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

**For internal use only** 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.

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.
static java.lang.Class	getClassForName(java.lang.String className) Replacement for Class.forName.
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

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

Method Detail

getClassForName

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

Replacement for Class.forName. This method loads a class using the context class loader if we're running under Java2 or higher. If we're running under Java1, this method just uses Class.forName to load the class.

Parameters:

className - Name of the class to load

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:

function - name of the function being tested

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 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:

TransformerException - if parsing trouble

callFunction

public abstract java.lang.Object callFunction(FuncExtFunction extFunction,
                                              java.util.Vector args,
                                              ExpressionContext exprContext)
                                       throws 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:

TransformerException - if parsing trouble

processElement

public abstract void processElement(java.lang.String localPart,
                                    ElemTemplateElement element,
                                    TransformerImpl transformer,
                                    Stylesheet stylesheetTree,
                                    java.lang.Object methodKey)
                             throws 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.

mode - The current mode.

sourceTree - The root of the source tree (but don't assume it's a Document).

sourceNode - The current context node.

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

TransformerException - if parsing trouble