org.apache.xpath

Class XPathVisitor

public class XPathVisitor extends Object

A derivation from this class can be passed to a class that implements the XPathVisitable interface, to have the appropriate method called for each component of the XPath. Aside from possible other uses, the main intention is to provide a reasonable means to perform expression rewriting.

Each method has the form boolean visitComponentType(ExpressionOwner owner, ComponentType compType). The ExpressionOwner argument is the owner of the component, and can be used to reset the expression for rewriting. If a method returns false, the sub hierarchy will not be traversed.

This class is meant to be a base class that will be derived by concrete classes, and doesn't much except return true for each method.

Method Summary
boolean	visitBinaryOperation(ExpressionOwner owner, Operation op) Visit a binary operation.
boolean	visitFunction(ExpressionOwner owner, Function func) Visit a function.
boolean	visitLocationPath(ExpressionOwner owner, LocPathIterator path) Visit a LocationPath.
boolean	visitMatchPattern(ExpressionOwner owner, StepPattern pattern) Visit a match pattern.
boolean	visitNumberLiteral(ExpressionOwner owner, XNumber num) Visit a number literal.
boolean	visitPredicate(ExpressionOwner owner, Expression pred) Visit a predicate within a location path.
boolean	visitStep(ExpressionOwner owner, NodeTest step) Visit a step within a location path.
boolean	visitStringLiteral(ExpressionOwner owner, XString str) Visit a string literal.
boolean	visitUnaryOperation(ExpressionOwner owner, UnaryOperation op) Visit a unary operation.
boolean	visitUnionPath(ExpressionOwner owner, UnionPathIterator path) Visit a UnionPath.
boolean	visitUnionPattern(ExpressionOwner owner, UnionPattern pattern) Visit a union pattern.
boolean	visitVariableRef(ExpressionOwner owner, Variable var) Visit a variable reference.

Method Detail

visitBinaryOperation

public boolean visitBinaryOperation(ExpressionOwner owner, Operation op)

Visit a binary operation.

Parameters: owner The owner of the expression, to which the expression can be reset if rewriting takes place. op The operation object.

Returns: true if the sub expressions should be traversed.

visitFunction

public boolean visitFunction(ExpressionOwner owner, Function func)

Visit a function.

Parameters: owner The owner of the expression, to which the expression can be reset if rewriting takes place. func The function reference object.

Returns: true if the sub expressions should be traversed.

visitLocationPath

public boolean visitLocationPath(ExpressionOwner owner, LocPathIterator path)

Visit a LocationPath.

Parameters: owner The owner of the expression, to which the expression can be reset if rewriting takes place. path The LocationPath object.

Returns: true if the sub expressions should be traversed.

visitMatchPattern

public boolean visitMatchPattern(ExpressionOwner owner, StepPattern pattern)

Visit a match pattern.

Parameters: owner The owner of the expression, to which the expression can be reset if rewriting takes place. pattern The match pattern object.

Returns: true if the sub expressions should be traversed.

visitNumberLiteral

public boolean visitNumberLiteral(ExpressionOwner owner, XNumber num)

Visit a number literal.

Parameters: owner The owner of the expression, to which the expression can be reset if rewriting takes place. num The number literal object.

Returns: true if the sub expressions should be traversed.

visitPredicate

public boolean visitPredicate(ExpressionOwner owner, Expression pred)

Visit a predicate within a location path. Note that there isn't a proper unique component for predicates, and that the expression will be called also for whatever type Expression is.

Parameters: owner The owner of the expression, to which the expression can be reset if rewriting takes place. pred The predicate object.

Returns: true if the sub expressions should be traversed.

visitStep

public boolean visitStep(ExpressionOwner owner, NodeTest step)

Visit a step within a location path.

Parameters: owner The owner of the expression, to which the expression can be reset if rewriting takes place. step The Step object.

Returns: true if the sub expressions should be traversed.

visitStringLiteral

public boolean visitStringLiteral(ExpressionOwner owner, XString str)

Visit a string literal.

Parameters: owner The owner of the expression, to which the expression can be reset if rewriting takes place. str The string literal object.

Returns: true if the sub expressions should be traversed.

visitUnaryOperation

public boolean visitUnaryOperation(ExpressionOwner owner, UnaryOperation op)

Visit a unary operation.

Parameters: owner The owner of the expression, to which the expression can be reset if rewriting takes place. op The operation object.

Returns: true if the sub expressions should be traversed.

visitUnionPath

public boolean visitUnionPath(ExpressionOwner owner, UnionPathIterator path)

Visit a UnionPath.

Parameters: owner The owner of the expression, to which the expression can be reset if rewriting takes place. path The UnionPath object.

Returns: true if the sub expressions should be traversed.

visitUnionPattern

public boolean visitUnionPattern(ExpressionOwner owner, UnionPattern pattern)

Visit a union pattern.

Parameters: owner The owner of the expression, to which the expression can be reset if rewriting takes place. pattern The union pattern object.

Returns: true if the sub expressions should be traversed.

visitVariableRef

public boolean visitVariableRef(ExpressionOwner owner, Variable var)

Visit a variable reference.

Parameters: owner The owner of the expression, to which the expression can be reset if rewriting takes place. var The variable reference object.

Returns: true if the sub expressions should be traversed.

Copyright B) 2006 Apache XML Project. All Rights Reserved.