01: /*
02: * $HeadURL: https://svn.apache.org/repos/asf/httpcomponents/httpcore/tags/4.0-beta1/module-main/src/main/java/org/apache/http/protocol/HttpDateGenerator.java $
03: * $Revision: 548066 $
04: * $Date: 2007-06-17 18:51:55 +0200 (Sun, 17 Jun 2007) $
05: *
06: * ====================================================================
07: * Licensed to the Apache Software Foundation (ASF) under one
08: * or more contributor license agreements. See the NOTICE file
09: * 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: */
31:
32: package org.apache.http.protocol;
33:
34: import java.text.DateFormat;
35: import java.text.SimpleDateFormat;
36: import java.util.Date;
37: import java.util.Locale;
38: import java.util.TimeZone;
39:
40: /**
41: * Generates a date in the format required by the HTTP protocol.
42: *
43: * @author <a href="mailto:oleg at ural.ru">Oleg Kalnichevski</a>
44: *
45: * @version $Revision: 548066 $
46: *
47: * @since 4.0
48: */
49: public class HttpDateGenerator {
50:
51: /** Date format pattern used to generate the header in RFC 1123 format. */
52: public static final String PATTERN_RFC1123 = "EEE, dd MMM yyyy HH:mm:ss zzz";
53:
54: /** The time zone to use in the date header. */
55: public static final TimeZone GMT = TimeZone.getTimeZone("GMT");
56:
57: private final DateFormat dateformat;
58:
59: private long dateAsLong = 0L;
60: private String dateAsText = null;
61:
62: public HttpDateGenerator() {
63: super ();
64: this .dateformat = new SimpleDateFormat(PATTERN_RFC1123,
65: Locale.US);
66: this .dateformat.setTimeZone(GMT);
67: }
68:
69: public synchronized String getCurrentDate() {
70: long now = System.currentTimeMillis();
71: if (now - this .dateAsLong > 1000) {
72: // Generate new date string
73: this .dateAsText = this .dateformat.format(new Date(now));
74: this.dateAsLong = now;
75: }
76: return this.dateAsText;
77: }
78:
79: }
|