Coding a music composition program

[Daimoth]

I'm coding a cross between a music composition program and a DAW. So like Finale or Guitar Pro, but with user provided audio samples (read: not necessarily midi bleeps) and some rudimentary effects/mixing that, ideally, won't require any external libraries which might threaten platform independence.

I'm at the point where it's time to nail down how I will go turn sheet music into code, into audio output. I'll be starting simply, with quarter notes in 4/4, but with variable tempo. How I begin implementing this is critical, so I wanted to ask around before diving into it. How would you go about it? Would it be prudent to make use of the midi package, or just code my own little framework by leveraging the Timing Framework API? I'll probably make use of that API regardless, actually. And I'll be using Swing.

Thanks in advance.

[KevinWorkman]

You might look into using JavaFX instead of Swing, since JavaFX supposedly has better audio support: https://docs.oracle.com/javafx/2/media/overview.htm