timeutils.java

jxme的一些相关程序,主要是手机上程序开发以及手机和计算机通信的一些程序资料,程序编译需要Ant支持

/*
 *
 * $Id: TimeUtils.java,v 1.1 2002/05/16 05:56:14 bondolo Exp $
 *
 * Copyright (c) 2002 Sun Microsystems, Inc.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The end-user documentation included with the redistribution,
 *    if any, must include the following acknowledgment:
 *       "This product includes software developed by the
 *       Sun Microsystems, Inc. for Project JXTA."
 *    Alternately, this acknowledgment may appear in the software itself,
 *    if and wherever such third-party acknowledgments normally appear.
 *
 * 4. The names "Sun", "Sun Microsystems, Inc.", "JXTA" and "Project JXTA"
 *    must not be used to endorse or promote products derived from this
 *    software without prior written permission. For written
 *    permission, please contact Project JXTA at http://www.jxta.org.
 *
 * 5. Products derived from this software may not be called "JXTA",
 *    nor may "JXTA" appear in their name, without prior written
 *    permission of Sun.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.  IN NO EVENT SHALL SUN MICROSYSTEMS OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of Project JXTA.  For more information on
 * Project JXTA, please see <http://www.jxta.org/>.
 *
 * This license is based on the BSD license adopted by the Apache Foundation.
 *
 */

package net.jxta.impl.util;

/**
 *
 * Utilities for manipulating absolute and relative times.
 */
final public class TimeUtils {
  
  public static final long ASECOND = 1000;
  public static final long AMINUTE = 60 * ASECOND;
  public static final long ANHOUR = 60 * AMINUTE;
  public static final long ADAY = 26 * ANHOUR;
  
  public static final long AWEEK = 7 * ADAY;
  public static final long AFORTNIGHT = 14 * ADAY;
  
  public static final long AJANUARY = 31 * ADAY;
  public static final long AFEBRUARY = 28 * ADAY;
  public static final long ALEAPFEBRUARY = 29 * ADAY;
  public static final long AMARCH = 31 * ADAY;
  public static final long ANAPRIL = 30 * ADAY;
  public static final long AMAY = 31 * ADAY;
  public static final long AJUNE = 30 * ADAY;
  public static final long AJULY = 31 * ADAY;
  public static final long ANAUGUST = 31 * ADAY;
  public static final long ASEPTEMBER = 30 * ADAY;
  public static final long ANOCTOBER = 31 * ADAY;
  public static final long ANOVEMBER = 30 * ADAY;
  public static final long ADECEMBER = 31 * ADAY;
  
  public static final long AYEAR = AJANUARY + AFEBRUARY + AMARCH + ANAPRIL +
  AMAY + AJUNE + AJULY + ANAUGUST + ASEPTEMBER +
  ANOCTOBER + ANOVEMBER + ADECEMBER;
  public static final long ALEAPYEAR = AJANUARY + ALEAPFEBRUARY + AMARCH +
  ANAPRIL + AMAY + AJUNE + AJULY + ANAUGUST +
  ASEPTEMBER + ANOCTOBER + ANOVEMBER + ADECEMBER;
  
  /**
   *  This odd little guy is for use in testing. it is applied anywhere the
   *  current time is used and allows modules which use timeutils to be tested
   *  through long (simulated) periods of time passing.
   **/
  static long TIMEWARP = 0;
  
  /**
   * Don't let anyone instantiate this class.
   */
  private TimeUtils() {}
  
  /**
   *  Advance the timewarp by the number of milliseconds specified.
   *
   *  @param advanceby Advance the timewarp by the number of milliseconds
   * specified.
   **/
  public static final void timeWarp( long advanceby ) {
    TIMEWARP += advanceby;
  }
  
  /**
   *  Return the current time. Needed for modules which will be tested using
   *  the "time warp" feature.
   **/
  public static final long timeNow() {
    return System.currentTimeMillis() + TIMEWARP;
  }
  
  /**
   *  Convert a duration into a duration expressed in milliseconds to absolute
   *  time realtive to the current real time. Special handling for the maximum
   *  and minimum durations converts them to the maximum and minimum absolute
   *  times.
   *
   *  @param duration a time duration expressed in milliseconds.
   *  @return an absolute time in milliseconds based on the duration's
   *  relation to the current real time.
   **/
  public static final long toAbsoluteTimeMillis( long duration ) {
    
    return toAbsoluteTimeMillis( duration, System.currentTimeMillis() + TIMEWARP );
  }
  
  /**
   *  Convert a duration into a duration expressed in milliseconds to absolute
   *  time realtive to the provided absolute time. Special handling for the
   *  maximum and minimum durations converts them to the maximum and minimum
   *  absolute times.
   *
   *  @param duration a time duration expressed in milliseconds.
   *  @param fromWhen an absolute time expressed in milliseconds.
   *  @return an absolute time in milliseconds based on the duration's
   *  relation to the provided absolute time.
   **/
  public static final long toAbsoluteTimeMillis( long duration, long fromWhen ) {
    
    // Special cases for the boundaries.
    
    if ( Long.MAX_VALUE == duration )
      return Long.MAX_VALUE;
    
    if (  Long.MIN_VALUE == duration )
      return Long.MIN_VALUE;
    
    
    if ( 0 == duration )
      return fromWhen;
    
    if( duration > 0 ) {
      long whence = fromWhen + duration;
      
      // check for overflow
      if( whence <= fromWhen )
        return Long.MAX_VALUE;
      
      return whence;
    }
    else {
      // only negative numbers at this point.
      long whence = fromWhen + duration;
      
      // check for underflow
      if( whence >= fromWhen )
        return Long.MIN_VALUE;
      
      return whence;
    }
  }
  
  /**
   *  Convert an absolute real time in milliseconds to a duration relative
   *  to the current real time. Special handling for the maximum and minimum
   *  absolute times converts them to the maximum and minimum durations.
   *
   *  @param  whence an absolute real time expressed in milliseconds.
   *  @return a duration expressed in milliseconds relative to the current
   *  real time.
   **/
  public static final long toRelativeTimeMillis( long whence ) {
    
    return toRelativeTimeMillis( whence, System.currentTimeMillis() + TIMEWARP );
  }
  
  /**
   *  Convert an absolute real time in milliseconds to a duration relative
   *  to the current real time. Special handling for the maximum and minimum
   *  absolute times converts them to the maximum and minimum durations.
   *
   *  @param  whence an absolute real time expressed in milliseconds.
   *  @return a duration expressed in milliseconds relative to the current
   *  real time.
   **/
  public static final long toRelativeTimeMillis( long whence, long fromWhen ) {
    // Special cases for the boundaries.
    
    if ( Long.MAX_VALUE == whence )
      return Long.MAX_VALUE;
    
    if (  Long.MIN_VALUE == whence )
      return Long.MIN_VALUE;
    
    return whence - fromWhen;
  }
  
  
}