improve setParameter() error handling

harmonize exception messages, more UI friendly messages
distinguish IllegalArgumentException and UnsupportedOperationException

usbSerialForAndroid/src/androidTest/java/com/hoho/android/usbserial/DeviceTest.java

@@ -553,33 +553,12 @@ public class DeviceTest implements SerialInputOutputManager.Listener {
         // invalid values
         try {
             usbParameters(-1, 8, 1, UsbSerialPort.PARITY_NONE);
-            if (usbSerialDriver instanceof Ch34xSerialDriver)
+            fail("invalid baud rate");
-                ; // todo: add range check in driver
-            else if (usbSerialDriver instanceof FtdiSerialDriver)
-                ; // todo: add range check in driver
-            else if (usbSerialDriver instanceof ProlificSerialDriver)
-                ; // todo: add range check in driver
-            else if (usbSerialDriver instanceof Cp21xxSerialDriver)
-                ; // todo: add range check in driver
-            else if (usbSerialDriver instanceof CdcAcmSerialDriver)
-                ; // todo: add range check in driver
-            else
-                fail("invalid baudrate 0");
-        } catch (IOException ignored) { // cp2105 second port
         } catch (IllegalArgumentException ignored) {
         }
         try {
             usbParameters(0, 8, 1, UsbSerialPort.PARITY_NONE);
-            if (usbSerialDriver instanceof ProlificSerialDriver)
+            fail("invalid baud rate");
-                ; // todo: add range check in driver
-            else if (usbSerialDriver instanceof Cp21xxSerialDriver)
-                ; // todo: add range check in driver
-            else if (usbSerialDriver instanceof CdcAcmSerialDriver)
-                ; // todo: add range check in driver
-            else
-                fail("invalid baudrate 0");
-        } catch (ArithmeticException ignored) { // ch340
-        } catch (IOException ignored) { // cp2105 second port
         } catch (IllegalArgumentException ignored) {
         }
         try {
@@ -593,8 +572,9 @@ public class DeviceTest implements SerialInputOutputManager.Listener {
             else if (usbSerialDriver instanceof CdcAcmSerialDriver)
                 ;
             else
-                fail("invalid baudrate 0");
+                fail("invalid baudrate 1");
-        } catch (IOException ignored) { // ch340
+        } catch (UnsupportedOperationException ignored) { // ch340
+        } catch (IOException ignored) { // cp2105 second port
         } catch (IllegalArgumentException ignored) {
         }
         try {
@@ -679,12 +659,7 @@ public class DeviceTest implements SerialInputOutputManager.Listener {
         for(int i: new int[] {0, 4, 9}) {
             try {
                 usbParameters(19200, i, 1, UsbSerialPort.PARITY_NONE);
-                if (usbSerialDriver instanceof ProlificSerialDriver)
+                fail("invalid databits "+i);
-                    ; // todo: add range check in driver
-                else if (usbSerialDriver instanceof CdcAcmSerialDriver)
-                    ; // todo: add range check in driver
-                else
-                    fail("invalid databits "+i);
             } catch (IllegalArgumentException ignored) {
             }
         }
@@ -721,7 +696,7 @@ public class DeviceTest implements SerialInputOutputManager.Listener {
             usbWrite(new byte[]{(byte) 0xff});
             data = telnetRead(2);
             assertThat("19000/7N1", data, equalTo(new byte[]{(byte) 0x80, (byte) 0xff}));
-        } catch (IllegalArgumentException e) {
+        } catch (UnsupportedOperationException e) {
                 if(!isCp21xxRestrictedPort)
                     throw e;
         }
@@ -732,7 +707,7 @@ public class DeviceTest implements SerialInputOutputManager.Listener {
             usbWrite(new byte[]{(byte) 0xff});
             data = telnetRead(2);
             assertThat("19000/6N1", data, equalTo(new byte[]{(byte) 0xc0, (byte) 0xff}));
-        } catch (IllegalArgumentException e) {
+        } catch (UnsupportedOperationException e) {
             if (!(isCp21xxRestrictedPort || usbSerialDriver instanceof FtdiSerialDriver))
                 throw e;
         }
@@ -743,7 +718,7 @@ public class DeviceTest implements SerialInputOutputManager.Listener {
             usbWrite(new byte[] {(byte)0xff});
             data = telnetRead(2);
             assertThat("19000/5N1", data, equalTo(new byte[] {(byte)0xe0, (byte)0xff}));
-        } catch (IllegalArgumentException e) {
+        } catch (UnsupportedOperationException e) {
             if (!(isCp21xxRestrictedPort || usbSerialDriver instanceof FtdiSerialDriver))
                 throw e;
         }
@@ -774,11 +749,11 @@ public class DeviceTest implements SerialInputOutputManager.Listener {
             try {
                 usbParameters(19200, 8, 1, UsbSerialPort.PARITY_MARK);
                 fail("parity mark");
-            } catch (IllegalArgumentException ignored) {}
+            } catch (UnsupportedOperationException ignored) {}
             try {
                 usbParameters(19200, 8, 1, UsbSerialPort.PARITY_SPACE);
                 fail("parity space");
-            } catch (IllegalArgumentException ignored) {}
+            } catch (UnsupportedOperationException ignored) {}
             return;
             // test below not possible as it requires unsupported 7 dataBits
         }
@@ -894,7 +869,7 @@ public class DeviceTest implements SerialInputOutputManager.Listener {
                 usbWrite(new byte[]{(byte) 0x41, (byte) 0xf9});
                 data = telnetRead(2);
                 assertThat("19200/8N1", data, equalTo(new byte[]{1, 11}));
-            } catch(IllegalArgumentException e) {
+            } catch(UnsupportedOperationException e) {
                 if(!isCp21xxRestrictedPort)
                     throw e;
             }
@@ -902,7 +877,7 @@ public class DeviceTest implements SerialInputOutputManager.Listener {
                 usbParameters(19200, 8, UsbSerialPort.STOPBITS_1_5, UsbSerialPort.PARITY_NONE);
                 // todo: could create similar test for 1.5 stopbits, by reading at double speed
                 //       but only some devices support 1.5 stopbits and it is basically not used any more
-            } catch(IllegalArgumentException ignored) {
+            } catch(UnsupportedOperationException ignored) {
             }
         }
     }

usbSerialForAndroid/src/main/java/com/hoho/android/usbserial/driver/CdcAcmSerialDriver.java

@@ -134,14 +134,14 @@ public class CdcAcmSerialDriver implements UsbSerialDriver {
             Log.d(TAG, "data iface=" + mDataInterface);
 
             if (!mConnection.claimInterface(mControlInterface, true)) {
-                throw new IOException("Could not claim shared control/data interface.");
+                throw new IOException("Could not claim shared control/data interface");
             }
 
             int endCount = mControlInterface.getEndpointCount();
 
             if (endCount < 3) {
                 Log.d(TAG,"not enough endpoints - need 3. count=" + mControlInterface.getEndpointCount());
-                throw new IOException("Insufficient number of endpoints(" + mControlInterface.getEndpointCount() + ")");
+                throw new IOException("Insufficient number of endpoints (" + mControlInterface.getEndpointCount() + ")");
             }
 
             // Analyse endpoints for their properties
@@ -198,26 +198,26 @@ public class CdcAcmSerialDriver implements UsbSerialDriver {
             }
 
             if(mControlInterface == null) {
-                throw new IOException("no control interface.");
+                throw new IOException("No control interface");
             }
             Log.d(TAG, "Control iface=" + mControlInterface);
 
             if (!mConnection.claimInterface(mControlInterface, true)) {
-                throw new IOException("Could not claim control interface.");
+                throw new IOException("Could not claim control interface");
             }
 
             mControlEndpoint = mControlInterface.getEndpoint(0);
             if (mControlEndpoint.getDirection() != UsbConstants.USB_DIR_IN || mControlEndpoint.getType() != UsbConstants.USB_ENDPOINT_XFER_INT) {
-                throw new IOException("invalid control endpoint");
+                throw new IOException("Invalid control endpoint");
             }
 
             if(mDataInterface == null) {
-                throw new IOException("no data interface.");
+                throw new IOException("No data interface");
             }
             Log.d(TAG, "data iface=" + mDataInterface);
 
             if (!mConnection.claimInterface(mDataInterface, true)) {
-                throw new IOException("Could not claim data interface.");
+                throw new IOException("Could not claim data interface");
             }
 
             mReadEndpoint = null;
@@ -230,7 +230,7 @@ public class CdcAcmSerialDriver implements UsbSerialDriver {
                     mWriteEndpoint = ep;
             }
             if (mReadEndpoint == null || mWriteEndpoint == null) {
-                throw new IOException("Could not get read&write endpoints.");
+                throw new IOException("Could not get read&write endpoints");
             }
         }
 
@@ -238,7 +238,7 @@ public class CdcAcmSerialDriver implements UsbSerialDriver {
             int len = mConnection.controlTransfer(
                     USB_RT_ACM, request, value, mControlIndex, buf, buf != null ? buf.length : 0, 5000);
             if(len < 0) {
-                throw new IOException("controlTransfer failed.");
+                throw new IOException("controlTransfer failed");
             }
             return len;
         }
@@ -276,7 +276,7 @@ public class CdcAcmSerialDriver implements UsbSerialDriver {
                 request.initialize(mConnection, mReadEndpoint);
                 final ByteBuffer buf = ByteBuffer.wrap(dest);
                 if (!request.queue(buf, dest.length)) {
-                    throw new IOException("Error queueing request.");
+                    throw new IOException("Error queueing request");
                 }
                 mUsbRequest = request;
                 final UsbRequest response = mConnection.requestWait();
@@ -340,12 +340,18 @@ public class CdcAcmSerialDriver implements UsbSerialDriver {
 
         @Override
         public void setParameters(int baudRate, int dataBits, int stopBits, int parity) throws IOException {
+            if(baudRate <= 0) {
+                throw new IllegalArgumentException("Invalid baud rate: " + baudRate);
+            }
+            if(dataBits < DATABITS_5 || dataBits > DATABITS_8) {
+                throw new IllegalArgumentException("Invalid data bits: " + dataBits);
+            }
             byte stopBitsByte;
             switch (stopBits) {
                 case STOPBITS_1: stopBitsByte = 0; break;
                 case STOPBITS_1_5: stopBitsByte = 1; break;
                 case STOPBITS_2: stopBitsByte = 2; break;
-                default: throw new IllegalArgumentException("Bad value for stopBits: " + stopBits);
+                default: throw new IllegalArgumentException("Invalid stop bits: " + stopBits);
             }
 
             byte parityBitesByte;
@@ -355,9 +361,8 @@ public class CdcAcmSerialDriver implements UsbSerialDriver {
                 case PARITY_EVEN: parityBitesByte = 2; break;
                 case PARITY_MARK: parityBitesByte = 3; break;
                 case PARITY_SPACE: parityBitesByte = 4; break;
-                default: throw new IllegalArgumentException("Bad value for parity: " + parity);
+                default: throw new IllegalArgumentException("Invalid parity: " + parity);
             }
-
             byte[] msg = {
                     (byte) ( baudRate & 0xff),
                     (byte) ((baudRate >> 8 ) & 0xff),

usbSerialForAndroid/src/main/java/com/hoho/android/usbserial/driver/Ch34xSerialDriver.java

@@ -99,7 +99,7 @@ public class Ch34xSerialDriver implements UsbSerialDriver {
 		@Override
 		public void open(UsbDeviceConnection connection) throws IOException {
 			if (mConnection != null) {
-				throw new IOException("Already opened.");
+				throw new IOException("Already open");
 			}
 
 			mConnection = connection;
@@ -108,7 +108,7 @@ public class Ch34xSerialDriver implements UsbSerialDriver {
 				for (int i = 0; i < mDevice.getInterfaceCount(); i++) {
 					UsbInterface usbIface = mDevice.getInterface(i);
 					if (!mConnection.claimInterface(usbIface, true)) {
-						throw new IOException("Could not claim data interface.");
+						throw new IOException("Could not claim data interface");
 					}
 				}
 
@@ -166,7 +166,7 @@ public class Ch34xSerialDriver implements UsbSerialDriver {
 				request.initialize(mConnection, mReadEndpoint);
 				final ByteBuffer buf = ByteBuffer.wrap(dest);
 				if (!request.queue(buf, dest.length)) {
-					throw new IOException("Error queueing request.");
+					throw new IOException("Error queueing request");
 				}
 				mUsbRequest = request;
 				final UsbRequest response = mConnection.requestWait();
@@ -275,7 +275,7 @@ public class Ch34xSerialDriver implements UsbSerialDriver {
 			checkState("init #1", 0x5f, 0, new int[]{-1 /* 0x27, 0x30 */, 0x00});
 
 			if (controlOut(0xa1, 0, 0) < 0) {
-				throw new IOException("init failed! #2");
+				throw new IOException("Init failed: #2");
 			}
 
 			setBaudRate(DEFAULT_BAUD_RATE);
@@ -283,13 +283,13 @@ public class Ch34xSerialDriver implements UsbSerialDriver {
 			checkState("init #4", 0x95, 0x2518, new int[]{-1 /* 0x56, c3*/, 0x00});
 
 			if (controlOut(0x9a, 0x2518, LCR_ENABLE_RX | LCR_ENABLE_TX | LCR_CS8) < 0) {
-				throw new IOException("init failed! #5");
+				throw new IOException("Init failed: #5");
 			}
 
 			checkState("init #6", 0x95, 0x0706, new int[]{0xff, 0xee});
 
 			if (controlOut(0xa1, 0x501f, 0xd90a) < 0) {
-				throw new IOException("init failed! #7");
+				throw new IOException("Init failed: #7");
 			}
 
 			setBaudRate(DEFAULT_BAUD_RATE);
@@ -313,25 +313,27 @@ public class Ch34xSerialDriver implements UsbSerialDriver {
 					}
 
 			if (factor > 0xfff0) {
-				throw new IOException("Baudrate " + baudRate + " not supported");
+				throw new UnsupportedOperationException("Unsupported baud rate: " + baudRate);
 			}
 
 			factor = 0x10000 - factor;
 
 			int ret = controlOut(0x9a, 0x1312, (int) ((factor & 0xff00) | divisor));
 			if (ret < 0) {
-				throw new IOException("Error setting baud rate. #1)");
+				throw new IOException("Error setting baud rate: #1)");
 			}
 
 			ret = controlOut(0x9a, 0x0f2c, (int) (factor & 0xff));
 			if (ret < 0) {
-				throw new IOException("Error setting baud rate. #2");
+				throw new IOException("Error setting baud rate: #2");
 			}
 		}
 
 		@Override
-		public void setParameters(int baudRate, int dataBits, int stopBits, int parity)
+		public void setParameters(int baudRate, int dataBits, int stopBits, int parity) throws IOException {
-				throws IOException {
+			if(baudRate <= 0) {
+				throw new IllegalArgumentException("Invalid baud rate: " + baudRate);
+			}
 			setBaudRate(baudRate);
 
 			int lcr = LCR_ENABLE_RX | LCR_ENABLE_TX;
@@ -350,7 +352,7 @@ public class Ch34xSerialDriver implements UsbSerialDriver {
 					lcr |= LCR_CS8;
 					break;
 				default:
-					throw new IllegalArgumentException("Unknown dataBits value: " + dataBits);
+					throw new IllegalArgumentException("Invalid data bits: " + dataBits);
 			}
 
 			switch (parity) {
@@ -369,19 +371,19 @@ public class Ch34xSerialDriver implements UsbSerialDriver {
 					lcr |= LCR_ENABLE_PAR | LCR_MARK_SPACE | LCR_PAR_EVEN;
 					break;
 				default:
-					throw new IllegalArgumentException("Unknown parity value: " + parity);
+					throw new IllegalArgumentException("Invalid parity: " + parity);
 			}
 
 			switch (stopBits) {
 				case STOPBITS_1:
 					break;
 				case STOPBITS_1_5:
-					throw new IllegalArgumentException("Unsupported stopBits value: 1.5");
+					throw new UnsupportedOperationException("Unsupported stop bits: 1.5");
 				case STOPBITS_2:
 					lcr |= LCR_STOP_BITS_2;
 					break;
 				default:
-					throw new IllegalArgumentException("Unknown stopBits value: " + stopBits);
+					throw new IllegalArgumentException("Invalid stop bits: " + stopBits);
 			}
 
 			int ret = controlOut(0x9a, 0x2518, lcr);

usbSerialForAndroid/src/main/java/com/hoho/android/usbserial/driver/CommonUsbSerialPort.java

@@ -132,8 +132,7 @@ abstract class CommonUsbSerialPort implements UsbSerialPort {
     public abstract int write(final byte[] src, final int timeoutMillis) throws IOException;
 
     @Override
-    public abstract void setParameters(
+    public abstract void setParameters(int baudRate, int dataBits, int stopBits, int parity) throws IOException;
-            int baudRate, int dataBits, int stopBits, int parity) throws IOException;
 
     @Override
     public abstract boolean getCD() throws IOException;

usbSerialForAndroid/src/main/java/com/hoho/android/usbserial/driver/Cp21xxSerialDriver.java

@@ -135,7 +135,7 @@ public class Cp21xxSerialDriver implements UsbSerialDriver {
         @Override
         public void open(UsbDeviceConnection connection) throws IOException {
             if (mConnection != null) {
-                throw new IOException("Already opened.");
+                throw new IOException("Already open");
             }
 
             mConnection = connection;
@@ -205,7 +205,7 @@ public class Cp21xxSerialDriver implements UsbSerialDriver {
                 request.initialize(mConnection, mReadEndpoint);
                 final ByteBuffer buf = ByteBuffer.wrap(dest);
                 if (!request.queue(buf, dest.length)) {
-                    throw new IOException("Error queueing request.");
+                    throw new IOException("Error queueing request");
                 }
                 mUsbRequest = request;
                 final UsbRequest response = mConnection.requestWait();
@@ -276,37 +276,39 @@ public class Cp21xxSerialDriver implements UsbSerialDriver {
             int ret = mConnection.controlTransfer(REQTYPE_HOST_TO_DEVICE, SILABSER_SET_BAUDRATE,
                     0, mPortNumber, data, 4, USB_WRITE_TIMEOUT_MILLIS);
             if (ret < 0) {
-                throw new IOException("Error setting baud rate.");
+                throw new IOException("Error setting baud rate");
             }
         }
 
         @Override
-        public void setParameters(int baudRate, int dataBits, int stopBits, int parity)
+        public void setParameters(int baudRate, int dataBits, int stopBits, int parity) throws IOException {
-                throws IOException {
+            if(baudRate <= 0) {
+                throw new IllegalArgumentException("Invalid baud rate: " + baudRate);
+            }
             setBaudRate(baudRate);
 
             int configDataBits = 0;
             switch (dataBits) {
                 case DATABITS_5:
                     if(mIsRestrictedPort)
-                        throw new IllegalArgumentException("Unsupported dataBits value: " + dataBits);
+                        throw new UnsupportedOperationException("Unsupported data bits: " + dataBits);
                     configDataBits |= 0x0500;
                     break;
                 case DATABITS_6:
                     if(mIsRestrictedPort)
-                        throw new IllegalArgumentException("Unsupported dataBits value: " + dataBits);
+                        throw new UnsupportedOperationException("Unsupported data bits: " + dataBits);
                     configDataBits |= 0x0600;
                     break;
                 case DATABITS_7:
                     if(mIsRestrictedPort)
-                        throw new IllegalArgumentException("Unsupported dataBits value: " + dataBits);
+                        throw new UnsupportedOperationException("Unsupported data bits: " + dataBits);
                     configDataBits |= 0x0700;
                     break;
                 case DATABITS_8:
                     configDataBits |= 0x0800;
                     break;
                 default:
-                    throw new IllegalArgumentException("Unknown dataBits value: " + dataBits);
+                    throw new IllegalArgumentException("Invalid data bits: " + dataBits);
             }
             
             switch (parity) {
@@ -320,30 +322,30 @@ public class Cp21xxSerialDriver implements UsbSerialDriver {
                     break;
                 case PARITY_MARK:
                     if(mIsRestrictedPort)
-                        throw new IllegalArgumentException("Unsupported parity value: mark");
+                        throw new UnsupportedOperationException("Unsupported parity: mark");
                     configDataBits |= 0x0030;
                     break;
                 case PARITY_SPACE:
                     if(mIsRestrictedPort)
-                        throw new IllegalArgumentException("Unsupported parity value: space");
+                        throw new UnsupportedOperationException("Unsupported parity: space");
                     configDataBits |= 0x0040;
                     break;
                 default:
-                    throw new IllegalArgumentException("Unknown parity value: " + parity);
+                    throw new IllegalArgumentException("Invalid parity: " + parity);
             }
             
             switch (stopBits) {
                 case STOPBITS_1:
                     break;
                 case STOPBITS_1_5:
-                    throw new IllegalArgumentException("Unsupported stopBits value: 1.5");
+                    throw new UnsupportedOperationException("Unsupported stop bits: 1.5");
                 case STOPBITS_2:
                     if(mIsRestrictedPort)
-                        throw new IllegalArgumentException("Unsupported stopBits value: 2");
+                        throw new UnsupportedOperationException("Unsupported stop bits: 2");
                     configDataBits |= 2;
                     break;
                 default:
-                    throw new IllegalArgumentException("Unknown stopBits value: " + stopBits);
+                    throw new IllegalArgumentException("Invalid stop bits: " + stopBits);
             }
             setConfigSingle(SILABSER_SET_LINE_CTL_REQUEST_CODE, configDataBits);
         }

usbSerialForAndroid/src/main/java/com/hoho/android/usbserial/driver/FtdiSerialDriver.java

@@ -287,7 +287,7 @@ public class FtdiSerialDriver implements UsbSerialDriver {
             try {
                 request.initialize(mConnection, endpoint);
                 if (!request.queue(buf, dest.length)) {
-                    throw new IOException("Error queueing request.");
+                    throw new IOException("Error queueing request");
                 }
 
                 final UsbRequest response = mConnection.requestWait();
@@ -360,21 +360,23 @@ public class FtdiSerialDriver implements UsbSerialDriver {
         }
 
         @Override
-        public void setParameters(int baudRate, int dataBits, int stopBits, int parity)
+        public void setParameters(int baudRate, int dataBits, int stopBits, int parity) throws IOException {
-                throws IOException {
+            if(baudRate <= 0) {
+                throw new IllegalArgumentException("Invalid baud rate: " + baudRate);
+            }
             setBaudRate(baudRate);
 
             int config = 0;
             switch (dataBits) {
                 case DATABITS_5:
                 case DATABITS_6:
-                    throw new IllegalArgumentException("Unsupported dataBits value: " + dataBits);
+                    throw new UnsupportedOperationException("Unsupported data bits: " + dataBits);
                 case DATABITS_7:
                 case DATABITS_8:
                     config |= dataBits;
                     break;
                 default:
-                    throw new IllegalArgumentException("Unknown dataBits value: " + dataBits);
+                    throw new IllegalArgumentException("Invalid data bits: " + dataBits);
             }
 
             switch (parity) {
@@ -394,7 +396,7 @@ public class FtdiSerialDriver implements UsbSerialDriver {
                     config |= (0x04 << 8);
                     break;
                 default:
-                    throw new IllegalArgumentException("Unknown parity value: " + parity);
+                    throw new IllegalArgumentException("Invalid parity: " + parity);
             }
 
             switch (stopBits) {
@@ -402,12 +404,12 @@ public class FtdiSerialDriver implements UsbSerialDriver {
                     config |= (0x00 << 11);
                     break;
                 case STOPBITS_1_5:
-                    throw new IllegalArgumentException("Unsupported stopBits value: 1.5");
+                    throw new UnsupportedOperationException("Unsupported stop bits: 1.5");
                 case STOPBITS_2:
                     config |= (0x02 << 11);
                     break;
                 default:
-                    throw new IllegalArgumentException("Unknown stopBits value: " + stopBits);
+                    throw new IllegalArgumentException("Invalid stop bits: " + stopBits);
             }
 
             int result = mConnection.controlTransfer(FTDI_DEVICE_OUT_REQTYPE,

usbSerialForAndroid/src/main/java/com/hoho/android/usbserial/driver/ProlificSerialDriver.java

@@ -380,7 +380,7 @@ public class ProlificSerialDriver implements UsbSerialDriver {
                 request.initialize(mConnection, mReadEndpoint);
                 final ByteBuffer buf = ByteBuffer.wrap(dest);
                 if (!request.queue(buf, dest.length)) {
-                    throw new IOException("Error queueing request.");
+                    throw new IOException("Error queueing request");
                 }
 
                 final UsbRequest response = mConnection.requestWait();
@@ -439,8 +439,7 @@ public class ProlificSerialDriver implements UsbSerialDriver {
         }
 
         @Override
-        public void setParameters(int baudRate, int dataBits, int stopBits,
+        public void setParameters(int baudRate, int dataBits, int stopBits, int parity) throws IOException {
-                int parity) throws IOException {
             if ((mBaudRate == baudRate) && (mDataBits == dataBits)
                     && (mStopBits == stopBits) && (mParity == parity)) {
                 // Make sure no action is performed if there is nothing to change
@@ -449,6 +448,9 @@ public class ProlificSerialDriver implements UsbSerialDriver {
 
             byte[] lineRequestData = new byte[7];
 
+            if(baudRate <= 0) {
+                throw new IllegalArgumentException("Invalid baud rate: " + baudRate);
+            }
             lineRequestData[0] = (byte) (baudRate & 0xff);
             lineRequestData[1] = (byte) ((baudRate >> 8) & 0xff);
             lineRequestData[2] = (byte) ((baudRate >> 16) & 0xff);
@@ -458,44 +460,39 @@ public class ProlificSerialDriver implements UsbSerialDriver {
             case STOPBITS_1:
                 lineRequestData[4] = 0;
                 break;
-
             case STOPBITS_1_5:
                 lineRequestData[4] = 1;
                 break;
-
             case STOPBITS_2:
                 lineRequestData[4] = 2;
                 break;
-
             default:
-                throw new IllegalArgumentException("Unknown stopBits value: " + stopBits);
+                throw new IllegalArgumentException("Invalid stop bits: " + stopBits);
             }
 
             switch (parity) {
             case PARITY_NONE:
                 lineRequestData[5] = 0;
                 break;
-
             case PARITY_ODD:
                 lineRequestData[5] = 1;
                 break;
-            
             case PARITY_EVEN:
                 lineRequestData[5] = 2;
                 break;
-
             case PARITY_MARK:
                 lineRequestData[5] = 3;
                 break;
-
             case PARITY_SPACE:
                 lineRequestData[5] = 4;
                 break;
-
             default:
-                throw new IllegalArgumentException("Unknown parity value: " + parity);
+                throw new IllegalArgumentException("Invalid parity: " + parity);
             }
 
+            if(dataBits < DATABITS_5 || dataBits > DATABITS_8) {
+                throw new IllegalArgumentException("Invalid data bits: " + dataBits);
+            }
             lineRequestData[6] = (byte) dataBits;
 
             ctrlOut(SET_LINE_REQUEST, 0, 0, lineRequestData);

usbSerialForAndroid/src/main/java/com/hoho/android/usbserial/driver/UsbId.java

@@ -76,7 +76,7 @@ public final class UsbId {
     public static final int ARM_MBED = 0x0204;
 
     private UsbId() {
-        throw new IllegalAccessError("Non-instantiable class.");
+        throw new IllegalAccessError("Non-instantiable class");
     }
 
 }

usbSerialForAndroid/src/main/java/com/hoho/android/usbserial/driver/UsbSerialPort.java

@@ -145,9 +145,9 @@ public interface UsbSerialPort {
      *            {@link #PARITY_EVEN}, {@link #PARITY_MARK}, or
      *            {@link #PARITY_SPACE}.
      * @throws IOException on error setting the port parameters
+     * @throws UnsupportedOperationException if not supported by a specific device
      */
-    public void setParameters(
+    public void setParameters(int baudRate, int dataBits, int stopBits, int parity) throws IOException;
-            int baudRate, int dataBits, int stopBits, int parity) throws IOException;
 
     /**
      * Gets the CD (Carrier Detect) bit from the underlying UART.

usbSerialForAndroid/src/main/java/com/hoho/android/usbserial/util/SerialInputOutputManager.java

@@ -125,12 +125,12 @@ public class SerialInputOutputManager implements Runnable {
     public void run() {
         synchronized (this) {
             if (getState() != State.STOPPED) {
-                throw new IllegalStateException("Already running.");
+                throw new IllegalStateException("Already running");
             }
             mState = State.RUNNING;
         }
 
-        Log.i(TAG, "Running ..");
+        Log.i(TAG, "Running ...");
         try {
             while (true) {
                 if (getState() != State.RUNNING) {
@@ -148,7 +148,7 @@ public class SerialInputOutputManager implements Runnable {
         } finally {
             synchronized (this) {
                 mState = State.STOPPED;
-                Log.i(TAG, "Stopped.");
+                Log.i(TAG, "Stopped");
             }
         }
     }