Add shutdown hook before starting web server to be able to stop

HA-Bridge from the command line (using SIGTERM signal).

src/main/java/com/bwssystems/HABridge/HABridge.java

@@ -44,7 +44,8 @@ public class HABridge {
         Version theVersion;
     	@SuppressWarnings("unused")
 		HttpClientPool thePool;
-       
+		ShutdownHook shutdownHook = null;
+
         log.info("HA Bridge startup sequence...");
         theVersion = new Version();
         // Singleton initialization
@@ -68,6 +69,14 @@ public class HABridge {
 	        // setup system control api first
 	        theSystem = new SystemControl(bridgeSettings, theVersion);
 	        theSystem.setupServer();
+
+			// Add shutdown hook to be able to properly stop server
+			if (shutdownHook != null) {
+				Runtime.getRuntime().removeShutdownHook(shutdownHook);
+			}
+			shutdownHook = new ShutdownHook(bridgeSettings, theSystem);
+			Runtime.getRuntime().addShutdownHook(shutdownHook);
+
 	        // setup the UDP Datagram socket to be used by the HueMulator and the upnpListener
 	        udpSender = UDPDatagramSender.createUDPDatagramSender(bridgeSettings.getBridgeSettingsDescriptor().getUpnpResponsePort());
 	        if(udpSender == null) {

src/main/java/com/bwssystems/HABridge/ShutdownHook.java

@@ -0,0 +1,48 @@
+package com.bwssystems.HABridge;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * This class implements the shutdown hook used to properly stop server from the
+ * command line (sending SIGTERM), or while shutting down the host machine.
+ * 
+ * @author gaudryc
+ */
+public class ShutdownHook extends Thread {
+
+	private final BridgeSettings bridgeSettings;
+	private final SystemControl theSystem;
+
+	/**
+	 * Constructor
+	 * 
+	 * @param bridgeSettings
+	 *            bridge settings
+	 * @param theSystem 
+	 */
+	public ShutdownHook(final BridgeSettings bridgeSettings, final SystemControl theSystem) {
+		this.bridgeSettings = bridgeSettings;
+		this.theSystem = theSystem;
+	}
+
+	@Override
+	public void run() {
+		Logger log = LoggerFactory.getLogger(ShutdownHook.class);
+		log.info("Shutdown requested...");
+		if (bridgeSettings != null) {
+			if (!bridgeSettings.getBridgeControl().isStop() && (theSystem != null)) {
+				log.info("Forcing system stop...");
+				theSystem.stop();
+				try {
+					Thread.sleep(5000);
+				} catch (InterruptedException e) {
+					log.error("Sleep error: " + e.getMessage());
+				}
+			} else {
+				log.info("Already stopped");
+			}
+		}
+	}
+
+}