001/* 002 * ==================================================================== 003 * Licensed to the Apache Software Foundation (ASF) under one 004 * or more contributor license agreements. See the NOTICE file 005 * distributed with this work for additional information 006 * regarding copyright ownership. The ASF licenses this file 007 * to you under the Apache License, Version 2.0 (the 008 * "License"); you may not use this file except in compliance 009 * with the License. You may obtain a copy of the License at 010 * 011 * http://www.apache.org/licenses/LICENSE-2.0 012 * 013 * Unless required by applicable law or agreed to in writing, 014 * software distributed under the License is distributed on an 015 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY 016 * KIND, either express or implied. See the License for the 017 * specific language governing permissions and limitations 018 * under the License. 019 * ==================================================================== 020 * 021 * This software consists of voluntary contributions made by many 022 * individuals on behalf of the Apache Software Foundation. For more 023 * information on the Apache Software Foundation, please see 024 * <http://www.apache.org/>. 025 * 026 */ 027package org.apache.http.impl.client; 028 029import org.apache.http.HeaderElement; 030import org.apache.http.HeaderElementIterator; 031import org.apache.http.HttpResponse; 032import org.apache.http.annotation.Contract; 033import org.apache.http.annotation.ThreadingBehavior; 034import org.apache.http.conn.ConnectionKeepAliveStrategy; 035import org.apache.http.message.BasicHeaderElementIterator; 036import org.apache.http.protocol.HTTP; 037import org.apache.http.protocol.HttpContext; 038import org.apache.http.util.Args; 039 040/** 041 * Default implementation of a strategy deciding duration 042 * that a connection can remain idle. 043 * 044 * The default implementation looks solely at the 'Keep-Alive' 045 * header's timeout token. 046 * 047 * @since 4.0 048 */ 049@Contract(threading = ThreadingBehavior.IMMUTABLE) 050public class DefaultConnectionKeepAliveStrategy implements ConnectionKeepAliveStrategy { 051 052 public static final DefaultConnectionKeepAliveStrategy INSTANCE = new DefaultConnectionKeepAliveStrategy(); 053 054 @Override 055 public long getKeepAliveDuration(final HttpResponse response, final HttpContext context) { 056 Args.notNull(response, "HTTP response"); 057 final HeaderElementIterator it = new BasicHeaderElementIterator( 058 response.headerIterator(HTTP.CONN_KEEP_ALIVE)); 059 while (it.hasNext()) { 060 final HeaderElement he = it.nextElement(); 061 final String param = he.getName(); 062 final String value = he.getValue(); 063 if (value != null && param.equalsIgnoreCase("timeout")) { 064 try { 065 return Long.parseLong(value) * 1000; 066 } catch(final NumberFormatException ignore) { 067 } 068 } 069 } 070 return -1; 071 } 072 073}