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.

Author:

Sanjiva Weerawarana (sanjiva@watson.ibm.com)

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.
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

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