org.apache.xpath.functions

Class FuncExtFunction

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.

UNKNOWN: advanced

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
voidcallArgVisitors(XPathVisitor visitor)
Call the visitors for the function arguments.
voidcheckNumberArgs(int argNum)
Check that the number of arguments passed to this function is correct.
XObjectexecute(XPathContext xctxt)
Execute the function.
voidexprSetParent(ExpressionNode n)
Set the parent node.
voidfixupVariables(Vector vars, int globalsSize)
This function is used to fixup variables from QNames to stack frame indexes at stylesheet build time.
ExpressiongetArg(int n)
Return the nth argument passed to the extension function.
intgetArgCount()
Return the number of arguments that were passed into this extension function.
StringgetFunctionName()
Return the name of the extension function.
ObjectgetMethodKey()
Return the method key of the extension function.
StringgetNamespace()
Return the namespace of the extension function.
voidsetArg(Expression arg, int argNum)
Set an argument expression for a function.
StringtoString()
Return the name of the extesion function in string format

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

callArgVisitors

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

checkNumberArgs

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

Parameters: argNum The number of arguments that is being passed to the function.

Throws: WrongNumberArgsException

execute

public XObject execute(XPathContext xctxt)
Execute the function. The function must return a valid object.

Parameters: xctxt The current execution context.

Returns: A valid XObject.

Throws: javax.xml.transform.TransformerException

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.

Parameters: n The parent node

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.

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

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.

getFunctionName

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

Returns: The name of the extension function.

getMethodKey

public Object getMethodKey()
Return the method key of the extension function.

Returns: The method key of the extension function.

getNamespace

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

Returns: The namespace of the extension function.

setArg

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

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.

toString

public String toString()
Return the name of the extesion function in string format
Copyright B) 2005 Apache XML Project. All Rights Reserved.