uk.org.retep.util.collections.stats.StatisticCollection Maven / Gradle / Ivy
/*
* Copyright (c) 1998-2010, Peter T Mount
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
*
* - Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* - 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.
*
* - Neither the name of the retep.org.uk nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
*
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS 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 THE COPYRIGHT OWNER
* OR 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.
*/
package uk.org.retep.util.collections.stats;
import java.util.Collection;
import java.util.LinkedList;
import javax.annotation.concurrent.ThreadSafe;
import uk.org.retep.annotations.WriteLock;
import uk.org.retep.util.cluster.ClusteredTime;
import uk.org.retep.util.collections.list.ConcurrentList;
/**
* A collection of {@link Statistic}'s with the capability of removing them when they
* become too old or when the collection reaches a specific size.
*
* @param Type of value stored in a {@link Statistic}
* @author peter
* @since 9.6
*/
@ThreadSafe
public class StatisticCollection
extends ConcurrentList>
{
private final int maxEntries;
private final long maxAge;
/**
* Construct a new collection limited to a specific capacity
*
* @param maxEntries Maximum number of entries permitted
*/
public StatisticCollection( final int maxEntries )
{
this( maxEntries, Long.MAX_VALUE );
}
/**
* Construct a new collection where {@link Statistic}'s will expire after
* a specified age
*
* @param maxAge Maximum age a Statistic can be before it is removed
*/
public StatisticCollection( final long maxAge )
{
this( Integer.MAX_VALUE, maxAge );
}
/**
* Construct a new collection who's {@link Statistic}'s are limited by
* number and by age
*
* @param maxEntries Maximum number of entries permitted
* @param maxAge Maximum age a Statistic can be before it is removed
*/
public StatisticCollection( final int maxEntries, final long maxAge )
{
super( new LinkedList>() );
this.maxEntries = Math.max( 0, maxEntries );
this.maxAge = Math.max( 1L, maxAge );
}
/**
* {@inheritDoc}
*/
public boolean addValue( final T value )
{
return add( new Statistic( value ) );
}
/**
* {@inheritDoc}
*/
@Override
@WriteLock
public boolean add( final Statistic e )
{
final boolean ret = super.add( e );
if( ret )
{
cleanUp();
}
return ret;
}
/**
* {@inheritDoc}
*/
@Override
@WriteLock
public boolean addAll( final Collection> c )
{
try
{
return super.addAll( c );
}
finally
{
cleanUp();
}
}
/**
* {@inheritDoc}
*/
@Override
@WriteLock
public boolean addAll( final int index,
final Collection> c )
{
try
{
return super.addAll( index, c );
}
finally
{
cleanUp();
}
}
/**
* {@inheritDoc}
*/
@Override
@WriteLock
public Statistic set( final int index, final Statistic element )
{
try
{
return super.set( index, element );
}
finally
{
cleanUp();
}
}
private long getAge( final Statistic stat )
{
if( stat == null )
{
return 0L;
}
else
{
return ClusteredTime.currentClusterTimeMillis() - stat.getTimestamp();
}
}
private void cleanUp()
{
while( !isEmpty() && (size() > maxEntries |
getAge( ((LinkedList>) list).getFirst() ) > maxAge) )
{
((LinkedList>) list).removeFirst();
}
}
}