Before Writing Native Code

Before writing the Native code, you will need to use javah and javap to get information for the JNI native code.

• If native code is to be called from Java methods possessing the native keyword, you need to run javah against the Java class files. Since the tools uses the class files rather than the source files, you must run the Java compiler before using the tool. The result of this is a C language header file (.h) that you will use as the template for writing the native code.

  javah -classpath target/classes uk.co.xfactorylibrarians.coremidi4j.CoreMidiClient \
       uk.co.xfactorylibrarians.coremidi4j.CoreMidiDestination \ 
       uk.co.xfactorylibrarians.coremidi4j.CoreMidiDeviceProvider \  
       uk.co.xfactorylibrarians.coremidi4j.CoreMidiDeviceInfo \
       uk.co.xfactorylibrarians.coremidi4j.CoreMidiInputPort \
       uk.co.xfactorylibrarians.coremidi4j.CoreMidiOutputPort \
       uk.co.xfactorylibrarians.coremidi4j.CoreMidiSource 
     

• If native code is to call methods and fields from the Java objects, you will need to run javap -s against the Java class files to obtain the method signatures for the Java methods. Once again, this must be run after compiling the Java source code and before writing the C language code calling the JNI API.

Any changes to the signatures for any of the Java methods using the native keyword may change the header file for all of the methods using the native keyword in that class.

Building Code

The following is the set of Maven commands that I used to build the jar file.

mvn clean compile javadoc:javadoc package

Creating Documentation

I am currently using Javadoc to create documentation for the Java classes used in the application. The Javadoc tool is run as part of the Maven build process.

At this time, I am using Doxygen to create the documentation for the C language files. I have added a Doxygen configuration file in the project directory (Doxyfile), but you may need to make some changes for your personal development environment.

Installing Snapshots in Repository

See this page for information on how to install a snapshot jar file in your local repository so that you can use it. If the jar file was created by a recent version of Apache Maven, you can use the command

mvn install:install-file -Dfile=<path-to-file>

When I created my own snapshot build, I set the version to 1.1BR-SNAPSHOT, so that the] artifact can by retrieved as
<groupId>uk.co.xfactory-librarians<groupId>
<artifactId>coremidi4j</artifactId>
<version>1.1BR-SNAPSHOT</version>