Class TreeEnumeration

java.lang.Object
net.sf.saxon.tree.linked.TreeEnumeration
All Implemented Interfaces:
SequenceIterator, AxisIterator, LookaheadIterator, UnfailingIterator
Direct Known Subclasses:
AncestorEnumeration, ChildEnumeration, DescendantEnumeration, FollowingEnumeration, FollowingSiblingEnumeration, PrecedingEnumeration, PrecedingOrAncestorEnumeration, PrecedingSiblingEnumeration
abstract class TreeEnumeration extends Object implements AxisIterator, LookaheadIterator

  • Field Details

    • start

      protected NodeImpl start

    • next

      protected NodeImpl next

    • nodeTest

      protected NodeTest nodeTest

    • current

      protected NodeImpl current

    • position

      protected int position

  • Constructor Details

    • TreeEnumeration

      public TreeEnumeration(NodeImpl origin, NodeTest nodeTest)
      Create an axis enumeration for a given type and name of node, from a given origin node
      Parameters:
      origin - the node from which the axis originates
      nodeTest - test to be satisfied by the returned nodes, or null if all nodes are to be returned.

  • Method Details

    • conforms

      protected boolean conforms(NodeImpl node)
      Test whether a node conforms to the node type and name constraints. Note that this returns true if the supplied node is null, this is a way of terminating a loop.
      Parameters:
      node - the node to be tested
      Returns:
      true if the node matches the requested node type and name

    • advance

      protected final void advance()
      Advance along the axis until a node is found that matches the required criteria

    • step

      protected abstract void step()
      Advance one step along the axis: the resulting node might not meet the required criteria for inclusion

    • hasNext

      public boolean hasNext()
      Determine whether there are more items to come. Note that this operation is stateless and it is not necessary (or usual) to call it before calling next(). It is used only when there is an explicit need to tell if we are at the last element.
      Specified by:
      hasNext in interface LookaheadIterator
      Returns:
      true if there are more items in the sequence

    • moveNext

      public boolean moveNext()
      Move to the next node, without returning it. Returns true if there is a next node, false if the end of the sequence has been reached. After calling this method, the current node may be retrieved using the current() function.
      Specified by:
      moveNext in interface AxisIterator
      Returns:
      true if there is a next node, false if the end of the sequence has been reached

    • next

      public final NodeInfo next()
      Return the next node in the enumeration
      Specified by:
      next in interface AxisIterator
      Specified by:
      next in interface SequenceIterator
      Specified by:
      next in interface UnfailingIterator
      Returns:
      the next Item. If there are no more nodes, return null.

    • current

      public final NodeInfo current()
      Return the current Item
      Specified by:
      current in interface AxisIterator
      Specified by:
      current in interface SequenceIterator
      Specified by:
      current in interface UnfailingIterator
      Returns:
      the current item, that is, the item most recently returned by next()

    • position

      public final int position()
      Return the current position
      Specified by:
      position in interface SequenceIterator
      Specified by:
      position in interface UnfailingIterator
      Returns:
      the position of the current item (the item most recently returned by next()), starting at 1 for the first node

    • close

      public void close()
      Description copied from interface: SequenceIterator
      Close the iterator. This indicates to the supplier of the data that the client does not require any more items to be delivered by the iterator. This may enable the supplier to release resources. After calling close(), no further calls on the iterator should be made; if further calls are made, the effect of such calls is undefined.

      (Currently, closing an iterator is important only when the data is being "pushed" in another thread. Closing the iterator terminates that thread and means that it needs to do no additional work. Indeed, failing to close the iterator may cause the push thread to hang waiting for the buffer to be emptied.)

      Specified by:
      close in interface SequenceIterator

    • iterateAxis

      public AxisIterator iterateAxis(byte axis, NodeTest test)
      Return an iterator over an axis, starting at the current node.
      Specified by:
      iterateAxis in interface AxisIterator
      Parameters:
      axis - the axis to iterate over, using a constant such as Axis.CHILD
      test - a predicate to apply to the nodes before returning them.
      Returns:
      an iterator over an axis, starting at the current node
      Throws:
      NullPointerException - if there is no current node

    • atomize

      public Value atomize() throws XPathException
      Return the atomized value of the current node.
      Specified by:
      atomize in interface AxisIterator
      Returns:
      the atomized value.
      Throws:
      NullPointerException - if there is no current node
      XPathException - if the current node cannot be atomized, for example because it is an element node with element-only content.

    • getStringValue

      public CharSequence getStringValue()
      Return the string value of the current node.
      Specified by:
      getStringValue in interface AxisIterator
      Returns:
      the string value, as an instance of CharSequence.
      Throws:
      NullPointerException - if there is no current node

    • getProperties

      public int getProperties()
      Get properties of this iterator, as a bit-significant integer.
      Specified by:
      getProperties in interface SequenceIterator
      Returns:
      the properties of this iterator. This will be some combination of properties such as SequenceIterator.GROUNDED, SequenceIterator.LAST_POSITION_FINDER, and SequenceIterator.LOOKAHEAD. It is always acceptable to return the value zero, indicating that there are no known special properties. It is acceptable for the properties of the iterator to change depending on its state.