001 // License: GPL. For details, see LICENSE file.
002 package org.openstreetmap.josm.tools;
003
004 import java.text.DateFormat;
005 import java.text.ParseException;
006 import java.text.SimpleDateFormat;
007 import java.util.ArrayList;
008 import java.util.Date;
009 import java.util.List;
010
011 /**
012 * Handles a number of different date formats encountered in OSM. This is built
013 * based on similar code in JOSM. This class is not threadsafe, a separate
014 * instance must be created per thread.
015 *
016 * @author Brett Henderson
017 */
018 public class FallbackDateParser {
019
020 private static final String[] formats = {
021 "yyyy-MM-dd'T'HH:mm:ss'Z'",
022 "yyyy-MM-dd'T'HH:mm:ssZ",
023 "yyyy-MM-dd'T'HH:mm:ss",
024 "yyyy-MM-dd'T'HH:mm:ss.SSS'Z'",
025 "yyyy-MM-dd'T'HH:mm:ss.SSSZ",
026 "yyyy-MM-dd HH:mm:ss",
027 "MM/dd/yyyy HH:mm:ss",
028 "MM/dd/yyyy'T'HH:mm:ss.SSS'Z'",
029 "MM/dd/yyyy'T'HH:mm:ss.SSSZ",
030 "MM/dd/yyyy'T'HH:mm:ss.SSS",
031 "MM/dd/yyyy'T'HH:mm:ssZ",
032 "MM/dd/yyyy'T'HH:mm:ss",
033 "yyyy:MM:dd HH:mm:ss"
034 };
035
036 private List<DateFormat> dateParsers;
037 private int activeDateParser;
038
039 /**
040 * Creates a new instance.
041 */
042 public FallbackDateParser() {
043 // Build a list of candidate date parsers.
044 dateParsers = new ArrayList<DateFormat>(formats.length);
045 for (int i = 0; i < formats.length; i++) {
046 dateParsers.add(new SimpleDateFormat(formats[i]));
047 }
048
049 // We haven't selected a date parser yet.
050 activeDateParser = -1;
051 }
052
053 /**
054 * Attempts to parse the specified date.
055 *
056 * @param date
057 * The date to parse.
058 * @return The date.
059 * @throws ParseException
060 * Occurs if the date does not match any of the supported date
061 * formats.
062 */
063 public Date parse(String date) throws ParseException {
064 String correctedDate;
065
066 // Try to fix ruby's broken xmlschema - format
067 // Replace this:
068 // 2007-02-12T18:43:01+00:00
069 // With this:
070 // 2007-02-12T18:43:01+0000
071 if (date.length() == 25 && date.charAt(22) == ':') {
072 correctedDate = date.substring(0, 22) + date.substring(23, 25);
073 } else {
074 correctedDate = date;
075 }
076
077 // If we have previously successfully used a date parser, we'll try it
078 // first.
079 if (activeDateParser >= 0) {
080 try {
081 return dateParsers.get(activeDateParser).parse(correctedDate);
082 } catch (ParseException e) {
083 // The currently active parser didn't work, so we must clear it
084 // and find a new appropriate parser.
085 activeDateParser = -1;
086 }
087 }
088
089 // Try the date parsers one by one until a suitable format is found.
090 for (int i = 0; i < dateParsers.size(); i++) {
091 try {
092 Date result;
093
094 // Attempt to parse with the current parser, if successful we
095 // store its index for next time.
096 result = dateParsers.get(i).parse(correctedDate);
097 activeDateParser = i;
098
099 return result;
100
101 } catch (ParseException pe) {
102 // Ignore parsing errors and try the next pattern.
103 }
104 }
105
106 throw new ParseException("The date string (" + date + ") could not be parsed.", 0);
107 }
108 }