Package org.apache.xpath.axes

Class OneStepIterator

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.BasicTestIterator
org.apache.xpath.axes.ChildTestIterator
org.apache.xpath.axes.OneStepIterator
All Implemented Interfaces:
Serializable, Cloneable, SourceLocator, DTMIterator, PathComponent, SubContextList, ExpressionNode, XPathVisitable
public class OneStepIterator
extends ChildTestIterator
This class implements a general iterator for those LocationSteps with only one step, and perhaps a predicate.
See Also:
org.apache.xpath.axes#LocPathIterator, Serialized Form

  • Field Details

    • m_axis

      protected int m_axis
      The traversal axis from where the nodes will be filtered.

    • m_iterator

      protected DTMAxisIterator m_iterator
      The DTM inner traversal class, that corresponds to the super axis.

  • Constructor Details

    • OneStepIterator

      public OneStepIterator​(DTMAxisIterator iterator, int axis) throws TransformerException
      Create a OneStepIterator object.
      Parameters:
      iterator - The DTM iterator which this iterator will use.
      axis - One of Axis.Child, etc., or -1 if the axis is unknown.
      Throws:
      TransformerException

  • Method Details

    • 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 ChildTestIterator
      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.

    • 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 ChildTestIterator

    • getNextNode

      protected int getNextNode()
      Get the next node via getFirstAttribute && getNextAttribute.
      Overrides:
      getNextNode in class ChildTestIterator
      Returns:
      The next node on the axis, or DTM.NULL.

    • clone

      public Object clone() throws CloneNotSupportedException
      Get a cloned iterator.
      Specified by:
      clone in interface DTMIterator
      Overrides:
      clone in class PredicatedNodeTest
      Returns:
      A new iterator that can be used without mutating this one.
      Throws:
      CloneNotSupportedException

    • 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 ChildTestIterator
      Returns:
      A cloned NodeIterator set of the start of the query.
      Throws:
      CloneNotSupportedException

    • isReverseAxes

      public boolean isReverseAxes()
      Tells if this is a reverse axes. Overrides AxesWalker#isReverseAxes.
      Overrides:
      isReverseAxes in class PredicatedNodeTest
      Returns:
      true for this class.

    • getProximityPosition

      protected int getProximityPosition​(int predicateIndex)
      Get the current sub-context position. In order to do the reverse axes count, for the moment this re-searches the axes up to the predicate. An optimization on this is to cache the nodes searched, but, for the moment, this case is probably rare enough that the added complexity isn't worth it.
      Overrides:
      getProximityPosition in class PredicatedNodeTest
      Parameters:
      predicateIndex - The predicate index of the proximity position.
      Returns:
      The pridicate index, or -1.

    • getLength

      public int getLength()
      The number of nodes in the list. The range of valid child node indices is 0 to length-1 inclusive.
      Specified by:
      getLength in interface DTMIterator
      Overrides:
      getLength in class LocPathIterator
      Returns:
      The number of nodes in the list, always greater or equal to zero.

    • countProximityPosition

      protected void countProximityPosition​(int i)
      Count backwards one proximity position.
      Overrides:
      countProximityPosition in class PredicatedNodeTest
      Parameters:
      i - The predicate index.

    • reset

      public void reset()
      Reset the iterator.
      Specified by:
      reset in interface DTMIterator
      Overrides:
      reset 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 ChildTestIterator
      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)