How to apply Strategy Pattern using Spring?

[DistillingSpring]

Hello,

I have the following situation (this example is pretty much like the one in the book "Head First Design Pattern"):

//Interface Behavior
interface BehaviorOne {
void credit()
}

//Interface Implementation
class BehaviorOneImpl implements BehaviorOne{
void credit () {
System.out.println("do something");
}
}

//class to use Behavior
class A {
double amount;

BehaviorOne behaviorOne;

executeCredit() {
behaviorOne.credit();
}

void setAmount(double amount) {
this.amount = amount;
}

double getAmount() {
return amount;
}

}

//class extends abstract class
class Aconcrete {
Aconcrete() {
behaviorOne = new BehaviorOneImpl();
}
}

//Client call
class Test {

public static void main(String[] args) {
A _aConcrete = new Aconcrete();
_aConcrete.executeCredit();
}
}

The result should be (I didn't test but this example should works):
"do something"


My problems:
------------
1st:
If in the BehaviorOneImpl class I need an information that was loaded in the A class, how do I get it? I have to do a composition like this:

class BehaviorOneImpl {
A _aMainClass = new A()
void credit () {
System.out.println("do something "+
"show amount = "+ _aMainClass.getAmount);
}
}

2nd:
How could I integrate the Strategy using Spring?

Thank you so much in advance for any help!

[jbetancourt]

This was discussed in the forums before.
For example, http://forum.springframework.org/sho...rategy+pattern

[wpoitras]

1) I would recommend you change your BehaviorOne interface so that credit would take an argument. It really isn't a good practice to have circular dependencies like you describe. I

[DistillingSpring]

Guys, to put it simple.. thanks for save my life!

[DistillingSpring]

I would like to take advantage of this thread to make sure that's correct a design that I implemented:

Let's say that for BehaviorOneImpl I have two other behaviors and two other concrete classes to access those behaviors. So,
I applied the Strategy pattern once again for BehaviorOneImpl and I have the following:

//Previous implementation "First Level Behavior"---------------------
...
//Interface Implementation
class BehaviorOneImpl implements BehaviorOne{
void credit () {
System.out.println("do something");
}
..
//------------------------------------------

//classes
class BehaviorOneImplClassOne extends BehaviorOneImpl {
...
}

class BehaviorOneImplClassTwo extends BehaviorOneImpl {
...
}

//interfaces
interface BehaviorOneImplClassOneInterface {
...
}

interface BehaviorOneImplClassTwoInterface {
...
}


//Implementations concrete class "Second Level Behavior"
class SecondLevelBehaviorClassOne implements BehaviorOneImplClassOneInterface {
...
}

class SecondLevelBehaviorClassTwo implements BehaviorOneImplClassTwoInterface {
...
}


//Since SecondLevelBehaviorClassOne has many subclasses, I created an interface and in this way it's possible to access the interface 
//instead using extends (concrete classes).
interface ISecondLevelBehaviorClassOneInterface  {
   public SecondLevelBehaviorClassOne getInformation(SecondLevelBehaviorClassOne secondLevelBehaviorClassOne);
}


//And finally, the implementation of the different classes. As you can see,  the goal here is the WhateverItIsOne access the interface
//ISecondLevelBehaviorClassOneInterface instead access the class SecondLevelBehaviorClassOne directly.
class WhateverItIsOne implements ISecondLevelBehaviorClassOneInterface{
	public SecondLevelBehaviorClassOne getInformation(SecondLevelBehaviorClassOne secondLevelBehaviorClassOne) {
              ....
	}
}

class WhateverItIsTwo implements ISecondLevelBehaviorClassOneInterface{
	public SecondLevelBehaviorClassOne getInformation(SecondLevelBehaviorClassOne secondLevelBehaviorClassOne) {
              ....
	}
}


class WhateverItIsThree implements ISecondLevelBehaviorClassOneInterface{
	public SecondLevelBehaviorClassOne getInformation(SecondLevelBehaviorClassOne secondLevelBehaviorClassOne) {
              ....
	}
}

//And the same for the BehaviorOneImplClassTwoInterface.

Note that my class BehaviorOneImpl represents the very same "position" as the class A in the above example.

I don't want you to do my job, but if you have a better idea or agree that it's ok, would be great.

Regards.

[DistillingSpring]

Hello,

I am still having some doubts regarding the last model that I sent. Would anyone mind to take a look on that? If you want, I can send a more detailled and functional source code.

Thanks for any help.