com.ibm.able.data
Class AbleExpression

java.lang.Object
  com.ibm.able.data.AbleLiteral
      com.ibm.able.data.AbleExpression

All Implemented Interfaces:

AbleRd, java.io.Serializable

public class AbleExpression

extends AbleLiteral

An AbleExpression contains a unary or binary operator along with one or two AbleRd objects (which themselves could be AbleExpressions).

See Also:

Serialized Form

Field Summary

static double	DefaultWeight A default weight.
protected AbleRd	myLhs myLhs represents the left-hand side of this clause.
protected AbleLocation	myLocation The location of this expression in the source ARL file.
protected int	myOp myOp is the unary or binary operator to be used to evaluate the left-hand side of this clause against the right-hand side of this clause.
protected AbleRd	myRhs myRhs represents the right-hand side of this clause.
protected AbleRd	myValue myValue represents the value of this expression when the left-hand side and the right-hand side values are computed and the operator is applied.
protected double	myWeight myWeight represents the weight that this expression should be given when it is converted to an antecedent clause This field is initialized to DefaultWeight which means "unweighted".

Constructor Summary

AbleExpression(AbleDataContext theRuleSet, java.lang.String theExprString)
Create a new expression from the String.

AbleExpression(AbleRd theLhs, int theOp, AbleRd theRhs)
Create a new clause with the specified parts.

Method Summary

java.lang.String	arlCRdString() Return a formal ARL "clause read" string that describes this data object.
java.lang.String	armlCRdString()
java.util.Vector	convertToConjunctiveNormalForm() Convert this Expression into conjunctive normal form a list of ANDed AbleExpressions
java.util.Vector	convertToDisjunctiveNormalForm() Convert this Expression into disjunctive normal form a list of ORed AbleExpressions
AbleExpression	createMatchExpression(java.util.Hashtable replacementVars) Create a duplicate of this expression using replacement vars
boolean	equals(AbleExpression theAbleExpression) Determine whether this expression is equal to some other expression.
boolean	equals(java.lang.Object theExpr)
boolean	getBooleanValue() Retrieve the value of this data object as a boolean value.
int	getDataType() Retrieve the data type of this data object.
java.lang.Class	getDataTypeClass() Return expression value data type
java.lang.String	getDataTypeClassName() Retrieve the name of the class of this object's underlying data type.
AbleFuzzySet	getFuzzyValue() Retrieve the value of this data object as a fuzzy value.
java.lang.Object	getGenericValue() Retrieve the value of this data object as an Object.
AbleRd	getLhs() Retrieve the expression's left-hand side.
AbleLocation	getLocation() Returns the location of the expression in the source ARL file
double	getNumericValue() Retrieve the value of this data object as a numeric value.
int	getOp() Retrieve the expression's operator.
java.lang.String	getOpAsString() Retrieve the expression's operator in human-readable string form.
java.util.BitSet	getReferents() Retrieve the Ids of the variables to which this data object refers, if any.
AbleRd	getRhs() Retrieve the expression's right-hand side.
java.lang.String	getStringValue() Retrieve the value of this data object as a string value.
java.lang.String	getTemplateString(java.util.Vector theTemplateVars) Retrieve a text format string for use by rule templates.
AbleLiteral	getValue() Compute the value of this expression clause and return the value as an AbleLiteral
java.util.HashSet	getVariableReferences() Retrieve the set of variables (if any) referenced by this expression (and subexpressions)
double	getWeight() Retrieve the weight used when the expression is converted to an antecedent clause.
int	hashCode()
boolean	isComplexExpression() Returns true if either LHS or RHS args are AbleExpressions
boolean	isCompoundExpression() Returns true if both LHS and RHS args are AbleExpressions
boolean	isConstant() Returns true if this AbleRd object is a constant value false, if it does not.
boolean	isSimpleExpression() Returns true if neither the LHS nor RHS args are AbleExpressions
void	setLocation(AbleLocation theLocation) Set the location of the expression in the source ARL file
void	setWeight(double theWeight) Set the weight to the specified value.
java.lang.String	traceString(int theTraceStringFlavor) Retrieve a string describing (the contents of) the object.
java.lang.String	xmlCRdString() Return a formal XML "clause read" string that describes this data object.

Methods inherited from class com.ibm.able.data.AbleLiteral

bitwiseAND, bitwiseNOT, bitwiseOR, bitwiseShiftLeft, bitwiseShiftRight, bitwiseShiftRightZeroFill, bitwiseXOR, cmpEq, cmpGt, cmpGtEq, cmpIs, cmpLt, cmpLtEq, cmpNeq, compDivide, compMinus, compModulo, compMultiply, compPlus, compUnaryMinus, getDataTypeAsString, getReferent, logicalAND, logicalNOT, logicalOR, toString

Methods inherited from class java.lang.Object

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

Field Detail

myLhs

protected AbleRd myLhs

myLhs represents the left-hand side of this clause. This field is initialized by the constructor.

myOp

protected int myOp

myOp is the unary or binary operator to be used to evaluate the left-hand side of this clause against the right-hand side of this clause. The value must be an AbleData.<Operator> constant. This field is initialized by the constructor.

myRhs

protected AbleRd myRhs

myRhs represents the right-hand side of this clause. This field is initialized by the constructor.

myValue

protected transient AbleRd myValue

myValue represents the value of this expression when the left-hand side and the right-hand side values are computed and the operator is applied.

This field is initialized by the constructor.

DefaultWeight

public static final double DefaultWeight

A default weight.

See Also:

Constant Field Values

myWeight

protected double myWeight

myWeight represents the weight that this expression should be given when it is converted to an antecedent clause This field is initialized to DefaultWeight which means "unweighted".

myLocation

protected AbleLocation myLocation

The location of this expression in the source ARL file.

Constructor Detail

AbleExpression

public AbleExpression(AbleRd theLhs,
                      int theOp,
                      AbleRd theRhs)

Create a new clause with the specified parts.

If either the left-hand side or the right-hand side is a variable, and that variable is keeping track of clauses in which the variable is referenced, the variable's set of references is updated to point to this clause.

Parameters:

theLhs - The left-hand side of the clause.

theOp - A relational operator with which to evaluate the two sides, or operands, of this clause. The value must be an AbleData.<Operator> constant.

theRhs - The right-hand side of the clause.

AbleExpression

public AbleExpression(AbleDataContext theRuleSet,
                      java.lang.String theExprString)
               throws AbleException

Create a new expression from the String.

Parameters:

theRuleSet - The data context used to parse the String into an expression

theExprString - The expression String.

Method Detail

createMatchExpression

public AbleExpression createMatchExpression(java.util.Hashtable replacementVars)

Create a duplicate of this expression using replacement vars

getLhs

public final AbleRd getLhs()

Retrieve the expression's left-hand side.

Returns:

An AbleData left-hand side object.

getOp

public final int getOp()

Retrieve the expression's operator.

Returns:

An AbleData.<Operator> constant.

getOpAsString

public java.lang.String getOpAsString()

Retrieve the expression's operator in human-readable string form.

Returns:

A string of the form: "n:AbleData.<Operator>", where n is the actual constant and "<Operator>" is the name of the constant.

getRhs

public final AbleRd getRhs()

Retrieve the expression's right-hand side.

Returns:

An AbleData "readable" object.

getReferents

public java.util.BitSet getReferents()

Retrieve the Ids of the variables to which this data object refers, if any. Must be overriden by subclasses which can refer to variables.

Specified by:

getReferents in interface AbleRd

Overrides:

getReferents in class AbleLiteral

Returns:

The Ids of the variables to which this data object refers, or AbleData.VarIdNull if the data object is a literal and therefore refers to no variable.

traceString

public java.lang.String traceString(int theTraceStringFlavor)

Description copied from class: AbleLiteral

Retrieve a string describing (the contents of) the object.

Specified by:

traceString in interface AbleRd

Specified by:

traceString in class AbleLiteral

Parameters:

theTraceStringFlavor - An AbleRuleSet.TraceStringFlavor value.

Returns:

A String containing the current contents of the object.

See Also:

AbleLiteral.traceString(int)

xmlCRdString

public java.lang.String xmlCRdString()

Description copied from class: AbleLiteral

Return a formal XML "clause read" string that describes this data object.

Specified by:

xmlCRdString in interface AbleRd

Specified by:

xmlCRdString in class AbleLiteral

Returns:

A String describing the data object in XML.

See Also:

AbleLiteral.xmlCRdString()

armlCRdString

public java.lang.String armlCRdString()

See Also:

AbleLiteral.xmlCRdString()

arlCRdString

public java.lang.String arlCRdString()

Description copied from class: AbleLiteral

Return a formal ARL "clause read" string that describes this data object.

Specified by:

arlCRdString in interface AbleRd

Specified by:

arlCRdString in class AbleLiteral

Returns:

A String describing the data object in formal rule language.

See Also:

AbleLiteral.arlCRdString()

convertToConjunctiveNormalForm

public java.util.Vector convertToConjunctiveNormalForm()

Convert this Expression into conjunctive normal form a list of ANDed AbleExpressions

Returns:

A Vector of AbleExpression objects

convertToDisjunctiveNormalForm

public java.util.Vector convertToDisjunctiveNormalForm()

Convert this Expression into disjunctive normal form a list of ORed AbleExpressions

Returns:

A Vector of AbleExpression objects

getTemplateString

public java.lang.String getTemplateString(java.util.Vector theTemplateVars)

Retrieve a text format string for use by rule templates. The string contains "{n}" strings, where the index 'n' corresponds to the template variables defined in the rule template. This string is based on the standard arlString() representation of the rule. After replacement of the template variable values, the resulting string must be a valid ARL format string that can be parsed.

Specified by:

getTemplateString in interface AbleRd

Overrides:

getTemplateString in class AbleLiteral

Parameters:

theTemplateVars - An ordered list of template variables referenced by this rule.

Returns:

A Text format string used to create a new rule instance.

getValue

public AbleLiteral getValue()
                     throws AbleDataException

Compute the value of this expression clause and return the value as an AbleLiteral

Specified by:

getValue in interface AbleRd

Specified by:

getValue in class AbleLiteral

Returns:

An AbleLiteral object.

Throws:

AbleDataException - If the value of this object cannot be represented as a literal.

See Also:

AbleLiteral.getValue()

getStringValue

public java.lang.String getStringValue()
                                throws AbleDataException

Description copied from class: AbleLiteral

Retrieve the value of this data object as a string value.

Specified by:

getStringValue in interface AbleRd

Specified by:

getStringValue in class AbleLiteral

Returns:

A String, if the value of this object can be represented as a string value.

Throws:

AbleDataException - If the value of this object cannot be represented as a string value.

See Also:

AbleLiteral.getStringValue()

getNumericValue

public double getNumericValue()
                       throws AbleDataException

Description copied from class: AbleLiteral

Retrieve the value of this data object as a numeric value.

Specified by:

getNumericValue in interface AbleRd

Specified by:

getNumericValue in class AbleLiteral

Returns:

A double, if the value of this object can be represented as a numeric value.

Throws:

AbleDataException - If the value of this object cannot be represented as a numeric value.

See Also:

AbleLiteral.getNumericValue()

getGenericValue

public java.lang.Object getGenericValue()
                                 throws AbleDataException

Description copied from class: AbleLiteral

Retrieve the value of this data object as an Object.

Specified by:

getGenericValue in interface AbleRd

Specified by:

getGenericValue in class AbleLiteral

Returns:

A Boolean, Double, String or Object object depending on the derived class.

Throws:

AbleDataException - If the value of this object cannot be represented as an Object.

See Also:

AbleLiteral.getGenericValue()

getFuzzyValue

public AbleFuzzySet getFuzzyValue()
                           throws AbleDataException

Description copied from class: AbleLiteral

Retrieve the value of this data object as a fuzzy value.

Specified by:

getFuzzyValue in interface AbleRd

Specified by:

getFuzzyValue in class AbleLiteral

Returns:

A fuzzy set, if the value of this object can be represented as a fuzzy value.

Throws:

AbleDataException - If the value of this object cannot be represented as a fuzzy value.

See Also:

AbleLiteral.getFuzzyValue()

getBooleanValue

public boolean getBooleanValue()
                        throws AbleDataException

Description copied from class: AbleLiteral

Retrieve the value of this data object as a boolean value.

Specified by:

getBooleanValue in interface AbleRd

Specified by:

getBooleanValue in class AbleLiteral

Returns:

A boolean, if the value of this object can be represented as a boolean value.

Throws:

AbleDataException - If the value of this object cannot be represented as a boolean value.

See Also:

AbleLiteral.getBooleanValue()

getDataTypeClass

public java.lang.Class getDataTypeClass()

Return expression value data type

Specified by:

getDataTypeClass in interface AbleRd

Specified by:

getDataTypeClass in class AbleLiteral

Returns:

The class of the underlying data type.

getDataTypeClassName

public java.lang.String getDataTypeClassName()

Description copied from class: AbleLiteral

Retrieve the name of the class of this object's underlying data type.

Specified by:

getDataTypeClassName in interface AbleRd

Specified by:

getDataTypeClassName in class AbleLiteral

Returns:

A String that is the name of the class of the underlying data type.

setWeight

public final void setWeight(double theWeight)

Set the weight to the specified value. The new weight replaces the current weight.

Parameters:

theWeight - The new weight used if the expression is converted to an antecedent clause.

getWeight

public final double getWeight()

Retrieve the weight used when the expression is converted to an antecedent clause.

Returns:

The weight.

getVariableReferences

public java.util.HashSet getVariableReferences()

Retrieve the set of variables (if any) referenced by this expression (and subexpressions)

equals

public boolean equals(AbleExpression theAbleExpression)

Determine whether this expression is equal to some other expression.

For the expressions to be considered equal:

• The left-hand sides must be ==
• The operators must be ==
• The right-hand sides must be ==
• The expression weights must be ==

Parameters:

theAbleExpression - The expression that is to be compared to this expression.

Returns:

true if the expressions are equal; false otherwise.

equals

public boolean equals(java.lang.Object theExpr)

hashCode

public int hashCode()

isSimpleExpression

public boolean isSimpleExpression()

Returns true if neither the LHS nor RHS args are AbleExpressions

isComplexExpression

public boolean isComplexExpression()

Returns true if either LHS or RHS args are AbleExpressions

isCompoundExpression

public boolean isCompoundExpression()

Returns true if both LHS and RHS args are AbleExpressions

isConstant

public boolean isConstant()

Description copied from interface: AbleRd

Returns true if this AbleRd object is a constant value false, if it does not.

Specified by:

isConstant in interface AbleRd

Overrides:

isConstant in class AbleLiteral

getDataType

public int getDataType()

Description copied from class: AbleLiteral

Retrieve the data type of this data object.

Specified by:

getDataType in interface AbleRd

Specified by:

getDataType in class AbleLiteral

Returns:

An AbleData.<DataType> constant.

See Also:

AbleRd.getDataType()

setLocation

public void setLocation(AbleLocation theLocation)

Set the location of the expression in the source ARL file

getLocation

public AbleLocation getLocation()

Returns the location of the expression in the source ARL file