64 lines
1.9 KiB
Java
64 lines
1.9 KiB
Java
/*
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* Copyright (C) 2011 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 com.android.email;
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import android.util.Log;
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import java.util.concurrent.atomic.AtomicBoolean;
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/**
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* Base class for a task that runs at most one instance at any given moment.
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*
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* Call {@link #run} to start the task. If the task is already running on another thread, it'll do
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* nothing.
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*/
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public abstract class SingleRunningTask<Param> {
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private final AtomicBoolean mIsRunning = new AtomicBoolean(false);
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private final String mLogTaskName;
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public SingleRunningTask(String logTaskName) {
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mLogTaskName = logTaskName;
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}
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/**
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* Calls {@link #runInternal} if it's not running already.
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*/
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public final void run(Param param) {
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if (mIsRunning.compareAndSet(false, true)) {
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Log.i(Email.LOG_TAG, mLogTaskName + ": start");
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try {
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runInternal(param);
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} finally {
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Log.i(Email.LOG_TAG, mLogTaskName + ": done");
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mIsRunning.set(false);
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}
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} else {
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// Already running -- do nothing.
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Log.i(Email.LOG_TAG, mLogTaskName + ": already running");
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}
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}
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/**
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* The actual task must be implemented by subclasses.
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*/
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protected abstract void runInternal(Param param);
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/* package */ boolean isRunningForTest() {
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return mIsRunning.get();
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}
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}
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