/*
* Copyright (c) 2001-2007 Sun Microsystems, Inc. All rights reserved.
*
* The Sun Project JXTA(TM) Software License
*
* 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 Sun Microsystems, Inc. for JXTA(TM) technology."
* 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
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* 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,
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*
* JXTA is a registered trademark of Sun Microsystems, Inc. in the United
* States and other countries.
*
* Please see the license information page at :
* <http://www.jxta.org/project/www/license.html> for instructions on use of
* the license in source files.
*
* ====================================================================
*
* 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.cm.srdi.inmemory;
import net.jxta.impl.cm.Srdi.Entry;
import net.jxta.impl.util.TimeUtils;
import net.jxta.impl.util.ternary.wild.WildcardTernarySearchTree;
import net.jxta.impl.util.ternary.wild.WildcardTernarySearchTreeImpl;
import net.jxta.impl.util.ternary.wild.WildcardTernarySearchTreeMatchListener;
import net.jxta.logging.Logging;
import net.jxta.peer.PeerID;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.logging.Level;
import java.util.logging.Logger;
/**
* This implementation relies on the use of a Ternary Tree (@see {@link TernarySearchTree})
* to store the PeerIDs for every key/attribute/value combination (hereafter called a {@link SearchKey}).
*/
public class SearchIndex {
private final static transient Logger LOG = Logger.getLogger( SearchIndex.class.getName( ) );
// The Ternary Tree key index that organises Peers Ids per key (Ternary tree Key)
// An alternative - tested successfully - is to make the Peer ID URI part of the Ternary Tree Key instead of using an HashMap
// This implementation relies on the fact that the HasMap is likely faster than the Tree for non partial matches on the Peer ID URI
private WildcardTernarySearchTree<Map<PeerIdKey, Long>> searchIndex = new WildcardTernarySearchTreeImpl<Map<PeerIdKey, Long>>( );
private final String indexName;
// Counter used for statistics only
private volatile int registrations;
public SearchIndex( String indexName ) {
this.indexName = indexName;
}
public void clear( ) {
synchronized ( this.searchIndex ) {
this.searchIndex.deleteTree( );
}
}
/**
* DEBUG only as it's VERY expensive to run
* @return A String containing printable statistics about this Index
*/
public String getStats( ) {
int prefixRegistrations = 0;
int suffixRegistrations = 0;
WildcardTernarySearchTreeMatchListener<Map<PeerIdKey, Long>> listener = new WildcardTernarySearchTreeMatchListener<Map<PeerIdKey, Long>>( ) {
public void resultFound( String key, Map<PeerIdKey, Long> map ) {
SearchIndex.this.registrations += map.size( );
}
public boolean continueSearch( ) {
return true;
}
};
synchronized ( searchIndex ) {
this.registrations = 0;
this.searchIndex.walkPrefixTree( listener );
prefixRegistrations = this.registrations;
this.registrations = 0;
this.searchIndex.walkSuffixTree( listener );
suffixRegistrations = this.registrations;
}
return "SearchIndex[" + this.indexName + "]: " + this.searchIndex.getSize( ) + " search terms\t" + prefixRegistrations +
" prefix map elements\t" + suffixRegistrations + " suffix map elements.";
}
public boolean remove( final SearchKey searchKey, final PeerIdKey peerIdKey ) {
boolean ret = true;
synchronized ( this.searchIndex ) {
Map<PeerIdKey, Long> peerIdsMap = this.searchIndex.get( searchKey.getKey( ) );
if ( peerIdsMap != null ) {
// Clean up the Peer Ids to IndexItems Map
if ( null == peerIdsMap.remove( peerIdKey ) ) {
if ( Logging.SHOW_WARNING && LOG.isLoggable( Level.WARNING ) ) {
LOG.log( Level.WARNING,
"[" + this.indexName + "] Remove map value using key: " + peerIdKey + " when map contains no previous value!" );
}
ret = false;
}
// If the map is empty, remove the entry
if ( peerIdsMap.size( ) == 0 ) {
if ( Logging.SHOW_DEBUG && LOG.isLoggable( Level.FINE ) ) {
LOG.fine( "[" + this.indexName + "] Keys Index: removing entry '" + searchKey.getKey( ) + "'" );
}
if ( false == this.searchIndex.remove( searchKey.getKey( ) ) ) {
if ( Logging.SHOW_WARNING && LOG.isLoggable( Level.WARNING ) ) {
LOG.log( Level.WARNING,
"[" + this.indexName + "] Remove value using key: " + searchKey +
" failed!" );
}
ret = false;
}
}
}
}
return ret;
}
public List<Entry> getValueList( final SearchKey searchKey ) {
// The results List
List<Entry> entries = Collections.synchronizedList( new ArrayList<Entry>( ) );
synchronized ( this.searchIndex ) {
// Only returns non-expired entries
long now = TimeUtils.timeNow( );
Map<PeerIdKey, Long> map = this.searchIndex.get( searchKey.getKey( ) );
if ( map != null ) {
for ( java.util.Map.Entry<PeerIdKey, Long> entry : map.entrySet( ) ) {
PeerIdKey peerIdKey = entry.getKey( );
Long expiration = entry.getValue( );
if ( expiration.longValue( ) >= now ) {
Entry srdiEntry = new Entry( peerIdKey.getPeerID( ), expiration );
entries.add( srdiEntry );
}
}
}
}
if ( Logging.SHOW_DEBUG && LOG.isLoggable( Level.FINE ) ) {
LOG.fine( "[" + this.indexName + "] getRecord on '" + searchKey + "' returned " + entries.size( ) +
" item(s) from the index" );
}
return entries;
}
public Long update( final SearchKey searchKey, final PeerIdKey peerIdKey, final Long expiry ) {
synchronized ( this.searchIndex ) {
// Get the map at this index or create the node with the default map
Map<PeerIdKey, Long> map = this.searchIndex.getOrCreate( searchKey.getKey( ),
Collections.synchronizedMap( new HashMap<PeerIdKey, Long>( ) ) );
// Update the value
return map.put( peerIdKey, expiry );
}
}
public List<PeerID> search( final SearchKey searchKey, final int threshold, final boolean prefixOnly ) {
// Only returns non-expired entries
final long now = TimeUtils.timeNow( );
// The results: a HashMap of PeerIds to avoid potential redundant Peer Ids - convenient but memory intensive
final Map<PeerIdKey, PeerID> peerIdsMap = Collections.synchronizedMap( new HashMap<PeerIdKey, PeerID>( ) );
// A wild-card tree listener that will stop the search when the threshold is reached
WildcardTernarySearchTreeMatchListener<Map<PeerIdKey, Long>> listener = new WildcardTernarySearchTreeMatchListener<Map<PeerIdKey, Long>>( ) {
public void resultFound( String key, Map<PeerIdKey, Long> map ) {
for ( java.util.Map.Entry<PeerIdKey, Long> entry : map.entrySet( ) ) {
if ( peerIdsMap.size( ) == threshold ) {
break;
}
PeerIdKey peerIdKey = entry.getKey( );
Long expiration = entry.getValue( );
if ( expiration.longValue( ) >= now ) {
peerIdsMap.put( peerIdKey, peerIdKey.getPeerID( ) );
}
}
}
public boolean continueSearch( ) {
return ( ( threshold < 0 ) || ( peerIdsMap.size( ) < threshold ) );
}
};
if ( prefixOnly ) {
// Extract items with matching prefix from the main index
synchronized ( this.searchIndex ) {
// Match the prefix - results are collected via the listener
this.searchIndex.matchPrefix( searchKey.getKey( ), listener );
}
LOG.fine( "[" + this.indexName + "] primary key query on '" + searchKey.getKey( ) + "' returned " + peerIdsMap.size( ) +
" item(s) from the index" );
} else {
//////////////////////////////////////////////////
//
// Standard Search
//
//////////////////////////////////////////////////
// Extract matching items from the main index
synchronized ( this.searchIndex ) {
// Standard search - results are collected via the listener
this.searchIndex.search( searchKey.getKey( ), listener );
}
LOG.fine( "[" + this.indexName + "] search query on '" + searchKey.getKey( ) + "' returned " + peerIdsMap.size( ) +
" item(s) from the index" );
}
return Collections.synchronizedList( new ArrayList<PeerID>( peerIdsMap.values( ) ) );
}
}