Package org.apache.xalan.extensions

Class ExtensionHandler

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

  • Field Details

    • m_namespaceUri

      protected String m_namespaceUri
      uri of the extension namespace

    • m_scriptLang

      protected String m_scriptLang
      scripting language of implementation

  • Constructor Details

    • ExtensionHandler

      protected ExtensionHandler​(String namespaceUri, 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 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.
      Throws:
      XSLProcessorException - thrown if something goes wrong while running the extension handler.
      MalformedURLException - if loading trouble
      FileNotFoundException - if loading trouble
      IOException - if loading trouble
      TransformerException - if parsing trouble