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Diffstat (limited to 'core/java/android/accounts/AccountManagerFuture.java')
| -rw-r--r-- | core/java/android/accounts/AccountManagerFuture.java | 117 |
1 files changed, 117 insertions, 0 deletions
diff --git a/core/java/android/accounts/AccountManagerFuture.java b/core/java/android/accounts/AccountManagerFuture.java new file mode 100644 index 0000000..a1ab00c --- /dev/null +++ b/core/java/android/accounts/AccountManagerFuture.java @@ -0,0 +1,117 @@ +/* + * 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</tt> 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</tt> when the computation has completed, blocking if + * necessary until it is ready. Cancellation is performed by the + * <tt>cancel</tt> 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</tt> for the sake + * of cancellability but not provide a usable result, you can + * declare types of the form <tt>Future<?></tt> and + * return <tt>null</tt> 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</tt> is called, + * this task should never run. If the task has already started, + * then the <tt>mayInterruptIfRunning</tt> 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</tt>. Subsequent calls to {@link #isCancelled} + * will always return <tt>true</tt> if this method returned <tt>true</tt>. + * + * @param mayInterruptIfRunning <tt>true</tt> if the thread executing this + * task should be interrupted; otherwise, in-progress tasks are allowed + * to complete + * @return <tt>false</tt> if the task could not be cancelled, + * typically because it has already completed normally; + * <tt>true</tt> otherwise + */ + boolean cancel(boolean mayInterruptIfRunning); + + /** + * Returns <tt>true</tt> if this task was cancelled before it completed + * normally. + * + * @return <tt>true</tt> if this task was cancelled before it completed + */ + boolean isCancelled(); + + /** + * Returns <tt>true</tt> 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</tt>. + * + * @return <tt>true</tt> 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; +}
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