org.apache.xpath
Class XPathVisitor
java.lang.Objectorg.apache.xpath.XPathVisitor
public class XPathVisitor
extends java.lang.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.
boolean | visitBinaryOperation(ExpressionOwner owner, Operation op)- Visit a binary operation.
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boolean | visitFunction(ExpressionOwner owner, Function func)- Visit a function.
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boolean | visitLocationPath(ExpressionOwner owner, LocPathIterator path)- Visit a LocationPath.
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boolean | visitMatchPattern(ExpressionOwner owner, StepPattern pattern)- Visit a match pattern.
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boolean | visitNumberLiteral(ExpressionOwner owner, XNumber num)- Visit a number literal.
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boolean | visitPredicate(ExpressionOwner owner, Expression pred)- Visit a predicate within a location path.
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boolean | visitStep(ExpressionOwner owner, NodeTest step)- Visit a step within a location path.
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boolean | visitStringLiteral(ExpressionOwner owner, XString str)- Visit a string literal.
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boolean | visitUnaryOperation(ExpressionOwner owner, UnaryOperation op)- Visit a unary operation.
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boolean | visitUnionPath(ExpressionOwner owner, UnionPathIterator path)- Visit a UnionPath.
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boolean | visitUnionPattern(ExpressionOwner owner, UnionPattern pattern)- Visit a union pattern.
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boolean | visitVariableRef(ExpressionOwner owner, Variable var)- Visit a variable reference.
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visitBinaryOperation
public boolean visitBinaryOperation(ExpressionOwner owner,
Operation op) Visit a binary operation.
owner - The owner of the expression, to which the expression can
be reset if rewriting takes place.op - The operation object.
- true if the sub expressions should be traversed.
visitFunction
public boolean visitFunction(ExpressionOwner owner,
Function func) Visit a function.
owner - The owner of the expression, to which the expression can
be reset if rewriting takes place.func - The function reference object.
- true if the sub expressions should be traversed.
visitLocationPath
public boolean visitLocationPath(ExpressionOwner owner,
LocPathIterator path) Visit a LocationPath.
owner - The owner of the expression, to which the expression can
be reset if rewriting takes place.path - The LocationPath object.
- true if the sub expressions should be traversed.
visitMatchPattern
public boolean visitMatchPattern(ExpressionOwner owner,
StepPattern pattern) Visit a match pattern.
owner - The owner of the expression, to which the expression can
be reset if rewriting takes place.pattern - The match pattern object.
- true if the sub expressions should be traversed.
visitNumberLiteral
public boolean visitNumberLiteral(ExpressionOwner owner,
XNumber num) Visit a number literal.
owner - The owner of the expression, to which the expression can
be reset if rewriting takes place.num - The number literal object.
- 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.
owner - The owner of the expression, to which the expression can
be reset if rewriting takes place.pred - The predicate object.
- true if the sub expressions should be traversed.
visitStep
public boolean visitStep(ExpressionOwner owner,
NodeTest step) Visit a step within a location path.
owner - The owner of the expression, to which the expression can
be reset if rewriting takes place.step - The Step object.
- true if the sub expressions should be traversed.
visitStringLiteral
public boolean visitStringLiteral(ExpressionOwner owner,
XString str) Visit a string literal.
owner - The owner of the expression, to which the expression can
be reset if rewriting takes place.str - The string literal object.
- true if the sub expressions should be traversed.
visitUnaryOperation
public boolean visitUnaryOperation(ExpressionOwner owner,
UnaryOperation op) Visit a unary operation.
owner - The owner of the expression, to which the expression can
be reset if rewriting takes place.op - The operation object.
- true if the sub expressions should be traversed.
visitUnionPath
public boolean visitUnionPath(ExpressionOwner owner,
UnionPathIterator path) Visit a UnionPath.
owner - The owner of the expression, to which the expression can
be reset if rewriting takes place.path - The UnionPath object.
- true if the sub expressions should be traversed.
visitUnionPattern
public boolean visitUnionPattern(ExpressionOwner owner,
UnionPattern pattern) Visit a union pattern.
owner - The owner of the expression, to which the expression can
be reset if rewriting takes place.pattern - The union pattern object.
- true if the sub expressions should be traversed.
visitVariableRef
public boolean visitVariableRef(ExpressionOwner owner,
Variable var) Visit a variable reference.
owner - The owner of the expression, to which the expression can
be reset if rewriting takes place.var - The variable reference object.
- true if the sub expressions should be traversed.
Copyright B) 2004 Apache XML Project. All Rights Reserved.