Package org.apache.commons.jxpath.ri.compiler

Class CoreOperationRelationalExpression

java.lang.Object

org.apache.commons.jxpath.ri.compiler.Expression

org.apache.commons.jxpath.ri.compiler.Operation

org.apache.commons.jxpath.ri.compiler.CoreOperation

org.apache.commons.jxpath.ri.compiler.CoreOperationRelationalExpression

Direct Known Subclasses:

CoreOperationGreaterThan, CoreOperationGreaterThanOrEqual, CoreOperationLessThan, CoreOperationLessThanOrEqual

public abstract class CoreOperationRelationalExpression
extends CoreOperation

Base implementation of Expression for the operations ">", ">=", "<", "<=".

Since:

JXPath 1.3

Version:

$Revision: 652845 $ $Date: 2008-05-02 12:46:46 -0500 (Fri, 02 May 2008) $

Author:

Matt Benson

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.commons.jxpath.ri.compiler.Expression

Expression.PointerIterator, Expression.ValueIterator

Field Summary

Fields inherited from class org.apache.commons.jxpath.ri.compiler.CoreOperation

ADD_PRECEDENCE, AND_PRECEDENCE, COMPARE_PRECEDENCE, MULTIPLY_PRECEDENCE, NEGATE_PRECEDENCE, OR_PRECEDENCE, RELATIONAL_EXPR_PRECEDENCE, UNION_PRECEDENCE

Fields inherited from class org.apache.commons.jxpath.ri.compiler.Operation

args

Fields inherited from class org.apache.commons.jxpath.ri.compiler.Expression

NOT_A_NUMBER, ONE, ZERO

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	CoreOperationRelationalExpression(Expression[] args)	Create a new CoreOperationRelationalExpression.

Method Summary

Modifier and Type	Method	Description
java.lang.Object	computeValue(EvalContext context)	Evaluates the expression.
protected abstract boolean	evaluateCompare(int compare)	Template method for subclasses to evaluate the result of a comparison.
protected int	getPrecedence()	Computes the precedence of the operation.
protected boolean	isSymmetric()	Returns true if the operation is not sensitive to the order of arguments, e.g.

Methods inherited from class org.apache.commons.jxpath.ri.compiler.CoreOperation

compute, getSymbol, toString

Methods inherited from class org.apache.commons.jxpath.ri.compiler.Operation

computeContextDependent, getArguments

Methods inherited from class org.apache.commons.jxpath.ri.compiler.Expression

isContextDependent, iterate, iteratePointers

Methods inherited from class java.lang.Object

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

Constructor Detail

CoreOperationRelationalExpression

protected CoreOperationRelationalExpression(Expression[] args)

Create a new CoreOperationRelationalExpression.

Parameters:

args - arguments

Method Detail

computeValue

public final java.lang.Object computeValue(EvalContext context)

Description copied from class: Expression

Evaluates the expression. If the result is a node set, returns the first element of the node set.

Specified by:

computeValue in class CoreOperation

Parameters:

context - evaluation context

Returns:

Object

getPrecedence

protected final int getPrecedence()

Description copied from class: CoreOperation

Computes the precedence of the operation.

Specified by:

getPrecedence in class CoreOperation

Returns:

int precedence

isSymmetric

protected final boolean isSymmetric()

Description copied from class: CoreOperation

Returns true if the operation is not sensitive to the order of arguments, e.g. "=", "and" etc, and false if it is, e.g. "<=", "div".

Specified by:

isSymmetric in class CoreOperation

Returns:

boolean

evaluateCompare

protected abstract boolean evaluateCompare(int compare)

Template method for subclasses to evaluate the result of a comparison.

Parameters:

compare - result of comparison to evaluate

Returns:

ultimate operation success/failure