Package net.sf.saxon.expr

Class ValueTailIterator

java.lang.Object
net.sf.saxon.expr.ValueTailIterator
All Implemented Interfaces:
Closeable, AutoCloseable, SequenceIterator, GroundedIterator, LookaheadIterator
public class ValueTailIterator extends Object implements SequenceIterator, GroundedIterator, LookaheadIterator
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 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 Item next()
      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
      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.

    • supportsHasNext

      public boolean supportsHasNext()
      Description copied from interface: LookaheadIterator
      Ask whether the hasNext() method can be called. This method must be called before calling hasNext(), because some iterators implement this interface, but only support look-ahead under particular circumstances (this is usually because they delegate to another iterator)
      Specified by:
      supportsHasNext in interface LookaheadIterator
      Returns:
      true if the LookaheadIterator.hasNext() method is available

    • 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 LookaheadIterator.supportsHasNext() is true.

      Specified by:
      hasNext in interface LookaheadIterator
      Returns:
      true if there are more items in the sequence

    • isActuallyGrounded

      public boolean isActuallyGrounded()
      Description copied from interface: GroundedIterator
      Ask if the iterator is actually grounded. This method must be called before calling GroundedIterator.materialize() or GroundedIterator.getResidue(), because the iterator might be grounded under some conditions and not others (usually when it delegates to another iterator)
      Specified by:
      isActuallyGrounded in interface GroundedIterator
      Returns:
      true if this iterator is grounded

    • materialize

      public GroundedValue 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
      Returns:
      the corresponding Value

    • getResidue

      public GroundedValue 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
      Returns:
      the corresponding Value