net.sourceforge.htmlunit.xpath.operations

Class Operation

java.lang.Object

net.sourceforge.htmlunit.xpath.Expression

net.sourceforge.htmlunit.xpath.operations.Operation

All Implemented Interfaces:

SourceLocator, ExpressionNode, XPathVisitable

Direct Known Subclasses:

And, Div, Equals, Gt, Gte, Lt, Lte, Minus, Mod, Mult, NotEquals, Or, Plus

public class Operation
extends Expression

The baseclass for a binary operation.

Field Summary

Fields

Modifier and Type	Field and Description
protected Expression	m_left The left operand expression.
protected Expression	m_right The right operand expression.

Constructor Summary

Constructors

Constructor and Description
Operation()

Method Summary

Modifier and Type	Method and Description
void	callVisitors(XPathVisitor visitor) This will traverse the hierarchy, calling the visitor for each member.
boolean	canTraverseOutsideSubtree() Tell if this expression or it's subexpressions can traverse outside the current subtree.
boolean	deepEquals(Expression expr) Compare this object with another object and see if they are equal, include the sub heararchy.
XObject	execute(XPathContext xctxt) Execute an expression in the XPath runtime context, and return the result of the expression.
XObject	operate(XObject left, XObject right) Apply the operation to two operands, and return the result.
void	setLeftRight(Expression l, Expression r) Set the left and right operand expressions for this operation.

Methods inherited from class net.sourceforge.htmlunit.xpath.Expression

asIterator, asNode, assertion, bool, error, execute, execute, execute, exprGetParent, exprSetParent, getColumnNumber, getExpressionOwner, getLineNumber, getPublicId, getSystemId, isSameClass, isStableNumber, num

Methods inherited from class java.lang.Object

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

Field Detail

m_left

protected Expression m_left

The left operand expression.

m_right

protected Expression m_right

The right operand expression.

Constructor Detail

Operation

public Operation()

Method Detail

canTraverseOutsideSubtree

public boolean canTraverseOutsideSubtree()

Tell if this expression or it's subexpressions can traverse outside the current subtree.

Overrides:

canTraverseOutsideSubtree in class Expression

Returns:

true if traversal outside the context node's subtree can occur.

setLeftRight

public void setLeftRight(Expression l,
                         Expression r)

Set the left and right operand expressions for this operation.

Parameters:

l - The left expression operand.

r - The right expression operand.

execute

public XObject execute(XPathContext xctxt)
                throws TransformerException

Execute an expression in the XPath runtime context, and return the result of the expression.

Specified by:

execute in class Expression

Parameters:

xctxt - The XPath runtime context.

Returns:

The result of the expression in the form of a XObject.

Throws:

TransformerException - if a runtime exception occurs.

operate

public XObject operate(XObject left,
                       XObject right)
                throws TransformerException

Apply the operation to two operands, and return the result.

Parameters:

left - non-null reference to the evaluated left operand.

right - non-null reference to the evaluated right operand.

Returns:

non-null reference to the XObject that represents the result of the operation.

Throws:

TransformerException - in case of error

callVisitors

public void callVisitors(XPathVisitor visitor)

This will traverse the hierarchy, calling the visitor for each member. If the called visitor method returns false, the subtree should not be called.

Parameters:

visitor - The visitor whose appropriate method will be called.

deepEquals

public boolean deepEquals(Expression expr)

Compare this object with another object and see if they are equal, include the sub heararchy.

Specified by:

deepEquals in class Expression

Parameters:

expr - Another expression object.

Returns:

true if this objects class and the expr object's class are the same, and the data contained within both objects are considered equal.