Report writeBytes errors via java exceptions

src/main/cpp/_nix_based/jssc.cpp

@@ -22,9 +22,11 @@
  * e-mail: scream3r.org@gmail.com
  * web-site: http://scream3r.org | http://code.google.com/p/java-simple-serial-connector/
  */
+#include <assert.h>
 #include <limits.h>
 #include <stdio.h>
 #include <fcntl.h>
+#include <string.h>
 #include <unistd.h>
 #include <sys/ioctl.h>
 #include <termios.h>
@@ -527,11 +529,21 @@ JNIEXPORT jboolean JNICALL Java_jssc_SerialNativeInterface_setDTR
  */
 JNIEXPORT jboolean JNICALL Java_jssc_SerialNativeInterface_writeBytes
   (JNIEnv *env, jobject, jlong portHandle, jbyteArray buffer){
+    jboolean ret = JNI_FALSE;
     jbyte* jBuffer = env->GetByteArrayElements(buffer, JNI_FALSE);
     jint bufferSize = env->GetArrayLength(buffer);
     jint result = write(portHandle, jBuffer, (size_t)bufferSize);
+    if( result == -1 ){
+        int err = errno; /*bakup errno*/
+        jclass exClz = env->FindClass("java/io/IOException");
+        assert(exClz != NULL);
+        env->ThrowNew(exClz, strerror(err));
+        goto Finally;
+    }
+    ret = (result == bufferSize) ? JNI_TRUE : JNI_FALSE;
+Finally:
     env->ReleaseByteArrayElements(buffer, jBuffer, 0);
-    return result == bufferSize ? JNI_TRUE : JNI_FALSE;
+    return ret;
 }
 
 /**

src/main/java/jssc/SerialNativeInterface.java

@@ -277,7 +277,7 @@ public static String getLibraryVersion() {
      * 
      * @return If the operation is successfully completed, the method returns true, otherwise false
      */
-    public native boolean writeBytes(long handle, byte[] buffer);
+    public native boolean writeBytes(long handle, byte[] buffer) throws IOException;
 
     /**
      * Get bytes count in buffers of port

src/main/java/jssc/SerialPort.java

@@ -24,6 +24,7 @@
  */
 package jssc;
 
+import java.io.IOException;
 import java.io.UnsupportedEncodingException;
 import java.lang.reflect.Method;
 
@@ -408,7 +409,11 @@ public boolean setDTR(boolean enabled) throws SerialPortException {
      */
     public boolean writeBytes(byte[] buffer) throws SerialPortException {
         checkPortOpened("writeBytes()");
-        return serialInterface.writeBytes(portHandle, buffer);
+        try {
+            return serialInterface.writeBytes(portHandle, buffer);
+        } catch(IOException ex) {
+            throw SerialPortException.wrapNativeException(ex, this, "writeBytes");
+        }
     }
 
     /**

src/main/java/jssc/SerialPortException.java

@@ -67,6 +67,9 @@ public class SerialPortException extends Exception {
      */
     final public static String TYPE_INCORRECT_SERIAL_PORT = "Incorrect serial port";
 
+    /** Exception occurred in native code */
+    final public static String TYPE_NATIVE_EXCEPTION = "Native exception occurred: %s";
+
     /** Serial port object **/
     private SerialPort port;
     /** Method name **/
@@ -110,6 +113,10 @@ public SerialPortException(String portName, String methodName, String exceptionT
         this.exceptionType = exceptionType;
     }
 
+    public static SerialPortException wrapNativeException(Exception ex, SerialPort port, String methodName) {
+        return new SerialPortException(port, methodName, String.format(TYPE_NATIVE_EXCEPTION, ex.getLocalizedMessage()));
+    }
+
     /**
      * Getting port name during operation with which the exception was called
      * Deprecated: Use <code>getPort().getName()</code> instead.

src/test/java/jssc/SerialNativeInterfaceTest.java

@@ -39,4 +39,12 @@ public void testPrintVersion() {
 
     }
 
+    @Test(expected = java.io.IOException.class)
+    public void reportsWriteErrorsAsIOException() throws Exception {
+        long fd = -1; /*bad file by intent*/
+        byte[] buf = new byte[]{ 0x6A, 0x73, 0x73, 0x63, 0x0A };
+        SerialNativeInterface testTarget = new SerialNativeInterface();
+        testTarget.writeBytes(fd, buf);
+    }
+
 }