1 /*
2 * Copyright 1999,2006 The Apache Software Foundation.
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 package org.apache.commons.feedparser.tools;
18
19 import java.text.SimpleDateFormat;
20 import java.util.Date;
21 import java.util.Locale;
22 import java.util.TimeZone;
23
24 /**
25 * ISO 8601 date parsing utility. Designed for parsing the ISO subset used in
26 * Dublin Core, RSS 1.0, and Atom.
27 *
28 * @author <a href="mailto:burton@apache.org">Kevin A. Burton (burtonator)</a>
29 * @version $Id: ISO8601DateParser.java 373572 2006-01-30 19:28:41Z mvdb $
30 */
31 public class ISO8601DateParser {
32
33 // 2004-06-14T19:GMT20:30Z
34 // 2004-06-20T06:GMT22:01Z
35
36 private static SimpleDateFormat df
37 = new SimpleDateFormat( "yyyy-MM-dd'T'hh:mm:ssz", Locale.ENGLISH );
38
39 // http://www.cl.cam.ac.uk/~mgk25/iso-time.html
40 //
41 // http://www.intertwingly.net/wiki/pie/DateTime
42 //
43 // http://www.w3.org/TR/NOTE-datetime
44 //
45 // Different standards may need different levels of granularity in the date and
46 // time, so this profile defines six levels. Standards that reference this
47 // profile should specify one or more of these granularities. If a given
48 // standard allows more than one granularity, it should specify the meaning of
49 // the dates and times with reduced precision, for example, the result of
50 // comparing two dates with different precisions.
51
52 // The formats are as follows. Exactly the components shown here must be
53 // present, with exactly this punctuation. Note that the "T" appears literally
54 // in the string, to indicate the beginning of the time element, as specified in
55 // ISO 8601.
56
57 // Year:
58 // YYYY (eg 1997)
59 // Year and month:
60 // YYYY-MM (eg 1997-07)
61 // Complete date:
62 // YYYY-MM-DD (eg 1997-07-16)
63 // Complete date plus hours and minutes:
64 // YYYY-MM-DDThh:mmTZD (eg 1997-07-16T19:20+01:00)
65 // Complete date plus hours, minutes and seconds:
66 // YYYY-MM-DDThh:mm:ssTZD (eg 1997-07-16T19:20:30+01:00)
67 // Complete date plus hours, minutes, seconds and a decimal fraction of a
68 // second
69 // YYYY-MM-DDThh:mm:ss.sTZD (eg 1997-07-16T19:20:30.45+01:00)
70
71 // where:
72
73 // YYYY = four-digit year
74 // MM = two-digit month (01=January, etc.)
75 // DD = two-digit day of month (01 through 31)
76 // hh = two digits of hour (00 through 23) (am/pm NOT allowed)
77 // mm = two digits of minute (00 through 59)
78 // ss = two digits of second (00 through 59)
79 // s = one or more digits representing a decimal fraction of a second
80 // TZD = time zone designator (Z or +hh:mm or -hh:mm)
81 public static Date parse( String input ) throws java.text.ParseException {
82
83 //NOTE: SimpleDateFormat uses GMT[-+]hh:mm for the TZ which breaks
84 //things a bit. Before we go on we have to repair this.
85
86 //this is zero time so we need to add that TZ indicator for
87 if ( input.endsWith( "Z" ) ) {
88 input = input.substring( 0, input.length() - 1) + "GMT-00:00";
89 } else {
90 int inset = 6;
91
92 String s0 = input.substring( 0, input.length() - inset );
93 String s1 = input.substring( input.length() - inset, input.length() );
94
95 input = s0 + "GMT" + s1;
96 }
97
98 return df.parse( input );
99
100 }
101
102 public static String toString( Date date ) {
103
104 TimeZone tz = TimeZone.getTimeZone( "UTC" );
105
106 df.setTimeZone( tz );
107
108 String output = df.format( date );
109
110 int inset0 = 9;
111 int inset1 = 6;
112
113 String s0 = output.substring( 0, output.length() - inset0 );
114 String s1 = output.substring( output.length() - inset1, output.length() );
115
116 String result = s0 + s1;
117
118 result = result.replaceAll( "UTC", "+00:00" );
119
120 return result;
121
122 }
123
124 public static void main( String[] args ) throws Exception {
125
126 System.out.println( parse( "2004-05-31T09:19:31-06:00" ) );
127 System.out.println( parse( "2004-06-23T17:25:31-00:00" ) );
128 System.out.println( parse( "2004-06-23T17:25:31Z" ) );
129
130 //2002-10-02T10:00:00-05:00
131 System.out.println( "v: " + toString( new Date( System.currentTimeMillis() ) ) );
132
133 }
134
135 }
136