001/*
002 * SonarQube, open source software quality management tool.
003 * Copyright (C) 2008-2013 SonarSource
004 * mailto:contact AT sonarsource DOT com
005 *
006 * SonarQube 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 * SonarQube 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 License
017 * along with this program; if not, write to the Free Software Foundation,
018 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
019 */
020package org.sonar.api.utils;
021
022import javax.annotation.Nullable;
023import java.io.NotSerializableException;
024import java.io.ObjectInputStream;
025import java.io.ObjectOutputStream;
026import java.lang.ref.Reference;
027import java.lang.ref.SoftReference;
028import java.text.DateFormat;
029import java.text.FieldPosition;
030import java.text.ParsePosition;
031import java.text.SimpleDateFormat;
032import java.util.Date;
033
034/**
035 * Parses and formats <a href="http://en.wikipedia.org/wiki/ISO_8601">ISO 8601</a> dates.
036 * This class is thread-safe.
037 *
038 * @since 2.7
039 */
040public final class DateUtils {
041  public static final String DATE_FORMAT = "yyyy-MM-dd";
042  public static final String DATETIME_FORMAT = "yyyy-MM-dd'T'HH:mm:ssZ";
043
044  private static final ThreadSafeDateFormat THREAD_SAFE_DATE_FORMAT = new ThreadSafeDateFormat(DATE_FORMAT);
045  private static final ThreadSafeDateFormat THREAD_SAFE_DATETIME_FORMAT = new ThreadSafeDateFormat(DATETIME_FORMAT);
046
047  private DateUtils() {
048  }
049
050  public static String formatDate(Date d) {
051    return THREAD_SAFE_DATE_FORMAT.format(d);
052  }
053
054  public static String formatDateTime(Date d) {
055    return THREAD_SAFE_DATETIME_FORMAT.format(d);
056  }
057
058  /**
059   * @param s string in format {@link #DATE_FORMAT}
060   * @throws SonarException when string cannot be parsed
061   */
062  public static Date parseDate(String s) {
063    ParsePosition pos = new ParsePosition(0);
064    Date result = THREAD_SAFE_DATE_FORMAT.parse(s, pos);
065    if (pos.getIndex() != s.length()) {
066      throw new SonarException("The date '" + s + "' does not respect format '" + DATE_FORMAT + "'");
067    }
068    return result;
069  }
070
071  /**
072   * Parse format {@link #DATE_FORMAT}. This method never throws exception.
073   *
074   * @param s any string
075   * @return the date, null if parsing error or null string
076   * @since 3.0
077   */
078  public static Date parseDateQuietly(@Nullable String s) {
079    Date date = null;
080    if (s != null) {
081      try {
082        date = parseDate(s);
083      } catch (RuntimeException e) {
084        // ignore
085      }
086
087    }
088    return date;
089  }
090
091  /**
092   * @param s string in format {@link #DATETIME_FORMAT}
093   * @throws SonarException when string cannot be parsed
094   */
095
096  public static Date parseDateTime(String s) {
097    ParsePosition pos = new ParsePosition(0);
098    Date result = THREAD_SAFE_DATETIME_FORMAT.parse(s, pos);
099    if (pos.getIndex() != s.length()) {
100      throw new SonarException("The date '" + s + "' does not respect format '" + DATETIME_FORMAT + "'");
101    }
102    return result;
103  }
104
105  /**
106   * Parse format {@link #DATETIME_FORMAT}. This method never throws exception.
107   *
108   * @param s any string
109   * @return the datetime, null if parsing error or null string
110   */
111  public static Date parseDateTimeQuietly(@Nullable String s) {
112    Date datetime = null;
113    if (s != null) {
114      try {
115        datetime = parseDateTime(s);
116      } catch (RuntimeException e) {
117        // ignore
118      }
119
120    }
121    return datetime;
122  }
123
124  static class ThreadSafeDateFormat extends DateFormat {
125    private final String format;
126
127    ThreadSafeDateFormat(String format) {
128      this.format = format;
129    }
130
131    private final ThreadLocal<Reference<DateFormat>> cache = new ThreadLocal<Reference<DateFormat>>() {
132      @Override
133      public Reference<DateFormat> get() {
134        Reference<DateFormat> softRef = super.get();
135        if (softRef == null || softRef.get() == null) {
136          softRef = new SoftReference<DateFormat>(new SimpleDateFormat(format));
137          super.set(softRef);
138        }
139        return softRef;
140      }
141    };
142
143    private DateFormat getDateFormat() {
144      return (DateFormat) ((Reference) cache.get()).get();
145    }
146
147    @Override
148    public StringBuffer format(Date date, StringBuffer toAppendTo, FieldPosition fieldPosition) {
149      return getDateFormat().format(date, toAppendTo, fieldPosition);
150    }
151
152    @Override
153    public Date parse(String source, ParsePosition pos) {
154      return getDateFormat().parse(source, pos);
155    }
156
157    private void readObject(ObjectInputStream ois) throws NotSerializableException {
158      throw new NotSerializableException();
159    }
160
161    private void writeObject(ObjectOutputStream ois) throws NotSerializableException {
162      throw new NotSerializableException();
163    }
164  }
165}