packages/DocumentsUI/src/com/android/documentsui/ProviderExecutor.java

/*
 * Copyright (C) 2013 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.documentsui;

import com.android.internal.annotations.GuardedBy;
import com.android.internal.util.Preconditions;
import com.google.android.collect.Maps;

import java.util.HashMap;
import java.util.concurrent.Executor;
import java.util.concurrent.LinkedBlockingQueue;

public class ProviderExecutor extends Thread implements Executor {

    @GuardedBy("sExecutors")
    private static HashMap<String, ProviderExecutor> sExecutors = Maps.newHashMap();

    public static Executor forAuthority(String authority) {
        synchronized (sExecutors) {
            ProviderExecutor executor = sExecutors.get(authority);
            if (executor == null) {
                executor = new ProviderExecutor();
                executor.setName("ProviderExecutor: " + authority);
                executor.start();
                sExecutors.put(authority, executor);
            }
            return executor;
        }
    }

    private final LinkedBlockingQueue<Runnable> mQueue = new LinkedBlockingQueue<Runnable>();

    @Override
    public void execute(Runnable command) {
        Preconditions.checkNotNull(command);
        mQueue.add(command);
    }

    @Override
    public void run() {
        while (true) {
            try {
                final Runnable command = mQueue.take();
                command.run();
            } catch (InterruptedException e) {
                // That was weird; let's go look for more tasks.
            }
        }
    }
}