Class AscendingRangeIterator

java.lang.Object
net.sf.saxon.tree.iter.RangeIterator
net.sf.saxon.expr.AscendingRangeIterator
All Implemented Interfaces:
Closeable, AutoCloseable, LastPositionFinder, SequenceIterator, AtomicIterator, GroundedIterator, LookaheadIterator, ReversibleIterator

public class AscendingRangeIterator extends RangeIterator implements AtomicIterator, ReversibleIterator, LastPositionFinder, LookaheadIterator, GroundedIterator
An Iterator that produces numeric values in a monotonic sequence, ascending or descending. Applying the reverse() function will produce a DescendinggRangeIterator.
  • Field Details

    • start

      long start
    • step

      long step
    • currentValue

      long currentValue
    • limit

      long limit
  • Constructor Details

    • AscendingRangeIterator

      public AscendingRangeIterator(long start, long step, long end)
      Create an iterator over a range of monotonically increasing integers
      Parameters:
      start - the first integer in the sequence
      step - the increment; must be GT 0
      end - the last integer in the sequence. Must be GE start.
  • Method Details

    • makeRangeIterator

      public static AtomicIterator makeRangeIterator(IntegerValue start, IntegerValue step, IntegerValue end) throws XPathException
      Throws:
      XPathException
    • makeLongRangeIterator

      public static AtomicIterator makeLongRangeIterator(long start, long step, long end) throws XPathException
      Factory method for use from bytecode
      Parameters:
      start - the first integer to return
      step - the interval between successive integers (positive or negative, not zero)
      end - stop the iteration when this value or one beyond it is reached
      Returns:
      an iterator over a range of integers
      Throws:
      XPathException - if, for example, implementation-defined limits are exceeded
    • getFirst

      public IntegerValue getFirst()
      Specified by:
      getFirst in class RangeIterator
    • getLast

      public IntegerValue getLast()
      Specified by:
      getLast in class RangeIterator
    • getMin

      public IntegerValue getMin()
      Specified by:
      getMin in class RangeIterator
    • getMax

      public IntegerValue getMax()
      Specified by:
      getMax in class RangeIterator
    • getStep

      public IntegerValue getStep()
      Get the increment between successive values. For a descending iterator this will be negatiive value.
      Specified by:
      getStep in class RangeIterator
      Returns:
      the increment between successive values
    • 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
    • next

      public IntegerValue next()
      Description copied from interface: AtomicIterator
      Get the next atomic value in the sequence.
      Specified by:
      next in interface AtomicIterator
      Specified by:
      next in interface SequenceIterator
      Returns:
      the next Item. If there are no more items, return null.
    • 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
    • supportsGetLength

      public boolean supportsGetLength()
      Description copied from interface: LastPositionFinder
      Ask whether this iterator supports use of the LastPositionFinder.getLength() method. This method should always be called before calling LastPositionFinder.getLength(), because an iterator that implements this interface may support use of LastPositionFinder.getLength() in some situations and not in others
      Specified by:
      supportsGetLength in interface LastPositionFinder
      Returns:
      true if the LastPositionFinder.getLength() method can be called to determine the length of the underlying sequence.
    • getLength

      public int getLength()
      Description copied from interface: LastPositionFinder
      Get the last position (that is, the number of items in the sequence). This method is non-destructive: it does not change the state of the iterator. The result is undefined if the next() method of the iterator has already returned null. This method must not be called unless the LastPositionFinder.supportsGetLength() has been called and has returned true.
      Specified by:
      getLength in interface LastPositionFinder
      Returns:
      the number of items in the sequence
    • getReverseIterator

      public AtomicIterator getReverseIterator()
      Description copied from interface: ReversibleIterator
      Get a new SequenceIterator that returns the same items in reverse order. If this SequenceIterator is an AxisIterator, then the returned SequenceIterator must also be an AxisIterator.
      Specified by:
      getReverseIterator in interface ReversibleIterator
      Returns:
      an iterator over the items in reverse order
    • 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 class: RangeIterator
      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
      Specified by:
      getResidue in class RangeIterator
      Returns:
      the corresponding Value