org.writersforge.catalan.transform
Class BaseNodeProcessor

java.lang.Object
  org.writersforge.catalan.transform.BaseNodeProcessor

All Implemented Interfaces:

org.writersforge.bellows.traverse.NodeProcessor

Direct Known Subclasses:

BeanToXml, Concatenator, DatumToObject, DebugProcessor, ExportJavaProcessor, ExportProcessor, FromAsciiConverter, GroupProcessor, ImportProcessor, ObjectToDatum, PdfgenProcessor, SqlProcessor, TextProcessor, TextToLattice, ToAsciiConverter, VelocityProcessor, XFormProcessor, XmlSelectProcessor, XmlToBean, XmlToHtml

public abstract class BaseNodeProcessor

extends java.lang.Object

implements org.writersforge.bellows.traverse.NodeProcessor

A common base implementation for NodeProcessor.

Author:

jsheets

Constructor Summary

BaseNodeProcessor()
Creates a new instance of BaseNodeProcessor.

Method Summary

protected void	addLeftover(java.lang.Object node) Add a node to the list of unprocessed nodes.
void	end(java.util.List nodes) Ends the current traversal.
protected java.util.List	getLeftovers() Retrieves the current list of unprocessed input nodes.
protected java.util.List	getNodes() Retrieves the current node processing list.
void	start(java.util.List nodes) Starts a new traversal.

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.writersforge.bellows.traverse.NodeProcessor

processNode

Constructor Detail

BaseNodeProcessor

public BaseNodeProcessor()

Creates a new instance of BaseNodeProcessor.

Method Detail

getNodes

protected java.util.List getNodes()

Retrieves the current node processing list. This should only have contents during traversals, and should only be modified by start() and end().

Returns:

a read only copy of the current node list

getLeftovers

protected java.util.List getLeftovers()

Retrieves the current list of unprocessed input nodes. This should only have contents during traversals, and is only really valid during the end() method.

Returns:

a read only copy of the current node list

addLeftover

protected void addLeftover(java.lang.Object node)

Add a node to the list of unprocessed nodes. The leftover nodes will typically be appended to the output in the end() method. Normally, it is preferrable to pass unprocessed nodes out of the processNode() method; however, when a processor requires more than one node for an operation, it must cache the results, and may not return any nodes until the end() post-processing step. In this case, returning any unprocessed nodes immediately from processNode() will result in those nodes appearing out of order in the output node list. To avoid this, you can cache nodes with addLeftover(), then access the full collection of leftovers with getLeftovers() in the end() method.

Parameters:

node - unprocessed input data node

start

public void start(java.util.List nodes)

Starts a new traversal. This method initializes the processor for a new traversal over a set of nodes. The nodes are not actually traversed or processed at this point, but the processor is allowed to perform any pre-traversal calculations, for example storing the total number of nodes for index calculations.

Specified by:

start in interface org.writersforge.bellows.traverse.NodeProcessor

Parameters:

nodes - the list of nodes that will later be traversed

end

public void end(java.util.List nodes)

Ends the current traversal. Any post-processing on the post-traversal nodes should be done here, for example removing duplicate nodes. This method should also clean up any temporary states created during a traversal. After end(), the processor should be ready for the next new traversal.

Specified by:

end in interface org.writersforge.bellows.traverse.NodeProcessor

Parameters:

nodes - the list of nodes that has just been traversed