org.drools.reteoo
Class ExistsNode

java.lang.Object
  org.drools.common.BaseNode
      org.drools.reteoo.TupleSource
          org.drools.reteoo.ExistsNode

All Implemented Interfaces:

java.io.Serializable, NetworkNode, NodeMemory, ObjectSink, ObjectSinkNode, TupleSink, TupleSinkNode

public class ExistsNode
extends TupleSource

ExistsNode extends BetaNode 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 cancelling any Activations 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 BetaNode provides the BetaMemory to store assserted ReteTuples and FactHandleImpls. Each fact handle is stored in the right memory.

Author:

Edson Tirelli

See Also:

Serialized Form

Field Summary

protected BetaConstraints	constraints
protected TupleSource	leftInput The left input TupleSource.
protected boolean	objectMemory
protected ObjectSource	rightInput The right input TupleSource.
protected boolean	tupleMemoryEnabled

Fields inherited from class org.drools.reteoo.TupleSource

sink

Fields inherited from class org.drools.common.BaseNode

id

Constructor Summary

ExistsNode(int id, TupleSource leftInput, ObjectSource rightInput, BetaConstraints joinNodeBinder, BuildContext context)
Construct.

Method Summary

void	assertObject(InternalFactHandle handle, PropagationContext context, InternalWorkingMemory workingMemory) Assert a new FactHandleImpl from the right input.
void	assertTuple(ReteTuple leftTuple, PropagationContext context, InternalWorkingMemory workingMemory) Assert a new ReteTuple from the left input.
void	attach() Attaches the node into the network.
void	attach(InternalWorkingMemory[] workingMemories)
java.lang.Object	createMemory(RuleBaseConfiguration config) Creates a BetaMemory for the BetaNode's memory.
void	dumpMemory(InternalWorkingMemory workingMemory)
boolean	equals(java.lang.Object object)
BetaNodeFieldConstraint[]	getConstraints()
ObjectSinkNode	getNextObjectSinkNode() Returns the next node
TupleSinkNode	getNextTupleSinkNode() Returns the next node
ObjectTypeNode	getObjectTypeNode()
ObjectSinkNode	getPreviousObjectSinkNode() Returns the previous node
TupleSinkNode	getPreviousTupleSinkNode() Returns the previous node
java.util.List	getRules()
int	hashCode() The hashCode return is simply the unique id of the node.
boolean	isObjectMemoryEnabled()
boolean	isTupleMemoryEnabled()
void	remove(RuleRemovalContext context, BaseNode node, InternalWorkingMemory[] workingMemories) Removes the node from teh network.
void	retractObject(InternalFactHandle handle, PropagationContext context, InternalWorkingMemory workingMemory) Retract the FactHandleImpl.
void	retractTuple(ReteTuple leftTuple, PropagationContext context, InternalWorkingMemory workingMemory) Retract the ReteTuple, any resulting propagated joins are also retracted.
void	setNextObjectSinkNode(ObjectSinkNode next) Sets the next node
void	setNextTupleSinkNode(TupleSinkNode next) Sets the next node
void	setObjectMemoryEnabled(boolean objectMemory)
void	setPreviousObjectSinkNode(ObjectSinkNode previous) Sets the previous node
void	setPreviousTupleSinkNode(TupleSinkNode previous) Sets the previous node
void	setTupleMemoryEnabled(boolean tupleMemoryEnabled)
java.lang.String	toString()
void	updateSink(TupleSink sink, PropagationContext context, InternalWorkingMemory workingMemory) Updates the given sink propagating all previously propagated tuples to it

Methods inherited from class org.drools.reteoo.TupleSource

addTupleSink, getSinkPropagator, isInUse, removeTupleSink

Methods inherited from class org.drools.common.BaseNode

getId

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface org.drools.common.NodeMemory

getId

Field Detail

leftInput

protected final TupleSource leftInput

The left input TupleSource.

rightInput

protected final ObjectSource rightInput

The right input TupleSource.

constraints

protected final BetaConstraints constraints

objectMemory

protected boolean objectMemory

tupleMemoryEnabled

protected boolean tupleMemoryEnabled

Constructor Detail

ExistsNode

public ExistsNode(int id,
                  TupleSource leftInput,
                  ObjectSource rightInput,
                  BetaConstraints joinNodeBinder,
                  BuildContext context)

Construct.

Parameters:

leftInput - The left input TupleSource.

rightInput - The right input ObjectSource.

joinNodeBinder - The constraints to be aplied to the right objects

Method Detail

assertTuple

public void assertTuple(ReteTuple leftTuple,
                        PropagationContext context,
                        InternalWorkingMemory workingMemory)

Assert a new ReteTuple from the left input. It iterates over the right FactHandleImpl's and if any match is found, a copy of the ReteTuple is made and propagated.

Parameters:

tuple - The Tuple being asserted.

context - The PropagationContext

workingMemory - The working memory seesion.

assertObject

public void assertObject(InternalFactHandle handle,
                         PropagationContext context,
                         InternalWorkingMemory workingMemory)

Assert a new FactHandleImpl from the right input. If it matches any left ReteTuple's that had no matches before, propagate tuple as an assertion.

Parameters:

handle - The FactHandleImpl being asserted.

context - The PropagationContext

workingMemory - The working memory seesion.

retractObject

public void retractObject(InternalFactHandle handle,
                          PropagationContext context,
                          InternalWorkingMemory workingMemory)

Retract the FactHandleImpl. If the handle has any ReteTuple matches and those tuples now have no other match, retract tuple

Parameters:

handle - the being retracted

context - The PropagationContext

workingMemory - The working memory seesion.

retractTuple

public void retractTuple(ReteTuple leftTuple,
                         PropagationContext context,
                         InternalWorkingMemory workingMemory)

Retract the ReteTuple, any resulting propagated joins are also retracted.

Parameters:

leftTuple - The tuple being retracted

context - The PropagationContext

workingMemory - The working memory seesion.

updateSink

public void updateSink(TupleSink sink,
                       PropagationContext context,
                       InternalWorkingMemory workingMemory)

Updates the given sink propagating all previously propagated tuples to it

Specified by:

updateSink in class TupleSource

toString

public java.lang.String toString()

getConstraints

public BetaNodeFieldConstraint[] getConstraints()

attach

public void attach()

Description copied from class: BaseNode

Attaches the node into the network. Usually to the parent ObjectSource or TupleSource

Specified by:

attach in class BaseNode

getRules

public java.util.List getRules()

getObjectTypeNode

public ObjectTypeNode getObjectTypeNode()

attach

public void attach(InternalWorkingMemory[] workingMemories)

Specified by:

attach in class BaseNode

remove

public void remove(RuleRemovalContext context,
                   BaseNode node,
                   InternalWorkingMemory[] workingMemories)

Description copied from class: BaseNode

Removes the node from teh network. Usually from the parent ObjectSource or TupleSource

Specified by:

remove in class BaseNode

isObjectMemoryEnabled

public boolean isObjectMemoryEnabled()

Specified by:

isObjectMemoryEnabled in interface ObjectSink

setObjectMemoryEnabled

public void setObjectMemoryEnabled(boolean objectMemory)

Specified by:

setObjectMemoryEnabled in interface ObjectSink

isTupleMemoryEnabled

public boolean isTupleMemoryEnabled()

Specified by:

isTupleMemoryEnabled in interface TupleSink

setTupleMemoryEnabled

public void setTupleMemoryEnabled(boolean tupleMemoryEnabled)

Specified by:

setTupleMemoryEnabled in interface TupleSink

dumpMemory

public void dumpMemory(InternalWorkingMemory workingMemory)

hashCode

public int hashCode()

Description copied from class: BaseNode

The hashCode return is simply the unique id of the node. It is expected that base classes will also implement equals(Object object).

Overrides:

hashCode in class BaseNode

equals

public boolean equals(java.lang.Object object)

Overrides:

equals in class java.lang.Object

createMemory

public java.lang.Object createMemory(RuleBaseConfiguration config)

Creates a BetaMemory for the BetaNode's memory.

Specified by:

createMemory in interface NodeMemory

getNextTupleSinkNode

public TupleSinkNode getNextTupleSinkNode()

Returns the next node

Specified by:

getNextTupleSinkNode in interface TupleSinkNode

Returns:

The next TupleSinkNode

setNextTupleSinkNode

public void setNextTupleSinkNode(TupleSinkNode next)

Sets the next node

Specified by:

setNextTupleSinkNode in interface TupleSinkNode

Parameters:

next - The next TupleSinkNode

getPreviousTupleSinkNode

public TupleSinkNode getPreviousTupleSinkNode()

Returns the previous node

Specified by:

getPreviousTupleSinkNode in interface TupleSinkNode

Returns:

The previous TupleSinkNode

setPreviousTupleSinkNode

public void setPreviousTupleSinkNode(TupleSinkNode previous)

Sets the previous node

Specified by:

setPreviousTupleSinkNode in interface TupleSinkNode

Parameters:

previous - The previous TupleSinkNode

getNextObjectSinkNode

public ObjectSinkNode getNextObjectSinkNode()

Returns the next node

Specified by:

getNextObjectSinkNode in interface ObjectSinkNode

Returns:

The next ObjectSinkNode

setNextObjectSinkNode

public void setNextObjectSinkNode(ObjectSinkNode next)

Sets the next node

Specified by:

setNextObjectSinkNode in interface ObjectSinkNode

Parameters:

next - The next ObjectSinkNode

getPreviousObjectSinkNode

public ObjectSinkNode getPreviousObjectSinkNode()

Returns the previous node

Specified by:

getPreviousObjectSinkNode in interface ObjectSinkNode

Returns:

The previous ObjectSinkNode

setPreviousObjectSinkNode

public void setPreviousObjectSinkNode(ObjectSinkNode previous)

Sets the previous node

Specified by:

setPreviousObjectSinkNode in interface ObjectSinkNode

Parameters:

previous - The previous ObjectSinkNode