org.apache.commons.jxpath.ri.compiler

Class CoreOperationSubtract

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.CoreOperationSubtract

public class CoreOperationSubtract
extends CoreOperation

Implementation of Expression for the operation "-".

Version:

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

Author:

Dmitri Plotnikov

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

Constructor and Description
CoreOperationSubtract(Expression arg1, Expression arg2) Create a new CoreOperationSubtract.

Method Summary

Methods

Modifier and Type	Method and Description
Object	computeValue(EvalContext context) Evaluates the expression.
protected int	getPrecedence() Computes the precedence of the operation.
String	getSymbol() Returns the XPath symbol for this operation, e.g.
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, 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

CoreOperationSubtract

public CoreOperationSubtract(Expression arg1,
                     Expression arg2)

Create a new CoreOperationSubtract.

Parameters:

arg1 - minuend

arg2 - subtrahend

Method Detail

computeValue

public 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 int getPrecedence()

Description copied from class: CoreOperation

Computes the precedence of the operation.

Specified by:

getPrecedence in class CoreOperation

Returns:

int precedence

isSymmetric

protected 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

getSymbol

public String getSymbol()

Description copied from class: CoreOperation

Returns the XPath symbol for this operation, e.g. "+", "div", etc.

Specified by:

getSymbol in class CoreOperation

Returns:

String symbol