code file (ManagerConnectDirect.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

basichttpparams, clientconnectionmanager, clientconnectionrequest, exception, httpcontext, httphost, httpparams, httprequest, httpresponse, httproute, managerconnectdirect, options, schemeregistry, threadsafeclientconnmanager

The ManagerConnectDirect.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.examples.conn;


import org.apache.http.Header;
import org.apache.http.HttpHost;
import org.apache.http.HttpRequest;
import org.apache.http.HttpResponse;
import org.apache.http.HttpVersion;
import org.apache.http.conn.ClientConnectionManager;
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.ClientConnectionRequest;
import org.apache.http.conn.ManagedClientConnection;
import org.apache.http.impl.conn.tsccm.ThreadSafeClientConnManager;
import org.apache.http.message.BasicHttpRequest;
import org.apache.http.params.BasicHttpParams;
import org.apache.http.params.HttpParams;
import org.apache.http.params.HttpProtocolParams;
import org.apache.http.protocol.HttpContext;
import org.apache.http.protocol.BasicHttpContext;



/**
 * How to open a direct connection using
 * {@link ClientConnectionManager ClientConnectionManager}.
 * This exemplifies the <i>opening of the connection only.
 * The subsequent message exchange in this example should not
 * be used as a template.
 *
 *
 *
 * @since 4.0
 */
public class ManagerConnectDirect {

    /**
     * The default parameters.
     * Instantiated in {@link #setup setup}.
     */
    private static HttpParams defaultParameters = null;

    /**
     * The scheme registry.
     * Instantiated in {@link #setup setup}.
     */
    private static SchemeRegistry supportedSchemes;


    /**
     * Main entry point to this example.
     *
     * @param args      ignored
     */
    public final static void main(String[] args)
        throws Exception {

        final HttpHost target = new HttpHost("jakarta.apache.org", 80, "http");

        setup(); // some general setup

        ClientConnectionManager clcm = createManager();

        HttpRequest req = createRequest(target);
        HttpContext ctx = createContext();

        System.out.println("preparing route to " + target);
        HttpRoute route = new HttpRoute
            (target, null, supportedSchemes.getScheme(target).isLayered());

        System.out.println("requesting connection for " + route);
        ClientConnectionRequest connRequest = clcm.requestConnection(route, null);
        ManagedClientConnection conn = connRequest.getConnection(0, null);
        try {
            System.out.println("opening connection");
            conn.open(route, ctx, getParams());

            System.out.println("sending request");
            conn.sendRequestHeader(req);
            // there is no request entity
            conn.flush();

            System.out.println("receiving response header");
            HttpResponse rsp = conn.receiveResponseHeader();

            System.out.println("----------------------------------------");
            System.out.println(rsp.getStatusLine());
            Header[] headers = rsp.getAllHeaders();
            for (int i=0; i<headers.length; i++) {
                System.out.println(headers[i]);
            }
            System.out.println("----------------------------------------");

            System.out.println("closing connection");
            conn.close();

        } finally {

            if (conn.isOpen()) {
                System.out.println("shutting down connection");
                try {
                    conn.shutdown();
                } catch (Exception x) {
                    System.out.println("problem during shutdown");
                    x.printStackTrace(System.out);
                }
            }

            System.out.println("releasing connection");
            clcm.releaseConnection(conn, -1, null);
        }

    } // main


    private final static ClientConnectionManager createManager() {

        return new ThreadSafeClientConnManager(getParams(), supportedSchemes);
    }


    /**
     * Performs general setup.
     * This should be called only once.
     */
    private final static void setup() {

        // Register the "http" protocol scheme, it is required
        // by the default operator to look up socket factories.
        supportedSchemes = new SchemeRegistry();
        SocketFactory sf = PlainSocketFactory.getSocketFactory();
        supportedSchemes.register(new Scheme("http", sf, 80));

        // Prepare parameters.
        // Since this example doesn't use the full core framework,
        // only few parameters are actually required.
        HttpParams params = new BasicHttpParams();
        HttpProtocolParams.setVersion(params, HttpVersion.HTTP_1_1);
        HttpProtocolParams.setUseExpectContinue(params, false);
        defaultParameters = params;

    } // setup


    private final static HttpParams getParams() {
        return defaultParameters;
    }


    /**
     * Creates a request to execute in this example.
     * In a real application, request interceptors should be used
     * to add the required headers.
     *
     * @param target    the target server for the request
     *
     * @return  a request without an entity
     */
    private final static HttpRequest createRequest(HttpHost target) {

        HttpRequest req = new BasicHttpRequest
            ("OPTIONS", "*", HttpVersion.HTTP_1_1);

        req.addHeader("Host", target.getHostName());

        return req;
    }


    /**
     * Creates a context for executing a request.
     * Since this example doesn't really use the execution framework,
     * the context can be left empty.
     *
     * @return  a new, empty context
     */
    private final static HttpContext createContext() {
        return new BasicHttpContext(null);
    }

} // class ManagerConnectDirect

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