Package org.apache.xpath.axes

Class FilterExprWalker

java.lang.Object
org.apache.xpath.Expression
org.apache.xpath.patterns.NodeTest
org.apache.xpath.axes.PredicatedNodeTest
org.apache.xpath.axes.AxesWalker
org.apache.xpath.axes.FilterExprWalker
All Implemented Interfaces:
Serializable, Cloneable, SourceLocator, PathComponent, SubContextList, ExpressionNode, ExpressionOwner, XPathVisitable
public class FilterExprWalker
extends AxesWalker
Walker for the OP_VARIABLE, or OP_EXTFUNCTION, or OP_FUNCTION, or OP_GROUP, op codes.
See Also:
XPath FilterExpr descriptions, Serialized Form

  • Constructor Details

    • FilterExprWalker

      public FilterExprWalker​(WalkingIterator locPathIterator)
      Construct a FilterExprWalker using a LocPathIterator.
      Parameters:
      locPathIterator - non-null reference to the parent iterator.

  • Method Details

    • init

      public void init​(Compiler compiler, int opPos, int stepType) throws TransformerException
      Init a FilterExprWalker.
      Overrides:
      init in class AxesWalker
      Parameters:
      compiler - non-null reference to the Compiler that is constructing.
      opPos - positive opcode position for this step.
      stepType - The type of step.
      Throws:
      TransformerException

    • detach

      public void detach()
      Detaches the walker from the set which it iterated over, releasing any computational resources and placing the iterator in the INVALID state.
      Overrides:
      detach in class AxesWalker

    • setRoot

      public void setRoot​(int root)
      Set the root node of the TreeWalker.
      Overrides:
      setRoot in class AxesWalker
      Parameters:
      root - non-null reference to the root, or starting point of the query.

    • clone

      public Object clone() throws CloneNotSupportedException
      Get a cloned FilterExprWalker.
      Overrides:
      clone in class AxesWalker
      Returns:
      A new FilterExprWalker that can be used without mutating this one.
      Throws:
      CloneNotSupportedException

    • acceptNode

      public short acceptNode​(int n)
      This method needs to override AxesWalker.acceptNode because FilterExprWalkers don't need to, and shouldn't, do a node test.
      Overrides:
      acceptNode in class PredicatedNodeTest
      Parameters:
      n - The node to check to see if it passes the filter or not.
      Returns:
      a constant to determine whether the node is accepted, rejected, or skipped, as defined above .

    • getNextNode

      public int getNextNode()
      Moves the TreeWalker to the next visible node in document order relative to the current node, and returns the new node. If the current node has no next node, or if the search for nextNode attempts to step upward from the TreeWalker's root node, returns null , and retains the current node.
      Overrides:
      getNextNode in class AxesWalker
      Returns:
      The new node, or null if the current node has no next node in the TreeWalker's logical view.

    • getLastPos

      public int getLastPos​(XPathContext xctxt)
      Get the index of the last node that can be itterated to.
      Specified by:
      getLastPos in interface SubContextList
      Overrides:
      getLastPos in class AxesWalker
      Parameters:
      xctxt - XPath runtime context.
      Returns:
      the index of the last node that can be itterated to.

    • fixupVariables

      public void fixupVariables​(Vector vars, int globalsSize)
      This function is used to fixup variables from QNames to stack frame indexes at stylesheet build time.
      Overrides:
      fixupVariables in class PredicatedNodeTest
      Parameters:
      vars - List of QNames that correspond to variables. This list should be searched backwards for the first qualified name that corresponds to the variable reference qname. The position of the QName in the vector from the start of the vector will be its position in the stack frame (but variables above the globalsTop value will need to be offset to the current stack frame).

    • getInnerExpression

      public Expression getInnerExpression()
      Get the inner contained expression of this filter.

    • setInnerExpression

      public void setInnerExpression​(Expression expr)
      Set the inner contained expression of this filter.

    • getAnalysisBits

      public int getAnalysisBits()
      Get the analysis bits for this walker, as defined in the WalkerFactory.
      Specified by:
      getAnalysisBits in interface PathComponent
      Overrides:
      getAnalysisBits in class AxesWalker
      Returns:
      One of WalkerFactory#BIT_DESCENDANT, etc.

    • isDocOrdered

      public boolean isDocOrdered()
      Returns true if all the nodes in the iteration well be returned in document order. Warning: This can only be called after setRoot has been called!
      Overrides:
      isDocOrdered in class AxesWalker
      Returns:
      true as a default.

    • getAxis

      public int getAxis()
      Returns the axis being iterated, if it is known.
      Overrides:
      getAxis in class AxesWalker
      Returns:
      Axis.CHILD, etc., or -1 if the axis is not known or is of multiple types.

    • callPredicateVisitors

      public void callPredicateVisitors​(XPathVisitor visitor)
      This will traverse the heararchy, calling the visitor for each member. If the called visitor method returns false, the subtree should not be called.
      Overrides:
      callPredicateVisitors in class PredicatedNodeTest
      Parameters:
      visitor - The visitor whose appropriate method will be called.

    • deepEquals

      public boolean deepEquals​(Expression expr)
      Description copied from class: Expression
      Compare this object with another object and see if they are equal, include the sub heararchy.
      Overrides:
      deepEquals in class AxesWalker
      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.
      See Also:
      Expression.deepEquals(Expression)