Generics with Factory as Interface

genericsproject_CustomCallback.java

package com.lbalmaceda.genericsproject;

import com.lbalmaceda.genericsproject.exceptions.BaseException;

/**
 * Created by lbalmaceda on 6/21/16.
 */
public interface CustomCallback<T, U extends BaseException> {

    void onSuccess(T response);

    void onFailure(U error);
}

genericsproject_ErrorFactory.java

package com.lbalmaceda.genericsproject;

import com.lbalmaceda.genericsproject.exceptions.BaseException;

import java.io.Reader;

/**
 * Created by lbalmaceda on 6/22/16.
 */
public interface ErrorFactory<U extends BaseException> {
    U from(Exception exception);

    U from(String message, Exception exception);

    U from(Reader jsonReader);
}

genericsproject_exceptions_AuthException.java

package com.lbalmaceda.genericsproject.exceptions;

/**
 * Created by lbalmaceda on 6/21/16.
 */
public class AuthException extends BaseException {
    public AuthException(String message) {
        super(message);
    }
}

genericsproject_exceptions_BaseException.java

package com.lbalmaceda.genericsproject.exceptions;

/**
 * Created by lbalmaceda on 6/21/16.
 */
public class BaseException extends Exception {
    public BaseException(String message) {
        super(message);
    }
}

genericsproject_exceptions_MgmtException.java

package com.lbalmaceda.genericsproject.exceptions;

/**
 * Created by lbalmaceda on 6/21/16.
 */
public class MgmtException extends BaseException {
    public MgmtException(String message) {
        super(message);
    }
}

genericsproject_MainActivity.java

package com.lbalmaceda.genericsproject;

import android.os.Bundle;
import android.os.Handler;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import android.widget.Toast;

import com.lbalmaceda.genericsproject.exceptions.AuthException;
import com.lbalmaceda.genericsproject.exceptions.MgmtException;
import com.lbalmaceda.genericsproject.requests.TRequest;
import com.lbalmaceda.genericsproject.requests.VoidRequest;

import java.io.Reader;

public class MainActivity extends AppCompatActivity {
    private static String TAG = MainActivity.class.getSimpleName();
    private Handler handler;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        handler = new Handler(MainActivity.this.getMainLooper());
        
        TRequest<String, AuthException> authTRequest = new TRequest<>(authErrorFactory, simpleCallback);
        authTRequest.start();
        VoidRequest<MgmtException> voidRequest = new VoidRequest<>(mgmtErrorFactory, voidCallback);
        voidRequest.start();
    }

    private void showToast(final String message) {
        handler.post(new Runnable() {
            @Override
            public void run() {
                Toast.makeText(MainActivity.this, message, Toast.LENGTH_SHORT).show();
            }
        });
    }

    private CustomCallback<String, AuthException> simpleCallback = new CustomCallback<String, AuthException>() {
        @Override
        public void onSuccess(String response) {
            Log.e(TAG, "OnSuccess for SimpleCallback");
            showToast("SimpleRequest fine!");
        }

        @Override
        public void onFailure(AuthException error) {
            Log.e(TAG, "OnFailure for SimpleCallback");
        }
    };

    private CustomCallback<Void, MgmtException> voidCallback = new CustomCallback<Void, MgmtException>() {
        @Override
        public void onSuccess(Void response) {
            Log.e(TAG, "OnSuccess for VoidCallback");
            showToast("VoidRequest fine!");
        }

        @Override
        public void onFailure(MgmtException error) {
            Log.e(TAG, "OnFailure for VoidCallback");
        }
    };

    private ErrorFactory<AuthException> authErrorFactory = new ErrorFactory<AuthException>() {
        @Override
        public AuthException from(Exception exception) {
            return null;
        }

        @Override
        public AuthException from(String message, Exception exception) {
            return null;
        }

        @Override
        public AuthException from(Reader jsonReader) {
            return null;
        }
    };

    private ErrorFactory<MgmtException> mgmtErrorFactory = new ErrorFactory<MgmtException>() {
        @Override
        public MgmtException from(Exception exception) {
            return null;
        }

        @Override
        public MgmtException from(String message, Exception exception) {
            return null;
        }

        @Override
        public MgmtException from(Reader jsonReader) {
            return null;
        }
    };


}

genericsproject_requests_BaseRequest.java

package com.lbalmaceda.genericsproject.requests;

import android.os.Handler;
import android.util.Log;

import com.lbalmaceda.genericsproject.CustomCallback;
import com.lbalmaceda.genericsproject.ErrorFactory;
import com.lbalmaceda.genericsproject.exceptions.BaseException;

import java.util.Random;

/**
 * Created by lbalmaceda on 6/21/16.
 */
abstract class BaseRequest<T, U extends BaseException> {

    private static final String TAG = BaseRequest.class.getSimpleName();
    private final ErrorFactory<U> errorGeneration;
    private final CustomCallback<T, U> callback;

    public BaseRequest(ErrorFactory<U> errorGeneration, CustomCallback<T, U> callback) {
        this.errorGeneration = errorGeneration;
        this.callback = callback;
    }

    public void start() {
        Handler handler = new Handler();
        handler.post(runnable);
    }

    private Runnable runnable = new Runnable() {
        @Override
        public void run() {
            Log.e(TAG, "Thread starting");
            try {
                Thread.sleep(3000);
                Random r = new Random();
                if (r.nextBoolean()) {
                    throw new InterruptedException("Fake");
                }
                callback.onSuccess(generateSuccess());
                Log.e(TAG, "Thread ended fine");
            } catch (InterruptedException ex) {
                Log.e(TAG, "Thread ended with error");
                final U err = errorGeneration.from(ex);
                callback.onFailure(err);
            }
        }
    };

    protected abstract T generateSuccess();
}

genericsproject_requests_TRequest.java

package com.lbalmaceda.genericsproject.requests;

import com.lbalmaceda.genericsproject.CustomCallback;
import com.lbalmaceda.genericsproject.ErrorFactory;
import com.lbalmaceda.genericsproject.exceptions.BaseException;

/**
 * Created by lbalmaceda on 6/21/16.
 */
public class TRequest<T, U extends BaseException> extends BaseRequest<T, U> {

    public TRequest(ErrorFactory<U> errorFactory, CustomCallback<T, U> callback) {
        super(errorFactory, callback);
    }

    @Override
    protected T generateSuccess() {
        return null;
    }

}

genericsproject_requests_VoidRequest.java

package com.lbalmaceda.genericsproject.requests;

import com.lbalmaceda.genericsproject.CustomCallback;
import com.lbalmaceda.genericsproject.ErrorFactory;
import com.lbalmaceda.genericsproject.exceptions.BaseException;

/**
 * Created by lbalmaceda on 6/21/16.
 */
public class VoidRequest<U extends BaseException> extends TRequest<Void, U> {

    public VoidRequest(ErrorFactory<U> errorFactory, CustomCallback<Void, U> callback) {
        super(errorFactory, callback);
    }

}