Class ExtensionHandler

java.lang.Object
org.apache.xalan.extensions.ExtensionHandler
Direct Known Subclasses:
ExtensionHandlerExsltFunction, ExtensionHandlerGeneral, ExtensionHandlerJava

public abstract class ExtensionHandler extends 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 Details

    • isFunctionAvailable

      public abstract boolean isFunctionAvailable(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(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 Object callFunction(String funcName, Vector args, 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 Object callFunction(FuncExtFunction extFunction, 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(String localPart, ElemTemplateElement element, TransformerImpl transformer, Stylesheet stylesheetTree, Object methodKey) throws TransformerException, 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.