org.apache.xalan.extensions
Class ExtensionHandler

java.lang.Object
  org.apache.xalan.extensions.ExtensionHandler

Direct Known Subclasses:

ExtensionHandlerExsltFunction, ExtensionHandlerGeneral, ExtensionHandlerJava

public abstract class ExtensionHandler
extends java.lang.Object

Abstract base class for handling an extension namespace for XPath. Provides functions to test a function's existence and call a function. Also provides functions for calling an element and testing for an element's existence.

Field Summary

protected java.lang.String	m_namespaceUri uri of the extension namespace
protected java.lang.String	m_scriptLang scripting language of implementation

Constructor Summary

protected

ExtensionHandler(java.lang.String namespaceUri, java.lang.String scriptLang) Construct a new extension namespace handler given all the information needed.

Method Summary

abstract java.lang.Object	callFunction(FuncExtFunction extFunction, java.util.Vector args, ExpressionContext exprContext) Process a call to a function.
abstract java.lang.Object	callFunction(java.lang.String funcName, java.util.Vector args, java.lang.Object methodKey, ExpressionContext exprContext) Process a call to a function.
(package private) static java.lang.Class	getClassForName(java.lang.String className) This method loads a class using the context class loader if we're running under Java2 or higher.
abstract boolean	isElementAvailable(java.lang.String element) Tests whether a certain element name is known within this namespace.
abstract boolean	isFunctionAvailable(java.lang.String function) Tests whether a certain function name is known within this namespace.
abstract void	processElement(java.lang.String localPart, ElemTemplateElement element, TransformerImpl transformer, Stylesheet stylesheetTree, java.lang.Object methodKey) Process a call to this extension namespace via an element.

Methods inherited from class java.lang.Object

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

Field Detail

m_namespaceUri

protected java.lang.String m_namespaceUri

uri of the extension namespace

m_scriptLang

protected java.lang.String m_scriptLang

scripting language of implementation

Constructor Detail

ExtensionHandler

protected ExtensionHandler(java.lang.String namespaceUri,
                           java.lang.String scriptLang)

Construct a new extension namespace handler given all the information needed.

Parameters:

namespaceUri - the extension namespace URI that I'm implementing

scriptLang - language of code implementing the extension

Method Detail

getClassForName

static java.lang.Class getClassForName(java.lang.String className)
                                throws java.lang.ClassNotFoundException

This method loads a class using the context class loader if we're running under Java2 or higher.

Parameters:

className - Name of the class to load

Throws:

java.lang.ClassNotFoundException

isFunctionAvailable

public abstract boolean isFunctionAvailable(java.lang.String function)

Tests whether a certain function name is known within this namespace.

Parameters:

function - name of the function being tested

Returns:

true if its known, false if not.

isElementAvailable

public abstract boolean isElementAvailable(java.lang.String element)

Tests whether a certain element name is known within this namespace.

Parameters:

element - Name of element to check

Returns:

true if its known, false if not.

callFunction

public abstract java.lang.Object callFunction(java.lang.String funcName,
                                              java.util.Vector args,
                                              java.lang.Object methodKey,
                                              ExpressionContext exprContext)
                                       throws javax.xml.transform.TransformerException

Process a call to a function.

Parameters:

funcName - Function name.

args - The arguments of the function call.

methodKey - A key that uniquely identifies this class and method call.

exprContext - The context in which this expression is being executed.

Returns:

the return value of the function evaluation.

Throws:

javax.xml.transform.TransformerException - if parsing trouble

callFunction

public abstract java.lang.Object callFunction(FuncExtFunction extFunction,
                                              java.util.Vector args,
                                              ExpressionContext exprContext)
                                       throws javax.xml.transform.TransformerException

Process a call to a function.

Parameters:

extFunction - The XPath extension function.

args - The arguments of the function call.

exprContext - The context in which this expression is being executed.

Returns:

the return value of the function evaluation.

Throws:

javax.xml.transform.TransformerException - if parsing trouble

processElement

public abstract void processElement(java.lang.String localPart,
                                    ElemTemplateElement element,
                                    TransformerImpl transformer,
                                    Stylesheet stylesheetTree,
                                    java.lang.Object methodKey)
                             throws javax.xml.transform.TransformerException,
                                    java.io.IOException

Process a call to this extension namespace via an element. As a side effect, the results are sent to the TransformerImpl's result tree.

Parameters:

localPart - Element name's local part.

element - The extension element being processed.

transformer - Handle to TransformerImpl.

stylesheetTree - The compiled stylesheet tree.

methodKey - A key that uniquely identifies this class and method call.

Throws:

XSLProcessorException - thrown if something goes wrong while running the extension handler.

MalformedURLException - if loading trouble

FileNotFoundException - if loading trouble

java.io.IOException - if loading trouble

javax.xml.transform.TransformerException - if parsing trouble