Made serial port's state volatile, added method for stopping modem.

briar-core/src/net/sf/briar/plugins/modem/Modem.java

@@ -13,7 +13,13 @@ interface Modem {
 	/**
 	 * Call this method after creating the modem and before making any calls.
 	 */
-	void init() throws IOException;
+	void start() throws IOException;
+
+	/**
+	 * Call this method when the modem is no longer needed. If a call is in
+	 * progress it will be terminated.
+	 */
+	void stop() throws IOException;
 
 	/**
 	 * Initiates an outgoing call and returns true if the call connects. If the

briar-core/src/net/sf/briar/plugins/modem/ModemImpl.java

@@ -51,7 +51,7 @@ class ModemImpl implements Modem, WriteHandler, SerialPortEventListener {
 		reliabilityLayer = new ReliabilityLayer(this);
 	}
 
-	public void init() throws IOException {
+	public void start() throws IOException {
 		if(LOG.isLoggable(INFO)) LOG.info("Initialising");
 		try {
 			if(!port.openPort())
@@ -90,6 +90,14 @@ class ModemImpl implements Modem, WriteHandler, SerialPortEventListener {
 			throw new IOException("Modem did not respond");
 	}
 
+	public void stop() throws IOException {
+		try {
+			port.closePort();
+		} catch(SerialPortException e) {
+			throw new IOException(e.toString());
+		}
+	}
+
 	public boolean dial(String number) throws IOException {
 		if(!offHook.tryAcquire()) {
 			if(LOG.isLoggable(INFO))
@@ -178,9 +186,8 @@ class ModemImpl implements Modem, WriteHandler, SerialPortEventListener {
 				if(LOG.isLoggable(INFO)) LOG.info("Modem status: " + s);
 				if(s.startsWith("CONNECT")) {
 					synchronized(connected) {
-						if(connected.getAndSet(true))
+						if(!connected.getAndSet(true))
-							throw new IOException("Connected twice");
+							connected.notifyAll();
-						connected.notifyAll();
 					}
 					// There might be data in the buffer as well as text
 					int off = i + 1;
@@ -190,6 +197,10 @@ class ModemImpl implements Modem, WriteHandler, SerialPortEventListener {
 						reliabilityLayer.handleRead(data);
 					}
 					return;
+				} else if(s.equals("BUSY") || s.equals("NO DIALTONE")) {
+					synchronized(connected) {
+						connected.notifyAll();
+					}
 				} else if(s.equals("OK")) {
 					synchronized(initialised) {
 						if(!initialised.getAndSet(true))

briar-core/src/net/sf/briar/plugins/modem/ModemPlugin.java

@@ -72,7 +72,7 @@ class ModemPlugin implements DuplexPlugin, Modem.Callback {
 				LOG.info("Trying to initialise modem on " + portName);
 			modem = modemFactory.createModem(this, portName);
 			try {
-				modem.init();
+				modem.start();
 				if(LOG.isLoggable(INFO))
 					LOG.info("Initialised modem on " + portName);
 				running = true;
@@ -86,6 +86,13 @@ class ModemPlugin implements DuplexPlugin, Modem.Callback {
 
 	public void stop() {
 		running = false;
+		if(modem != null) {
+			try {
+				modem.stop();
+			} catch(IOException e) {
+				if(LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
+			}
+		}
 	}
 
 	private boolean resetModem() {
@@ -93,7 +100,7 @@ class ModemPlugin implements DuplexPlugin, Modem.Callback {
 		for(String portName : SerialPortList.getPortNames()) {
 			modem = modemFactory.createModem(this, portName);
 			try {
-				modem.init();
+				modem.start();
 				if(LOG.isLoggable(INFO))
 					LOG.info("Initialised modem on " + portName);
 				return true;