1/*
2 * $HeadURL: $
3 * $Revision: $
4 * $Date: $
5 *
6 * ====================================================================
7 * Licensed to the Apache Software Foundation (ASF) under one
8 * or more contributor license agreements.  See the NOTICE file
9 * distributed with this work for additional information
10 * regarding copyright ownership.  The ASF licenses this file
11 * to you under the Apache License, Version 2.0 (the
12 * "License"); you may not use this file except in compliance
13 * with the License.  You may obtain a copy of the License at
14 *
15 *   http://www.apache.org/licenses/LICENSE-2.0
16 *
17 * Unless required by applicable law or agreed to in writing,
18 * software distributed under the License is distributed on an
19 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
20 * KIND, either express or implied.  See the License for the
21 * specific language governing permissions and limitations
22 * under the License.
23 * ====================================================================
24 *
25 * This software consists of voluntary contributions made by many
26 * individuals on behalf of the Apache Software Foundation.  For more
27 * information on the Apache Software Foundation, please see
28 * <http://www.apache.org/>.
29 *
30 */
31package org.apache.http.impl.client;
32
33import org.apache.http.HeaderElement;
34import org.apache.http.HeaderElementIterator;
35import org.apache.http.HttpResponse;
36import org.apache.http.conn.ConnectionKeepAliveStrategy;
37import org.apache.http.message.BasicHeaderElementIterator;
38import org.apache.http.protocol.HTTP;
39import org.apache.http.protocol.HttpContext;
40
41/**
42 * Default implementation of a strategy deciding duration
43 * that a connection can remain idle.
44 *
45 * The default implementation looks solely at the 'Keep-Alive'
46 * header's timeout token.
47 *
48 * @author <a href="mailto:sberlin at gmail.com">Sam Berlin</a>
49 *
50 * @version $Revision: $
51 *
52 * @since 4.0
53 */
54public class DefaultConnectionKeepAliveStrategy implements ConnectionKeepAliveStrategy {
55
56    public long getKeepAliveDuration(HttpResponse response, HttpContext context) {
57        if (response == null) {
58            throw new IllegalArgumentException("HTTP response may not be null");
59        }
60        HeaderElementIterator it = new BasicHeaderElementIterator(
61                response.headerIterator(HTTP.CONN_KEEP_ALIVE));
62        while (it.hasNext()) {
63            HeaderElement he = it.nextElement();
64            String param = he.getName();
65            String value = he.getValue();
66            if (value != null && param.equalsIgnoreCase("timeout")) {
67                try {
68                    return Long.parseLong(value) * 1000;
69                } catch(NumberFormatException ignore) {
70                }
71            }
72        }
73        return -1;
74    }
75
76}
77