If I add a property to all instances of BPMNElementNode subclasses, what components do I need to extend and rebuild?

[chrisesposito4]

I'm working on an application where I need to add 2 user-editable properties (let's call them 'PropertyA' and 'PropertyB', each with a text value) to all instances of any node in the diagram (i.e., all subclasses of BPMNElementNode). From what I understand after reading the docs at https://www.open-bpmn.org/glsp-server/BPMN_EXTENSIONS.html , I need to implement the BPMNElementExtension interface as part of the process for getting the new properties to show up on an element's property page.

What's less clear to me is whether or not I also need to implement the BPMNModelExtension interface if I want these new properties to be saved and loaded as part of the diagram, just the same way that the Name and Documentation properties are saved and loaded.

[rsoika]

Hi @chrisesposito4
yes you can place a standard extension into the default process of your bpmn file. This is where we place the open-bpmn:auto-align property.
You can see the code managing this property here:

open-bpmn/open-bpmn.glsp-server/src/main/java/org/openbpmn/glsp/model/BPMNGModelState.java

Line 96 in 885d99c

public void setAutoAlign(boolean _autoAlign) {

You do not need to care about the saving of this property into your file. This is done automatically. So this is how you add a BPMN 2.0 extension element into a BPMN Process element (Open-BPMN Meta Project)

The other question is how to control an extension property from the property panel in the modelling tool. This is where the open-bpmn extensions come into the play. You can define a new extension and extend the class AbstractBPMNElementExtension. This class will mainly define how to display an UI widget in the property panel and how to map the value into the model.
To register your own extensions you need your own Server implementation. But This is quite simple as you can extend the core implementation. For example to register your extension you overwrite the BPMNDiagramModule

public class ImixsBPMNDiagramModule extends BPMNDiagramModule {
    @SuppressWarnings("unused")
    private static Logger logger = Logger.getLogger(ImixsBPMNDiagramModule.class.getName());

    /**
     * This method adds the custom Imixs BPMN Extensions
     *
     * @param binding
     */
    @Override
    public void configureBPMNElementExtensions(final Multibinder<BPMNElementExtension> binding) {
        // bind BPMN default extensions
        super.configureBPMNElementExtensions(binding);

        // Imixs Task Extensions
        binding.addBinding().to(ImixsBPMNDefinitionsExtension.class);
        binding.addBinding().to(ImixsBPMNTaskExtension.class);
        binding.addBinding().to(ImixsBPMNTaskACLExtension.class);

        // Imixs Event Extensions
        binding.addBinding().to(ImixsBPMNEventExtension.class);
        binding.addBinding().to(ImixsBPMNEventHistoryExtension.class);
        binding.addBinding().to(ImixsBPMNEventRuleExtension.class);
        binding.addBinding().to(ImixsBPMNEventSchedulerExtension.class);
        binding.addBinding().to(ImixsBPMNEventACLExtension.class);
        binding.addBinding().to(ImixsBPMNEventMailExtension.class);
        binding.addBinding().to(ImixsBPMNEventReportExtension.class);

        // Imixs DataObject Extensions
        binding.addBinding().to(ImixsBPMNDataObjectExtension.class);

    }

    /**
     * This method adds the BPMN default model extensions
     * <p>
     * Overwrite this method to add custom BPMN Extensions
     *
     * @param binding
     */
    @Override
    public void configureBPMNModelExtensions(final Multibinder<BPMNModelExtension> binding) {
        super.configureBPMNModelExtensions(binding);
        // bind Imixs model extensions
        binding.addBinding().to(ImixsModelValidatorExtension.class);

    }
}

This is an example from our custom imixs-bpmn-server part. You can find the source code from the Imixs-Server part here:

https://github.com/imixs/imixs-open-bpmn