CODEWITHSUNDEEP
javaspringfactory-pattern
MychaL
MychaL

Reputation: 999

Spring : How to manage a dynamic factory?

I would like to create a factory, but it's not simple with Spring and again I'm lost in space :p

This is what i would like to do.

I have an abstract class which implements multiple interface (Runnable and some personal interfaces)

public abstract class AbstractDocMan implements Runnable, DocMan {

    protected AbstractDocUnit docUnit;

    // some attributes

    // some getter & setter
}

I have some classes which extends from this abstract class, i will call them : W, S & E :p And some classes for the Abstract attribute (docUnit) called : WD for W, SD for S and ED for E :)

Now considering a parameter, i would like to instantiate the good class in my main controller. I would like a generic code, but working with specific class considering the good process.

Something like that.

@Component("mainVm")
@Scope("prototype")
public class MainVm {

   @Autowired
   private DocManFactory docManFactory;

   // ???
   private AbstractDocMan docMan;

   ...

   public void setProcess(String myProcess) {
       docMan = docManFactory.getDocMan(myProcess);
   } 
}

For moment, i have a factory defined strangely. It is working but i don't think it's a good practice :

public class DocManFactory {

    @Autowired
    private S s;
    @Autowired
    private W w;
    @Autowired
    private E e;

    @Autowired
    private SD sd;
    @Autowired
    private WD wd;
    @Autowired
    private ED ed;

    public AbstractDocMan getDocMan(String myProcess) {
        AbstractDocMan adm = null;
        if ("S".equals(myProcess)) {
            s.setDocUnit(sd);
            adm = s;
        } else if ("W".equals(myProcess)) {
            w.setDocUnit(wd);
            adm = w;
        } else if ("E".equals(myProcess)) {
            e.setDocUnit(ed);
            adm = e;
        }
        return adm;
    }
}

So my questions : - How to inject dynamically the good docUnit in the factory ? cause here all object are instantiate (s,e,w,sd,ed,wd) zzz - Is there a way to annotate the attribute in main controller ?

So...How to do a good factory with Spring (v3.1.1).

Thank you.

Upvotes: 1

Views: 441

Answers (1)

duffymo
duffymo

Reputation: 308763

I think generics and a Map are the solutions here.

Your instinct is correct: this implementation is far too brittle. Start with this: 

public DocManFactory {

    // You can inject or hard wire these
    private static final Map<String, AbstractDocMan> INSTANCES; 


    public static AbstractDocMan getDocMan(String processName, Process process) {
        AbstractDocMan docMan = INSTANCES.get(processName);
        process.setDocUnit(docMan);
        return docMan;
    }
}

Generics can help if the Process class that I assumed varies.

Upvotes: 1

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