org.drools.jsr94.rules
Class StatefulRuleSessionImpl

java.lang.Object
  org.drools.jsr94.rules.StatefulRuleSessionImpl

public class StatefulRuleSessionImpl
extends java.lang.Object

The Drools implementation of the StatefulRuleSession interface which is a representation of a stateful rules engine session. A stateful rules engine session exposes a stateful rule execution API to an underlying rules engine. The session allows arbitrary objects to be added and removed to and from the rule session state. Additionally, objects currently part of the rule session state may be updated.

There are inherently side-effects to adding objects to the rule session state. The execution of a RuleExecutionSet can add, remove and update objects in the rule session state. The objects in the rule session state are therefore dependent on the rules within the RuleExecutionSet as well as the rule engine vendor's specific rule engine behavior.

Handle instances are used by the rule engine vendor to track Objects added to the rule session state. This allows multiple instances of equivalent Objects to be added to the session state and identified, even after serialization.

See Also:

StatefulRuleSession

Method Summary

Handle	addObject(java.lang.Object object) Adds a given object to the rule session state of this rule session.
java.util.List	addObjects(java.util.List objList) Adds a List of Objects to the rule session state of this rule session.
protected void	applyFilter(java.util.List objects, ObjectFilter objectFilter) Applies the given ObjectFilter to the List of Objects, removing all Objects from the given List that do not pass the filter.
protected void	checkRuleSessionValidity() Ensures this RuleSession is not in an illegal rule session state.
boolean	containsObject(Handle objectHandle) Returns true if the given object is contained within rulesession state of this rule session.
void	executeRules() Executes the rules in the bound rule execution set using the objects present in the rule session state.
java.util.List	getHandles() Returns a List of the Handles being used for object identity.
java.lang.Object	getObject(Handle handle)
java.util.List	getObjects() Returns a List of all objects in the rule session state of this rule session.
java.util.List	getObjects(ObjectFilter filter) Returns a List over the objects in rule session state of this rule session.
protected java.util.Map	getProperties() Returns the additional properties used to create this RuleSession.
protected RuleExecutionSetImpl	getRuleExecutionSet() Returns the Drools RuleExecutionSet associated with this RuleSession.
RuleExecutionSetMetadata	getRuleExecutionSetMetadata() Returns the meta data for the rule execution set bound to this rule session.
int	getType() Returns the type identifier for this RuleSession.
protected WorkingMemory	getWorkingMemory() Returns the Drools WorkingMemory associated with this RuleSession.
protected void	initWorkingMemory() Initialize this RuleSession with a new WorkingMemory.
protected WorkingMemory	newWorkingMemory() Creates a new WorkingMemory for this RuleSession.
void	release() Releases all resources used by this rule session.
void	removeObject(Handle handleObject) Removes a given object from the rule session state of this rule session.
void	reset() Resets this rule session.
protected void	setProperties(java.util.Map properties) Sets additional properties used to create this RuleSession.
protected void	setRuleExecutionSet(RuleExecutionSetImpl ruleExecutionSet) Sets the Drools RuleExecutionSet associated with this RuleSession.
protected void	setWorkingMemory(WorkingMemory workingMemory) Sets the Drools WorkingMemory associated with this RuleSession.
void	updateObject(Handle objectHandle, java.lang.Object newObject) Notifies the rules engine that a given object in the rule session state has changed.

Methods inherited from class java.lang.Object

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

Method Detail

containsObject

public boolean containsObject(Handle objectHandle)

Returns true if the given object is contained within rulesession state of this rule session.

Parameters:

objectHandle - the handle to the target object.

Returns:

true if the given object is contained within the rule session state of this rule session.

addObject

public Handle addObject(java.lang.Object object)
                 throws InvalidRuleSessionException

Adds a given object to the rule session state of this rule session. The argument to this method is Object because in the non-managed env. not all objects should have to implement Serializable. If the RuleSession is Serializable and it contains non-serializable fields a runtime exception will be thrown.

Parameters:

object - the object to be added.

Returns:

the Handle for the newly added Object

Throws:

InvalidRuleSessionException - on illegal rule session state.

addObjects

public java.util.List addObjects(java.util.List objList)
                          throws InvalidRuleSessionException

Adds a List of Objects to the rule session state of this rule session.

Parameters:

objList - the objects to be added.

Returns:

a List of Handles, one for each added Object. The List must be ordered in the same order as the input objList.

Throws:

InvalidRuleSessionException - on illegal rule session state.

updateObject

public void updateObject(Handle objectHandle,
                         java.lang.Object newObject)
                  throws InvalidRuleSessionException,
                         InvalidHandleException

Notifies the rules engine that a given object in the rule session state has changed.

The semantics of this call are equivalent to calling removeObject followed by addObject. The original Handle is rebound to the new value for the Object however.

Parameters:

objectHandle - the handle to the original object.

newObject - the new object to bind to the handle.

Throws:

InvalidRuleSessionException - on illegal rule session state.

InvalidHandleException - if the input Handle is no longer valid

removeObject

public void removeObject(Handle handleObject)
                  throws InvalidRuleSessionException,
                         InvalidHandleException

Removes a given object from the rule session state of this rule session.

Parameters:

handleObject - the handle to the object to be removed from the rule session state.

Throws:

InvalidRuleSessionException - on illegal rule session state.

InvalidHandleException - if the input Handle is no longer valid

getObjects

public java.util.List getObjects()
                          throws InvalidRuleSessionException

Returns a List of all objects in the rule session state of this rule session. The objects should pass the default filter test of the default RuleExecutionSet filter (if present).

This may not neccessarily include all objects added by calls to addObject, and may include Objects created by side-effects. The execution of a RuleExecutionSet can add, remove and update objects as part of the rule session state. Therefore the rule session state is dependent on the rules that are part of the executed RuleExecutionSet as well as the rule vendor's specific rule engine behavior.

Returns:

a List of all objects part of the rule session state.

Throws:

InvalidRuleSessionException - on illegal rule session state.

getObjects

public java.util.List getObjects(ObjectFilter filter)
                          throws InvalidRuleSessionException

Returns a List over the objects in rule session state of this rule session. The objects should pass the filter test on the specified ObjectFilter.

This may not neccessarily include all objects added by calls to addObject, and may include Objects created by side-effects. The execution of a RuleExecutionSet can add, remove and update objects as part of the rule session state. Therefore the rule session state is dependent on the rules that are part of the executed RuleExecutionSet as well as the rule vendor's specific rule engine behavior.

Parameters:

filter - the object filter.

Returns:

a List of all the objects in the rule session state of this rule session based upon the given object filter.

Throws:

InvalidRuleSessionException - on illegal rule session state.

executeRules

public void executeRules()
                  throws InvalidRuleSessionException

Executes the rules in the bound rule execution set using the objects present in the rule session state. This will typically modify the rule session state - and may add, remove or update Objects bound to Handles.

Throws:

InvalidRuleSessionException - on illegal rule session state.

getObject

public java.lang.Object getObject(Handle handle)
                           throws InvalidRuleSessionException,
                                  InvalidHandleException

Throws:

InvalidRuleSessionException

InvalidHandleException

See Also:

StatefulRuleSessionImpl

getHandles

public java.util.List getHandles()

Returns a List of the Handles being used for object identity.

Returns:

a List of Handles present in the currect state of the rule session.

initWorkingMemory

protected void initWorkingMemory()

Initialize this RuleSession with a new WorkingMemory.

See Also:

newWorkingMemory()

newWorkingMemory

protected WorkingMemory newWorkingMemory()

Creates a new WorkingMemory for this RuleSession. All properties set prior to calling this method are added as application data to the new WorkingMemory. The created WorkingMemory uses the default conflict resolution strategy.

Returns:

the new WorkingMemory.

See Also:

setProperties(Map), WorkingMemory.setApplicationData(String, Object)

setProperties

protected void setProperties(java.util.Map properties)

Sets additional properties used to create this RuleSession.

Parameters:

properties - additional properties used to create the RuleSession implementation.

getProperties

protected java.util.Map getProperties()

Returns the additional properties used to create this RuleSession.

Returns:

the additional properties used to create this RuleSession.

setWorkingMemory

protected void setWorkingMemory(WorkingMemory workingMemory)

Sets the Drools WorkingMemory associated with this RuleSession.

Parameters:

workingMemory - the WorkingMemory to associate with this RuleSession.

getWorkingMemory

protected WorkingMemory getWorkingMemory()

Returns the Drools WorkingMemory associated with this RuleSession.

Returns:

the Drools WorkingMemory to associate with this RuleSession.

setRuleExecutionSet

protected void setRuleExecutionSet(RuleExecutionSetImpl ruleExecutionSet)

Sets the Drools RuleExecutionSet associated with this RuleSession.

Parameters:

ruleExecutionSet - the Drools RuleExecutionSet to associate with this RuleSession.

getRuleExecutionSet

protected RuleExecutionSetImpl getRuleExecutionSet()

Returns the Drools RuleExecutionSet associated with this RuleSession.

Returns:

the Drools RuleExecutionSet associated with this RuleSession.

checkRuleSessionValidity

protected void checkRuleSessionValidity()
                                 throws InvalidRuleSessionException

Ensures this RuleSession is not in an illegal rule session state.

Throws:

InvalidRuleSessionException - on illegal rule session state.

applyFilter

protected void applyFilter(java.util.List objects,
                           ObjectFilter objectFilter)

Applies the given ObjectFilter to the List of Objects, removing all Objects from the given List that do not pass the filter.

Parameters:

objects - List of Objects to be filtered

objectFilter - the ObjectFilter to be applied

getRuleExecutionSetMetadata

public RuleExecutionSetMetadata getRuleExecutionSetMetadata()

Returns the meta data for the rule execution set bound to this rule session.

Returns:

the RuleExecutionSetMetaData bound to this rule session.

getType

public int getType()
            throws InvalidRuleSessionException

Returns the type identifier for this RuleSession. The type identifiers are defined in the RuleRuntime interface.

Returns:

the type identifier for this RuleSession

Throws:

InvalidRuleSessionException - on illegal rule session state.

See Also:

RuleRuntime#STATEFUL_SESSION_TYPE, RuleRuntime#STATELESS_SESSION_TYPE

release

public void release()

Releases all resources used by this rule session. This method renders this rule session unusable until it is reacquired through the RuleRuntime.

reset

public void reset()

Resets this rule session. Calling this method will bring the rule session state to its initial state for this rule session and will reset any other state associated with this rule session.

A reset will not reset the state on the default object filter for a RuleExecutionSet.