net.sf.saxon.tree.iter

Class TwoItemIterator

java.lang.Object

net.sf.saxon.tree.iter.TwoItemIterator

All Implemented Interfaces:

java.io.Closeable, java.lang.AutoCloseable, LastPositionFinder, SequenceIterator, GroundedIterator, LookaheadIterator

public class TwoItemIterator
extends java.lang.Object
implements SequenceIterator, LookaheadIterator, GroundedIterator, LastPositionFinder

An iterator over a pair of objects (typically sub-expressions of an expression)

Constructor Summary

Constructors

Constructor and Description
TwoItemIterator(Item one, Item two) Create an iterator over two objects

Method Summary

Modifier and Type	Method and Description
int	getLength() Get the last position (that is, the number of items in the sequence).
GroundedValue	getResidue() Return a GroundedValue containing all the remaining items in the sequence returned by this SequenceIterator, starting at the current position.
boolean	hasNext() Returns true if the iteration has more elements.
boolean	isActuallyGrounded() Ask if the iterator is actually grounded.
Item	next() Returns the next element in the iteration.
boolean	supportsGetLength() Ask whether this iterator supports use of the LastPositionFinder.getLength() method.
boolean	supportsHasNext() Ask whether the hasNext() method can be called.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface net.sf.saxon.tree.iter.GroundedIterator

materialize

Methods inherited from interface net.sf.saxon.om.SequenceIterator

close, discharge

Constructor Detail

TwoItemIterator

public TwoItemIterator(Item one,
                       Item two)

Create an iterator over two objects

Parameters:

one - the first object to be returned

two - the second object to be returned

Method Detail

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()

Returns true if the iteration has more elements. (In other words, returns true if next would return an element rather than throwing an exception.)

Specified by:

hasNext in interface LookaheadIterator

Returns:

true if the iterator has more elements.

next

public Item next()

Returns the next element in the iteration.

Specified by:

next in interface SequenceIterator

Returns:

the next element in the iteration, or null if there are no more

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

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

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