Storing custom java object inside Matlab Simulink block for a custom Toolbox

1
votes

I'm working on building a custom Simulink block as a Matlab Toolbox. In order to avoid matlab's language to program the system, I'd like to make the system in Java as much as possible. I've researched the Matlab <-> Java interface, and it seems possible to do this. However, the one thing I couldn't find any information about was storing my custom Java object (holding the block's data) inside the Simulink block.

I conducted a quick test, and it seems storing a Java.lang.String instance is possible. However, that was a relatively simple test. Before jumping in head first, I wanted to check if this was even possible. Does anyone have experience with a similar setup? Does the object simply need to be Serializable to work?

For background information, I'm looking to implement the non-math part (GUI code, processing, etc) in Java. Math related elements would likely remain in matlab.

1
javamatlabsimulink
Have you looked at the UserData block parameter? It can store any data type. - wakjah
That is where I was planning on storing the Java object. I just wanted to make sure there isn't any issues doing so. If you know for a fact that is fine, please create an answer so I can mark it accepted. :-) - MJD

1 Answers

1
votes

To store your Java object inside the block you should use its UserData block parameter. According to the documentation, you can put any data type in this parameter.

The only problems I can see with this are saving/loading and creation of new blocks. Saving/loading should be solved using serialization, but you will have to try it to see. If this doesn't work, then you could create a hidden mask parameter for your blocks, serialize your Java object to a string, and save the data in this mask during the PreSaveFcn callback. The data could be deserialized from the mask parameter in the LoadFcn callback.

For the creation of new blocks, you should set the PreCopyFcn callback of your library block and create your new Java object there. I have the feeling that if you don't do this, then MATLAB will copy the reference to your object from UserData (if one exists there already), which is probably not what you want.

You probably also want to override the OpenFcn callback since your aim is to use your Java object as a kind of souped-up mask, so that when a user double-clicks on the block you can show your custom UI.

For more information on block callback parameters, see this.