Package org.apache.xpath.axes

Class DescendantIterator

java.lang.Object
org.apache.xpath.Expression
org.apache.xpath.patterns.NodeTest
org.apache.xpath.axes.PredicatedNodeTest
org.apache.xpath.axes.LocPathIterator
org.apache.xpath.axes.DescendantIterator
All Implemented Interfaces:
Serializable, Cloneable, SourceLocator, DTMIterator, PathComponent, SubContextList, ExpressionNode, XPathVisitable
public class DescendantIterator
extends LocPathIterator
This class implements an optimized iterator for descendant, descendant-or-self, or "//foo" patterns.
See Also:
LocPathIterator, Serialized Form

  • Field Details

    • m_traverser

      protected transient DTMAxisTraverser m_traverser
      The traverser to use to navigate over the descendants.

    • m_axis

      protected int m_axis
      The axis that we are traversing.

    • m_extendedTypeID

      protected int m_extendedTypeID
      The extended type ID, not set until setRoot.

  • Constructor Details

    • DescendantIterator

      public DescendantIterator()
      Create a DescendantIterator object.

  • Method Details

    • cloneWithReset

      public DTMIterator cloneWithReset() throws CloneNotSupportedException
      Get a cloned Iterator that is reset to the beginning of the query.
      Specified by:
      cloneWithReset in interface DTMIterator
      Overrides:
      cloneWithReset in class LocPathIterator
      Returns:
      A cloned NodeIterator set of the start of the query.
      Throws:
      CloneNotSupportedException

    • nextNode

      public int nextNode()
      Returns the next node in the set and advances the position of the iterator in the set. After a NodeIterator is created, the first call to nextNode() returns the first node in the set.
      Specified by:
      nextNode in interface DTMIterator
      Specified by:
      nextNode in class LocPathIterator
      Returns:
      The next Node in the set being iterated over, or null if there are no more members in that set.
      Throws:
      DOMException - INVALID_STATE_ERR: Raised if this method is called after the detach method was invoked.

    • setRoot

      public void setRoot​(int context, Object environment)
      Initialize the context values for this expression after it is cloned.
      Specified by:
      setRoot in interface DTMIterator
      Overrides:
      setRoot in class LocPathIterator
      Parameters:
      context - The XPath runtime context for this transformation.
      environment - The environment object. The environment in which this iterator operates, which should provide:
      • a node (the context node... same value as "root" defined below)
      • a pair of non-zero positive integers (the context position and the context size)
      • a set of variable bindings
      • a function library
      • the set of namespace declarations in scope for the expression.

          • At this time the exact implementation of this environment is application dependent. Probably a proper interface will be created fairly soon.

    • asNode

      public int asNode​(XPathContext xctxt) throws TransformerException
      Return the first node out of the nodeset, if this expression is a nodeset expression. This is the default implementation for nodesets.

      WARNING: Do not mutate this class from this function!

      Overrides:
      asNode in class LocPathIterator
      Parameters:
      xctxt - The XPath runtime context.
      Returns:
      the first node out of the nodeset, or DTM.NULL.
      Throws:
      TransformerException

    • detach

      public void detach()
      Detaches the iterator from the set which it iterated over, releasing any computational resources and placing the iterator in the INVALID state. Afterdetach has been invoked, calls to nextNode orpreviousNode will raise the exception INVALID_STATE_ERR.
      Specified by:
      detach in interface DTMIterator
      Overrides:
      detach in class LocPathIterator

    • getAxis

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

    • 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 PredicatedNodeTest
      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)