Package org.loboevolution.apache.xpath

Class XPathVisitor

java.lang.Object
org.loboevolution.apache.xpath.XPathVisitor
Direct Known Subclasses:
HasPositionalPredChecker
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.

  • Constructor Details

    • XPathVisitor

      public XPathVisitor()

  • Method Details

    • visitLocationPath

      public boolean visitLocationPath()
      Visit a LocationPath.
      Returns:
      true if the sub expressions should be traversed.

    • visitUnionPath

      public boolean visitUnionPath()
      Visit a UnionPath.
      Returns:
      true if the sub expressions should be traversed.

    • visitStep

      public boolean visitStep()
      Visit a step within a location path.
      Returns:
      true if the sub expressions should be traversed.

    • visitPredicate

      public boolean visitPredicate(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:
      pred - The predicate object.
      Returns:
      true if the sub expressions should be traversed.

    • visitBinaryOperation

      public boolean visitBinaryOperation()
      Visit a binary operation.
      Returns:
      true if the sub expressions should be traversed.

    • visitUnaryOperation

      public boolean visitUnaryOperation()
      Visit a unary operation.
      Returns:
      true if the sub expressions should be traversed.

    • visitFunction

      public boolean visitFunction(Function func)
      Visit a function.
      Parameters:
      func - The function reference object.
      Returns:
      true if the sub expressions should be traversed.

    • visitMatchPattern

      public boolean visitMatchPattern()
      Visit a match pattern.
      Returns:
      true if the sub expressions should be traversed.

    • visitUnionPattern

      public void visitUnionPattern()
      Visit a union pattern.

    • visitStringLiteral

      public void visitStringLiteral()
      Visit a string literal.

    • visitNumberLiteral

      public void visitNumberLiteral()
      Visit a number literal.