Android example source code file (AccountManagerFuture.java)

This example Android source code file (AccountManagerFuture.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Android by Example" ^TM.

Java - Android tags/keywords

accountmanagerfuture, authenticatorexception, io, ioexception, operationcanceledexception, threading, threads, timeunit, v

The AccountManagerFuture.java Android example source code

/*
 * Copyright (C) 2009 The Android Open Source Project
 *
 * 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 android.accounts;

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

/**
 * A <tt>AccountManagerFuture represents the result of an asynchronous
 * {@link AccountManager} call.  Methods are provided to check if the computation is
 * complete, to wait for its completion, and to retrieve the result of
 * the computation.  The result can only be retrieved using method
 * <tt>get when the computation has completed, blocking if
 * necessary until it is ready.  Cancellation is performed by the
 * <tt>cancel method.  Additional methods are provided to
 * determine if the task completed normally or was cancelled. Once a
 * computation has completed, the computation cannot be cancelled.
 * If you would like to use a <tt>Future for the sake
 * of cancellability but not provide a usable result, you can
 * declare types of the form <tt>Future<?> and
 * return <tt>null as a result of the underlying task.
 */
public interface AccountManagerFuture<V> {
    /**
     * Attempts to cancel execution of this task.  This attempt will
     * fail if the task has already completed, has already been cancelled,
     * or could not be cancelled for some other reason. If successful,
     * and this task has not started when <tt>cancel is called,
     * this task should never run.  If the task has already started,
     * then the <tt>mayInterruptIfRunning parameter determines
     * whether the thread executing this task should be interrupted in
     * an attempt to stop the task.
     *
     * <p>After this method returns, subsequent calls to {@link #isDone} will
     * always return <tt>true.  Subsequent calls to {@link #isCancelled}
     * will always return <tt>true if this method returned true.
     *
     * @param mayInterruptIfRunning <tt>true if the thread executing this
     * task should be interrupted; otherwise, in-progress tasks are allowed
     * to complete
     * @return <tt>false if the task could not be cancelled,
     * typically because it has already completed normally;
     * <tt>true otherwise
     */
    boolean cancel(boolean mayInterruptIfRunning);

    /**
     * Returns <tt>true if this task was cancelled before it completed
     * normally.
     *
     * @return <tt>true if this task was cancelled before it completed
     */
    boolean isCancelled();

    /**
     * Returns <tt>true if this task completed.
     *
     * Completion may be due to normal termination, an exception, or
     * cancellation -- in all of these cases, this method will return
     * <tt>true.
     *
     * @return <tt>true if this task completed
     */
    boolean isDone();

    /**
     * Accessor for the future result the {@link AccountManagerFuture} represents. This
     * call will block until the result is available. In order to check if the result is
     * available without blocking, one may call {@link #isDone()} and  {@link #isCancelled()}.
     * If the request that generated this result fails or is canceled then an exception
     * will be thrown rather than the call returning normally.
     * @return the actual result
     * @throws android.accounts.OperationCanceledException if the request was canceled for any
     * reason
     * @throws android.accounts.AuthenticatorException if there was an error communicating with
     * the authenticator or if the authenticator returned an invalid response
     * @throws java.io.IOException if the authenticator returned an error response that indicates
     * that it encountered an IOException while communicating with the authentication server
     */
    V getResult() throws OperationCanceledException, IOException, AuthenticatorException;

    /**
     * Accessor for the future result the {@link AccountManagerFuture} represents. This
     * call will block until the result is available. In order to check if the result is
     * available without blocking, one may call {@link #isDone()} and  {@link #isCancelled()}.
     * If the request that generated this result fails or is canceled then an exception
     * will be thrown rather than the call returning normally. If a timeout is specified then
     * the request will automatically be canceled if it does not complete in that amount of time.
     * @param timeout the maximum time to wait
     * @param unit the time unit of the timeout argument. This must not be null.
     * @return the actual result
     * @throws android.accounts.OperationCanceledException if the request was canceled for any
     * reason
     * @throws android.accounts.AuthenticatorException if there was an error communicating with
     * the authenticator or if the authenticator returned an invalid response
     * @throws java.io.IOException if the authenticator returned an error response that indicates
     * that it encountered an IOException while communicating with the authentication server
     */
    V getResult(long timeout, TimeUnit unit)
            throws OperationCanceledException, IOException, AuthenticatorException;
}