AbstractDragSourceListener.java

package org.csstudio.sds.ui.internal.editor.dnd;

import java.util.Collections;
import java.util.List;

import org.csstudio.platform.model.pvs.IProcessVariableAddress;
import org.csstudio.platform.model.pvs.IProcessVariableAdressProvider;
import org.eclipse.gef.EditPartViewer;
import org.eclipse.gef.dnd.AbstractTransferDragSourceListener;
import org.eclipse.gef.editparts.AbstractEditPart;
import org.eclipse.swt.dnd.DragSourceEvent;
import org.eclipse.swt.dnd.Transfer;

abstract class AbstractDragSourceListener<E> extends
		AbstractTransferDragSourceListener {

	public AbstractDragSourceListener(EditPartViewer viewer, Transfer transfer) {
		super(viewer, transfer);
	}

	@Override
	@SuppressWarnings("unchecked")
	public final void dragSetData(DragSourceEvent event) {
		List<AbstractEditPart> controllers = getViewer().getSelectedEditParts();

		E transferDataObject = null;

		for (AbstractEditPart controller : controllers) {
			if (controller instanceof IProcessVariableAdressProvider) {
				IProcessVariableAdressProvider provider = (IProcessVariableAdressProvider) controller;

				transferDataObject = convert(
						provider.getPVAdress(),
						provider.getProcessVariableAdresses() != null ? provider
								.getProcessVariableAdresses()
								: Collections.EMPTY_LIST);

			}
		}

		event.doit = (transferDataObject != null);
		event.data = transferDataObject;
	}

	protected abstract E convert(IProcessVariableAddress mainAddress,
			List<IProcessVariableAddress> allAddresses);
}