Changed SocketThread and GPSEndpoint to reconnect if connectivity is

Tim Williscroft · Tim Williscroft · commit b719dac42bca · 2016-08-13T09:54:53.000+10:00
lost to the GPSd TCP socket.
diff --git a/src/main/java/de/taimos/gpsd4java/backend/GPSdEndpoint.java b/src/main/java/de/taimos/gpsd4java/backend/GPSdEndpoint.java
@@ -56,11 +56,11 @@ public class GPSdEndpoint {
 	
 	private static final Logger LOG = LoggerFactory.getLogger(GPSdEndpoint.class);
 	
-	private final Socket socket;
+	private Socket socket;
 	
-	private final BufferedReader in;
+	private BufferedReader in;
 	
-	private final BufferedWriter out;
+	private BufferedWriter out;
 	
 	private SocketThread listenThread;
 	
@@ -73,6 +73,12 @@ public class GPSdEndpoint {
 	private final Object asyncWaitMutex = new Object();
 	
 	private final AbstractResultParser resultParser;
+
+	private String server;
+
+	private int port;
+
+	private JSONObject watch;
 	
 	
 	/**
@@ -87,6 +93,8 @@ public class GPSdEndpoint {
 	 * @throws IOException
 	 */
 	public GPSdEndpoint(final String server, final int port, final AbstractResultParser resultParser) throws UnknownHostException, IOException {
+		this.server = server;
+		this.port = port;
 		if (server == null) {
 			throw new IllegalArgumentException("server can not be null!");
 		}
@@ -121,6 +129,7 @@ public void start() {
 	 * Stops the endpoint.
 	 */
 	public void stop() {
+		
 		try {
 			this.socket.close();
 		} catch (final IOException e1) {
@@ -169,7 +178,7 @@ public WatchObject watch(final boolean enable, final boolean dumpData) throws IO
 	 * @throws JSONException
 	 */
 	public WatchObject watch(final boolean enable, final boolean dumpData, final String device) throws IOException, JSONException {
-		final JSONObject watch = new JSONObject();
+		watch = new JSONObject();
 		watch.put("class", "WATCH");
 		watch.put("enable", enable);
 		watch.put("json", dumpData);
@@ -320,4 +329,23 @@ public void kickDevice(String path) throws IOException, JSONException {
 		d.put("path", path);
 		this.voidCommand("?DEVICE=" + d);
 	}
+
+	/**
+	 * Our socket thread got disconnect and is exiting.
+	 */
+	void handleDisconnected() throws IOException{
+		synchronized (this.asyncMutex) {
+			socket.close();
+			this.socket = new Socket(server, port);
+			this.in = new BufferedReader(new InputStreamReader(this.socket.getInputStream()));
+			this.out = new BufferedWriter(new OutputStreamWriter(this.socket.getOutputStream()));		
+			
+			this.listenThread = new SocketThread(this.in, this, this.resultParser);
+			this.listenThread.start();
+			if( watch!=null){
+					this.syncCommand("?WATCH=" + watch.toString(), WatchObject.class);					
+			}
+		}
+		
+	}
 }
diff --git a/src/main/java/de/taimos/gpsd4java/backend/SocketThread.java b/src/main/java/de/taimos/gpsd4java/backend/SocketThread.java
@@ -23,7 +23,6 @@
 import java.io.BufferedReader;
 import java.io.IOException;
 import java.net.SocketException;
-import java.util.concurrent.atomic.AtomicBoolean;
 
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -43,7 +42,7 @@ public class SocketThread extends Thread {
 	
 	private final AbstractResultParser resultParser;
 	
-	private final AtomicBoolean running = new AtomicBoolean(true);
+	private final WaitableBoolean running = new WaitableBoolean(true);
 	
 	
 	/**
@@ -86,11 +85,32 @@ public void run() {
 					this.endpoint.handle(this.resultParser.parse(s));
 				}
 			} catch (final SocketException e) {
-				// stop if socket fails
-				break;
+				break; // stop 
 			} catch (final Exception e) {
 				// TODO handle this better
 				SocketThread.LOG.warn("Problem encountered while reading/parsing/handling line", e);
+			} 
+		}
+		if( running.get() && !Thread.interrupted()){
+			SocketThread.LOG.warn("Problem encountered while reading/parsing/handling line, attempting restart");
+			retry();
+		}
+	}
+	
+	
+	protected void retry(){
+		SocketThread.LOG.debug("Disconnected from GPS socket, retrying connection");
+
+		while(this.running.get()){
+			try {
+				running.waitFor(1000);
+				this.endpoint.handleDisconnected();
+				SocketThread.LOG.debug("Reconnected to GPS socket");
+				running.set(false);
+			} catch (InterruptedException ix){
+				break;
+			} catch (IOException e) {
+				SocketThread.LOG.debug("Still disconnected from GPS socket, retrying connection again");
 			}
 		}
 	}
@@ -110,3 +130,27 @@ public void halt() throws InterruptedException {
 		this.join(1000);
 	}
 }
+/**
+ * Not as efficient as AtomicBoolean but you can wait on it.
+ * @author TimW
+ *
+ */
+class WaitableBoolean {
+	private boolean val;
+	
+	public WaitableBoolean(boolean b) {
+		val=b;
+	}
+
+	synchronized void set(boolean value){
+		this.val=value;
+		notifyAll();
+	}
+	
+	synchronized boolean get(){
+		return val;
+	}
+	synchronized public void waitFor(long millis) throws InterruptedException{
+		super.wait(millis);
+	}
+}
