The MidiBus is a MIDI library for Processing which provides a fast and easy way to send and receive MIDI data. The MidiBus is desgined primarily for real time MIDI applications. It's focused on MIDI I/O and keeps the frills to a minimum; currently it has no built in sequencer, file read/write, MIDI recording/playback.
The best way to install the MidiBus is via the Processing Library Manager. This way Processing will automatically notify you when a new version is available.
If you want to install the MidiBus manually you can get the latest stable build including binaries, examples and documentation via direct downloadd.
Before you get started, it is important to understand that the MidiBus offers little functionality that isn't available from Java's native javax.sound.midi package. Anyone interested in working with MIDI in Java should take the time to read the documentation for the javax.sound.midi package. It offers a more full featured and flexible alternative to this package but it is also more complicated to use. In addition, it is also worthwhile to skim the "official" Java Tutorial for the javax.sound.* packages.
The MidiBus is very straight forwards to use. A good place to start is the included Basic.pde example. From there you can look at the JavaDocs either online or bundled with your library in the "reference" subdirectory. The JavaDocs are a comprehensive reference of all the MidiBus' available functionality. There are also a few advanced examples which can (hopefully) help answer most common questions: how to work with multiple input/output devices, how to send uncommon MIDI messages and how to receive uncommon MIDI messages.
Please do not hesitate to contact me with any questions, comments or bug reports.
The Apple MIDI subsystem has a number of problems. Most notably it doesn't seem to support MIDI messages with a status byte >= 0xF0 such as SysEx messages. You can use MMJ as an alternate subsystem. To do so, download mmj and add both mmj.jar and libmmj.jnilib to the midibus library subdirectory. You will also need to disable timestamps in your MidiBus instance otherwise MMJ won't work properly. You can do this by calling mybus.sendTimestamp(false)