org.apache.xpath.functions
Class FuncExtFunction

java.lang.Object
  extended byorg.apache.xpath.Expression
      extended byorg.apache.xpath.functions.Function
          extended byorg.apache.xpath.functions.FuncExtFunction
All Implemented Interfaces:
ExpressionNode, Serializable, javax.xml.transform.SourceLocator, XPathVisitable

public class FuncExtFunction
extends Function

An object of this class represents an extension call expression. When the expression executes, it calls ExtensionsTable#extFunction, and then converts the result to the appropriate XObject.

See Also:
Serialized Form

Nested Class Summary
(package private)  class FuncExtFunction.ArgExtOwner
           
 
Field Summary
(package private)  Vector m_argVec
          Array of static expressions which represent the parameters to the function.
(package private)  String m_extensionName
          The local name of the extension.
(package private)  Object m_methodKey
          Unique method key, which is passed to ExtensionsTable#extFunction in order to allow caching of the method.
(package private)  String m_namespace
          The namespace for the extension function, which should not normally be null or empty.
 
Fields inherited from class org.apache.xpath.Expression
 
Constructor Summary
FuncExtFunction(String namespace, String extensionName, Object methodKey)
          Create a new FuncExtFunction based on the qualified name of the extension, and a unique method key.
 
Method Summary
 void callArgVisitors(XPathVisitor visitor)
          Call the visitors for the function arguments.
 void checkNumberArgs(int argNum)
          Check that the number of arguments passed to this function is correct.
 XObject execute(XPathContext xctxt)
          Execute the function.
 void exprSetParent(ExpressionNode n)
          Set the parent node.
 void fixupVariables(Vector vars, int globalsSize)
          This function is used to fixup variables from QNames to stack frame indexes at stylesheet build time.
 Expression getArg(int n)
          Return the nth argument passed to the extension function.
 int getArgCount()
          Return the number of arguments that were passed into this extension function.
 String getFunctionName()
          Return the name of the extension function.
 String getNamespace()
          Return the namespace of the extension function.
protected  void reportWrongNumberArgs()
          Constructs and throws a WrongNumberArgException with the appropriate message for this function object.
 void setArg(Expression arg, int argNum)
          Set an argument expression for a function.
 
Methods inherited from class org.apache.xpath.functions.Function
callVisitors, deepEquals, postCompileStep
 
Methods inherited from class org.apache.xpath.Expression
asIterator, asIteratorRaw, asNode, assertion, bool, canTraverseOutsideSubtree, error, execute, execute, execute, executeCharsToContentHandler, exprAddChild, exprGetChild, exprGetNumChildren, exprGetParent, getColumnNumber, getExpressionOwner, getLineNumber, getPublicId, getSystemId, isNodesetExpr, isSameClass, isStableNumber, num, warn, xstr
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

m_namespace

String m_namespace
The namespace for the extension function, which should not normally be null or empty.


m_extensionName

String m_extensionName
The local name of the extension.


m_methodKey

Object m_methodKey
Unique method key, which is passed to ExtensionsTable#extFunction in order to allow caching of the method.


m_argVec

Vector m_argVec
Array of static expressions which represent the parameters to the function.

Constructor Detail

FuncExtFunction

public FuncExtFunction(String namespace,
                       String extensionName,
                       Object methodKey)
Create a new FuncExtFunction based on the qualified name of the extension, and a unique method key.

Parameters:
namespace - The namespace for the extension function, which should not normally be null or empty.
extensionName - The local name of the extension.
methodKey - Unique method key, which is passed to ExtensionsTable#extFunction in order to allow caching of the method.
Method Detail

fixupVariables

public void fixupVariables(Vector vars,
                           int globalsSize)
This function is used to fixup variables from QNames to stack frame indexes at stylesheet build time.

Specified by:
fixupVariables in class Expression
Parameters:
vars - List of QNames that correspond to variables. This list should be searched backwards for the first qualified name that corresponds to the variable reference qname. The position of the QName in the vector from the start of the vector will be its position in the stack frame (but variables above the globalsTop value will need to be offset to the current stack frame). NEEDSDOC @param globalsSize

getNamespace

public String getNamespace()
Return the namespace of the extension function.

Returns:
The namespace of the extension function.

getFunctionName

public String getFunctionName()
Return the name of the extension function.

Returns:
The name of the extension function.

getArg

public Expression getArg(int n)
Return the nth argument passed to the extension function.

Parameters:
n - The argument number index.
Returns:
The Expression object at the given index.

getArgCount

public int getArgCount()
Return the number of arguments that were passed into this extension function.

Returns:
The number of arguments.

execute

public XObject execute(XPathContext xctxt)
                throws javax.xml.transform.TransformerException
Execute the function. The function must return a valid object.

Overrides:
execute in class Function
Parameters:
xctxt - The current execution context.
Returns:
A valid XObject.
Throws:
javax.xml.transform.TransformerException

setArg

public void setArg(Expression arg,
                   int argNum)
            throws WrongNumberArgsException
Set an argument expression for a function. This method is called by the XPath compiler.

Overrides:
setArg in class Function
Parameters:
arg - non-null expression that represents the argument.
argNum - The argument number index.
Throws:
WrongNumberArgsException - If the argNum parameter is beyond what is specified for this function.

checkNumberArgs

public void checkNumberArgs(int argNum)
                     throws WrongNumberArgsException
Check that the number of arguments passed to this function is correct.

Overrides:
checkNumberArgs in class Function
Parameters:
argNum - The number of arguments that is being passed to the function.
Throws:
WrongNumberArgsException

callArgVisitors

public void callArgVisitors(XPathVisitor visitor)
Call the visitors for the function arguments.

Overrides:
callArgVisitors in class Function

exprSetParent

public void exprSetParent(ExpressionNode n)
Set the parent node. For an extension function, we also need to set the parent node for all argument expressions.

Specified by:
exprSetParent in interface ExpressionNode
Overrides:
exprSetParent in class Expression
Parameters:
n - The parent node

reportWrongNumberArgs

protected void reportWrongNumberArgs()
                              throws WrongNumberArgsException
Constructs and throws a WrongNumberArgException with the appropriate message for this function object. This class supports an arbitrary number of arguments, so this method must never be called.

Overrides:
reportWrongNumberArgs in class Function
Throws:
WrongNumberArgsException