The reusable implementation of Future<T> Blocking callback in Android Volley

ReusableFuture.java

/*
 * Copyright 2016 Elmar Rhex Gomez.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import com.android.volley.Request;
import com.android.volley.Response;
import com.android.volley.VolleyError;

import java.util.concurrent.ExecutionException;
import java.util.concurrent.Future;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.TimeoutException;

public class ReusableFuture<T> implements Future<T>, Response.Listener<T>,
        Response.ErrorListener {
    private Request<?> mRequest;
    private boolean mResultReceived = false;
    private T mResult;
    private VolleyError mException;

    public static <E> ReusableFuture<E> newFuture() {
        return new ReusableFuture<E>();
    }

    private ReusableFuture() {
    }

    public void setRequest(Request<?> request) {
        mRequest = request;
    }

    @Override
    public synchronized boolean cancel(boolean mayInterruptIfRunning) {
        if (mRequest == null) {
            return false;
        }

        if (!isDone()) {
            mRequest.cancel();
            return true;
        } else {
            return false;
        }
    }

    @Override
    public T get() throws InterruptedException, ExecutionException {
        try {
            return doGet(null);
        } catch (TimeoutException e) {
            throw new AssertionError(e);
        }
    }

    @Override
    public T get(long timeout, TimeUnit unit)
            throws InterruptedException, ExecutionException, TimeoutException {
        return doGet(TimeUnit.MILLISECONDS.convert(timeout, unit));
    }

    private synchronized T doGet(Long timeoutMs)
            throws InterruptedException, ExecutionException, TimeoutException {
        if (mException != null) {
            throw new ExecutionException(mException);
        }

        if (mResultReceived) {
            T res = mResult;
            reset();
            return res;
        }

        if (timeoutMs == null) {
            wait(0);
        } else if (timeoutMs > 0) {
            wait(timeoutMs);
        }

        if (mException != null) {
            throw new ExecutionException(mException);
        }

        if (!mResultReceived) {
            throw new TimeoutException();
        }

        T res = mResult;
        reset();
        return res;
    }

    public T getReliableResponse() throws ExecutionException, InterruptedException {
        T response = null;
        while (!mResultReceived) {
            try {
                response = get(50, TimeUnit.MILLISECONDS);
            } catch (TimeoutException e) {
                // Do nothing
            }
        }
        return response;
    }

    @Override
    public boolean isCancelled() {
        if (mRequest == null) {
            return false;
        }
        return mRequest.isCanceled();
    }

    @Override
    public synchronized boolean isDone() {
        return mResultReceived || mException != null || isCancelled();
    }

    @Override
    public synchronized void onResponse(T response) {
        mResultReceived = true;
        mResult = response;
        notifyAll();
    }

    @Override
    public synchronized void onErrorResponse(VolleyError error) {
        mException = error;
        notifyAll();
    }

    private void reset() {
        mRequest = null;
        mResultReceived = false;
        mResult = null;
        mException = null;
    }
}

Usecase:

 ReusableFuture<JSONObject> listener = new ReusableFuture.newFuture();
 JsonObjectRequest uploadRequest = new JsonObjectRequest(....... , listener, listener);

 // Your singleton implementation
 VolleySingleton.init(mContext).requestQueue().add(uploadRequest);

 try {
    JSONObject blockingResponse = listener.getReliableResponse();
     // Do something here or reuse the class again.
 } catch (ExecutionException e) {
 } catch (InterruptedException e) {
 }