Interface that defines the generic signature of the methods to be implemented

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Interface that defines the generic signature of the methods to be implemented

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#1 by (4 votes)

3

I have three classes:

Request Repository

RepositoryMotorist

RepositoryTravel

All have the following methods with the exception of RepositorioTravel which does not have the "Change". The Object can refer to the Driver, Applicant, and Travel classes.

Add void

Remove void

Change boolean

Find Object

View all void

SearchAll ArrayList

I would like to know how to implement a single Interface for the 3 Repositories with the methods above in a generic way, so I can use any class I pass. Be added with Requester, Driver or Trip.

java interface

asked by anonymous 28.11.2016 / 18:22

1 answer

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score 4 · Accepted Answer

You can use a generic type in interface as follows:

import java.util.ArrayList;

public interface ICRUD<T> {
  void adicionar(T objeto);
  void remover(T objeto);
  boolean alterar(T objeto);
  T buscar(int id);
  void exibirTodos();
  ArrayList<T> buscarTodos();
}

And use it, for example, as follows:

import java.util.ArrayList;

public class CRUDRepositorioSolicitante implements ICRUD<RepositorioSolicitante>{...}

If you want to force objects to be inherited from a class (let's say it is Repositorio you just need to change the interface declaration to:

public interface ICRUD<T extends Repositorio> {...}

EDIT

In the case of the class that will not have method alterar you can throw the following exception:

throw new UnsupportedOperationException("Não suportado.");