| /* |
| * Copyright (C) 2011 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 com.android.emailcommon.utility; |
| |
| import com.google.common.annotations.VisibleForTesting; |
| |
| import android.os.Handler; |
| |
| import java.util.ArrayList; |
| import java.util.LinkedList; |
| |
| /** |
| * Class that helps post {@link Runnable}s to a {@link Handler}, and cancel pending ones |
| * at once. |
| */ |
| public class DelayedOperations { |
| private final Handler mHandler; |
| |
| @VisibleForTesting |
| final LinkedList<QueuedOperation> mPendingOperations = new LinkedList<QueuedOperation>(); |
| |
| private class QueuedOperation implements Runnable { |
| private final Runnable mActualRannable; |
| |
| public QueuedOperation(Runnable actualRannable) { |
| mActualRannable = actualRannable; |
| } |
| |
| @Override |
| public void run() { |
| mPendingOperations.remove(this); |
| mActualRannable.run(); |
| } |
| |
| public void cancel() { |
| mPendingOperations.remove(this); |
| cancelRunnable(this); |
| } |
| } |
| |
| public DelayedOperations(Handler handler) { |
| mHandler = handler; |
| } |
| |
| /** |
| * Post a {@link Runnable} to the handler. Equivalent to {@link Handler#post(Runnable)}. |
| */ |
| public void post(Runnable r) { |
| final QueuedOperation qo = new QueuedOperation(r); |
| mPendingOperations.add(qo); |
| postRunnable(qo); |
| } |
| |
| /** |
| * Cancel a runnable that's been posted with {@link #post(Runnable)}. |
| * |
| * Equivalent to {@link Handler#removeCallbacks(Runnable)}. |
| */ |
| public void removeCallbacks(Runnable r) { |
| QueuedOperation found = null; |
| for (QueuedOperation qo : mPendingOperations) { |
| if (qo.mActualRannable == r) { |
| found = qo; |
| break; |
| } |
| } |
| if (found != null) { |
| found.cancel(); |
| } |
| } |
| |
| /** |
| * Cancel all pending {@link Runnable}s. |
| */ |
| public void removeCallbacks() { |
| // To avoid ConcurrentModificationException |
| final ArrayList<QueuedOperation> temp = new ArrayList<QueuedOperation>(mPendingOperations); |
| for (QueuedOperation qo : temp) { |
| qo.cancel(); |
| } |
| } |
| |
| /** Overridden by test, as Handler is not mockable. */ |
| void postRunnable(Runnable r) { |
| mHandler.post(r); |
| } |
| |
| /** Overridden by test, as Handler is not mockable. */ |
| void cancelRunnable(Runnable r) { |
| mHandler.removeCallbacks(r); |
| } |
| } |