com.ibm.able.rules
Class AbleDecisionTreeEngine

java.lang.Object
  com.ibm.able.rules.AbleInferenceEngine
      com.ibm.able.rules.AbleDecisionTreeEngine

All Implemented Interfaces:

java.io.Serializable

public class AbleDecisionTreeEngine

extends AbleInferenceEngine

implements java.io.Serializable

This class provides the algorithm for processing a decision tree or table represented by a single tree rule or by a set of if-then rules.

The AbleDecisionTreeEngine processes AbleAssertionRules and either a single AbleTreeRule, a single AbleIfThenElseRule or a set of AbleConditionalRules and ignores all others.

The major processing method is infer() which is called by the AbleRuleSet bean as part of the normal bean process() method.

Instances of this class are not directly constructed by the user but are dynamically created by the AbleRuleBlock init() method.

See Also:

AbleRuleSet, AbleRuleBlock, AbleAssertionRule, AbleConditionalRule, Serialized Form

Field Summary

Fields inherited from class com.ibm.able.rules.AbleInferenceEngine

myDebugLevel, myRuleBlock, myRuleSet, myRulesFiredCount, myTracer, myWorkingMemory

Constructor Summary

AbleDecisionTreeEngine(AbleRuleSet theRuleSet, AbleLogger theTracer)
Create a new inference engine.

AbleDecisionTreeEngine(AbleRuleSet theRuleSet, AbleLogger theTracer, AbleRuleBlock theRuleBlock)
Create a new inference engine.

Method Summary

boolean	evalTree(AbleTreeNode theRootNode) Evaluate the decision tree structure directly via depth-first search of the tree When a leaf node is reached, perform all of the actions in the action node.
java.lang.Object	getControlParameter(java.lang.String theControlParameter) Returns the specified control parameter on the associated inference engine.
void	infer(AbleRuleBlock theRuleBlock) Fires the rules in the ruleset as if they were a decision tree.
boolean	isRuleBlockValid(AbleRuleBlock theRuleBlock) Make sure the current ruleblock is "executable" by examining the rule types and rule object configurations.
void	reset() Reset the rule block so that rules can be fired again: all rules are set to their original state.
void	setControlParameter(java.lang.String theControlParameter, java.lang.Object theValue) Set the specified control parameter on the associated inference engine.

Methods inherited from class com.ibm.able.rules.AbleInferenceEngine

allocateWorkingMemory, askUser, conditionalRulesValid, evalAntecedentClause, evalAntecedentExpression, evalAssertionClause, evalAssertionRule, evalConditionalRule, evalConsequentClause, evalDoUntilRule, evalDoWhileRule, evalForLoopRule, evalIfThenElseRule, evalPatternMatchRule, evalSwitchRule, evaluateDoActions, evalWhileDoRule, fireEngineBreakpoint, firePropertyChange, getRuleSet, getRulesFiredCount, getWorkingMemory, init, processAssertions, processConsequent, processConsequent, processConsequentClauses, processRuleBlock, resetRuleSet, setControlParameters, setDebugLevel, setInferenceContext, setInferenceContext, setInferenceContext, setRuleSet, setWorkingMemory, startDebugConsole, stopDebugConsole, toString

Methods inherited from class java.lang.Object

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

Constructor Detail

AbleDecisionTreeEngine

public AbleDecisionTreeEngine(AbleRuleSet theRuleSet,
                              AbleLogger theTracer)

Create a new inference engine.

Parameters:

theRuleSet - A ruleset whose rules are to be used for inferencing by this inference engine.

theTracer - A tracer object to which this inference engine can log information. This may be null, in which case no information is logged.

AbleDecisionTreeEngine

public AbleDecisionTreeEngine(AbleRuleSet theRuleSet,
                              AbleLogger theTracer,
                              AbleRuleBlock theRuleBlock)

Create a new inference engine.

Parameters:

theRuleSet - A ruleset whose context is used for inferencing by this inference engine.

theTracer - A tracer object to which this inference engine can log information. This may be null, in which case no information is logged.

theRuleBlock - A ruleblock whose rules are to be used for inferencing by this inference engine.

Method Detail

isRuleBlockValid

public boolean isRuleBlockValid(AbleRuleBlock theRuleBlock)

Make sure the current ruleblock is "executable" by examining the rule types and rule object configurations.

The ruleblock is invalid if any of the following are present in the ruleblock:

Predicate rule

Iteration rule

Pattern match rule

All reasons for validation failures are appended to the AbleRuleSet's myIsExReason variable. If validation fails, the inference engine must call myRuleSet.addIsExReason(java.lang.String) to append the reason.

Specified by:

isRuleBlockValid in class AbleInferenceEngine

Returns:

true, if the ruleset is OK; false, if the ruleset is not executable.

infer

public void infer(AbleRuleBlock theRuleBlock)
           throws AbleDataException

Fires the rules in the ruleset as if they were a decision tree.

The infer() method is called by the AbleRuleSet process() method as part of the overall ruleset bean processing sequence.

The order of processing is as follows:

1. Sequentially evaluate all assertion rules in declaration order.
2. Evaluate all enabled conditional rules in sequential order, and fire the first triggered rule.

Specified by:

infer in class AbleInferenceEngine

Parameters:

theRuleBlock - The ruleblock to be processed.

Throws:

AbleDataException - When any error occurs.

evalTree

public boolean evalTree(AbleTreeNode theRootNode)
                 throws AbleDataException

Evaluate the decision tree structure directly via depth-first search of the tree When a leaf node is reached, perform all of the actions in the action node.

Throws:

AbleDataException

setControlParameter

public void setControlParameter(java.lang.String theControlParameter,
                                java.lang.Object theValue)
                         throws AbleDataException

Set the specified control parameter on the associated inference engine.

Specified by:

setControlParameter in class AbleInferenceEngine

Throws:

AbleDataException

getControlParameter

public java.lang.Object getControlParameter(java.lang.String theControlParameter)
                                     throws AbleDataException

Returns the specified control parameter on the associated inference engine.

Specified by:

getControlParameter in class AbleInferenceEngine

Throws:

AbleDataException

reset

public void reset()

Reset the rule block so that rules can be fired again: all rules are set to their original state. Note that the "processed" flag is not reset.

This is a no-op in this engine.

Overrides:

reset in class AbleInferenceEngine