Android Open Source - wristband-android Request Future

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License

The source code is released under:

The Artistic License 2.0 Copyright (c) 2014 Allan Pichardo Everyone is permitted to copy and distribute verbatim copies of this license document, but changing it is not allowed...

Java Source Code

/*
 * Copyright (C) 2011 The Android Open Source Project
 */*w  w  w  . j a v a 2  s .  c  o m*/
 * 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.
 */

package com.android.volley.toolbox;

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;

/**
 * A Future that represents a Volley request.
 *
 * Used by providing as your response and error listeners. For example:
 * <pre>
 * RequestFuture&lt;JSONObject&gt; future = RequestFuture.newFuture();
 * MyRequest request = new MyRequest(URL, future, future);
 *
 * // If you want to be able to cancel the request:
 * future.setRequest(requestQueue.add(request));
 *
 * // Otherwise:
 * requestQueue.add(request);
 *
 * try {
 *   JSONObject response = future.get();
 *   // do something with response
 * } catch (InterruptedException e) {
 *   // handle the error
 * } catch (ExecutionException e) {
 *   // handle the error
 * }
 * </pre>
 *
 * @param <T> The type of parsed response this future expects.
 */
public class RequestFuture<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> RequestFuture<E> newFuture() {
        return new RequestFuture<E>();
    }

    private RequestFuture() {}

    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) {
            return mResult;
        }

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

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

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

        return mResult;
    }

    @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();
    }
}

Java Source Code List

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