buffer~ in mxj~

Hey Tommy,
I too had a hair pulling experience with accessing MSPBuffers from mxj! Took me over a month to filter through hundreds of tutorials and example patches. I can help you out... a lot.

Firstly:

The class should extend MaxObject as usual for max object creation from mxj.
like this "public class genInverseFilter extends MaxObject {"

If you want to access a buffer from your patch window in max and you want to supply the name of that buffer
as an argument then you need to create a global variable -
"String bufname = null;"

Then your usual declare inlets and outlets inside your constructor - titled the same as your classname with:
"(Atom[] args)"

Still in the constructor...
"if(args.length>0)
            set(args[0].toString()); "

This code will check your arguments to see if they are present.

Your first method will be:
"public void set(String s) {
        bufname = s;
    }
"

This will set the string variable "bufname" to the argument you supplied when you created the object inside max msp. Sorry this is a long winded explanation..

Now onto the important stuff:
To access the buffer you simply use a single line of code:

"float[] s = MSPBuffer.peek(bufname);"
This will "peek" inot the buffer with the name you have supplied as an argument and that has been set as a global variable. The data will then be stored in the "float[] s" array or whatever you decide to call it. One thing to note - MSPBuffer peek returns float values and not double. This means if you are doing math using java.math you will have to do some annoying casting for loops "(double) ....".

Once you have performed all of the functions neccessary to fill a new buffer or replace the data in the original buffer you have to:

Designate a new buffername or supply the original in the code somehow - this can be as an argument to your method which accesses the buffer or has to be done in the same way as I showed you before.

    "int channels = MSPBuffer.getChannels(bufname); // this calculates how many channels are on the original channel.
                MSPBuffer.setSize(destBuf, channels, size); // size should be a long type variable and is total number of samples.
                MSPBuffer.poke(destBuf, dataArray); "
This is fairly self explanatory. Array has to, as mentioned earlier be a float array.

Hope that helps!