net.sf.saxon.expr

Class ValueTailIterator

java.lang.Object

net.sf.saxon.expr.ValueTailIterator

All Implemented Interfaces:

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

public class ValueTailIterator
extends java.lang.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.

Nested Class Summary

Nested classes/interfaces inherited from interface net.sf.saxon.om.SequenceIterator

SequenceIterator.Property

Constructor Summary

Constructors

Constructor and Description
ValueTailIterator(GroundedValue base, int start) Construct a ValueTailIterator

Method Summary

Modifier and Type	Method and Description
java.util.EnumSet<SequenceIterator.Property>	getProperties() Get properties of this iterator, as a bit-significant integer.
GroundedValue	getResidue() Return a GroundedValue containing all the remaining items in the sequence returned by this SequenceIterator, starting at the current position.
boolean	hasNext() Determine whether there are more items to come.
GroundedValue	materialize() Return a Value containing all the items in the sequence returned by this SequenceIterator.
Item	next() Get the next item in the sequence.

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.om.SequenceIterator

close, forEachOrFail

Constructor Detail

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 Detail

next

public Item 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

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 property SequenceIterator.Property.LOOKAHEAD

Specified by:

hasNext in interface LookaheadIterator

Returns:

true if there are more items in the sequence

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 SequenceIterator

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

getProperties

public java.util.EnumSet<SequenceIterator.Property> 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.Property.GROUNDED, SequenceIterator.Property.LAST_POSITION_FINDER, and SequenceIterator.Property.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.