/**
* Copyright 2010 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.reteoo;
import org.drools.base.DroolsQuery;
import org.drools.common.BetaConstraints;
import org.drools.common.InternalFactHandle;
import org.drools.common.InternalWorkingMemory;
import org.drools.core.util.Iterator;
import org.drools.reteoo.builder.BuildContext;
import org.drools.rule.Behavior;
import org.drools.spi.PropagationContext;
/**
* <code>ExistsNode</code> extends <code>BetaNode</code> to perform tests for
* the existence of a Fact plus one or more conditions. Where existence
* is found the left ReteTuple is copied and propagated. Further to this it
* maintains the "truth" by canceling any
* <code>Activation<code>s that are no longer
* considered true by the retraction of ReteTuple's or FactHandleImpl.
* Tuples are considered to be asserted from the left input and facts from the right input.
* The <code>BetaNode</code> provides the BetaMemory to store asserted ReteTuples and
* <code>FactHandleImpl<code>s. Each fact handle is stored in the right
* memory.
*
* @author <a href="mailto:etirelli@redhat.com">Edson Tirelli</a>
*
*/
public class ExistsNode extends BetaNode {
private static final long serialVersionUID = 510l;
static int notAssertObject = 0;
static int notAssertTuple = 0;
public ExistsNode() {
}
// ------------------------------------------------------------
// Instance methods
// ------------------------------------------------------------
/**
* Construct.
*
* @param id
* The unique id for this node.
* @param leftInput
* The left input <code>TupleSource</code>.
* @param rightInput
* The right input <code>ObjectSource</code>.
* @param joinNodeBinder
* The constraints to be applied to the right objects
*/
public ExistsNode(final int id,
final LeftTupleSource leftInput,
final ObjectSource rightInput,
final BetaConstraints joinNodeBinder,
final Behavior[] behaviors,
final BuildContext context) {
super( id,
context.getPartitionId(),
context.getRuleBase().getConfiguration().isMultithreadEvaluation(),
leftInput,
rightInput,
joinNodeBinder,
behaviors );
this.tupleMemoryEnabled = context.isTupleMemoryEnabled();
}
/**
* Assert a new <code>ReteTuple</code> from the left input. It iterates
* over the right <code>FactHandleImpl</code>'s and if any match is found,
* a copy of the <code>ReteTuple</code> is made and propagated.
*
* @param tuple
* The <code>Tuple</code> being asserted.
* @param context
* The <code>PropagationContext</code>
* @param workingMemory
* The working memory session.
*/
public void assertLeftTuple(final LeftTuple leftTuple,
final PropagationContext context,
final InternalWorkingMemory workingMemory) {
final BetaMemory memory = (BetaMemory) workingMemory.getNodeMemory( this );
this.constraints.updateFromTuple( memory.getContext(),
workingMemory,
leftTuple );
boolean useLeftMemory = true;
if ( !this.tupleMemoryEnabled ) {
// This is a hack, to not add closed DroolsQuery objects
Object object = ((InternalFactHandle) context.getFactHandle()).getObject();
if ( memory.getLeftTupleMemory() == null || object instanceof DroolsQuery && !((DroolsQuery) object).isOpen() ) {
useLeftMemory = false;
}
}
for ( RightTuple rightTuple = memory.getRightTupleMemory().getFirst( leftTuple,
(InternalFactHandle) context.getFactHandle() ); rightTuple != null; rightTuple = (RightTuple) rightTuple.getNext() ) {
if ( this.constraints.isAllowedCachedLeft( memory.getContext(),
rightTuple.getFactHandle() ) ) {
leftTuple.setBlocker( rightTuple );
if ( useLeftMemory ) {
rightTuple.addBlocked( leftTuple );
}
break;
}
}
this.constraints.resetTuple( memory.getContext() );
if ( leftTuple.getBlocker() != null ) {
// tuple is not blocked to propagate
this.sink.propagateAssertLeftTuple( leftTuple,
context,
workingMemory,
useLeftMemory );
} else if ( useLeftMemory ) {
// LeftTuple is not blocked, so add to memory so other RightTuples can match
memory.getLeftTupleMemory().add( leftTuple );
}
}
/**
* Assert a new <code>FactHandleImpl</code> from the right input. If it
* matches any left ReteTuple's that had no matches before, propagate
* tuple as an assertion.
*
* @param factHandle
* The <code>FactHandleImpl</code> being asserted.
* @param context
* The <code>PropagationContext</code>
* @param workingMemory
* The working memory session.
*/
public void assertObject(final InternalFactHandle factHandle,
final PropagationContext context,
final InternalWorkingMemory workingMemory) {
final RightTuple rightTuple = new RightTuple( factHandle,
this );
final BetaMemory memory = (BetaMemory) workingMemory.getNodeMemory( this );
if ( !behavior.assertRightTuple( memory.getBehaviorContext(),
rightTuple,
workingMemory ) ) {
// destroy right tuple
rightTuple.unlinkFromRightParent();
return;
}
memory.getRightTupleMemory().add( rightTuple );
if ( memory.getLeftTupleMemory() == null || memory.getLeftTupleMemory().size() == 0 ) {
// do nothing here, as no left memory
return;
}
this.constraints.updateFromFactHandle( memory.getContext(),
workingMemory,
factHandle );
for ( LeftTuple leftTuple = memory.getLeftTupleMemory().getFirst( rightTuple ); leftTuple != null; ) {
// preserve next now, in case we remove this leftTuple
LeftTuple temp = (LeftTuple) leftTuple.getNext();
// we know that only unblocked LeftTuples are still in the memory
if ( this.constraints.isAllowedCachedRight( memory.getContext(),
leftTuple ) ) {
leftTuple.setBlocker( rightTuple );
rightTuple.addBlocked( leftTuple );
memory.getLeftTupleMemory().remove( leftTuple );
this.sink.propagateAssertLeftTuple( leftTuple,
context,
workingMemory,
true );
}
leftTuple = temp;
}
this.constraints.resetFactHandle( memory.getContext() );
}
/**
* Retract the <code>FactHandleImpl</code>. If the handle has any
* <code>ReteTuple</code> matches and those tuples now have no
* other match, retract tuple
*
* @param handle
* the <codeFactHandleImpl</code> being retracted
* @param context
* The <code>PropagationContext</code>
* @param workingMemory
* The working memory session.
*/
public void retractRightTuple(final RightTuple rightTuple,
final PropagationContext context,
final InternalWorkingMemory workingMemory) {
final RightTuple rootBlocker = (RightTuple) rightTuple.getNext();
final BetaMemory memory = (BetaMemory) workingMemory.getNodeMemory( this );
behavior.retractRightTuple( memory.getBehaviorContext(),
rightTuple,
workingMemory );
memory.getRightTupleMemory().remove( rightTuple );
if ( rightTuple.getBlocked() == null ) {
return;
}
for ( LeftTuple leftTuple = (LeftTuple) rightTuple.getBlocked(); leftTuple != null; ) {
LeftTuple temp = leftTuple.getBlockedNext();
leftTuple.setBlocker( null );
leftTuple.setBlockedPrevious( null );
leftTuple.setBlockedNext( null );
this.constraints.updateFromTuple( memory.getContext(),
workingMemory,
leftTuple );
// we know that older tuples have been checked so continue previously
for ( RightTuple newBlocker = rootBlocker; newBlocker != null; newBlocker = (RightTuple) newBlocker.getNext() ) {
if ( this.constraints.isAllowedCachedLeft( memory.getContext(),
newBlocker.getFactHandle() ) ) {
leftTuple.setBlocker( newBlocker );
newBlocker.addBlocked( leftTuple );
break;
}
}
if ( leftTuple.getBlocker() == null ) {
// was previous blocked and not in memory, so add
memory.getLeftTupleMemory().add( leftTuple );
this.sink.propagateRetractLeftTuple( leftTuple,
context,
workingMemory );
}
leftTuple = temp;
}
rightTuple.nullBlocked();
this.constraints.resetTuple( memory.getContext() );
}
/**
* Retract the
* <code>ReteTuple<code>, any resulting propagated joins are also retracted.
*
* @param leftTuple
* The tuple being retracted
* @param context
* The <code>PropagationContext</code>
* @param workingMemory
* The working memory session.
*/
public void retractLeftTuple(final LeftTuple leftTuple,
final PropagationContext context,
final InternalWorkingMemory workingMemory) {
RightTuple blocker = leftTuple.getBlocker();
final BetaMemory memory = (BetaMemory) workingMemory.getNodeMemory( this );
if ( blocker != null ) {
this.sink.propagateRetractLeftTuple( leftTuple,
context,
workingMemory );
blocker.removeBlocked( leftTuple );
} else {
memory.getLeftTupleMemory().remove( leftTuple );
}
}
public void modifyLeftTuple(LeftTuple leftTuple,
PropagationContext context,
InternalWorkingMemory workingMemory) {
final BetaMemory memory = (BetaMemory) workingMemory.getNodeMemory( this );
RightTupleMemory rightMemory = memory.getRightTupleMemory();
// If in memory, remove it, because we'll need to add it anyway if it's not blocked, to ensure iteration order
RightTuple blocker = leftTuple.getBlocker();
if ( blocker == null ) {
memory.getLeftTupleMemory().remove( leftTuple );
} else {
// check if we changed bucket
if ( rightMemory.isIndexed() && rightMemory.getFirst( blocker ) != rightMemory.getFirst( leftTuple,
(InternalFactHandle) context.getFactHandle() ) ) {
// we changed bucket, so blocker no longer blocks
blocker.removeBlocked( leftTuple );
leftTuple.setBlocker( null );
leftTuple.setBlockedPrevious( null );
leftTuple.setBlockedNext( null );
blocker = null;
}
}
this.constraints.updateFromTuple( memory.getContext(),
workingMemory,
leftTuple );
// if we where not blocked before (or changed buckets), or the previous blocker no longer blocks, then find the next blocker
if ( blocker == null || !this.constraints.isAllowedCachedLeft( memory.getContext(),
blocker.getFactHandle() ) ) {
if ( blocker != null ) {
// remove previous blocker if it exists, as we know it doesn't block any more
blocker.removeBlocked( leftTuple );
leftTuple.setBlocker( null );
leftTuple.setBlockedPrevious( null );
leftTuple.setBlockedNext( null );
}
// find first blocker, because it's a modify, we need to start from the beginning again
RightTuple rightTuple = rightMemory.getFirst( leftTuple,
(InternalFactHandle) context.getFactHandle() );
for ( RightTuple newBlocker = rightTuple; newBlocker != null; newBlocker = (RightTuple) newBlocker.getNext() ) {
if ( this.constraints.isAllowedCachedLeft( memory.getContext(),
newBlocker.getFactHandle() ) ) {
leftTuple.setBlocker( newBlocker );
newBlocker.addBlocked( leftTuple );
break;
}
}
}
if ( leftTuple.getBlocker() == null ) {
// not blocked
memory.getLeftTupleMemory().add( leftTuple ); // add to memory so other fact handles can attempt to match
if ( leftTuple.firstChild != null ) {
// with previous children, retract
this.sink.propagateRetractLeftTuple( leftTuple,
context,
workingMemory );
}
// with no previous children. do nothing.
} else if ( leftTuple.firstChild == null ) {
// blocked, with no previous children, assert
this.sink.propagateAssertLeftTuple( leftTuple,
context,
workingMemory,
true );
} else {
// blocked, with previous children, modify
this.sink.propagateModifyChildLeftTuple( leftTuple,
context,
workingMemory,
true );
}
this.constraints.resetTuple( memory.getContext() );
}
public void modifyRightTuple(RightTuple rightTuple,
PropagationContext context,
InternalWorkingMemory workingMemory) {
final BetaMemory memory = (BetaMemory) workingMemory.getNodeMemory( this );
if ( memory.getLeftTupleMemory() == null || (memory.getLeftTupleMemory().size() == 0 && rightTuple.getBlocked() == null) ) {
// do nothing here, as we know there are no left tuples
//normally do this at the end, but as we are exiting early, make sure the buckets are still correct.
memory.getRightTupleMemory().remove( rightTuple );
memory.getRightTupleMemory().add( rightTuple );
return;
}
// TODO: wtd with behaviours?
// if ( !behavior.assertRightTuple( memory.getBehaviorContext(),
// rightTuple,
// workingMemory ) ) {
// // destroy right tuple
// rightTuple.unlinkFromRightParent();
// return;
// }
this.constraints.updateFromFactHandle( memory.getContext(),
workingMemory,
rightTuple.getFactHandle() );
LeftTupleMemory leftMemory = memory.getLeftTupleMemory();
LeftTuple firstLeftTuple = leftMemory.getFirst( rightTuple );
LeftTuple firstBlocked = rightTuple.getBlocked();
// we now have reference to the first Blocked, so null it in the rightTuple itself, so we can rebuild
rightTuple.nullBlocked();
// first process non-blocked tuples, as we know only those ones are in the left memory.
for ( LeftTuple leftTuple = firstLeftTuple; leftTuple != null; ) {
// preserve next now, in case we remove this leftTuple
LeftTuple temp = (LeftTuple) leftTuple.getNext();
// we know that only unblocked LeftTuples are still in the memory
if ( this.constraints.isAllowedCachedRight( memory.getContext(),
leftTuple ) ) {
leftTuple.setBlocker( rightTuple );
rightTuple.addBlocked( leftTuple );
// this is now blocked so remove from memory
leftMemory.remove( leftTuple );
// subclasses like ForallNotNode might override this propagation
this.sink.propagateAssertLeftTuple( leftTuple,
context,
workingMemory,
true );
}
leftTuple = temp;
}
if ( firstBlocked != null ) {
// now process existing blocks, we only process existing and not new from above loop
final RightTuple rootBlocker = (RightTuple) rightTuple.getNext();
// iterate all the existing previous blocked LeftTuples
for ( LeftTuple leftTuple = (LeftTuple) firstBlocked; leftTuple != null; ) {
LeftTuple temp = leftTuple.getBlockedNext();
leftTuple.setBlockedPrevious( null ); // must null these as we are re-adding them to the list
leftTuple.setBlockedNext( null );
if ( this.constraints.isAllowedCachedRight( memory.getContext(),
leftTuple ) ) {
// in the same bucket and it still blocks, so add back into blocked list
rightTuple.addBlocked( leftTuple ); // no need to set on LeftTuple, as it already has the reference
leftTuple = temp;
continue;
}
leftTuple.setBlocker( null );
this.constraints.updateFromTuple( memory.getContext(),
workingMemory,
leftTuple );
// we know that older tuples have been checked so continue next
for ( RightTuple newBlocker = rootBlocker; newBlocker != null; newBlocker = (RightTuple) newBlocker.getNext() ) {
if ( this.constraints.isAllowedCachedLeft( memory.getContext(),
newBlocker.getFactHandle() ) ) {
leftTuple.setBlocker( newBlocker );
newBlocker.addBlocked( leftTuple );
break;
}
}
if ( leftTuple.getBlocker() == null ) {
// was previous blocked and not in memory, so add
memory.getLeftTupleMemory().add( leftTuple );
// subclasses like ForallNotNode might override this propagation
this.sink.propagateRetractLeftTuple( leftTuple,
context,
workingMemory );
}
leftTuple = temp;
}
}
this.constraints.resetFactHandle( memory.getContext() );
this.constraints.resetTuple( memory.getContext() );
// Add and remove to make sure we are in the right bucket and at the end
// this is needed to fix for indexing and deterministic iterations
// we do this at the end, rather than at the bigging as normal, so we don't iterate onto ourself when looking for other blockers
memory.getRightTupleMemory().remove( rightTuple );
memory.getRightTupleMemory().add( rightTuple );
}
/**
* Updates the given sink propagating all previously propagated tuples to it
*
*/
public void updateSink(final LeftTupleSink sink,
final PropagationContext context,
final InternalWorkingMemory workingMemory) {
final BetaMemory memory = (BetaMemory) workingMemory.getNodeMemory( this );
Iterator it = memory.getRightTupleMemory().iterator();
// Relies on the fact that any propagated LeftTuples are blocked, but due to lazy blocking
// they will only be blocked once. So we can iterate the right memory to find the left tuples to propagate
for ( RightTuple rightTuple = (RightTuple) it.next(); rightTuple != null; rightTuple = (RightTuple) it.next() ) {
LeftTuple leftTuple = rightTuple.getBlocked();
while ( leftTuple != null ) {
sink.assertLeftTuple( new LeftTuple( leftTuple,
sink,
true ),
context,
workingMemory );
leftTuple = leftTuple.getBlockedNext();
}
}
}
public String toString() {
ObjectSource source = this.rightInput;
while ( source != null && source.getClass() != ObjectTypeNode.class ) {
source = source.source;
}
return "[ExistsNode(" + this.getId() + ") - " + ((source != null) ? ((ObjectTypeNode) source).getObjectType() : "<source from a subnetwork>") + "]";
}
public short getType() {
return NodeTypeEnums.ExistsNode;
}
}