/* This file is part of the db4o object database http://www.db4o.com
Copyright (C) 2004 - 2011 Versant Corporation http://www.versant.com
db4o is free software; you can redistribute it and/or modify it under
the terms of version 3 of the GNU General Public License as published
by the Free Software Foundation.
db4o 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, see http://www.gnu.org/licenses/. */
package com.db4o.cluster;
import com.db4o.*;
import com.db4o.internal.cluster.*;
import com.db4o.query.*;
/**
* allows running Queries against multiple ObjectContainers.
* @exclude
*/
public class Cluster {
public final ObjectContainer[] _objectContainers;
/**
* use this constructor to create a Cluster and call
* add() to add ObjectContainers
*/
public Cluster(ObjectContainer[] objectContainers){
if(objectContainers == null){
throw new NullPointerException();
}
if(objectContainers.length < 1){
throw new IllegalArgumentException();
}
for (int i = 0; i < objectContainers.length; i++) {
if(objectContainers[i] == null){
throw new IllegalArgumentException();
}
}
_objectContainers = objectContainers;
}
/**
* starts a query against all ObjectContainers in
* this Cluster.
* @return the Query
*/
public Query query(){
synchronized(this){
Query[] queries = new Query[_objectContainers.length];
for (int i = 0; i < _objectContainers.length; i++) {
queries[i] = _objectContainers[i].query();
}
return new ClusterQuery(this, queries);
}
}
/**
* returns the ObjectContainer in this cluster where the passed object
* is stored or null, if the object is not stored to any ObjectContainer
* in this cluster
* @param obj the object
* @return the ObjectContainer
*/
public ObjectContainer objectContainerFor(Object obj){
synchronized(this){
for (int i = 0; i < _objectContainers.length; i++) {
if(_objectContainers[i].ext().isStored(obj)){
return _objectContainers[i];
}
}
}
return null;
}
}