/src/com/commonsware/cwac/wakeful/WakefulIntentService.java

/***
        Copyright (c) 2009 CommonsWare, LLC

        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.commonsware.cwac.wakeful;

//~--- imports ----------------------------------------------------------------

import android.app.IntentService;

import android.content.Context;
import android.content.Intent;
import android.content.pm.PackageManager;

import android.os.PowerManager;


//~--- classes ----------------------------------------------------------------

abstract public class WakefulIntentService
        extends IntentService {
    private static final String LOCK_NAME_STATIC =
        "com.commonsware.cwac.wakeful.WakefulIntentService";
    private static PowerManager.WakeLock lockStatic = null;


    //~--- constructors -------------------------------------------------------

    public WakefulIntentService(String name) {
        super(name);
    }

    //~--- methods ------------------------------------------------------------

    abstract protected void doWakefulWork(Intent intent);
    
    @Override
    final protected void onHandleIntent(Intent intent) {
        try {
            doWakefulWork(intent);
        } finally {
            getLock(this).release();
        }
    }

    @Override
    public void onStart(Intent intent, int startId) {
        if (!getLock(this).isHeld()) {    // fail-safe for crash restart
            getLock(this).acquire();
        }

        super.onStart(intent, startId);
    }

    public static void sendWakefulWork(Context ctxt, Class clsService) {
        sendWakefulWork(ctxt, new Intent(ctxt, clsService));
    }

    public static void sendWakefulWork(Context ctxt, Intent i) {
        if (PackageManager.PERMISSION_DENIED
                == ctxt.getPackageManager().checkPermission(
                    "android.permission.WAKE_LOCK", ctxt.getPackageName())) {
            throw new RuntimeException(
                "Application requires the WAKE_LOCK permission!");
        }

        getLock(ctxt).acquire();
        ctxt.startService(i);
    }

    //~--- get methods --------------------------------------------------------

    synchronized private static PowerManager.WakeLock getLock(Context context) {
        if (lockStatic == null) {
            PowerManager mgr =
                (PowerManager) context.getSystemService(Context.POWER_SERVICE);

            lockStatic = mgr.newWakeLock(PowerManager.PARTIAL_WAKE_LOCK,
                                         LOCK_NAME_STATIC);

            lockStatic.setReferenceCounted(true);
        }

        return (lockStatic);
    }
}