net.snowflake.common.util

Class FunctionPointer

java.lang.Object

net.snowflake.common.util.FunctionPointer

public class FunctionPointer
extends Object

Function Pointer holds a reference to a static function at compiler time, resolves it a runtime and invokes it. The function being called must be a public static function with 0 to 6 parameters of type Object. i.e. public static String callbackFnWith1Param(Object o)

Author:

amotivala

Constructor Summary

Constructors

Constructor and Description
FunctionPointer(String functionName, int argCount) Create a function pointer reference using a function name of the format <class>:<method>.
FunctionPointer(String className, String function, int argCount) Create a function pointer reference.

Method Summary

Modifier and Type	Method and Description
Object	invoke(Object... args) Invokes the function pointer

Methods inherited from class java.lang.Object

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

Constructor Detail

FunctionPointer

public FunctionPointer(String functionName,
                       int argCount)
                throws ClassNotFoundException,
                       NoSuchMethodException

Create a function pointer reference using a function name of the format <class>:<method>. The

Parameters:

functionName - a function name.

argCount - number of Object.class arguments that the function takes

Throws:

ClassNotFoundException - thrown if class not found

NoSuchMethodException - thrown if no method is found

FunctionPointer

public FunctionPointer(String className,
                       String function,
                       int argCount)
                throws ClassNotFoundException,
                       NoSuchMethodException

Create a function pointer reference.

Parameters:

className - name of the class

function - static function to call in the class

argCount - number of Object.class arguments that the function takes

Throws:

ClassNotFoundException - thrown if class not found

NoSuchMethodException - thrown if no method is found

Method Detail

invoke

public Object invoke(Object... args)
              throws IllegalAccessException,
                     InvocationTargetException,
                     IllegalArgumentException

Invokes the function pointer

Parameters:

args - the arguments to pass to the function pointer

Returns:

the object returned by the invocation

Throws:

IllegalAccessException - thrown if method is not accessible

InvocationTargetException - thrown if target function is invalid

IllegalArgumentException - thrown if the arguments don't match