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      1 /*
      2  * Copyright (C) 2016 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License
     15  */
     16 
     17 package android.telecom.Logging;
     18 
     19 import android.telecom.Log;
     20 
     21 /**
     22  * Encapsulates session logging in a Runnable to reduce code duplication when continuing subsessions
     23  * in a handler/thread.
     24  * @hide
     25  */
     26 public abstract class Runnable {
     27 
     28     private Session mSubsession;
     29     private final String mSubsessionName;
     30     private final Object mLock;
     31     private final java.lang.Runnable mRunnable = new java.lang.Runnable() {
     32         @Override
     33         public void run() {
     34             synchronized (mLock) {
     35                 try {
     36                     Log.continueSession(mSubsession, mSubsessionName);
     37                     loggedRun();
     38                 } finally {
     39                     if (mSubsession != null) {
     40                         Log.endSession();
     41                         mSubsession = null;
     42                     }
     43                 }
     44             }
     45         }
     46     };
     47 
     48     /**
     49      * Creates a new Telecom Runnable that incorporates Session Logging into it. Useful for carrying
     50      * Logging Sessions through different threads as well as through handlers.
     51      * @param subsessionName The name that will be used in the Logs to mark this Session
     52      * @param lock The synchronization lock that will be used to lock loggedRun().
     53      */
     54     public Runnable(String subsessionName, Object lock) {
     55         if (lock == null) {
     56             mLock = new Object();
     57         } else {
     58             mLock = lock;
     59         }
     60         mSubsessionName = subsessionName;
     61     }
     62 
     63     /**
     64      * Return the runnable that will be canceled in the handler queue.
     65      * @return Runnable object to cancel.
     66      */
     67     public final java.lang.Runnable getRunnableToCancel() {
     68         return mRunnable;
     69     }
     70 
     71     /**
     72      * Creates a Runnable and a logging subsession that can be used in a handler/thread. Be sure to
     73      * call cancel() if this session is never going to be run (removed from a handler queue, for
     74      * for example).
     75      * @return A Java Runnable that can be used in a handler queue or thread.
     76      */
     77     public java.lang.Runnable prepare() {
     78         cancel();
     79         mSubsession = Log.createSubsession();
     80         return mRunnable;
     81     }
     82 
     83     /**
     84      * This method is used to clean up the active session if the Runnable gets removed from a
     85      * handler and is never run.
     86      */
     87     public void cancel() {
     88         synchronized (mLock) {
     89             Log.cancelSubsession(mSubsession);
     90             mSubsession = null;
     91         }
     92     }
     93 
     94     /**
     95      * The method that will be run in the handler/thread.
     96      */
     97     abstract public void loggedRun();
     98 
     99 }