Java tutorial
/* * ==================================================================== * 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.http2.impl.conn; import java.io.IOException; import java.net.ConnectException; import java.net.InetSocketAddress; import java.net.Socket; import java.net.InetAddress; import java.net.UnknownHostException; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.apache.http2.annotation.ThreadSafe; import org.apache.http2.HttpHost; import org.apache.http2.params.HttpParams; import org.apache.http2.params.HttpConnectionParams; import org.apache.http2.protocol.HttpContext; import org.apache.http2.conn.ConnectTimeoutException; import org.apache.http2.conn.HttpHostConnectException; import org.apache.http2.conn.HttpInetSocketAddress; import org.apache.http2.conn.OperatedClientConnection; import org.apache.http2.conn.ClientConnectionOperator; import org.apache.http2.conn.scheme.SchemeLayeredSocketFactory; import org.apache.http2.conn.scheme.Scheme; import org.apache.http2.conn.scheme.SchemeRegistry; import org.apache.http2.conn.scheme.SchemeSocketFactory; import org.apache.http2.conn.DnsResolver; /** * Default implementation of a {@link ClientConnectionOperator}. It uses a {@link SchemeRegistry} * to look up {@link SchemeSocketFactory} objects. * <p> * This connection operator is multihome network aware and will attempt to retry failed connects * against all known IP addresses sequentially until the connect is successful or all known * addresses fail to respond. Please note the same * {@link org.apache.http.params.CoreConnectionPNames#CONNECTION_TIMEOUT} value will be used * for each connection attempt, so in the worst case the total elapsed time before timeout * can be <code>CONNECTION_TIMEOUT * n</code> where <code>n</code> is the number of IP addresses * of the given host. One can disable multihome support by overriding * the {@link #resolveHostname(String)} method and returning only one IP address for the given * host name. * <p> * The following parameters can be used to customize the behavior of this * class: * <ul> * <li>{@link org.apache.http.params.CoreProtocolPNames#HTTP_ELEMENT_CHARSET}</li> * <li>{@link org.apache.http.params.CoreConnectionPNames#SO_TIMEOUT}</li> * <li>{@link org.apache.http.params.CoreConnectionPNames#SO_LINGER}</li> * <li>{@link org.apache.http.params.CoreConnectionPNames#SO_REUSEADDR}</li> * <li>{@link org.apache.http.params.CoreConnectionPNames#TCP_NODELAY}</li> * <li>{@link org.apache.http.params.CoreConnectionPNames#SOCKET_BUFFER_SIZE}</li> * <li>{@link org.apache.http.params.CoreConnectionPNames#CONNECTION_TIMEOUT}</li> * <li>{@link org.apache.http.params.CoreConnectionPNames#MAX_LINE_LENGTH}</li> * </ul> * * @since 4.0 */ @ThreadSafe public class DefaultClientConnectionOperator implements ClientConnectionOperator { private final Log log = LogFactory.getLog(getClass()); /** The scheme registry for looking up socket factories. */ protected final SchemeRegistry schemeRegistry; // @ThreadSafe /** the custom-configured DNS lookup mechanism. */ protected final DnsResolver dnsResolver; /** * Creates a new client connection operator for the given scheme registry. * * @param schemes the scheme registry * * @since 4.2 */ public DefaultClientConnectionOperator(final SchemeRegistry schemes) { if (schemes == null) { throw new IllegalArgumentException("Scheme registry amy not be null"); } this.schemeRegistry = schemes; this.dnsResolver = new SystemDefaultDnsResolver(); } /** * Creates a new client connection operator for the given scheme registry * and the given custom DNS lookup mechanism. * * @param schemes * the scheme registry * @param dnsResolver * the custom DNS lookup mechanism */ public DefaultClientConnectionOperator(final SchemeRegistry schemes, final DnsResolver dnsResolver) { if (schemes == null) { throw new IllegalArgumentException("Scheme registry may not be null"); } if (dnsResolver == null) { throw new IllegalArgumentException("DNS resolver may not be null"); } this.schemeRegistry = schemes; this.dnsResolver = dnsResolver; } public OperatedClientConnection createConnection() { return new DefaultClientConnection(); } public void openConnection(final OperatedClientConnection conn, final HttpHost target, final InetAddress local, final HttpContext context, final HttpParams params) throws IOException { if (conn == null) { throw new IllegalArgumentException("Connection may not be null"); } if (target == null) { throw new IllegalArgumentException("Target host may not be null"); } if (params == null) { throw new IllegalArgumentException("Parameters may not be null"); } if (conn.isOpen()) { throw new IllegalStateException("Connection must not be open"); } Scheme schm = schemeRegistry.getScheme(target.getSchemeName()); SchemeSocketFactory sf = schm.getSchemeSocketFactory(); InetAddress[] addresses = resolveHostname(target.getHostName()); int port = schm.resolvePort(target.getPort()); for (int i = 0; i < addresses.length; i++) { InetAddress address = addresses[i]; boolean last = i == addresses.length - 1; Socket sock = sf.createSocket(params); conn.opening(sock, target); InetSocketAddress remoteAddress = new HttpInetSocketAddress(target, address, port); InetSocketAddress localAddress = null; if (local != null) { localAddress = new InetSocketAddress(local, 0); } if (this.log.isDebugEnabled()) { this.log.debug("Connecting to " + remoteAddress); } try { Socket connsock = sf.connectSocket(sock, remoteAddress, localAddress, params); if (sock != connsock) { sock = connsock; conn.opening(sock, target); } prepareSocket(sock, context, params); conn.openCompleted(sf.isSecure(sock), params); return; } catch (ConnectException ex) { if (last) { throw new HttpHostConnectException(target, ex); } } catch (ConnectTimeoutException ex) { if (last) { throw ex; } } if (this.log.isDebugEnabled()) { this.log.debug("Connect to " + remoteAddress + " timed out. " + "Connection will be retried using another IP address"); } } } public void updateSecureConnection(final OperatedClientConnection conn, final HttpHost target, final HttpContext context, final HttpParams params) throws IOException { if (conn == null) { throw new IllegalArgumentException("Connection may not be null"); } if (target == null) { throw new IllegalArgumentException("Target host may not be null"); } if (params == null) { throw new IllegalArgumentException("Parameters may not be null"); } if (!conn.isOpen()) { throw new IllegalStateException("Connection must be open"); } final Scheme schm = schemeRegistry.getScheme(target.getSchemeName()); if (!(schm.getSchemeSocketFactory() instanceof SchemeLayeredSocketFactory)) { throw new IllegalArgumentException( "Target scheme (" + schm.getName() + ") must have layered socket factory."); } SchemeLayeredSocketFactory lsf = (SchemeLayeredSocketFactory) schm.getSchemeSocketFactory(); Socket sock; try { sock = lsf.createLayeredSocket(conn.getSocket(), target.getHostName(), target.getPort(), params); } catch (ConnectException ex) { throw new HttpHostConnectException(target, ex); } prepareSocket(sock, context, params); conn.update(sock, target, lsf.isSecure(sock), params); } /** * Performs standard initializations on a newly created socket. * * @param sock the socket to prepare * @param context the context for the connection * @param params the parameters from which to prepare the socket * * @throws IOException in case of an IO problem */ protected void prepareSocket(final Socket sock, final HttpContext context, final HttpParams params) throws IOException { sock.setTcpNoDelay(HttpConnectionParams.getTcpNoDelay(params)); sock.setSoTimeout(HttpConnectionParams.getSoTimeout(params)); int linger = HttpConnectionParams.getLinger(params); if (linger >= 0) { sock.setSoLinger(linger > 0, linger); } } /** * Resolves the given host name to an array of corresponding IP addresses, based on the * configured name service on the provided DNS resolver. If one wasn't provided, the system * configuration is used. * * @param host host name to resolve * @return array of IP addresses * @exception UnknownHostException if no IP address for the host could be determined. * * @see DnsResolver * @see SystemDefaultDnsResolver * * @since 4.1 */ protected InetAddress[] resolveHostname(final String host) throws UnknownHostException { return dnsResolver.resolve(host); } }