Package net.sf.saxon.expr

Class ValueTailIterator<T extends Item<?>>

java.lang.Object
net.sf.saxon.expr.ValueTailIterator<T>
All Implemented Interfaces:
Closeable, AutoCloseable, SequenceIterator<T>, GroundedIterator<T>, LookaheadIterator<T>
public class ValueTailIterator<T extends Item<?>> extends Object implements SequenceIterator<T>, GroundedIterator<T>, LookaheadIterator<T>
ValueTailIterator iterates over a base sequence starting at an element other than the first. It is used in the case where the base sequence is "grounded", that is, it exists in memory and supports efficient direct addressing.

  • Constructor Details

    • ValueTailIterator

      public ValueTailIterator(GroundedValue<T> base, int start)
      Construct a ValueTailIterator
      Parameters:
      base - The items to be filtered
      start - The position of the first item to be included (zero-based)

  • Method Details

    • next

      public T next() throws XPathException
      Description copied from interface: SequenceIterator
      Get the next item in the sequence. This method changes the state of the iterator.
      Specified by:
      next in interface SequenceIterator<T extends Item<?>>
      Returns:
      the next item, or null if there are no more items. Once a call on next() has returned null, no further calls should be made. The preferred action for an iterator if subsequent calls on next() are made is to return null again, and all implementations within Saxon follow this rule.
      Throws:
      XPathException - if an error occurs retrieving the next item

    • hasNext

      public boolean hasNext()
      Description copied from interface: LookaheadIterator
      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.

      This method must not be called unless the result of getProperties() on the iterator includes the bit setting SequenceIterator.LOOKAHEAD

      Specified by:
      hasNext in interface LookaheadIterator<T extends Item<?>>
      Returns:
      true if there are more items in the sequence

    • materialize

      public GroundedValue<T> materialize()
      Return a Value containing all the items in the sequence returned by this SequenceIterator. This should be an "in-memory" value, not a Closure.
      Specified by:
      materialize in interface GroundedIterator<T extends Item<?>>
      Specified by:
      materialize in interface SequenceIterator<T extends Item<?>>
      Returns:
      the corresponding Value

    • getResidue

      public GroundedValue<T> getResidue()
      Description copied from interface: GroundedIterator
      Return a GroundedValue containing all the remaining items in the sequence returned by this SequenceIterator, starting at the current position. This should be an "in-memory" value, not a Closure. This method does not change the state of the iterator (in particular, it does not consume the iterator).
      Specified by:
      getResidue in interface GroundedIterator<T extends Item<?>>
      Returns:
      the corresponding Value

    • getProperties

      public int getProperties()
      Get properties of this iterator, as a bit-significant integer.
      Specified by:
      getProperties in interface SequenceIterator<T extends Item<?>>
      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.