001    /*
002     * Sonar, open source software quality management tool.
003     * Copyright (C) 2008-2011 SonarSource
004     * mailto:contact AT sonarsource DOT com
005     *
006     * Sonar is free software; you can redistribute it and/or
007     * modify it under the terms of the GNU Lesser General Public
008     * License as published by the Free Software Foundation; either
009     * version 3 of the License, or (at your option) any later version.
010     *
011     * Sonar is distributed in the hope that it will be useful,
012     * but WITHOUT ANY WARRANTY; without even the implied warranty of
013     * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
014     * Lesser General Public License for more details.
015     *
016     * You should have received a copy of the GNU Lesser General Public
017     * License along with Sonar; if not, write to the Free Software
018     * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02
019     */
020    package org.sonar.api.utils;
021    
022    import java.lang.ref.Reference;
023    import java.lang.ref.SoftReference;
024    import java.text.DateFormat;
025    import java.text.FieldPosition;
026    import java.text.ParsePosition;
027    import java.text.SimpleDateFormat;
028    import java.util.Date;
029    
030    /**
031     * Parses and formats <a href="http://en.wikipedia.org/wiki/ISO_8601">ISO 8601</a> dates.
032     * This class is thread-safe.
033     *
034     * @since 2.7
035     */
036    public final class DateUtils {
037      public static final String DATE_FORMAT = "yyyy-MM-dd";
038      public static final String DATETIME_FORMAT = "yyyy-MM-dd'T'HH:mm:ssZ";
039    
040      private static final ThreadSafeDateFormat THREAD_SAFE_DATE_FORMAT = new ThreadSafeDateFormat(DATE_FORMAT);
041      private static final ThreadSafeDateFormat THREAD_SAFE_DATETIME_FORMAT = new ThreadSafeDateFormat(DATETIME_FORMAT);
042    
043      private DateUtils() {
044      }
045    
046      public static String formatDate(Date d) {
047        return THREAD_SAFE_DATE_FORMAT.format(d);
048      }
049    
050      public static String formatDateTime(Date d) {
051        return THREAD_SAFE_DATETIME_FORMAT.format(d);
052      }
053    
054      /**
055       * @param s string in format {@link #DATE_FORMAT}
056       * @throws SonarException when string cannot be parsed
057       */
058      public static Date parseDate(String s) {
059        ParsePosition pos = new ParsePosition(0);
060        Date result = THREAD_SAFE_DATE_FORMAT.parse(s, pos);
061        if (pos.getIndex() != s.length()) {
062          throw new SonarException("The date '" + s + "' does not respect format '" + DATE_FORMAT + "'");
063        }
064        return result;
065      }
066    
067      /**
068       * @param s string in format {@link #DATETIME_FORMAT}
069       * @throws SonarException when string cannot be parsed
070       */
071      public static Date parseDateTime(String s) {
072        ParsePosition pos = new ParsePosition(0);
073        Date result = THREAD_SAFE_DATETIME_FORMAT.parse(s, pos);
074        if (pos.getIndex() != s.length()) {
075          throw new SonarException("The date '" + s + "' does not respect format '" + DATETIME_FORMAT + "'");
076        }
077        return result;
078      }
079    
080      static class ThreadSafeDateFormat extends DateFormat {
081        private static final long serialVersionUID = -8856468429474634301L;
082        private final String format;
083    
084        ThreadSafeDateFormat(String format) {
085          this.format = format;
086        }
087    
088        private final transient ThreadLocal<Reference<DateFormat>> cache = new ThreadLocal<Reference<DateFormat>>() {
089          public Reference<DateFormat> get() {
090            Reference<DateFormat> softRef = super.get();
091            if (softRef == null || softRef.get() == null) {
092              softRef = new SoftReference<DateFormat>(new SimpleDateFormat(format));
093              super.set(softRef);
094            }
095            return softRef;
096          }
097        };
098    
099        private DateFormat getDateFormat() {
100          return (DateFormat) ((Reference) cache.get()).get();
101        }
102    
103        public StringBuffer format(Date date, StringBuffer toAppendTo, FieldPosition fieldPosition) {
104          return getDateFormat().format(date, toAppendTo, fieldPosition);
105        }
106    
107        public Date parse(String source, ParsePosition pos) {
108          return getDateFormat().parse(source, pos);
109        }
110      }
111    }