net.sf.saxon.tree.wrapper

Class VirtualCopy.VirtualCopier

java.lang.Object

net.sf.saxon.tree.wrapper.VirtualCopy.VirtualCopier

All Implemented Interfaces:

java.io.Closeable, java.lang.AutoCloseable, SequenceIterator, AxisIterator

Enclosing class:

VirtualCopy

protected static class VirtualCopy.VirtualCopier
extends java.lang.Object
implements AxisIterator

VirtualCopier implements the XPath axes as applied to a VirtualCopy node. It works by applying the requested axis to the node of which this is a copy. There are two complications: firstly, all nodes encountered must themselves be (virtually) copied to give them a new identity. Secondly, axes that stray outside the subtree rooted at the original copied node must be truncated.

Field Summary

Fields

Modifier and Type	Field and Description
protected AxisIterator	base
protected VirtualCopy	node
protected boolean	testInclusion

Constructor Summary

Constructors

Constructor and Description
VirtualCopier(VirtualCopy node, AxisIterator base, VirtualCopy parent, boolean testInclusion)

Method Summary

Modifier and Type	Method and Description
void	close() Close the iterator.
void	discharge() Calling this method instructs the iterator to release any resources it holds, while still remaining able to deliver the remaining items in the sequence.
NodeInfo	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

Field Detail

node

protected VirtualCopy node

base

protected AxisIterator base

testInclusion

protected boolean testInclusion

Constructor Detail

VirtualCopier

public VirtualCopier(VirtualCopy node,
                     AxisIterator base,
                     VirtualCopy parent,
                     boolean testInclusion)

Method Detail

next

public NodeInfo next()

Get the next item in the sequence.

Specified by:

next in interface SequenceIterator

Specified by:

next in interface AxisIterator

Returns:

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

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.

For example, the iterator returned by the unparsed-text-lines() function has a close() method that causes the underlying input stream to be closed, whether or not the file has been read to completion.

Closing an iterator is important 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.

Closing an iterator is not necessary if the iterator is read to completion: if a call on SequenceIterator.next() returns null, the iterator will be closed automatically. An explicit call on SequenceIterator.close() is needed only when iteration is abandoned prematurely.

Specified by:

close in interface java.io.Closeable

Specified by:

close in interface java.lang.AutoCloseable

Specified by:

close in interface SequenceIterator

discharge

public void discharge()

Description copied from interface: SequenceIterator

Calling this method instructs the iterator to release any resources it holds, while still remaining able to deliver the remaining items in the sequence. This may require the iterator to calculate the rest of the sequence eagerly. The method is called by a client if it anticipates that it might not read the iterator to completion, but it cannot guarantee that SequenceIterator.close() will be called when no more items are needed.

Specified by:

discharge in interface SequenceIterator