Merge pull request #36 from jderda/master

Fixed issue #8; added serial exceptions

pi4j-core/src/main/java/com/pi4j/io/serial/Serial.java

@@ -70,9 +70,10 @@ public interface Serial {
  * GPIO header.
  * @param baudRate The baud rate to use with the serial port.
  * 
- * @return The return value is the file descriptor or -1 for any error.
+ * @return The return value is the file descriptor.
+ * @throws SerialException Exception thrown on any error.
  */
- int open(String device, int baudRate);
+ void open(String device, int baudRate) throws SerialException;
 
  /**
  * This method is called to close a currently open open serial port.

pi4j-core/src/main/java/com/pi4j/io/serial/SerialException.java

@@ -0,0 +1,85 @@
+package com.pi4j.io.serial;
+
+/*
+ * #%L
+ * **********************************************************************
+ * ORGANIZATION : Pi4J
+ * PROJECT : Pi4J :: Java Library (Core)
+ * FILENAME : SerialException.java 
+ * 
+ * This file is part of the Pi4J project. More information about 
+ * this project can be found here: http://www.pi4j.com/
+ * **********************************************************************
+ * %%
+ * Copyright (C) 2013 Pi4J
+ * %%
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ * 
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * #L%
+ */
+
+
+/**
+ * <p> This class represents Exception that might occur in Serial interface.</p>
+ * 
+ * <p>
+ * Before using the Pi4J library, you need to ensure that the Java VM in configured with access to
+ * the following system libraries:
+ * <ul>
+ * <li>pi4j</li>
+ * <li>wiringPi</li>
+ * </ul>
+ * <blockquote> This library depends on the wiringPi native system library.</br> (developed by
+ * Gordon Henderson @ <a href="https://projects.drogon.net/">https://projects.drogon.net/</a>)
+ * </blockquote>
+ * </p>
+ * 
+ * @see #com.pi4j.io.serial.Serial
+ * 
+ * @see <a href="http://www.pi4j.com/">http://www.pi4j.com/</a>
+ * @author Jakub Derda (<a
+ * href="http://www.ardeo.pl">http://www.ardeo.pl</a>)
+ */
+public class SerialException extends Exception {
+
+ /**
+ * Default serial version ID
+ */
+ private static final long serialVersionUID = 1L;
+
+ /**
+ * Default no argument constructor.
+ */
+ public SerialException() {
+ super();
+ }
+
+ /**
+ * Constructor with description.
+ * 
+ * @param message Description of error that occured.
+ */
+ public SerialException(String message) {
+ super(message);
+ }
+
+
+ /**
+ * Constructor with cause.
+ * 
+ * @param cause Cause of SerialException.
+ */
+ public SerialException(Throwable cause) {
+ super(cause);
+ }
+
+}

pi4j-core/src/main/java/com/pi4j/io/serial/impl/SerialImpl.java

@@ -32,6 +32,7 @@
 
 import com.pi4j.io.serial.Serial;
 import com.pi4j.io.serial.SerialDataListener;
+import com.pi4j.io.serial.SerialException;
 
 /**
  * <p> This implementation class implements the 'Serial' interface using the WiringPi Serial library.</p>
@@ -65,19 +66,22 @@ public class SerialImpl implements Serial {
  protected boolean isshutdown = false;
 
  /**
- * This method is call to open a serial port for communication.
+ * This method is call to open a serial port for communication. Throws SerialException on error.
  * 
  * @see #DEFAULT_COM_PORT
  * 
  * @param device The device address of the serial port to access. You can use constant
  * 'DEFAULT_COM_PORT' if you wish to access the default serial port provided via the
  * GPIO header.
  * @param baudRate The baud rate to use with the serial port.
- * @return The return value is the file descriptor or -1 for any error.
+ * @return The return value is the file descriptor.
+ * @throws SerialException Exception thrown on any error.
  */
- public int open(String device, int baudRate) {
+ public void open(String device, int baudRate) throws SerialException {
  fileDescriptor = com.pi4j.wiringpi.Serial.serialOpen(device, baudRate);
- return fileDescriptor;
+ if (fileDescriptor == -1) {
+ throw new SerialException("Cannot open serial port");
+ }
  }
 
  /**
@@ -93,8 +97,12 @@ public boolean isOpen() {
  /**
  * This method is called to close a currently open open serial port.
  */
- public void close() {
- com.pi4j.wiringpi.Serial.serialClose(fileDescriptor);
+ public void close() throws IllegalStateException {
+ if (isOpen()) {
+ com.pi4j.wiringpi.Serial.serialClose(fileDescriptor);
+ } else {
+ throw new IllegalStateException("Serial connection is not open, cannot close");
+ }
  }
 
  /**