com.versionone.util
Class Delegator

java.lang.Object
  com.versionone.util.Delegator

public class Delegator
extends java.lang.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

Nested Class Summary

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

static Delegator[]	EMPTY_ARRAY
static java.lang.reflect.Method[]	EMPTY_METHOD_ARRAY
static java.lang.Object[]	EMPTY_OBJECT_ARRAY
static Delegator	RUNNABLE_DELEGATE

Constructor Summary

Delegator(java.lang.Class TheInterface)

Delegator(java.lang.Class[] params, java.lang.Class retClass)

Method Summary

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

EMPTY_OBJECT_ARRAY

public static final java.lang.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(java.lang.Class[] params,
                 java.lang.Class retClass)

Parameters:

params - non-null array of arguments

retClass - possibly null return class null says do not care

Delegator

public Delegator(java.lang.Class TheInterface)

Parameters:

TheInterface - an non-null interface with EXACTLY one method

Method Detail

buildRunnable

public static java.lang.Runnable buildRunnable(java.lang.Object item,
                                               java.lang.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 java.lang.Runnable buildRunnable(java.lang.Class item,
                                               java.lang.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 java.lang.Class getReturn()

accessor for return class

getArguments

public java.lang.Class[] getArguments()

accessor for argument classes

getInterface

public java.lang.Class getInterface()

build

public IDelegate build(java.lang.Class target,
                       java.lang.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 prozy implementing that interface

build

public IDelegate build(java.lang.Object target,
                       java.lang.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 prozy implementing that interface

isSuitableMethod

protected static boolean isSuitableMethod(java.lang.reflect.Method testMethod,
                                          java.lang.Class[] args,
                                          java.lang.Class retClass)

utility method to test suitability

getCandidateMethods

protected static java.lang.reflect.Method[] getCandidateMethods(java.lang.Class targetClass,
                                                                java.lang.String MethodName,
                                                                int nargs)

utility method to get candidate methods to search

isValidReturn

protected static boolean isValidReturn(java.lang.reflect.Method test,
                                       java.lang.Class retClass)

utility method to test return

findSuitableMethod

protected static java.lang.reflect.Method findSuitableMethod(java.lang.Class targetClass,
                                                             java.lang.String MethodName,
                                                             Delegator templ)

Utility method to locate a proper Method object

findMethod

protected static java.lang.reflect.Method findMethod(java.lang.Class TheInterface)

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