package org.drools.core.beliefsystem.simple;
import org.drools.core.beliefsystem.BeliefSet;
import org.drools.core.beliefsystem.BeliefSystem;
import org.drools.core.common.InternalFactHandle;
import org.drools.core.common.LogicalDependency;
import org.drools.core.common.NamedEntryPoint;
import org.drools.core.common.SimpleLogicalDependency;
import org.drools.core.common.TruthMaintenanceSystem;
import org.drools.core.common.WorkingMemoryAction;
import org.drools.core.common.TruthMaintenanceSystem.LogicalCallback;
import org.drools.core.util.LinkedListEntry;
import org.drools.core.reteoo.ObjectTypeConf;
import org.drools.core.spi.Activation;
import org.drools.core.spi.PropagationContext;
/**
* Default implementation emulates classical Drools TMS behaviour.
*
*/
public class SimpleBeliefSystem
implements
BeliefSystem {
private NamedEntryPoint ep;
private TruthMaintenanceSystem tms;
public SimpleBeliefSystem(NamedEntryPoint ep,
TruthMaintenanceSystem tms) {
super();
this.ep = ep;
this.tms = tms;
}
public TruthMaintenanceSystem getTruthMaintenanceSystem() {
return this.tms;
}
public void insert(LogicalDependency node,
BeliefSet beliefSet,
PropagationContext context,
ObjectTypeConf typeConf) {
boolean empty = beliefSet.isEmpty();
beliefSet.add( node.getJustifierEntry() );
if ( empty ) {
InternalFactHandle handle = beliefSet.getFactHandle();
ep.insert( handle,
handle.getObject(),
node.getJustifier().getRule(),
node.getJustifier(),
typeConf,
null );
}
}
public void read(LogicalDependency node,
BeliefSet beliefSet,
PropagationContext context,
ObjectTypeConf typeConf) {
//insert(node, beliefSet, context, typeConf );
beliefSet.add( node.getJustifierEntry() );
}
public void delete(LogicalDependency node,
BeliefSet beliefSet,
PropagationContext context) {
SimpleBeliefSet sBeliefSet = (SimpleBeliefSet) beliefSet;
beliefSet.remove( node.getJustifierEntry() );
InternalFactHandle bfh = beliefSet.getFactHandle();
if ( beliefSet.isEmpty() &&
!((context.getType() == PropagationContext.DELETION || context.getType() == PropagationContext.MODIFICATION) // retract and modifies clean up themselves
&&
context.getFactHandle() == bfh) ) {
if ( sBeliefSet.getWorkingMemoryAction() == null ) {
WorkingMemoryAction action = new LogicalCallback( bfh,
context,
node.getJustifier(),
false,
true );
ep.enQueueWorkingMemoryAction( action );
sBeliefSet.setWorkingMemoryAction( action );
} else {
// was previous scheduled, so make sure it's a full retract and not an update
LogicalCallback callback = ( LogicalCallback ) sBeliefSet.getWorkingMemoryAction();
callback.setUpdate( false );
callback.setFullyRetract( true );
}
} else if ( !beliefSet.isEmpty() && beliefSet.getFactHandle().getObject() == node.getObject() ) {
// prime has changed, to update new object
// Equality might have changed on the object, so remove (which uses the handle id) and add back in
((NamedEntryPoint)bfh.getEntryPoint()).getObjectStore().updateHandle( bfh, ((LinkedListEntry<LogicalDependency>) beliefSet.getFirst()).getObject().getObject() );
if ( sBeliefSet.getWorkingMemoryAction() == null ) {
// Only schedule if we don't already have one scheduled
WorkingMemoryAction action = new LogicalCallback( bfh,
context,
node.getJustifier(),
true,
false );
ep.enQueueWorkingMemoryAction( action );
sBeliefSet.setWorkingMemoryAction( action );
}
}
// if ( beliefSet.size() > 1 && beliefSet.getFactHandle().getObject() == node.getObject() ) {
// // The "Prime" Object no longer has a backer, so it needs to be updated
// beliefSet.remove( node.getJustifierEntry() );
//
// if ( beliefSet.isEmpty() ) {
// WorkingMemoryAction action = new LogicalCallback( tms,
// node,
// beliefSet,
// context,
// node.getJustifier() );
// ep.queueWorkingMemoryAction( action );
// }
// } else {
// beliefSet.remove( node.getJustifierEntry() );
//
// if ( beliefSet.isEmpty() ) {
// WorkingMemoryAction action = new LogicalCallback( tms,
// node,
// beliefSet,
// context,
// node.getJustifier() );
// ep.queueWorkingMemoryAction( action );
// }
// }
}
public BeliefSet newBeliefSet(InternalFactHandle fh) {
return new SimpleBeliefSet( this, fh );
}
public LogicalDependency newLogicalDependency(Activation activation,
BeliefSet beliefSet,
Object object,
Object value) {
return new SimpleLogicalDependency( activation, beliefSet, object, value );
}
}