EDIT

package eu.etaxonomy.taxeditor.editor.view.derivate.handler;

import java.util.Collections;

import java.util.UUID;

import org.eclipse.core.commands.ExecutionEvent;

import org.eclipse.e4.ui.model.application.ui.basic.MPart;

import org.eclipse.e4.ui.workbench.modeling.EPartService;

import org.eclipse.e4.ui.workbench.modeling.EPartService.PartState;

import eu.etaxonomy.cdm.api.service.IDescriptionService;

import eu.etaxonomy.cdm.model.description.DescriptionElementBase;

import eu.etaxonomy.cdm.model.description.IndividualsAssociation;

import eu.etaxonomy.cdm.model.occurrence.SpecimenOrObservationBase;

import eu.etaxonomy.taxeditor.editor.AppModelId;

import eu.etaxonomy.taxeditor.editor.l10n.Messages;

import eu.etaxonomy.taxeditor.editor.view.derivate.DerivateView;

import eu.etaxonomy.taxeditor.editor.view.derivate.DerivateViewEditorInput;

import eu.etaxonomy.taxeditor.handler.defaultHandler.DefaultOpenHandlerBase;

import eu.etaxonomy.taxeditor.model.MessagingUtils;

import eu.etaxonomy.taxeditor.store.CdmStore;

import eu.etaxonomy.taxeditor.store.internal.TaxeditorStorePlugin;

public class OpenDerivativeEditorForDescriptionElement extends DefaultOpenHandlerBase<IndividualsAssociation> {

    @Override

    protected IndividualsAssociation getEntity(UUID uuid) {

        DescriptionElementBase descriptionElement = CdmStore.getService(IDescriptionService.class).loadDescriptionElement(uuid, null);

        if(descriptionElement!=null && descriptionElement.isInstanceOf(IndividualsAssociation.class)){

            return (IndividualsAssociation) descriptionElement;

        }

        return null;

    }

    @Override

    protected void open(ExecutionEvent event, IndividualsAssociation entity) {

    	if(entity==null || entity.getAssociatedSpecimenOrObservation()==null){

    		MessagingUtils.messageDialog(Messages.OpenDerivativeEditorForDescriptionElement_NO_SPECIMENS, this, Messages.OpenDerivativeEditorForDescriptionElement_NO_SPECIMENS_MESSAGE);

    		return;

    	}

        SpecimenOrObservationBase associatedSpecimenOrObservation = entity.getAssociatedSpecimenOrObservation();

        if(associatedSpecimenOrObservation!=null){

            UUID specimenUuid = associatedSpecimenOrObservation.getUuid();

            DerivateViewEditorInput input = new DerivateViewEditorInput(Collections.singletonList(specimenUuid));

            MPart part = TaxeditorStorePlugin.getDefault().getWorkbench().getActiveWorkbenchWindow().getService(EPartService.class).showPart(

                    AppModelId.PARTDESCRIPTOR_EU_ETAXONOMY_TAXEDITOR_EDITOR_VIEW_DERIVATE_DERIVATEVIEW, PartState.ACTIVATE);

            DerivateView derivateView = (DerivateView) part.getObject();

            derivateView.init(input);

        }

    }

}