/*
* 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.
*/
package org.drools.core.common;
import org.drools.core.beliefsystem.BeliefSet;
import org.drools.core.beliefsystem.BeliefSystem;
import org.drools.core.beliefsystem.simple.SimpleMode;
import org.drools.core.definitions.rule.impl.RuleImpl;
import org.drools.core.impl.StatefulKnowledgeSessionImpl;
import org.drools.core.reteoo.ObjectTypeConf;
import org.drools.core.spi.Activation;
import org.drools.core.spi.PropagationContext;
import org.drools.core.util.ObjectHashMap;
import org.kie.internal.runtime.beliefs.Mode;
/**
* The Truth Maintenance System is responsible for tracking two things. Firstly
* It maintains a Map to track the classes with the same Equality, using the
* EqualityKey. The EqualityKey has an internal datastructure which references
* all the handles which are equal. Secondly It maintains another map tracking
* the justificiations for logically asserted facts.
*/
public class TruthMaintenanceSystem {
private StatefulKnowledgeSessionImpl wm;
private ObjectHashMap equalityKeyMap;
private BeliefSystem defaultBeliefSystem;
public TruthMaintenanceSystem() {}
public TruthMaintenanceSystem(StatefulKnowledgeSessionImpl wm,
NamedEntryPoint ep) {
this.wm = wm;
//this.justifiedMap = new ObjectHashMap();
this.equalityKeyMap = new ObjectHashMap();
this.equalityKeyMap.setComparator( EqualityKeyComparator.getInstance() );
defaultBeliefSystem = wm.getKnowledgeBase().getConfiguration().getComponentFactory().getBeliefSystemFactory().createBeliefSystem(wm.getSessionConfiguration().getBeliefSystemType(), ep, this);
}
public ObjectHashMap getEqualityKeyMap() {
return this.equalityKeyMap;
}
public Object put(final EqualityKey key) {
return this.equalityKeyMap.put( key,
key,
false );
}
public EqualityKey get(final EqualityKey key) {
return (EqualityKey) this.equalityKeyMap.get( key );
}
public EqualityKey get(final Object object) {
return (EqualityKey) this.equalityKeyMap.get( object );
}
public EqualityKey remove(final EqualityKey key) {
return (EqualityKey) this.equalityKeyMap.remove( key );
}
/**
* Adds a justification for the FactHandle to the justifiedMap.
*
* @param handle
* @param activation
* @param context
* @param rule
* @param typeConf
*/
public void readLogicalDependency(final InternalFactHandle handle,
final Object object,
final Object value,
final Activation activation,
final PropagationContext context,
final RuleImpl rule,
final ObjectTypeConf typeConf) {
addLogicalDependency( handle, object, value, activation, context, rule, typeConf, true );
}
public void addLogicalDependency(final InternalFactHandle handle,
final Object object,
final Object value,
final Activation activation,
final PropagationContext context,
final RuleImpl rule,
final ObjectTypeConf typeConf) {
addLogicalDependency( handle, object, value, activation, context, rule, typeConf, false );
}
public void addLogicalDependency(final InternalFactHandle handle,
final Object object,
final Object value,
final Activation activation,
final PropagationContext context,
final RuleImpl rule,
final ObjectTypeConf typeConf,
final boolean read) {
BeliefSystem beliefSystem = defaultBeliefSystem;
if ( value != null && value instanceof Mode & !( value instanceof SimpleMode ) ) {
Mode mode = (Mode) value;
beliefSystem = (BeliefSystem) mode.getBeliefSystem();
}
BeliefSet beliefSet = handle.getEqualityKey().getBeliefSet();
if ( beliefSet == null ) {
if ( context.getType() == PropagationContext.MODIFICATION ) {
// if this was a update, chances are its trying to retract a logical assertion
}
beliefSet = beliefSystem.newBeliefSet( handle );
handle.getEqualityKey().setBeliefSet( beliefSet );
}
final LogicalDependency node = beliefSystem.newLogicalDependency( activation, beliefSet, object, value );
activation.getRule().setHasLogicalDependency( true );
activation.addLogicalDependency( node );
if ( read ) {
// used when deserialising
beliefSystem.read( node, beliefSet, context, typeConf );
} else {
beliefSystem.insert( node, beliefSet, context, typeConf );
}
}
public void clear() {
this.equalityKeyMap.clear();
}
public BeliefSystem getBeliefSystem() {
return defaultBeliefSystem;
}
}