package org.drools.common;
/*
* Copyright 2005 JBoss Inc
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
import java.io.Serializable;
import org.drools.RuleBaseConfiguration;
import org.drools.reteoo.BetaMemory;
import org.drools.reteoo.FactHandleMemory;
import org.drools.reteoo.ReteTuple;
import org.drools.util.FactHashTable;
import org.drools.util.FactList;
import org.drools.util.LinkedList;
import org.drools.util.TupleHashTable;
public class EmptyBetaConstraints
implements
Serializable,
BetaConstraints {
private static final BetaConstraints INSTANCE = new EmptyBetaConstraints();
public static BetaConstraints getInstance() {
return EmptyBetaConstraints.INSTANCE;
}
/**
*
*/
private static final long serialVersionUID = 400L;
private EmptyBetaConstraints() {
}
/* (non-Javadoc)
* @see org.drools.common.BetaNodeConstraints#updateFromTuple(org.drools.reteoo.ReteTuple)
*/
public void updateFromTuple(final InternalWorkingMemory workingMemory,
final ReteTuple tuple) {
}
/* (non-Javadoc)
* @see org.drools.common.BetaNodeConstraints#updateFromFactHandle(org.drools.common.InternalFactHandle)
*/
public void updateFromFactHandle(final InternalWorkingMemory workingMemory,
final InternalFactHandle handle) {
}
/* (non-Javadoc)
* @see org.drools.common.BetaNodeConstraints#isAllowedCachedLeft(java.lang.Object)
*/
public boolean isAllowedCachedLeft(final Object object) {
return true;
}
/* (non-Javadoc)
* @see org.drools.common.BetaNodeConstraints#isAllowedCachedRight(org.drools.reteoo.ReteTuple)
*/
public boolean isAllowedCachedRight(final ReteTuple tuple) {
return true;
}
public boolean isIndexed() {
return false;
}
public int getIndexCount() {
return 0;
}
public boolean isEmpty() {
return true;
}
public BetaMemory createBetaMemory(final RuleBaseConfiguration config) {
final BetaMemory memory = new BetaMemory( config.isSequential() ? null : new TupleHashTable(),
config.isSequential() ? (FactHandleMemory) new FactList() : (FactHandleMemory) new FactHashTable() );
return memory;
}
public int hashCode() {
return 1;
}
/* (non-Javadoc)
* @see org.drools.common.BetaNodeConstraints#getConstraints()
*/
public LinkedList getConstraints() {
final LinkedList list = new LinkedList();
return list;
}
/**
* Determine if another object is equal to this.
*
* @param object
* The object to test.
*
* @return <code>true</code> if <code>object</code> is equal to this,
* otherwise <code>false</code>.
*/
public boolean equals(final Object object) {
if ( this == object ) {
return true;
}
return (object != null && (object instanceof EmptyBetaConstraints));
}
}