org.eclipse.jetty.util.DateCache Maven / Gradle / Ivy
Go to download
Show more of this group Show more artifacts with this name
Show all versions of ehcache Show documentation
Show all versions of ehcache Show documentation
Ehcache is an open source, standards-based cache used to boost performance,
offload the database and simplify scalability. Ehcache is robust, proven and full-featured and
this has made it the most widely-used Java-based cache.
//
// ========================================================================
// Copyright (c) 1995-2012 Mort Bay Consulting Pty. Ltd.
// ------------------------------------------------------------------------
// All rights reserved. This program and the accompanying materials
// are made available under the terms of the Eclipse Public License v1.0
// and Apache License v2.0 which accompanies this distribution.
//
// The Eclipse Public License is available at
// http://www.eclipse.org/legal/epl-v10.html
//
// The Apache License v2.0 is available at
// http://www.opensource.org/licenses/apache2.0.php
//
// You may elect to redistribute this code under either of these licenses.
// ========================================================================
//
package org.eclipse.jetty.util;
import java.text.DateFormatSymbols;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.Locale;
import java.util.TimeZone;
/* ------------------------------------------------------------ */
/** Date Format Cache.
* Computes String representations of Dates and caches
* the results so that subsequent requests within the same minute
* will be fast.
*
* Only format strings that contain either "ss" or "ss.SSS" are
* handled.
*
* The timezone of the date may be included as an ID with the "zzz"
* format string or as an offset with the "ZZZ" format string.
*
* If consecutive calls are frequently very different, then this
* may be a little slower than a normal DateFormat.
*
*
*
*/
public class DateCache
{
public static String DEFAULT_FORMAT="EEE MMM dd HH:mm:ss zzz yyyy";
private static long __hitWindow=60*60;
private String _formatString;
private String _tzFormatString;
private SimpleDateFormat _tzFormat;
private String _minFormatString;
private SimpleDateFormat _minFormat;
private String _secFormatString;
private String _secFormatString0;
private String _secFormatString1;
private long _lastMinutes = -1;
private long _lastSeconds = -1;
private int _lastMs = -1;
private String _lastResult = null;
private Locale _locale = null;
private DateFormatSymbols _dfs = null;
/* ------------------------------------------------------------ */
/** Constructor.
* Make a DateCache that will use a default format. The default format
* generates the same results as Date.toString().
*/
public DateCache()
{
this(DEFAULT_FORMAT);
getFormat().setTimeZone(TimeZone.getDefault());
}
/* ------------------------------------------------------------ */
/** Constructor.
* Make a DateCache that will use the given format
*/
public DateCache(String format)
{
_formatString=format;
setTimeZone(TimeZone.getDefault());
}
/* ------------------------------------------------------------ */
public DateCache(String format,Locale l)
{
_formatString=format;
_locale = l;
setTimeZone(TimeZone.getDefault());
}
/* ------------------------------------------------------------ */
public DateCache(String format,DateFormatSymbols s)
{
_formatString=format;
_dfs = s;
setTimeZone(TimeZone.getDefault());
}
/* ------------------------------------------------------------ */
/** Set the timezone.
* @param tz TimeZone
*/
public synchronized void setTimeZone(TimeZone tz)
{
setTzFormatString(tz);
if( _locale != null )
{
_tzFormat=new SimpleDateFormat(_tzFormatString,_locale);
_minFormat=new SimpleDateFormat(_minFormatString,_locale);
}
else if( _dfs != null )
{
_tzFormat=new SimpleDateFormat(_tzFormatString,_dfs);
_minFormat=new SimpleDateFormat(_minFormatString,_dfs);
}
else
{
_tzFormat=new SimpleDateFormat(_tzFormatString);
_minFormat=new SimpleDateFormat(_minFormatString);
}
_tzFormat.setTimeZone(tz);
_minFormat.setTimeZone(tz);
_lastSeconds=-1;
_lastMinutes=-1;
}
/* ------------------------------------------------------------ */
public TimeZone getTimeZone()
{
return _tzFormat.getTimeZone();
}
/* ------------------------------------------------------------ */
/** Set the timezone.
* @param timeZoneId TimeZoneId the ID of the zone as used by
* TimeZone.getTimeZone(id)
*/
public void setTimeZoneID(String timeZoneId)
{
setTimeZone(TimeZone.getTimeZone(timeZoneId));
}
/* ------------------------------------------------------------ */
private synchronized void setTzFormatString(final TimeZone tz )
{
int zIndex = _formatString.indexOf( "ZZZ" );
if( zIndex >= 0 )
{
String ss1 = _formatString.substring( 0, zIndex );
String ss2 = _formatString.substring( zIndex+3 );
int tzOffset = tz.getRawOffset();
StringBuilder sb = new StringBuilder(_formatString.length()+10);
sb.append(ss1);
sb.append("'");
if( tzOffset >= 0 )
sb.append( '+' );
else
{
tzOffset = -tzOffset;
sb.append( '-' );
}
int raw = tzOffset / (1000*60); // Convert to seconds
int hr = raw / 60;
int min = raw % 60;
if( hr < 10 )
sb.append( '0' );
sb.append( hr );
if( min < 10 )
sb.append( '0' );
sb.append( min );
sb.append( '\'' );
sb.append(ss2);
_tzFormatString=sb.toString();
}
else
_tzFormatString=_formatString;
setMinFormatString();
}
/* ------------------------------------------------------------ */
private void setMinFormatString()
{
int i = _tzFormatString.indexOf("ss.SSS");
int l = 6;
if (i>=0)
throw new IllegalStateException("ms not supported");
i = _tzFormatString.indexOf("ss");
l=2;
// Build a formatter that formats a second format string
String ss1=_tzFormatString.substring(0,i);
String ss2=_tzFormatString.substring(i+l);
_minFormatString =ss1+"'ss'"+ss2;
}
/* ------------------------------------------------------------ */
/** Format a date according to our stored formatter.
* @param inDate
* @return Formatted date
*/
public synchronized String format(Date inDate)
{
return format(inDate.getTime());
}
/* ------------------------------------------------------------ */
/** Format a date according to our stored formatter.
* @param inDate
* @return Formatted date
*/
public synchronized String format(long inDate)
{
long seconds = inDate / 1000;
// Is it not suitable to cache?
if (seconds<_lastSeconds ||
_lastSeconds>0 && seconds>_lastSeconds+__hitWindow)
{
// It's a cache miss
Date d = new Date(inDate);
return _tzFormat.format(d);
}
// Check if we are in the same second
// and don't care about millis
if (_lastSeconds==seconds )
return _lastResult;
Date d = new Date(inDate);
// Check if we need a new format string
long minutes = seconds/60;
if (_lastMinutes != minutes)
{
_lastMinutes = minutes;
_secFormatString=_minFormat.format(d);
int i=_secFormatString.indexOf("ss");
int l=2;
_secFormatString0=_secFormatString.substring(0,i);
_secFormatString1=_secFormatString.substring(i+l);
}
// Always format if we get here
_lastSeconds = seconds;
StringBuilder sb=new StringBuilder(_secFormatString.length());
sb.append(_secFormatString0);
int s=(int)(seconds%60);
if (s<10)
sb.append('0');
sb.append(s);
sb.append(_secFormatString1);
_lastResult=sb.toString();
return _lastResult;
}
/* ------------------------------------------------------------ */
/** Format to string buffer.
* @param inDate Date the format
* @param buffer StringBuilder
*/
public void format(long inDate, StringBuilder buffer)
{
buffer.append(format(inDate));
}
/* ------------------------------------------------------------ */
/** Get the format.
*/
public SimpleDateFormat getFormat()
{
return _minFormat;
}
/* ------------------------------------------------------------ */
public String getFormatString()
{
return _formatString;
}
/* ------------------------------------------------------------ */
public String now()
{
long now=System.currentTimeMillis();
_lastMs=(int)(now%1000);
return format(now);
}
/* ------------------------------------------------------------ */
public int lastMs()
{
return _lastMs;
}
}