ModelLoadingListeners

ModelLoadingListeners are custom logic that hook into the Model Loading logic.

Listeners can be defined in DataResources, they describe a ModelLoadingStep to which to subscribe and an implementation that point to a java class. After the step in the model loading process has been performed, all listeners subscribed to that step will be executed.

You can subscribe to any of these steps:

• ExtractResourcesStep
• PrepareModelStep
• ReadModelStep
• ConvertModelStep
• EnrichModelStep
• ConfigureExpansionStep

modelLoadingListeners.xml

Add a DataResource file to your expansion-resource:

modelLoadingListeners.xml

<dataResource type="expansionControl::ModelLoadingListener">
  <modelLoadingListener name="MyModelLoaderListener">
    <modelLoadingStep name="ExtractResourcesStep"/>
    <implementation>org.example.MyModelLoaderListener</implementation>
  </modelLoadingListener>
</dataResource>

MyModelLoaderListener.java

Provide a java class that implements the ModelLoadingStepListener interface. The interface is typed with the result class of the step (always named after the step, but replace Step with Result).

import net.democritus.model.common.ModelLoadingContext;
import net.democritus.model.common.ModelLoadingStepListener;
import net.democritus.model.resources.ExtractResourcesResult;

public class MyModelLoaderListener implements ModelLoadingStepListener\<ExtractResourcesResult> {
  @Override
  public void afterStep(ExtractResourcesResult result, ModelLoadingContext context) {
      // Do stuff
  }
}

Traversing the model

The net.democritus.mapping.CompositeElementFinder class has a findAll() method that can be used to find all instances of a composite in a ExpansionCompositeModel object, which can otherwise be hard to traverse.

Set<ValueFieldComposite> valueFields = CompositeElementFinder
    .findAll(result.getExpansionCompositeModel(), ValueFieldComposite.class);