Fix library cleanup by making the Telemetry TimerTask a daemon and ma…

…king the StatsDProcessor use daemon threads in its executor (DataDog#117)

src/main/java/com/timgroup/statsd/StatsDNonBlockingProcessor.java

@@ -125,10 +125,6 @@ protected boolean send(final Message message) {
         return false;
     }
 
-    boolean isShutdown() {
-        return shutdown;
-    }
-
     void shutdown() {
         shutdown = true;
     }

src/main/java/com/timgroup/statsd/StatsDProcessor.java

@@ -19,6 +19,7 @@
 import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Executors;
+import java.util.concurrent.ThreadFactory;
 import java.util.concurrent.atomic.AtomicInteger;
 
 public abstract class StatsDProcessor implements Runnable {
@@ -73,7 +74,17 @@ protected void writeBuilderToSendBuffer(ByteBuffer sendBuffer) {
         this.workers = workers;
         this.qcapacity = queueSize;
 
-        this.executor = Executors.newFixedThreadPool(workers);
+        this.executor = Executors.newFixedThreadPool(workers, new ThreadFactory() {
+            final ThreadFactory delegate = Executors.defaultThreadFactory();
+            @Override
+            public Thread newThread(final Runnable runnable) {
+                final Thread result = delegate.newThread(runnable);
+                result.setName("StatsD-Processor-" + result.getName());
+                result.setDaemon(true);
+                return result;
+            }
+        });
+
         this.bufferPool = new BufferPool(poolSize, maxPacketSizeBytes, true);
         this.outboundQueue = new ArrayBlockingQueue<ByteBuffer>(poolSize);
         this.endSignal = new CountDownLatch(workers);
@@ -86,7 +97,16 @@ protected void writeBuilderToSendBuffer(ByteBuffer sendBuffer) {
         this.workers = processor.workers;
         this.qcapacity = processor.getQcapacity();
 
-        this.executor = Executors.newFixedThreadPool(this.workers);
+        this.executor = Executors.newFixedThreadPool(workers, new ThreadFactory() {
+            final ThreadFactory delegate = Executors.defaultThreadFactory();
+            @Override
+            public Thread newThread(final Runnable runnable) {
+                final Thread result = delegate.newThread(runnable);
+                result.setName("StatsD-Processor-" + result.getName());
+                result.setDaemon(true);
+                return result;
+            }
+        });
         this.bufferPool = new BufferPool(processor.bufferPool);
         this.outboundQueue = new ArrayBlockingQueue<ByteBuffer>(this.bufferPool.getSize());
         this.endSignal = new CountDownLatch(this.workers);
@@ -127,6 +147,7 @@ public void run() {
     }
 
     boolean isShutdown() {
+        executor.shutdown();
         return shutdown;
     }
 

src/main/java/com/timgroup/statsd/Telemetry.java

@@ -85,7 +85,7 @@ public final void writeTo(StringBuilder builder) {
      */
     public void start(final long flushInterval) {
         // flush the telemetry at regualar interval
-        this.timer = new Timer();
+        this.timer = new Timer(true);
         this.timer.scheduleAtFixedRate(new TelemetryTask(this), flushInterval, flushInterval);
     }