Ensure that calling closePort() from within a LISTENING_EVENT_PORT_DISCONNECTED callback works

Author: hedgecrw

src/main/java/com/fazecast/jSerialComm/SerialPort.java

@@ -729,9 +729,9 @@ public final boolean closePort()
 	 *    }
 	 *    {@literal @}Override
 	 *    public void serialEvent(SerialPortEvent serialPortEvent) {
-	 *       if (serialPortEvent.getEventType() == SerialPort.LISTENING_EVENT_PORT_DISCONNECTED)
+	 *       if ((serialPortEvent.getEventType() & SerialPort.LISTENING_EVENT_PORT_DISCONNECTED) > 0)
 	 *          port.closePort();
-	 *       else if (serialPortEvent.getEventType() == SerialPort.LISTENING_EVENT_DATA_RECEIVED)
+	 *       else if ((serialPortEvent.getEventType() & SerialPort.LISTENING_EVENT_DATA_RECEIVED) > 0)
 	 *          // ... you get the idea
 	 *    }
 	 * });
@@ -742,9 +742,12 @@ public final boolean closePort()
 	 * {@link SerialPort} object:
 	 * <pre>
 	 * if (!port.isOpen())
-	 *    port.open();
+	 *    port.openPort();
 	 * </pre>
 	 * <p>
+	 * Note that you <b>CANNOT</b> call <code>port.openPort()</code> from within the <code>serialEvent()</code>
+	 * handler. Port re-opening <b>must</b> be done within your own application context.
+	 * <p>
 	 * Note that once a USB serial port has been unplugged and reconnected, it's unlikely to work again until the
 	 * port's {@link #closePort()} and {@link openPort(int, int, int)} methods have both been called to
 	 * re-establish the connection.
@@ -1153,6 +1156,9 @@ private SerialPort(String port, String friendly, String description, String loca
 	 * <p>
 	 * Only one listener can be registered at a time; however, that listener can be used to detect multiple types of serial port events.
 	 * Refer to {@link SerialPortDataListener}, {@link SerialPortDataListenerWithExceptions}, {@link SerialPortPacketListener}, {@link SerialPortMessageListener}, and {@link SerialPortMessageListenerWithExceptions} for more information.
+	 * <p>
+	 * Note that if you register to listen for {@link SerialPort#LISTENING_EVENT_PORT_DISCONNECTED} events, you <b>CANNOT</b> call <code>openPort()</code> to re-open a disconnected port from within the <code>serialEvent()</code>
+	 * handler. Port re-opening <b>must</b> be done within your own application context.
 	 *
 	 * @param listener A {@link SerialPortDataListener}, {@link SerialPortDataListenerWithExceptions}, {@link SerialPortPacketListener}, {@link SerialPortMessageListener}, or {@link SerialPortMessageListenerWithExceptions} implementation to be used for event-based serial port communications.
 	 * @return Whether the listener was successfully registered with the serial port.
@@ -2207,9 +2213,17 @@ else if (dataPacket.length == 0)
 			}
 			if (eventListenerRunning && !isShuttingDown && (event != SerialPort.LISTENING_EVENT_TIMED_OUT))
 			{
-				userDataListener.serialEvent(new SerialPortEvent(SerialPort.this, event));
-				if (event == SerialPort.LISTENING_EVENT_PORT_DISCONNECTED)
+				// If disconnected, invoke the user data listener from a new thread to allow them to close the port without blocking
+				if ((event & SerialPort.LISTENING_EVENT_PORT_DISCONNECTED) > 0)
+				{
 					eventListenerRunning = false;
+					SerialPortThreadFactory.get().newThread(new Runnable() {
+						@Override
+						public void run() { userDataListener.serialEvent(new SerialPortEvent(SerialPort.this, SerialPort.LISTENING_EVENT_PORT_DISCONNECTED)); }
+					}).start();
+				}
+				else
+					userDataListener.serialEvent(new SerialPortEvent(SerialPort.this, event));
 			}
 		}
 	}

src/main/java/com/fazecast/jSerialComm/SerialPortDataListener.java

@@ -53,7 +53,8 @@ public interface SerialPortDataListener extends EventListener
 	 * &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;{@link SerialPort#LISTENING_EVENT_SOFTWARE_OVERRUN_ERROR}<br>
 	 * &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;{@link SerialPort#LISTENING_EVENT_PARITY_ERROR}<br>
 	 * <p>
-	 * Two or more events may be OR'd together to listen for multiple events; however, if {@link SerialPort#LISTENING_EVENT_DATA_AVAILABLE} is OR'd with {@link SerialPort#LISTENING_EVENT_DATA_RECEIVED}, the {@link SerialPort#LISTENING_EVENT_DATA_RECEIVED} flag will take precedence.
+	 * Two or more events may be OR'd together to listen for multiple events; however, if {@link SerialPort#LISTENING_EVENT_DATA_AVAILABLE} is OR'd with
+	 * {@link SerialPort#LISTENING_EVENT_DATA_RECEIVED}, the {@link SerialPort#LISTENING_EVENT_DATA_RECEIVED} flag will take precedence.
 	 * <p>
 	 * Note that event-based <i>write</i> callbacks are only supported on Windows operating systems. As such, the {@link SerialPort#LISTENING_EVENT_DATA_WRITTEN}
 	 * event will never be called on a non-Windows system.
@@ -83,7 +84,23 @@ public interface SerialPortDataListener extends EventListener
 	/**
 	 * Called whenever one or more of the serial port events specified by the {@link #getListeningEvents()} method occurs.
 	 * <p>
-	 * Note that your implementation of this function should always perform as little data processing as possible, as the speed at which this callback will fire is at the mercy of the underlying operating system. If you need to collect a large amount of data, application-level buffering should be implemented and data processing should occur on a separate thread.
+	 * Note that your implementation of this function should always perform as little data processing as possible,
+	 * as the speed at which this callback will fire is at the mercy of the underlying operating system. If you need to collect a large amount of data,
+	 * application-level buffering should be implemented and data processing should occur on a separate thread.
+	 * <p>
+	 * Also note that if you are listening for multiple types of events (for instance, {@link SerialPort#LISTENING_EVENT_DATA_AVAILABLE} and
+	 * {@link SerialPort#LISTENING_EVENT_PORT_DISCONNECTED}) at the same time, this callback <i>may<i> be invoked only once for multiple event
+	 * types. As such, you should test for your event of interest by bit-masking and not by testing for equivalence. The following code shows
+	 * the correct way to do this:
+	 * <pre>
+	 * {@literal @}Override
+	 * public void serialEvent(SerialPortEvent serialPortEvent) {
+	 *    if ((serialPortEvent.getEventType() & SerialPort.LISTENING_EVENT_PORT_DISCONNECTED) > 0)
+	 *       port.closePort();
+	 *    else if ((serialPortEvent.getEventType() & SerialPort.LISTENING_EVENT_DATA_AVAILABLE) > 0)
+	 *       // ... you get the idea
+	 * }
+	 * </pre>
 	 * 
 	 * @param event A {@link SerialPortEvent} object containing information and/or data about the serial events that occurred.
 	 * @see SerialPortEvent

src/test/java/com/fazecast/jSerialComm/SerialPortTest.java

@@ -280,7 +280,7 @@ public int getListeningEvents() { return SerialPort.LISTENING_EVENT_PARITY_ERROR
 			public void serialEvent(SerialPortEvent event)
 			{
 				System.out.println("Received event type: " + event.toString());
-				if (event.getEventType() == SerialPort.LISTENING_EVENT_DATA_AVAILABLE)
+				if ((event.getEventType() & SerialPort.LISTENING_EVENT_DATA_AVAILABLE) > 0)
 				{
 					byte[] buffer = new byte[event.getSerialPort().bytesAvailable()];
 					event.getSerialPort().readBytes(buffer, buffer.length);
@@ -302,20 +302,29 @@ public void serialEvent(SerialPortEvent event)
 		ubxPort.setComPortTimeouts(SerialPort.TIMEOUT_READ_BLOCKING, 0, 0);
 		ubxPort.addDataListener(new SerialPortDataListener() {
 			@Override
-			public int getListeningEvents() { return SerialPort.LISTENING_EVENT_DATA_AVAILABLE; }
+			public int getListeningEvents() { return SerialPort.LISTENING_EVENT_DATA_AVAILABLE | SerialPort.LISTENING_EVENT_PORT_DISCONNECTED; }
 			@Override
 			public void serialEvent(SerialPortEvent event)
 			{
 				SerialPort comPort = event.getSerialPort();
-				System.out.println("Available: " + comPort.bytesAvailable() + " bytes.");
-				byte[] newData = new byte[comPort.bytesAvailable()];
-				int numRead = comPort.readBytes(newData, newData.length);
-				System.out.println("Read " + numRead + " bytes.");
+				if ((event.getEventType() & SerialPort.LISTENING_EVENT_DATA_AVAILABLE) > 0)
+				{
+					System.out.println("Available: " + comPort.bytesAvailable() + " bytes.");
+					byte[] newData = new byte[comPort.bytesAvailable()];
+					int numRead = comPort.readBytes(newData, newData.length);
+					System.out.println("Read " + numRead + " bytes.");
+				}
+				else if ((event.getEventType() & SerialPort.LISTENING_EVENT_PORT_DISCONNECTED) > 0)
+				{
+					System.out.println("Serial port was physically disconnected!");
+					System.out.println("\nClosing from within event callback: " + comPort.closePort());
+				}
 			}
 		});
 		try { Thread.sleep(10000); } catch (Exception e) {}
 		ubxPort.removeDataListener();
-		System.out.println("\nClosing " + ubxPort.getDescriptivePortName() + ": " + ubxPort.closePort());
+		if (ubxPort.isOpen())
+			System.out.println("\nClosing " + ubxPort.getDescriptivePortName() + ": " + ubxPort.closePort());
 
 		/*System.out.println("\n\nAttempting to read from two serial ports simultaneously\n");
 		System.out.println("\nAvailable Ports:\n");