Fix for Port Binding Conflicts in ArtNetClient and ArtNetServer

[tylerstraub]

This PR addresses an issue (#26) where the ArtNetClient and ArtNetServer classes were causing port binding conflicts when used as a sender and receiver simultaneously on the same machine. By introducing a new parameter to control whether the client/server should bind to a port or use an ephemeral port, we resolve the conflicts and improve the flexibility of the library.

Changes Made:

1. ArtNetClient.java:

   • Added a new start(boolean isReceiver) method to allow specifying the mode (sender or receiver) directly.
   • Modified existing start methods to preserve backward compatibility and default to using the input buffer to determine the receiver mode.

2. ArtNetServer.java:

   • Updated the start method to accept a boolean isReceiver parameter to control whether to bind to the specified port or use an ephemeral port.

Testing:

• Tested with Processing 4 application to ensure the ArtNetClient can be started as a sender using artnet.start(false).
• Verified that no port binding conflicts occur when running multiple instances as both sender and receiver on the same machine.

Documentation:

Usage Example:

To start an ArtNetClient as a sender (without port binding):

import ch.bildspur.artnet.*;

ArtNetClient artnet;
byte[] dmxData = new byte[512];

void setup() {
  size(500, 250);
  
  colorMode(HSB, 360, 100, 100);
  textAlign(CENTER, CENTER);
  textSize(20);

  // create artnet client without buffer (no receiving needed)
  artnet = new ArtNetClient(null);
  artnet.start(false); // false indicates it is a sender
}

void draw() {
  // create color
  int c = color(frameCount % 360, 80, 100);

  background(c);

  // fill dmx array
  dmxData[0] = (byte) red(c);
  dmxData[1] = (byte) green(c);
  dmxData[2] = (byte) blue(c);

  // send dmx to localhost
  artnet.unicastDmx("127.0.0.1", 0, 0, dmxData);

  // show values
  text("R: " + (int)red(c) + " Green: " + (int)green(c) + " Blue: " + (int)blue(c), width / 2, height / 2);
}

Backward Compatibility:

• The existing methods are preserved to maintain backward compatibility.
• The new parameter defaults to true for receiver mode when not specified.

Conclusion:

These changes improve the flexibility and usability of the artnet4j library by resolving port binding conflicts and allowing users to specify the mode of the client/server.

I really needed this behavior for my own application so I didn't go too deeply into an optimal fix. A better solution may be to infer if the connection is a reciever or sender somehow, but this was beyond the limits of what I had time for and to be honest my Java is not that great.

If the maintainers feel like this solution is adequate though, great!

All the best,

-T

[tylerstraub]

You know what... this commit is not suitable for main branch after testing and thinking through further.

This commit would cause a breaking change and require updating existing code beacuse passing null into .start() results in the server launching in ephemeral mode.

Sorry I didn't catch this before sending the PR. I will close for now and push another one that retains the pre-existing behavior when start() is passed with a null value.

[tylerstraub]

Fixing the issue now it's a one line change.

[tylerstraub]

Alright, it's safe now.