oracle.xml.pipeline.controller
Class Process

java.lang.Object
oracle.xml.pipeline.controller.Process

All Implemented Interfaces:

ErrorHandler, PipelineConstants, java.lang.Runnable

Direct Known Subclasses:

CompressReaderProcess, CompressWriterProcess, DOMParserProcess, SAXParserProcess, XPathProcess, XSDSchemaBuilder, XSDValProcess, XSLProcess, XSLStylesheetProcess

public class Process

extends java.lang.Object

implements java.lang.Runnable, PipelineConstants, ErrorHandler

Base class for all pipeline process definitions. To create a custom pipeline process, you need to create a class which extends from the Process class. At the minimum, every custom process should overwrite the initialize() and execute() method of this class. If the custom process takes SAX events as input, it should overwrite the SAXContentHandler() method to return the appropriate ContentHandler which will handle incoming SAX events.

Field Summary

Fields inherited from interface oracle.xml.pipeline.controller.PipelineConstants

COMPSTREAMRESULT, COMPSTREAMSOURCE, DOCFRAG, DOCUMENT, DOMRESULT, DOMSOURCE, ELEMENT, PROCESS_WAITING, SAXRESULT, SAXSOURCE, STREAMRESULT, STREAMSOURCE

Method Summary

void	convertFromDOM(DOMResult res, Output output) Should be called by the Process which outputs DOM.
void	convertFromSAX(SAXResult result, Output output) Should be called by the Process which outputs SAX events.
void	convertFromStream(StreamResult res, Output output) Should be called by the Process which outputs xml as Stream.
void	error(int type, java.lang.Exception e) Called by a custom Process whenever an error occurs.
protected void	execute() Does nothing by default, to be implemented by classes extending from the Process class.
XMLDocument	getErrorDocument(java.lang.String errorName, boolean convert) Get the error element as an XML Document tree
Source	getErrorSource(java.lang.String errorName) Retrieve the error element as Source
java.io.InputStream	getErrorStream(java.lang.String errorName, boolean convert) Get the error element as an Input stream for reading error.
void	getErrorStream(java.lang.String errorName, java.io.OutputStream out, boolean convert) Write the error element to the outputstream provided.
java.lang.Object	getInParamValue(java.lang.String name) Get an input param value based on its name
Input	getInput(java.lang.String inputName) Retrieve the Input object by name
java.lang.Object	getOutParamValue(java.lang.String name) Get the output param value based on its name
Output	getOutput(java.lang.String outputName) Retrieve a particular output by name
java.io.OutputStream	getOutputStream(java.lang.String outputName) Get the output stream for printing to a specific output
java.io.Writer	getOutputWriter(java.lang.String outputName) Get the output writer for writing to a specific output
ContentHandler	getSAXContentHandler(Output out) Get the ContentHandler which will handle the sax events generated.
ErrorHandler	getSAXErrorHandler(Output out) Get the SAX ErrorHandler which will handle the sax error events generated.
void	info(java.lang.String msg) Called by a Process to report an informational message and continue with execution.
protected void	initialize() Does nothing by default, to be implemented by the classes extending from the Process class.
protected ContentHandler	SAXContentHandler() Each Process which handles SAX as input should overwrite this method to return the ContentHandler.
protected ErrorHandler	SAXErrorHandler() Each Process produces SAX events as output can overwrite this method to return the ErrorHandler.
void	setOutputResult(java.lang.String outputName, Result res) All user defined processes (extending from Process) need to create a Result object and set it in the output using this method.

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.lang.Runnable

run

Methods inherited from interface org.xml.sax.ErrorHandler

error, fatalError, warning

Method Detail

initialize

protected void initialize()

Does nothing by default, to be implemented by the classes extending from the Process class. This method will be called to intialize the process before execution. Use getInput() to fetch a specific input object associated with the process element and call supportType() to indicate the types of the input supported. Similarly call getOutput() to fetch an output object associated with the process element, and call supportType to set the types of output supported by the process.

getInput

public final Input getInput(java.lang.String inputName)

Retrieve the Input object by name

Parameters:

inputName - input name as String

Returns:

Input object if there one by inputName, otherwise null

getOutput

public Output getOutput(java.lang.String outputName)

Retrieve a particular output by name

Parameters:

outputName - as a String

Returns:

Output object, null if no output by this name exists

getInParamValue

public final java.lang.Object getInParamValue(java.lang.String name)

Get an input param value based on its name

Parameters:

name - name of InParam as String

Returns:

InParam value as type Object, null if none exists

getOutParamValue

public final java.lang.Object getOutParamValue(java.lang.String name)

Get the output param value based on its name

Parameters:

name - OutParam name as String

Returns:

OutParam value of type Object

execute

protected void execute()
                throws PipelineException

Does nothing by default, to be implemented by classes extending from the Process class. Use getInParaValue(), getInput() or getInputSource() to fetch the inputs to the process. If a custom process outputs SAX events, it should call getSAXContentHandler() and getSAXErrorHandler methods in execute() to get the SAX handlers of the following process(es) in the pipeline. Set the outputs or outparams generated by this process using setOutputResult(), getOutputStream(), getOutputWriter() or setOutParam(). You can access the pipeline error element associated with this process element by calling getErrorSource(), getErrorStream() or getErrorDocument(). If an exception occurs during execute() it can be propagated to the PipelineErrorHandler by calling error() or info().

Throws:

PipelineException

setOutputResult

public final void setOutputResult(java.lang.String outputName,
                                  Result res)

All user defined processes (extending from Process) need to create a Result object and set it in the output using this method.

Parameters:

outputName - as String

res - Result object

getOutputStream

public final java.io.OutputStream getOutputStream(java.lang.String outputName)
                                           throws java.io.FileNotFoundException,
                                                  java.io.IOException

Get the output stream for printing to a specific output

Parameters:

outputName - name of output

Returns:

OutputStream for printing

Throws:

java.io.FileNotFoundException

java.io.IOException

getOutputWriter

public final java.io.Writer getOutputWriter(java.lang.String outputName)
                                     throws java.io.FileNotFoundException,
                                            java.io.IOException

Get the output writer for writing to a specific output

Parameters:

outputName - name of output

Returns:

Writer for printing

Throws:

java.io.FileNotFoundException

java.io.IOException

getErrorSource

public Source getErrorSource(java.lang.String errorName)

Retrieve the error element as Source

Parameters:

errorName - name of error from pipeline document

Returns:

Source error element as a Source object

getErrorStream

public void getErrorStream(java.lang.String errorName,
                           java.io.OutputStream out,
                           boolean convert)
                    throws java.io.IOException

Write the error element to the outputstream provided. If convert is true then convert from error node to stream.

Parameters:

errorName - name of error element

out - outputstream to write to

convert - convert from DOM to stream or not

Throws:

java.io.IOException - while writing to outputstream

getErrorStream

public final java.io.InputStream getErrorStream(java.lang.String errorName,
                                                boolean convert)
                                         throws java.io.IOException

Get the error element as an Input stream for reading error.

Parameters:

errorName - error element name as String

convert - convert from Node to InputStream or not

Returns:

InputStream of of error element

Throws:

java.io.IOException - reading from error element

getErrorDocument

public XMLDocument getErrorDocument(java.lang.String errorName,
                                    boolean convert)
                             throws SAXException,
                                    XMLParseException,
                                    java.io.IOException

Get the error element as an XML Document tree

Parameters:

errorName - error element name as String

convert - convert from stream to DOM if necessary

Returns:

XMLDocument error element as XMLDocument

Throws:

SAXException - while parsing

XMLParseException - while parsing

java.io.IOException

error

public final void error(int type,
                        java.lang.Exception e)
                 throws PipelineException

Called by a custom Process whenever an error occurs.

Parameters:

type - error type as defined in PipelineConstants

e - exception

Throws:

PipelineException

info

public void info(java.lang.String msg)

Called by a Process to report an informational message and continue with execution.

Parameters:

msg - - message to report

getSAXContentHandler

public final ContentHandler getSAXContentHandler(Output out)
                                          throws PipelineException

Get the ContentHandler which will handle the sax events generated. This function will handle the conversion from SAX to DOM or Stream if its necessary. If this method returns null, then call setProcessStatus(PROCESS_WAITING), and return from execute().

Parameters:

out - the Output object which is the SAX source

Returns:

ContentHandler for taking SAX events as input to this process

Throws:

PipelineException

getSAXErrorHandler

public final ErrorHandler getSAXErrorHandler(Output out)

Get the SAX ErrorHandler which will handle the sax error events generated.

Parameters:

out - Output object which is the SAX source

Returns:

ErrorHandler will be called on input SAX error

Throws:

PipelineException

SAXContentHandler

protected ContentHandler SAXContentHandler()
                                    throws PipelineException

Each Process which handles SAX as input should overwrite this method to return the ContentHandler. If any dependencies (i.e. output or outparam from other processes are not available (are null) at this time, please return null. Once these dependencies are available the method will be executed till the end.

Returns:

ContentHandler to be passed on to prevProcess

Throws:

PipelineException

SAXErrorHandler

protected ErrorHandler SAXErrorHandler()

Each Process produces SAX events as output can overwrite this method to return the ErrorHandler. Otherwise the default error handler implemented by this class will be used to handle SAX errors.

Returns:

ErrorHandler to be passed on to prevProcess

convertFromSAX

public final void convertFromSAX(SAXResult result,
                                 Output output)
                          throws java.io.FileNotFoundException,
                                 java.io.IOException

Should be called by the Process which outputs SAX events. It is assumed that the ContentHandler used by the Process has been fetched using getSAXContentHandler. This function will check the input type of the dependent process or processes and perform the conversion from SAX to DOM/Stream. The function will call setOutputResult as there could be multiple results to be set for multiple inputs

Parameters:

result - the process result as a SAXResult object

output - output object to be associated with the SAX, to be piped into the input of the next process in pipeline

Throws:

FileNoFoundException

java.io.IOException

java.io.FileNotFoundException

convertFromDOM

public final void convertFromDOM(DOMResult res,
                                 Output output)
                          throws SAXException,
                                 java.io.IOException,
                                 PipelineException

Should be called by the Process which outputs DOM. This function will check the input type of the dependent process or processes and perform the conversion from DOM to SAX/Stream. The function will call setOutputResult as there could be multiple results to be set for multiple inputs

Parameters:

res - the process result as a DOMResult object

output - output object associated with result, to be piped to the next process in pipeline

Throws:

SAXException

java.io.IOException

PipelineException

convertFromStream

public final void convertFromStream(StreamResult res,
                                    Output output)
                             throws SAXException,
                                    java.io.IOException,
                                    PipelineException

Should be called by the Process which outputs xml as Stream. This function will check the input type of the dependent process or processes and perform the conversion from Stream to DOM/SAX. The function will call setOutputResult as there could be multiple results to be set for multiple inputs.

Parameters:

res - the process result as a StreamResult object

output - output object to be associated with the result, to be piped to the input of the next process in the pipeline

Throws:

SAXException

java.io.IOException

PipelineException