throw UnsupportedOperationException instead of returning false

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

@@ -239,21 +239,6 @@ public class CdcAcmSerialDriver implements UsbSerialDriver {
             sendAcmControlMessage(SET_LINE_CODING, 0, msg);
         }
 
-        @Override
-        public boolean getCD() throws IOException {
-            return false;  // TODO
-        }
-
-        @Override
-        public boolean getCTS() throws IOException {
-            return false;  // TODO
-        }
-
-        @Override
-        public boolean getDSR() throws IOException {
-            return false;  // TODO
-        }
-
         @Override
         public boolean getDTR() throws IOException {
             return mDtr;
@@ -265,11 +250,6 @@ public class CdcAcmSerialDriver implements UsbSerialDriver {
             setDtrRts();
         }
 
-        @Override
-        public boolean getRI() throws IOException {
-            return false;  // TODO
-        }
-
         @Override
         public boolean getRTS() throws IOException {
             return mRts;

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

@@ -212,28 +212,28 @@ public abstract class CommonUsbSerialPort implements UsbSerialPort {
     public abstract void setParameters(int baudRate, int dataBits, int stopBits, int parity) throws IOException;
 
     @Override
-    public abstract boolean getCD() throws IOException;
+    public boolean getCD() throws IOException { throw new UnsupportedOperationException(); }
 
     @Override
-    public abstract boolean getCTS() throws IOException;
+    public boolean getCTS() throws IOException { throw new UnsupportedOperationException(); }
 
     @Override
-    public abstract boolean getDSR() throws IOException;
+    public boolean getDSR() throws IOException { throw new UnsupportedOperationException(); }
 
     @Override
-    public abstract boolean getDTR() throws IOException;
+    public boolean getDTR() throws IOException { throw new UnsupportedOperationException(); }
 
     @Override
-    public abstract void setDTR(boolean value) throws IOException;
+    public void setDTR(boolean value) throws IOException { throw new UnsupportedOperationException(); }
 
     @Override
-    public abstract boolean getRI() throws IOException;
+    public boolean getRI() throws IOException { throw new UnsupportedOperationException(); }
 
     @Override
-    public abstract boolean getRTS() throws IOException;
+    public boolean getRTS() throws IOException { throw new UnsupportedOperationException(); }
 
     @Override
-    public abstract void setRTS(boolean value) throws IOException;
+    public void setRTS(boolean value) throws IOException { throw new UnsupportedOperationException(); }
 
     @Override
     public abstract EnumSet<ControlLine> getControlLines() throws IOException;
@@ -242,8 +242,8 @@ public abstract class CommonUsbSerialPort implements UsbSerialPort {
     public abstract EnumSet<ControlLine> getSupportedControlLines() throws IOException;
 
     @Override
-    public boolean purgeHwBuffers(boolean purgeWriteBuffers, boolean purgeReadBuffers) throws IOException {
-        return false;
+    public void purgeHwBuffers(boolean purgeWriteBuffers, boolean purgeReadBuffers) throws IOException {
+        throw new UnsupportedOperationException();
     }
 
 }

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

@@ -305,15 +305,13 @@ public class Cp21xxSerialDriver implements UsbSerialDriver {
 
         @Override
         // note: only working on some devices, on other devices ignored w/o error
-        public boolean purgeHwBuffers(boolean purgeWriteBuffers, boolean purgeReadBuffers) throws IOException {
+        public void purgeHwBuffers(boolean purgeWriteBuffers, boolean purgeReadBuffers) throws IOException {
             int value = (purgeReadBuffers ? FLUSH_READ_CODE : 0)
                     | (purgeWriteBuffers ? FLUSH_WRITE_CODE : 0);
 
             if (value != 0) {
                 setConfigSingle(SILABSER_FLUSH_REQUEST_CODE, value);
             }
-
-            return true;
         }
 
     }

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

@@ -337,7 +337,7 @@ public class FtdiSerialDriver implements UsbSerialDriver {
         }
 
         @Override
-        public boolean purgeHwBuffers(boolean purgeWriteBuffers, boolean purgeReadBuffers) throws IOException {
+        public void purgeHwBuffers(boolean purgeWriteBuffers, boolean purgeReadBuffers) throws IOException {
             if (purgeWriteBuffers) {
                 int result = mConnection.controlTransfer(REQTYPE_HOST_TO_DEVICE, RESET_REQUEST,
                         RESET_PURGE_RX, mPortNumber+1, null, 0, USB_WRITE_TIMEOUT_MILLIS);
@@ -353,7 +353,6 @@ public class FtdiSerialDriver implements UsbSerialDriver {
                     throw new IOException("purge read buffer failed: result=" + result);
                 }
             }
-            return true;
         }
 
         public void setLatencyTimer(int latencyTime) throws IOException {

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

@@ -464,7 +464,7 @@ public class ProlificSerialDriver implements UsbSerialDriver {
         }
 
         @Override
-        public boolean purgeHwBuffers(boolean purgeWriteBuffers, boolean purgeReadBuffers) throws IOException {
+        public void purgeHwBuffers(boolean purgeWriteBuffers, boolean purgeReadBuffers) throws IOException {
             if (purgeWriteBuffers) {
                 vendorOut(FLUSH_RX_REQUEST, 0, null);
             }
@@ -472,8 +472,6 @@ public class ProlificSerialDriver implements UsbSerialDriver {
             if (purgeReadBuffers) {
                 vendorOut(FLUSH_TX_REQUEST, 0, null);
             }
-
-            return true;
         }
     }
 

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

@@ -152,32 +152,36 @@ public interface UsbSerialPort extends Closeable {
     /**
      * Gets the CD (Carrier Detect) bit from the underlying UART.
      *
-     * @return the current state, or {@code false} if not supported.
+     * @return the current state
      * @throws IOException if an error occurred during reading
+     * @throws UnsupportedOperationException if not supported
      */
     public boolean getCD() throws IOException;
 
     /**
      * Gets the CTS (Clear To Send) bit from the underlying UART.
      *
-     * @return the current state, or {@code false} if not supported.
+     * @return the current state
      * @throws IOException if an error occurred during reading
+     * @throws UnsupportedOperationException if not supported
      */
     public boolean getCTS() throws IOException;
 
     /**
      * Gets the DSR (Data Set Ready) bit from the underlying UART.
      *
-     * @return the current state, or {@code false} if not supported.
+     * @return the current state
      * @throws IOException if an error occurred during reading
+     * @throws UnsupportedOperationException if not supported
      */
     public boolean getDSR() throws IOException;
 
     /**
      * Gets the DTR (Data Terminal Ready) bit from the underlying UART.
      *
-     * @return the current state, or {@code false} if not supported.
+     * @return the current state
      * @throws IOException if an error occurred during reading
+     * @throws UnsupportedOperationException if not supported
      */
     public boolean getDTR() throws IOException;
 
@@ -186,22 +190,25 @@ public interface UsbSerialPort extends Closeable {
      *
      * @param value the value to set
      * @throws IOException if an error occurred during writing
+     * @throws UnsupportedOperationException if not supported
      */
     public void setDTR(boolean value) throws IOException;
 
     /**
      * Gets the RI (Ring Indicator) bit from the underlying UART.
      *
-     * @return the current state, or {@code false} if not supported.
+     * @return the current state
      * @throws IOException if an error occurred during reading
+     * @throws UnsupportedOperationException if not supported
      */
     public boolean getRI() throws IOException;
 
     /**
      * Gets the RTS (Request To Send) bit from the underlying UART.
      *
-     * @return the current state, or {@code false} if not supported.
+     * @return the current state
      * @throws IOException if an error occurred during reading
+     * @throws UnsupportedOperationException if not supported
      */
     public boolean getRTS() throws IOException;
 
@@ -210,6 +217,7 @@ public interface UsbSerialPort extends Closeable {
      *
      * @param value the value to set
      * @throws IOException if an error occurred during writing
+     * @throws UnsupportedOperationException if not supported
      */
     public void setRTS(boolean value) throws IOException;
 
@@ -235,11 +243,10 @@ public interface UsbSerialPort extends Closeable {
      *
      * @param purgeWriteBuffers {@code true} to discard non-transmitted output data
      * @param purgeReadBuffers {@code true} to discard non-read input data
-     * @return {@code true} if the operation was successful, or
-     *         {@code false} if the operation is not supported by the driver or device
      * @throws IOException if an error occurred during flush
+     * @throws UnsupportedOperationException if not supported
      */
-    public boolean purgeHwBuffers(boolean purgeWriteBuffers, boolean purgeReadBuffers) throws IOException;
+    public void purgeHwBuffers(boolean purgeWriteBuffers, boolean purgeReadBuffers) throws IOException;
 
     /**
      * Returns the current state of the connection.