getNamespace

Unique identifier specifying the Extension namespace. The default namespace is ‘bpmn2’. Implementations should overwrite this method.

    @Override
    public String getNamespace() {
        return "foo";
    }

getNamespaceURI

Unique target namespace URI

   @Override
   public String getNamespaceURI() {
       return "http://www.foo.org/bpmn2";
   }

getLabel

Returns the Extension label to be used in the Tool Palette

    @Override
    public String getLabel() {
        return "My-Extension";
    }

handlesElementTypeId

Returns true if the given ElementTypeID can be handled by this extension. This method is used to verify if a custom implementation of an extension can be applied to a BPMNModelElement.

    @Override
    public boolean handlesElementTypeId(final String elementTypeId) {
        return (BPMNTypes.TASK.equals(elementTypeId));
    }

handlesBPMNElement

Validates whether the given {@link BPMNBaseElement} can be handled by this BPMN extension. The default implementation returns true. Implementations can accept only specific BPMN element types or elements containing specific BPMN 2.0 extensions.

    @Override
    public boolean handlesBPMNElement(final BPMNElement bpmnElement) {
        if (bpmnElement instanceof Activity) {
            Activity task = (Activity) bpmnElement;
            if (task.getType().equals(BPMNTypes.TASK)) {
                // next check the extension attribute imixs:username
                if (task.hasAttribute(getNamespace() + ":username")) {
                    return true;
                }
            }
        }
        return false;
    }

getPriority

Returns the priority of this action handler. The priority is used to derive the execution order if multiple extension handlers should execute the same BPMNBaseElement. The default priority is 0 and the priority is sorted descending. This means handlers with a priority > 0 are executed before handlers with a default priority and handlers with a priority >0 are executed afterwards.

addExtension

Adds an extension to a given BPMN Element

    public void addExtension(final BPMNElement bpmnElement) {
        if (bpmnElement instanceof Activity) {
            bpmnElement.setExtensionAttribute(getNamespace(), "username", "100");
        }
    }

buildPropertiesForm

This Method is called to generate a JSON Forms Object when the element is loaded. The method adds the BPMNElement properties into a JSON Schema.

You can add a new data field by calling

	builder.add("myField","someData")
             uiSchemaBuilder. //
                addCategory("General"). //
                addLayout(Layout.HORIZONTAL). //
                addElements("username", "category"). //

     schemaBuilder.addProperty("username", "string", "Please enter your name");

This JsonObjectBuilder is used on the BPMNGmodelFactory to generate the JsonForms

updatePropertiesData

Updates the properties data provided by the modeling tool in the corresponding BPMN Element. The method receives the BPMNElement and a json object containing all new values. An extension can also update the given json object during this operation if needed.

onLoad

This method is called after a BPMNModel was loaded the first time. The model can be modified. The parameter path provides the file path the model was loaded from.

    @Override
    public void onLoad(BPMNModel model, Path path) {
        ....
    }

onSave

This method is called before the BPMNModel is stored to disk. The parameter path provides the file path the model was loaded from.

    @Override
    public void onLoad(BPMNModel model, Path path) {
        ....
    }

getPriority

Returns the priority of this action handler. The priority is used to derive the execution order if multiple extension handlers should execute the same BPMNBaseElement. The default priority is 0 and the priority is sorted descending. This means handlers with a priority > 0 are executed before handlers with a default priority and handlers with a priority >0 are executed afterwards.