net.sf.saxon.tree.iter
Class NodeWrappingAxisIterator<T extends NodeInfo,B>

java.lang.Object
  net.sf.saxon.tree.iter.NodeWrappingAxisIterator<T,B>

All Implemented Interfaces:

SequenceIterator<T>, AxisIterator<T>, LookaheadIterator<T>, UnfailingIterator<T>

public abstract class NodeWrappingAxisIterator<T extends NodeInfo,B>
extends Object
implements AxisIterator<T>, LookaheadIterator<T>, UnfailingIterator<T>

An AxisIterator that wraps a Java Iterator. This is an abstract class, because the Java iterator does not hold enough information to support the getAnother() method, needed to implement the XPath last() function

Field Summary

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

GROUNDED, LAST_POSITION_FINDER, LOOKAHEAD

Constructor Summary

NodeWrappingAxisIterator(Iterator<B> base, NodeWrappingFunction<B,T> wrappingFunction)
Create a SequenceIterator over a given iterator

Method Summary

Value	atomize() Return the atomized value of the current node.
void	close() Close the iterator.
T	current() Get the current item in the sequence.
abstract AxisIterator<T>	getAnother() Get another iterator over the same sequence of items, positioned at the start of the sequence.
int	getProperties() Get properties of this iterator, as a bit-significant integer.
CharSequence	getStringValue() Return the string value of the current node.
boolean	hasNext() Determine whether there are more items to come.
AxisIterator	iterateAxis(byte axis, NodeTest test) Return an iterator over an axis, starting at the current node.
boolean	moveNext() Move to the next node, without returning it.
T	next() Get the next item in the sequence.
int	position() Get the current position

Methods inherited from class java.lang.Object

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

Constructor Detail

NodeWrappingAxisIterator

public NodeWrappingAxisIterator(Iterator<B> base,
                                NodeWrappingFunction<B,T> wrappingFunction)

Create a SequenceIterator over a given iterator

Parameters:

base - the base Iterator

wrappingFunction - a function that wraps objects of type B in a Saxon NodeInfo

Method Detail

moveNext

public boolean moveNext()

Description copied from interface: AxisIterator

Move to the next node, without returning it. Returns true if there is a next node, false if the end of the sequence has been reached. After calling this method, the current node may be retrieved using the current() function.

Specified by:

moveNext in interface AxisIterator<T extends NodeInfo>

Returns:

true if there is a next node, false if the end of the sequence has been reached

iterateAxis

public AxisIterator iterateAxis(byte axis,
                                NodeTest test)

Description copied from interface: AxisIterator

Return an iterator over an axis, starting at the current node.

Specified by:

iterateAxis in interface AxisIterator<T extends NodeInfo>

Parameters:

axis - the axis to iterate over, using a constant such as Axis.CHILD

test - a predicate to apply to the nodes before returning them.

Returns:

an iterator over an axis, starting at the current node

atomize

public Value atomize()
              throws XPathException

Description copied from interface: AxisIterator

Return the atomized value of the current node.

Specified by:

atomize in interface AxisIterator<T extends NodeInfo>

Returns:

the atomized value.

Throws:

XPathException - if the current node cannot be atomized, for example because it is an element node with element-only content.

getStringValue

public CharSequence getStringValue()

Description copied from interface: AxisIterator

Return the string value of the current node.

Specified by:

getStringValue in interface AxisIterator<T extends NodeInfo>

Returns:

the string value, as an instance of CharSequence.

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 NodeInfo>

Returns:

true if there are more items in the sequence

next

public T next()

Description copied from interface: UnfailingIterator

Get the next item in the sequence.

Specified by:

next in interface SequenceIterator<T extends NodeInfo>

Specified by:

next in interface AxisIterator<T extends NodeInfo>

Specified by:

next in interface UnfailingIterator<T extends NodeInfo>

Returns:

the next Item. If there are no more nodes, return null.

current

public T current()

Description copied from interface: UnfailingIterator

Get the current item in the sequence.

Specified by:

current in interface SequenceIterator<T extends NodeInfo>

Specified by:

current in interface AxisIterator<T extends NodeInfo>

Specified by:

current in interface UnfailingIterator<T extends NodeInfo>

Returns:

the current item, that is, the item most recently returned by next()

position

public int position()

Description copied from interface: UnfailingIterator

Get the current position

Specified by:

position in interface SequenceIterator<T extends NodeInfo>

Specified by:

position in interface UnfailingIterator<T extends NodeInfo>

Returns:

the position of the current item (the item most recently returned by next()), starting at 1 for the first node

close

public void close()

Description copied from interface: SequenceIterator

Close the iterator. This indicates to the supplier of the data that the client does not require any more items to be delivered by the iterator. This may enable the supplier to release resources. After calling close(), no further calls on the iterator should be made; if further calls are made, the effect of such calls is undefined.

(Currently, closing an iterator is important only when the data is being "pushed" in another thread. Closing the iterator terminates that thread and means that it needs to do no additional work. Indeed, failing to close the iterator may cause the push thread to hang waiting for the buffer to be emptied.)

Specified by:

close in interface SequenceIterator<T extends NodeInfo>

getAnother

public abstract AxisIterator<T> getAnother()

Description copied from interface: UnfailingIterator

Get another iterator over the same sequence of items, positioned at the start of the sequence. It must be possible to call this method at any time, whether none, some, or all of the items in the original iterator have been read. The method is non-destructive: it does not change the state of the original iterator.

Specified by:

getAnother in interface SequenceIterator<T extends NodeInfo>

Specified by:

getAnother in interface AxisIterator<T extends NodeInfo>

Specified by:

getAnother in interface UnfailingIterator<T extends NodeInfo>

Returns:

a new iterator over the same sequence

getProperties

public int getProperties()

Get properties of this iterator, as a bit-significant integer.

Specified by:

getProperties in interface SequenceIterator<T extends NodeInfo>

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.