001    /*
002     * Sonar, open source software quality management tool.
003     * Copyright (C) 2008-2012 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.io.NotSerializableException;
023    import java.io.ObjectInputStream;
024    import java.io.ObjectOutputStream;
025    import java.lang.ref.Reference;
026    import java.lang.ref.SoftReference;
027    import java.text.DateFormat;
028    import java.text.FieldPosition;
029    import java.text.ParsePosition;
030    import java.text.SimpleDateFormat;
031    import java.util.Date;
032    
033    /**
034     * Parses and formats <a href="http://en.wikipedia.org/wiki/ISO_8601">ISO 8601</a> dates.
035     * This class is thread-safe.
036     *
037     * @since 2.7
038     */
039    public final class DateUtils {
040      public static final String DATE_FORMAT = "yyyy-MM-dd";
041      public static final String DATETIME_FORMAT = "yyyy-MM-dd'T'HH:mm:ssZ";
042    
043      private static final ThreadSafeDateFormat THREAD_SAFE_DATE_FORMAT = new ThreadSafeDateFormat(DATE_FORMAT);
044      private static final ThreadSafeDateFormat THREAD_SAFE_DATETIME_FORMAT = new ThreadSafeDateFormat(DATETIME_FORMAT);
045    
046      private DateUtils() {
047      }
048    
049      public static String formatDate(Date d) {
050        return THREAD_SAFE_DATE_FORMAT.format(d);
051      }
052    
053      public static String formatDateTime(Date d) {
054        return THREAD_SAFE_DATETIME_FORMAT.format(d);
055      }
056    
057      /**
058       * @param s string in format {@link #DATE_FORMAT}
059       * @throws SonarException when string cannot be parsed
060       */
061      public static Date parseDate(String s) {
062        ParsePosition pos = new ParsePosition(0);
063        Date result = THREAD_SAFE_DATE_FORMAT.parse(s, pos);
064        if (pos.getIndex() != s.length()) {
065          throw new SonarException("The date '" + s + "' does not respect format '" + DATE_FORMAT + "'");
066        }
067        return result;
068      }
069    
070      /**
071       * @param s string in format {@link #DATETIME_FORMAT}
072       * @throws SonarException when string cannot be parsed
073       */
074      public static Date parseDateTime(String s) {
075        ParsePosition pos = new ParsePosition(0);
076        Date result = THREAD_SAFE_DATETIME_FORMAT.parse(s, pos);
077        if (pos.getIndex() != s.length()) {
078          throw new SonarException("The date '" + s + "' does not respect format '" + DATETIME_FORMAT + "'");
079        }
080        return result;
081      }
082    
083      static class ThreadSafeDateFormat extends DateFormat {
084        private final String format;
085    
086        ThreadSafeDateFormat(String format) {
087          this.format = format;
088        }
089    
090        private final ThreadLocal<Reference<DateFormat>> cache = new ThreadLocal<Reference<DateFormat>>() {
091          public Reference<DateFormat> get() {
092            Reference<DateFormat> softRef = super.get();
093            if (softRef == null || softRef.get() == null) {
094              softRef = new SoftReference<DateFormat>(new SimpleDateFormat(format));
095              super.set(softRef);
096            }
097            return softRef;
098          }
099        };
100    
101        private DateFormat getDateFormat() {
102          return (DateFormat) ((Reference) cache.get()).get();
103        }
104    
105        public StringBuffer format(Date date, StringBuffer toAppendTo, FieldPosition fieldPosition) {
106          return getDateFormat().format(date, toAppendTo, fieldPosition);
107        }
108    
109        public Date parse(String source, ParsePosition pos) {
110          return getDateFormat().parse(source, pos);
111        }
112    
113        private void readObject(ObjectInputStream ois) throws NotSerializableException {
114          throw new NotSerializableException();
115        }
116    
117        private void writeObject(ObjectOutputStream ois) throws NotSerializableException {
118          throw new NotSerializableException();
119        }
120      }
121    }