org.drools.common
Class TruthMaintenanceSystem

java.lang.Object
  org.drools.common.TruthMaintenanceSystem

public class TruthMaintenanceSystem
extends Object

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.

Nested Class Summary

static class

TruthMaintenanceSystem.LogicalRetractCallback

Constructor Summary

TruthMaintenanceSystem()

TruthMaintenanceSystem(AbstractWorkingMemory wm)

Method Summary

void	addLogicalDependency(InternalFactHandle handle, Object value, Activation activation, PropagationContext context, Rule rule, ObjectTypeConf typeConf)
void	addLogicalDependency(InternalFactHandle handle, Object value, Activation activation, PropagationContext context, Rule rule, ObjectTypeConf typeConf, boolean read)
void	clear()
EqualityKey	get(EqualityKey key)
EqualityKey	get(Object object)
ObjectHashMap	getAssertMap()
ObjectHashMap	getJustifiedMap()
BeliefSet	newTMSbeliefSet()
Object	put(EqualityKey key)
void	readLogicalDependency(InternalFactHandle handle, Object value, Activation activation, PropagationContext context, Rule rule, ObjectTypeConf typeConf) Adds a justification for the FactHandle to the justifiedMap.
EqualityKey	remove(EqualityKey key)
void	removeLogicalDependencies(Activation activation, PropagationContext context, Rule rule) An Activation is no longer true so it no longer justifies any of the logical facts it logically asserted.
void	removeLogicalDependencies(InternalFactHandle handle) The FactHandle is being removed from the system so remove any logical dependencies between the justified FactHandle and its justifiers.
void	removeLogicalDependency(Activation activation, LogicalDependency node, PropagationContext context)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

TruthMaintenanceSystem

public TruthMaintenanceSystem()

TruthMaintenanceSystem

public TruthMaintenanceSystem(AbstractWorkingMemory wm)

Method Detail

getJustifiedMap

public ObjectHashMap getJustifiedMap()

getAssertMap

public ObjectHashMap getAssertMap()

put

public Object put(EqualityKey key)

get

public EqualityKey get(EqualityKey key)

get

public EqualityKey get(Object object)

remove

public EqualityKey remove(EqualityKey key)

removeLogicalDependencies

public void removeLogicalDependencies(InternalFactHandle handle)
                               throws FactException

The FactHandle is being removed from the system so remove any logical dependencies between the justified FactHandle and its justifiers. Removes the FactHandle key from the justifiedMap. It then iterates over all the LogicalDependency nodes, if any, in the returned Set and removes the LogicalDependency node from the LinkedList maintained by the Activation.

Parameters:

handle - - The FactHandle to be removed

Throws:

FactException

See Also:

LogicalDependency

removeLogicalDependencies

public void removeLogicalDependencies(Activation activation,
                                      PropagationContext context,
                                      Rule rule)
                               throws FactException

An Activation is no longer true so it no longer justifies any of the logical facts it logically asserted. It iterates over the Activation's LinkedList of DependencyNodes it retrieves the justitication set for each DependencyNode's FactHandle and removes itself. If the Set is empty it retracts the FactHandle from the WorkingMemory.

Parameters:

activation -

context -

rule -

Throws:

FactException

removeLogicalDependency

public void removeLogicalDependency(Activation activation,
                                    LogicalDependency node,
                                    PropagationContext context)

readLogicalDependency

public void readLogicalDependency(InternalFactHandle handle,
                                  Object value,
                                  Activation activation,
                                  PropagationContext context,
                                  Rule rule,
                                  ObjectTypeConf typeConf)
                           throws FactException

Adds a justification for the FactHandle to the justifiedMap.

Parameters:

handle -

activation -

context -

rule -

typeConf -

Throws:

FactException

addLogicalDependency

public void addLogicalDependency(InternalFactHandle handle,
                                 Object value,
                                 Activation activation,
                                 PropagationContext context,
                                 Rule rule,
                                 ObjectTypeConf typeConf)
                          throws FactException

Throws:

FactException

addLogicalDependency

public void addLogicalDependency(InternalFactHandle handle,
                                 Object value,
                                 Activation activation,
                                 PropagationContext context,
                                 Rule rule,
                                 ObjectTypeConf typeConf,
                                 boolean read)
                          throws FactException

Throws:

FactException

clear

public void clear()

newTMSbeliefSet

public BeliefSet newTMSbeliefSet()