117 lines
5.7 KiB
Java
117 lines
5.7 KiB
Java
/*
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* Copyright (C) 2009 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package android.accounts;
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import java.util.concurrent.Future;
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import java.util.concurrent.TimeUnit;
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import java.util.concurrent.ExecutionException;
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import java.util.concurrent.TimeoutException;
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import java.io.IOException;
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/**
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* A <tt>AccountManagerFuture</tt> represents the result of an asynchronous
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* {@link AccountManager} call. Methods are provided to check if the computation is
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* complete, to wait for its completion, and to retrieve the result of
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* the computation. The result can only be retrieved using method
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* <tt>get</tt> when the computation has completed, blocking if
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* necessary until it is ready. Cancellation is performed by the
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* <tt>cancel</tt> method. Additional methods are provided to
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* determine if the task completed normally or was cancelled. Once a
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* computation has completed, the computation cannot be cancelled.
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* If you would like to use a <tt>Future</tt> for the sake
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* of cancellability but not provide a usable result, you can
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* declare types of the form <tt>Future<?></tt> and
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* return <tt>null</tt> as a result of the underlying task.
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*/
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public interface AccountManagerFuture<V> {
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/**
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* Attempts to cancel execution of this task. This attempt will
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* fail if the task has already completed, has already been cancelled,
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* or could not be cancelled for some other reason. If successful,
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* and this task has not started when <tt>cancel</tt> is called,
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* this task should never run. If the task has already started,
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* then the <tt>mayInterruptIfRunning</tt> parameter determines
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* whether the thread executing this task should be interrupted in
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* an attempt to stop the task.
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*
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* <p>After this method returns, subsequent calls to {@link #isDone} will
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* always return <tt>true</tt>. Subsequent calls to {@link #isCancelled}
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* will always return <tt>true</tt> if this method returned <tt>true</tt>.
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*
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* @param mayInterruptIfRunning <tt>true</tt> if the thread executing this
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* task should be interrupted; otherwise, in-progress tasks are allowed
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* to complete
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* @return <tt>false</tt> if the task could not be cancelled,
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* typically because it has already completed normally;
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* <tt>true</tt> otherwise
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*/
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boolean cancel(boolean mayInterruptIfRunning);
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/**
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* Returns <tt>true</tt> if this task was cancelled before it completed
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* normally.
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*
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* @return <tt>true</tt> if this task was cancelled before it completed
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*/
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boolean isCancelled();
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/**
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* Returns <tt>true</tt> if this task completed.
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*
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* Completion may be due to normal termination, an exception, or
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* cancellation -- in all of these cases, this method will return
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* <tt>true</tt>.
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*
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* @return <tt>true</tt> if this task completed
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*/
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boolean isDone();
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/**
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* Accessor for the future result the {@link AccountManagerFuture} represents. This
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* call will block until the result is available. In order to check if the result is
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* available without blocking, one may call {@link #isDone()} and {@link #isCancelled()}.
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* If the request that generated this result fails or is canceled then an exception
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* will be thrown rather than the call returning normally.
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* @return the actual result
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* @throws android.accounts.OperationCanceledException if the request was canceled for any
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* reason
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* @throws android.accounts.AuthenticatorException if there was an error communicating with
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* the authenticator or if the authenticator returned an invalid response
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* @throws java.io.IOException if the authenticator returned an error response that indicates
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* that it encountered an IOException while communicating with the authentication server
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*/
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V getResult() throws OperationCanceledException, IOException, AuthenticatorException;
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/**
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* Accessor for the future result the {@link AccountManagerFuture} represents. This
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* call will block until the result is available. In order to check if the result is
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* available without blocking, one may call {@link #isDone()} and {@link #isCancelled()}.
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* If the request that generated this result fails or is canceled then an exception
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* will be thrown rather than the call returning normally. If a timeout is specified then
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* the request will automatically be canceled if it does not complete in that amount of time.
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* @param timeout the maximum time to wait
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* @param unit the time unit of the timeout argument. This must not be null.
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* @return the actual result
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* @throws android.accounts.OperationCanceledException if the request was canceled for any
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* reason
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* @throws android.accounts.AuthenticatorException if there was an error communicating with
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* the authenticator or if the authenticator returned an invalid response
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* @throws java.io.IOException if the authenticator returned an error response that indicates
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* that it encountered an IOException while communicating with the authentication server
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*/
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V getResult(long timeout, TimeUnit unit)
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throws OperationCanceledException, IOException, AuthenticatorException;
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} |