org.apache.xpath.functions
Class FuncExtFunction

java.lang.Object
  |
  +--org.apache.xpath.Expression
        |
        +--org.apache.xpath.functions.Function
              |
              +--org.apache.xpath.functions.FuncExtFunction

public class FuncExtFunction

extends Function

**For advanced use only** 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

Constructor Summary

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

Method Summary

void	checkNumberArgs(int argNum) Check that the number of arguments passed to this function is correct.
XObject	execute(XPathContext xctxt) Execute the function.
void	setArg(Expression arg, int argNum) Set an argument expression for a function.

Methods inherited from class org.apache.xpath.Expression

assert, canTraverseOutsideSubtree, error, setSourceLocator, warn

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

FuncExtFunction

public FuncExtFunction(java.lang.String namespace,
                       java.lang.String extensionName,
                       java.lang.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

execute

public XObject execute(XPathContext xctxt)
                throws TransformerException

Execute the function. The function must return a valid object.

Parameters:

xctxt - The current execution context.

Returns:

A valid XObject.

Throws:

TransformerException -

Overrides:

execute in class Function

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.

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.

Overrides:

setArg in class Function

checkNumberArgs

public void checkNumberArgs(int argNum)
                     throws WrongNumberArgsException

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 -

Overrides:

checkNumberArgs in class Function