com.versionone.utils

Class Delegator

java.lang.Object

com.versionone.utils.Delegator

public class Delegator
extends Object

Delegator class from the article http://www.onjava.com/pub/a/onjava/2003/05/21/delegates.html?page=1 Class representing a delegate template - also a factory returning the real delegate object

Author:

Steve Lewis smlewis@lordjoe.com

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	Delegator.DelegateInvokeException All problems become this type of exception As a runtime we do not impose burdens on the calling code
protected class	Delegator.DelegateProxy

Field Summary

Fields

Modifier and Type	Field and Description
static Delegator[]	EMPTY_ARRAY
static Method[]	EMPTY_METHOD_ARRAY
static Object[]	EMPTY_OBJECT_ARRAY
static Delegator	RUNNABLE_DELEGATE

Constructor Summary

Constructors

Constructor and Description
Delegator(Class TheInterface)
Delegator(Class[] params, Class retClass)

Method Summary

Modifier and Type	Method and Description
IDelegate	build(Class target, String MethodName)
IDelegate	build(Object target, String MethodName)
static Runnable	buildRunnable(Class item, String methodName) Convenience method to make a runnable delegate
static Runnable	buildRunnable(Object item, String methodName) Convenience method to make a runnable delegate
protected static Method	findMethod(Class TheInterface) utility code to find the one suitable method in the passed in interface.
protected static Method	findSuitableMethod(Class targetClass, String MethodName, Delegator templ) Utility method to locate a proper Method object
Class[]	getArguments() accessor for argument classes
protected static Method[]	getCandidateMethods(Class targetClass, String MethodName, int nargs) utility method to get candidate methods to search
Class	getInterface()
Class	getReturn() accessor for return class
protected static boolean	isSuitableMethod(Method testMethod, Class[] args, Class retClass) utility method to test suitability
protected static boolean	isValidReturn(Method test, Class retClass) utility method to test return

Methods inherited from class java.lang.Object

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

Field Detail

EMPTY_METHOD_ARRAY

public static final Method[] EMPTY_METHOD_ARRAY

EMPTY_OBJECT_ARRAY

public static final Object[] EMPTY_OBJECT_ARRAY

EMPTY_ARRAY

public static final Delegator[] EMPTY_ARRAY

RUNNABLE_DELEGATE

public static final Delegator RUNNABLE_DELEGATE

Constructor Detail

Delegator

public Delegator(Class[] params,
                 Class retClass)

Parameters:

params - non-null array of arguments

retClass - possibly null return class null says do not care

Delegator

public Delegator(Class TheInterface)

Parameters:

TheInterface - an non-null interface with EXACTLY one method

Method Detail

buildRunnable

public static Runnable buildRunnable(Object item,
                                     String methodName)

Convenience method to make a runnable delegate

Parameters:

item - non-null target object

methodName - non-null name of a method of type void ()

Returns:

non-null Runnable proxy

buildRunnable

public static Runnable buildRunnable(Class item,
                                     String methodName)

Convenience method to make a runnable delegate

Parameters:

item - non-null target class

methodName - non-null name of a method of type void ()

Returns:

non-null Runnable proxy

getReturn

public Class getReturn()

accessor for return class

Returns:

class - Class

getArguments

public Class[] getArguments()

accessor for argument classes

Returns:

class - Class[]

getInterface

public Class getInterface()

build

public IDelegate build(Class target,
                       String MethodName)

Parameters:

target - non-null class with a bindable static method

MethodName - name of the static method

Returns:

non-null IDelegate if getInterface() is non-null it will be a dynamic proxy implementing that interface

build

public IDelegate build(Object target,
                       String MethodName)

Parameters:

target - non-null target with a bindable method

MethodName - name of the method

Returns:

non-null IDelegate if getInterface() is non-null it will be a dynamic proxy implementing that interface

isSuitableMethod

protected static boolean isSuitableMethod(Method testMethod,
                                          Class[] args,
                                          Class retClass)

utility method to test suitability

Parameters:

args - - Class[]

retClass - - Class

testMethod - - Method

Returns:

boolean - boolean

getCandidateMethods

protected static Method[] getCandidateMethods(Class targetClass,
                                              String MethodName,
                                              int nargs)

utility method to get candidate methods to search

Parameters:

MethodName - - String

nargs - - int

targetClass - - Class

Returns:

Method - Method[]

isValidReturn

protected static boolean isValidReturn(Method test,
                                       Class retClass)

utility method to test return

Parameters:

retClass - - Class

test - - Method

Returns:

boolean - boolean

findSuitableMethod

protected static Method findSuitableMethod(Class targetClass,
                                           String MethodName,
                                           Delegator templ)

Utility method to locate a proper Method object

Parameters:

targetClass - - Class

MethodName - - String

templ - - Delegator

Returns:

Method - Method

findMethod

protected static Method findMethod(Class TheInterface)

utility code to find the one suitable method in the passed in interface.

Parameters:

TheInterface - - Class

Returns:

Method - Method