public class SLDFeatureProvider extends DefaultFeatureProvider {
	
	private IAddFeature wireAddFeature    = new WireAddFeature(this);
	private IAddFeature busbarAddFeature  = new BusbarAddFeature(this);
	
	public SLDFeatureProvider(IDiagramTypeProvider dtp) {
		super(dtp);
	}

	@Override
	public ICreateFeature[] getCreateFeatures() {
		return new ICreateFeature[] { new BusbarCreateFeature(this) };
	}

	@Override
	public ICreateConnectionFeature[] getCreateConnectionFeatures() {
	    return new ICreateConnectionFeature[] { new WireCreateFeature(this) };
	}
	
	@Override
	public IAddFeature getAddFeature(IAddContext context) {
		if (context.getNewObject() instanceof Wire) {
			return wireAddFeature;
		}
		else if (context.getNewObject() instanceof Busbar) {
			return busbarAddFeature;
		}
		return super.getAddFeature(context);
	}
}

public class WireCreateFeature extends AbstractCreateConnectionFeature {

    public WireCreateFeature(IFeatureProvider fp) {
        super(fp, "Wire", "Create a Wire");
    }
    
    private Element getElement(Anchor anchor) {
        if (anchor != null) {
            Object object = getBusinessObjectForPictogramElement(anchor.getParent());
            if (object instanceof Element) {
                return (Element) object;
            }
        }
        return null;
    }
 
    @Override
    public boolean canStartConnection(ICreateConnectionContext context) {
        return getElement(context.getSourceAnchor()) != null;
    }

    @Override
    public boolean canCreate(ICreateConnectionContext context) {
    	PictogramElement sourcePictogramElement = context.getSourcePictogramElement();
		PictogramElement targetPictogramElement = context.getTargetPictogramElement();

		if (sourcePictogramElement == null || targetPictogramElement == null) {
			return false;
		}

		Object sourceDomainObject = getBusinessObjectForPictogramElement(sourcePictogramElement);
		Object targetDomainObject = getBusinessObjectForPictogramElement(targetPictogramElement);

		return sourceDomainObject instanceof Element
				&& targetDomainObject instanceof Element;
    }
 
    @Override
    public Connection create(ICreateConnectionContext context) {
        Element source = getElement(context.getSourceAnchor());
        Element target = getElement(context.getTargetAnchor());
        if (source == null || target == null) {
            throw new IllegalStateException("Cannot retrieve the source or target.");
        }
 
        Wire wire = SLDFactory.eINSTANCE.createWire();
        wire.setStartPoint(source);
        wire.setEndPoint(target);
        
        AddConnectionContext addContext = new AddConnectionContext(context.getSourceAnchor(),
                context.getTargetAnchor());
        addContext.setNewObject(wire);
        return (Connection) getFeatureProvider().addIfPossible(addContext);
    }
}