com.novell.xml.xpath
Interface Expression

All Known Implementing Classes:

AbsoluteLocationPath, AndExpr, AVT, BadExpression, BinaryExpr, BooleanExpr, BooleanValue, BrokenNotEqualsExpr, ComparisonExpr, DivExpr, EqualsExpr, FilterExpr, FunctionCall, GreaterThanEqualsExpr, GreaterThanExpr, IdentityExpr, LessThanEqualsExpr, LessThanExpr, MinusExpr, ModExpr, MulExpr, NodeSet, NodeSetExpr, NotEqualsExpr, NumberExpr, NumberValue, OrExpr, PathExpr, PlusExpr, RelativeLocationPath, StringValue, UnaryExpr, UnionExpr, VariablePlaceholder, VariableReference, VariableTemplate

public interface Expression

Interface that describes the basic functionality of XPath expressions

Method Summary

void	dump(PrintWriter writer, int indent) Print the expression in a readable form for debugging.
ExpressionValue	evaluate(Node contextNode, ExpressionContext context) Evaluate the expression with repect to the passed context Note: The contextNode and context parameters may be null if and only if isConstant() returns true for the expression implementation.
Class	getResultType() Return the Class object describing the result type of the expression.
boolean	isConstant() Return true if the expression is a constant value.
void	registerForReset(XPathResetRegistrar registrar) Register this expression or any subexpression that implements XPathResetCache with an object that wants to call resetCache()

Method Detail

evaluate

public ExpressionValue evaluate(Node contextNode,
                                ExpressionContext context)
                         throws XPathEvaluationException

Evaluate the expression with repect to the passed context Note: The contextNode and context parameters may be null if and only if isConstant() returns true for the expression implementation.

Parameters:

contextNode - context node for expression evaluation

context - expression context for expression evaluation

Returns:

result of evaluating expression

Throws:

XPathEvaluationException

isConstant

public boolean isConstant()

Return true if the expression is a constant value.

Returns:

True is expression is constant, false otherwise.

getResultType

public Class getResultType()

Return the Class object describing the result type of the expression.

Returns:

A Class object.

registerForReset

public void registerForReset(XPathResetRegistrar registrar)

Register this expression or any subexpression that implements XPathResetCache with an object that wants to call resetCache()

dump

public void dump(PrintWriter writer,
                 int indent)

Print the expression in a readable form for debugging.

Parameters:

writer - The output device.

indent - Number of tabs to indent the result.