Created listener for worker state change

https://github.com/awslabs/amazon-kinesis-client/issues/275

Update WorkerTest.java

src/main/java/com/amazonaws/services/kinesis/clientlibrary/lib/worker/NoOpWorkerStateChangeListener.java

@@ -0,0 +1,18 @@
+package com.amazonaws.services.kinesis.clientlibrary.lib.worker;
+
+import com.amazonaws.services.kinesis.clientlibrary.lib.worker.Worker.WorkerStateChangeListener;
+
+public class NoOpWorkerStateChangeListener implements WorkerStateChangeListener {
+
+	/**
+	 * Empty constructor for NoOp Worker State Change Listener
+	 */
+	public NoOpWorkerStateChangeListener() {
+
+	}
+
+	@Override
+	public void onWorkerStateChange(WorkerState newState) {
+
+	}
+}

src/main/java/com/amazonaws/services/kinesis/clientlibrary/lib/worker/Worker.java

@@ -93,7 +93,6 @@ public class Worker implements Runnable {
     private final Optional<Integer> retryGetRecordsInSeconds;
     private final Optional<Integer> maxGetRecordsThreadPool;
 
-    // private final KinesisClientLeaseManager leaseManager;
     private final KinesisClientLibLeaseCoordinator leaseCoordinator;
     private final ShardSyncTaskManager controlServer;
 
@@ -119,6 +118,8 @@ public class Worker implements Runnable {
     @VisibleForTesting
     protected GracefulShutdownCoordinator gracefulShutdownCoordinator = new GracefulShutdownCoordinator();
 
+    private WorkerStateChangeListener workerStateChangeListener;
+
     /**
      * Constructor.
      *
@@ -276,7 +277,8 @@ public class Worker implements Runnable {
                 config.getSkipShardSyncAtWorkerInitializationIfLeasesExist(),
                 config.getShardPrioritizationStrategy(),
                 config.getRetryGetRecordsInSeconds(),
-                config.getMaxGetRecordsThreadPool());
+                config.getMaxGetRecordsThreadPool(),
+                new NoOpWorkerStateChangeListener());
 
         // If a region name was explicitly specified, use it as the region for Amazon Kinesis and Amazon DynamoDB.
         if (config.getRegionName() != null) {
@@ -348,7 +350,7 @@ public class Worker implements Runnable {
         this(applicationName, recordProcessorFactory, config, streamConfig, initialPositionInStream, parentShardPollIntervalMillis,
                 shardSyncIdleTimeMillis, cleanupLeasesUponShardCompletion, checkpoint, leaseCoordinator, execService,
                 metricsFactory, taskBackoffTimeMillis, failoverTimeMillis, skipShardSyncAtWorkerInitializationIfLeasesExist,
-                shardPrioritization, Optional.empty(), Optional.empty());
+                shardPrioritization, Optional.empty(), Optional.empty(), new NoOpWorkerStateChangeListener());
     }
 
     /**
@@ -395,7 +397,7 @@ public class Worker implements Runnable {
            KinesisClientLibLeaseCoordinator leaseCoordinator, ExecutorService execService,
            IMetricsFactory metricsFactory, long taskBackoffTimeMillis, long failoverTimeMillis,
            boolean skipShardSyncAtWorkerInitializationIfLeasesExist, ShardPrioritization shardPrioritization,
-           Optional<Integer> retryGetRecordsInSeconds, Optional<Integer> maxGetRecordsThreadPool) {
+           Optional<Integer> retryGetRecordsInSeconds, Optional<Integer> maxGetRecordsThreadPool, WorkerStateChangeListener workerStateChangeListener) {
         this.applicationName = applicationName;
         this.recordProcessorFactory = recordProcessorFactory;
         this.config = config;
@@ -417,6 +419,8 @@ public class Worker implements Runnable {
         this.shardPrioritization = shardPrioritization;
         this.retryGetRecordsInSeconds = retryGetRecordsInSeconds;
         this.maxGetRecordsThreadPool = maxGetRecordsThreadPool;
+        this.workerStateChangeListener = workerStateChangeListener;
+        workerStateChangeListener.onWorkerStateChange(WorkerStateChangeListener.WorkerState.CREATED);
     }
 
     /**
@@ -440,6 +444,7 @@ public class Worker implements Runnable {
         if (shutdown) {
             return;
         }
+        workerStateChangeListener.onWorkerStateChange(WorkerStateChangeListener.WorkerState.INITIALIZING);
 
         try {
             initialize();
@@ -449,6 +454,7 @@ public class Worker implements Runnable {
             shutdown();
         }
 
+        workerStateChangeListener.onWorkerStateChange(WorkerStateChangeListener.WorkerState.STARTED);
         while (!shouldShutdown()) {
             runProcessLoop();
         }
@@ -593,10 +599,10 @@ public class Worker implements Runnable {
 
     /**
      * Starts the requestedShutdown process, and returns a future that can be used to track the process.
-     * 
+     *
      * This is deprecated in favor of {@link #startGracefulShutdown()}, which returns a more complete future, and
      * indicates the process behavior
-     * 
+     *
      * @return a future that will be set once shutdown is completed.
      */
     @Deprecated
@@ -640,7 +646,7 @@ public class Worker implements Runnable {
      * Requests a graceful shutdown of the worker, notifying record processors, that implement
      * {@link IShutdownNotificationAware}, of the impending shutdown. This gives the record processor a final chance to
      * checkpoint.
-     * 
+     *
      * This will only create a single shutdown future. Additional attempts to start a graceful shutdown will return the
      * previous future.
      *
@@ -755,6 +761,10 @@ public class Worker implements Runnable {
         return shardInfoShardConsumerMap;
     }
 
+    WorkerStateChangeListener getWorkerStateChangeListener() {
+        return workerStateChangeListener;
+    }
+
     /**
      * Signals worker to shutdown. Worker will try initiating shutdown of all record processors. Note that if executor
      * services were passed to the worker by the user, worker will not attempt to shutdown those resources.
@@ -775,6 +785,7 @@ public class Worker implements Runnable {
             LOG.warn("Shutdown requested a second time.");
             return;
         }
+        workerStateChangeListener.onWorkerStateChange(WorkerStateChangeListener.WorkerState.SHUTTING_DOWN);
         LOG.info("Worker shutdown requested.");
 
         // Set shutdown flag, so Worker.run can start shutdown process.
@@ -801,13 +812,14 @@ public class Worker implements Runnable {
         if (metricsFactory instanceof WorkerCWMetricsFactory) {
             ((CWMetricsFactory) metricsFactory).shutdown();
         }
+        workerStateChangeListener.onWorkerStateChange(WorkerStateChangeListener.WorkerState.SHUT_DOWN);
         shutdownComplete = true;
     }
 
     /**
      * Returns whether worker can shutdown immediately. Note that this method is called from Worker's {{@link #run()}
      * method before every loop run, so method must do minimum amount of work to not impact shard processing timings.
-     * 
+     *
      * @return Whether worker should shutdown immediately.
      */
     @VisibleForTesting
@@ -874,6 +886,22 @@ public class Worker implements Runnable {
 
     }
 
+    /**
+     * A listener for callbacks on changes worker state
+     */
+    @FunctionalInterface
+    public interface WorkerStateChangeListener {
+        enum WorkerState {
+            CREATED,
+            INITIALIZING,
+            STARTED,
+            SHUTTING_DOWN,
+            SHUT_DOWN
+        }
+
+        void onWorkerStateChange(WorkerState newState);
+    }
+
     /**
      * Logger for suppressing too much INFO logging. To avoid too much logging information Worker will output logging at
      * INFO level for a single pass through the main loop every minute. At DEBUG level it will output all INFO logs on
@@ -1012,7 +1040,7 @@ public class Worker implements Runnable {
 
     /**
      * Given configuration, returns appropriate metrics factory.
-     * 
+     *
      * @param cloudWatchClient
      *            Amazon CloudWatch client
      * @param config
@@ -1039,7 +1067,7 @@ public class Worker implements Runnable {
 
     /**
      * Returns default executor service that should be used by the worker.
-     * 
+     *
      * @return Default executor service that should be used by the worker.
      */
     private static ExecutorService getExecutorService() {
@@ -1089,6 +1117,7 @@ public class Worker implements Runnable {
         private ExecutorService execService;
         private ShardPrioritization shardPrioritization;
         private IKinesisProxy kinesisProxy;
+        private WorkerStateChangeListener workerStateChangeListener;
 
         /**
          * Default constructor.
@@ -1209,10 +1238,10 @@ public class Worker implements Runnable {
 
         /**
          * Provides logic how to prioritize shard processing.
-         * 
+         *
          * @param shardPrioritization
          *            shardPrioritization is responsible to order shards before processing
-         * 
+         *
          * @return A reference to this updated object so that method calls can be chained together.
          */
         public Builder shardPrioritization(ShardPrioritization shardPrioritization) {
@@ -1233,6 +1262,17 @@ public class Worker implements Runnable {
             return this;
         }
 
+        /**
+         * Set WorkerStateChangeListener for the worker
+         * @param workerStateChangeListener
+         *             Sets the WorkerStateChangeListener
+         * @return A reference to this updated object so that method calls can be chained together.
+         */
+        public Builder workerStateChangeListener(WorkerStateChangeListener workerStateChangeListener) {
+            this.workerStateChangeListener = workerStateChangeListener;
+            return this;
+        }
+
         /**
          * Build the Worker instance.
          *
@@ -1305,6 +1345,10 @@ public class Worker implements Runnable {
                 kinesisProxy = new KinesisProxy(config, kinesisClient);
             }
 
+            if (workerStateChangeListener == null){
+                workerStateChangeListener = new NoOpWorkerStateChangeListener();
+            }
+
             return new Worker(config.getApplicationName(),
                     recordProcessorFactory,
                     config,
@@ -1336,9 +1380,8 @@ public class Worker implements Runnable {
                     config.getSkipShardSyncAtWorkerInitializationIfLeasesExist(),
                     shardPrioritization,
                     config.getRetryGetRecordsInSeconds(),
-                    config.getMaxGetRecordsThreadPool());
+                    config.getMaxGetRecordsThreadPool(),
-
+                    workerStateChangeListener);
         }
-
     }
 }

src/test/java/com/amazonaws/services/kinesis/clientlibrary/lib/worker/WorkerTest.java

@@ -142,7 +142,7 @@ public class WorkerTest {
 
     private static final String KINESIS_SHARD_ID_FORMAT = "kinesis-0-0-%d";
     private static final String CONCURRENCY_TOKEN_FORMAT = "testToken-%d";
-    
+
     private RecordsFetcherFactory recordsFetcherFactory;
     private KinesisClientLibConfiguration config;
 
@@ -170,7 +170,7 @@ public class WorkerTest {
     private Future<TaskResult> taskFuture;
     @Mock
     private TaskResult taskResult;
-    
+
     @Before
     public void setup() {
         config = spy(new KinesisClientLibConfiguration("app", null, null, null));
@@ -179,7 +179,7 @@ public class WorkerTest {
     }
 
     // CHECKSTYLE:IGNORE AnonInnerLengthCheck FOR NEXT 50 LINES
-    private static final com.amazonaws.services.kinesis.clientlibrary.interfaces.IRecordProcessorFactory SAMPLE_RECORD_PROCESSOR_FACTORY = 
+    private static final com.amazonaws.services.kinesis.clientlibrary.interfaces.IRecordProcessorFactory SAMPLE_RECORD_PROCESSOR_FACTORY =
             new com.amazonaws.services.kinesis.clientlibrary.interfaces.IRecordProcessorFactory() {
 
         @Override
@@ -212,8 +212,8 @@ public class WorkerTest {
             };
         }
     };
-    
+
-    private static final IRecordProcessorFactory SAMPLE_RECORD_PROCESSOR_FACTORY_V2 = 
+    private static final IRecordProcessorFactory SAMPLE_RECORD_PROCESSOR_FACTORY_V2 =
             new V1ToV2RecordProcessorFactoryAdapter(SAMPLE_RECORD_PROCESSOR_FACTORY);
 
 
@@ -619,7 +619,7 @@ public class WorkerTest {
                 return null;
             }
         }).when(v2RecordProcessor).processRecords(any(ProcessRecordsInput.class));
-        
+
         RecordsFetcherFactory recordsFetcherFactory = mock(RecordsFetcherFactory.class);
         GetRecordsCache getRecordsCache = mock(GetRecordsCache.class);
         when(config.getRecordsFetcherFactory()).thenReturn(recordsFetcherFactory);
@@ -659,7 +659,7 @@ public class WorkerTest {
      * This test is testing the {@link Worker}'s shutdown behavior and by extension the behavior of
      * {@link ThreadPoolExecutor#shutdownNow()}. It depends on the thread pool sending an interrupt to the pool threads.
      * This behavior makes the test a bit racy, since we need to ensure a specific order of events.
-     * 
+     *
      * @throws Exception
      */
     @Test
@@ -1356,7 +1356,7 @@ public class WorkerTest {
                 executorService,
                 metricsFactory,
                 taskBackoffTimeMillis,
-                failoverTimeMillis, 
+                failoverTimeMillis,
                 false,
                 shardPrioritization);
 
@@ -1432,7 +1432,7 @@ public class WorkerTest {
                 config,
                 streamConfig,
                 INITIAL_POSITION_TRIM_HORIZON,
-                parentShardPollIntervalMillis, 
+                parentShardPollIntervalMillis,
                 shardSyncIntervalMillis,
                 cleanupLeasesUponShardCompletion,
                 leaseCoordinator,
@@ -1500,6 +1500,16 @@ public class WorkerTest {
         Assert.assertTrue(worker.getStreamConfig().getStreamProxy() instanceof KinesisLocalFileProxy);
     }
 
+    @Test
+    public void testBuilderForWorkerStateListener() {
+        IRecordProcessorFactory recordProcessorFactory = mock(IRecordProcessorFactory.class);
+        Worker worker = new Worker.Builder()
+                .recordProcessorFactory(recordProcessorFactory)
+                .config(config)
+                .build();
+        Assert.assertTrue(worker.getWorkerStateChangeListener() instanceof NoOpWorkerStateChangeListener);
+    }
+
     @Test
     public void testBuilderWithDefaultLeaseManager()  {
         IRecordProcessorFactory recordProcessorFactory = mock(IRecordProcessorFactory.class);
@@ -1801,7 +1811,7 @@ public class WorkerTest {
         TestStreamletFactory recordProcessorFactory = new TestStreamletFactory(recordCounter, shardSequenceVerifier);
 
         ExecutorService executorService = Executors.newFixedThreadPool(threadPoolSize);
-        
+
         WorkerThread workerThread = runWorker(
                 shardList, initialLeases, callProcessRecordsForEmptyRecordList, failoverTimeMillis,
                 numberOfRecordsPerShard, fileBasedProxy, recordProcessorFactory, executorService, nullMetricsFactory, clientConfig);
@@ -1857,7 +1867,7 @@ public class WorkerTest {
                 idleTimeInMilliseconds,
                 callProcessRecordsForEmptyRecordList,
                 skipCheckpointValidationValue, InitialPositionInStreamExtended.newInitialPositionAtTimestamp(timestamp));
-        
+
         Worker worker =
                 new Worker(stageName,
                         recordProcessorFactory,
@@ -1874,7 +1884,7 @@ public class WorkerTest {
                         failoverTimeMillis,
                         KinesisClientLibConfiguration.DEFAULT_SKIP_SHARD_SYNC_AT_STARTUP_IF_LEASES_EXIST,
                         shardPrioritization);
-        
+
         WorkerThread workerThread = new WorkerThread(worker);
         workerThread.start();
         return workerThread;