/*
* Created on Oct 29, 2008
* Created by Paul Gardner
*
* Copyright 2008 Vuze, Inc. All rights reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; version 2 of the License only.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307, USA.
*/
package com.aelitis.azureus.core.util.bloom.impl;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import com.aelitis.azureus.core.util.bloom.BloomFilter;
public class
BloomFilterRotator
implements BloomFilter
{
private volatile BloomFilter current_filter;
private int current_filter_index;
private final BloomFilter[] filters;
public
BloomFilterRotator(
BloomFilter _target,
int _num )
{
filters = new BloomFilter[_num];
filters[0] = _target;
for (int i=1;i<filters.length;i++){
filters[i] = _target.getReplica();
}
current_filter = _target;
current_filter_index = 0;
}
public
BloomFilterRotator(
Map<String,Object> x )
{
List<Map<String,Object>> list = (List<Map<String,Object>>)x.get( "list" );
filters = new BloomFilter[ list.size() ];
for (int i=0;i<filters.length;i++){
filters[i] = BloomFilterImpl.deserialiseFromMap( list.get(i));
}
current_filter_index = ((Long)x.get( "index" )).intValue();
current_filter = filters[ current_filter_index ];
}
public Map<String, Object>
serialiseToMap()
{
Map<String, Object> m = new HashMap<String, Object>();
serialiseToMap( m );
return( m );
}
protected void
serialiseToMap(
Map<String,Object> x )
{
String cla = this.getClass().getName();
if ( cla.startsWith( BloomFilterImpl.MY_PACKAGE )){
cla = cla.substring( BloomFilterImpl.MY_PACKAGE.length());
}
x.put( "_impl", cla );
List<Map<String,Object>> list = new ArrayList<Map<String,Object>>();
for ( BloomFilter filter: filters ){
list.add( filter.serialiseToMap());
}
x.put( "list", list );
x.put( "index", new Long( current_filter_index ));
}
public int
add(
byte[] value )
{
synchronized( filters ){
int filter_size = current_filter.getSize();
int filter_entries = current_filter.getEntryCount();
int limit = filter_size / 8; // capacity limit
if ( filter_entries > limit ){
filter_entries = limit;
}
int update_chunk = limit / filters.length;
int num_to_update = ( filter_entries / update_chunk ) + 1;
if ( num_to_update > filters.length ){
num_to_update = filters.length;
}
//System.out.println( "rot_bloom: cur=" + current_filter_index + ", upd=" + num_to_update + ",ent=" + filter_entries );
int res = 0;
for (int i=current_filter_index;i<current_filter_index+num_to_update;i++){
int r = filters[i%filters.length].add( value );
if ( i == current_filter_index ){
res = r;
}
}
if ( current_filter.getEntryCount() > limit ){
filters[current_filter_index] = current_filter.getReplica();
current_filter_index = (current_filter_index+1)%filters.length;
current_filter = filters[ current_filter_index ];
}
return( res );
}
}
public int
remove(
byte[] value )
{
int res = 0;
for (int i=0;i<filters.length;i++){
BloomFilter filter = filters[i];
int r = filter.remove( value );
if ( filter == current_filter ){
res = r;
}
}
return( res );
}
public boolean
contains(
byte[] value )
{
return( current_filter.contains(value));
}
public int
count(
byte[] value )
{
return( current_filter.count( value ));
}
public int
getEntryCount()
{
return( current_filter.getEntryCount());
}
public int
getSize()
{
return( current_filter.getSize());
}
public BloomFilter
getReplica()
{
return( new BloomFilterRotator( current_filter, filters.length ));
}
public String
getString()
{
return( "ind=" + current_filter_index + ",filt=" + current_filter.getString());
}
}