import com.vaadin.event.Transferable; //导入依赖的package包/类
/**
 * Validate the drop.
 *
 * @param event
 *            DragAndDropEvent reference
 * @return Boolean
 */
private Boolean validate(final DragAndDropEvent event) {
    final Transferable transferable = event.getTransferable();
    final Component compsource = transferable.getSourceComponent();
    if (!(compsource instanceof AbstractTable)) {
        notification.displayValidationError(i18n.getMessage(SPUILabelDefinitions.ACTION_NOT_ALLOWED));
        return false;
    }

    final TableTransferable tabletransferable = (TableTransferable) transferable;

    final AbstractTable<?> source = (AbstractTable<?>) tabletransferable.getSourceComponent();

    if (!validateIfSourceisTargetTable(source) && !checkForTargetUpdatePermission()) {
        return false;
    }

    final Set<Long> deletedEntityByTransferable = source.getDeletedEntityByTransferable(tabletransferable);
    if (deletedEntityByTransferable.isEmpty()) {
        final String actionDidNotWork = i18n.getMessage("message.action.did.not.work", new Object[] {});
        notification.displayValidationError(actionDidNotWork);
        return false;
    }

    return true;
}
 

import com.vaadin.event.Transferable; //导入依赖的package包/类
protected boolean isDropValid(final DragAndDropEvent dragEvent) {
    final Transferable transferable = dragEvent.getTransferable();
    final Component compsource = transferable.getSourceComponent();

    if (!hasDropPermission()) {
        notification.displayValidationError(i18n.getMessage("message.permission.insufficient"));
        return false;
    }

    if (compsource instanceof Table) {
        return validateTable((Table) compsource)
                && validateDropList(getDraggedTargetList((TableTransferable) transferable, (Table) compsource));
    }

    if (compsource instanceof DragAndDropWrapper) {
        return validateDragAndDropWrapper((DragAndDropWrapper) compsource)
                && validateDropList(getDraggedTargetList(dragEvent));
    }
    notification.displayValidationError(i18n.getMessage(ACTION_NOT_ALLOWED_MSG));
    return false;
}
 

import com.vaadin.event.Transferable; //导入依赖的package包/类
@Override
public void drop(DragAndDropEvent event) {
	final Transferable t = event.getTransferable();
	AbstractSelect.AbstractSelectTargetDetails dropData = ((AbstractSelect.AbstractSelectTargetDetails) event.getTargetDetails());
	Object sourceItemId = ((DataBoundTransferable) t).getItemId();
	Object targetItemId = dropData.getItemIdOver();
	VerticalDropLocation location = dropData.getDropLocation();
	
	Item sourceItem = tree.getItem(sourceItemId);
	NavNode sourceNode = (NavNode) sourceItem.getItemProperty("object").getValue();

	Item targetItem = tree.getItem(targetItemId);
	NavNode targetNode = (NavNode) targetItem.getItemProperty("object").getValue();
	
	NavigationView.this.move(sourceNode, targetNode, location);
	// Sorting goes as
          // - If dropped ON (MIDDLE) a node, we preppend it as a child
          // - If dropped on the TOP part of a node, we move/add it before the node
          // - If dropped on the BOTTOM part of a node, we move/add it after the node if it has no children, or prepend it as a child if it has children
}
 

import com.vaadin.event.Transferable; //导入依赖的package包/类
public void drop(DragAndDropEvent event) {
    AbstractSelectTargetDetails targetDetails = (AbstractSelectTargetDetails) event.getTargetDetails();
    Transferable transferable = event.getTransferable();
    if (transferable.getSourceComponent() == table) {
        FlowParameter target = (FlowParameter) targetDetails.getItemIdOver();
        int targetIndex = container.indexOfId(target);
        FlowParameter source = (FlowParameter) transferable.getData("itemId");
        if (targetIndex == -1) {
            targetIndex = 0;
        }
        container.removeItem(source);
        container.addItemAt(targetIndex, source);
        table.select(source);
        saveAllPositions();
    }
}
 

import com.vaadin.event.Transferable; //导入依赖的package包/类
public void drop(DragAndDropEvent event) {
    AbstractSelectTargetDetails targetDetails = (AbstractSelectTargetDetails) event.getTargetDetails();
    Transferable transferable = event.getTransferable();
    if (transferable.getSourceComponent() == entityTable) {
        EntitySettings target = (EntitySettings) targetDetails.getItemIdOver();
        moveItemsTo(getSelectedItems(), entitySettingsContainer.indexOfId(target));
    }
}
 

import com.vaadin.event.Transferable; //导入依赖的package包/类
public void drop(DragAndDropEvent event) {
    AbstractSelectTargetDetails targetDetails = (AbstractSelectTargetDetails) event.getTargetDetails();
    Transferable transferable = event.getTransferable();
    if (transferable.getSourceComponent() == table) {
        RecordFormat target = (RecordFormat) targetDetails.getItemIdOver();
        moveItemsTo(getSelectedItems(), container.indexOfId(target));
    }
}
 

import com.vaadin.event.Transferable; //导入依赖的package包/类
@Override
public void drop(DragAndDropEvent event) {
	Transferable t = event.getTransferable();
	Component source = t.getSourceComponent();
	if (source != this.treeWorkspace) {
		assert(false);
		throw new IllegalArgumentException();
	}
	TableTransferable tt = (TableTransferable) t;
	File sourceFile = (File) tt.getItemId();
	
	AbstractSelectTargetDetails target = (AbstractSelectTargetDetails)event.getTargetDetails();
	File targetFile = (File) target.getItemIdOver();
	
	if (sourceFile.isFile() && targetFile != null && targetFile.isDirectory()) {
		//
		// Construct destination filename
		//
		Path dest = targetFile.toPath().resolve(sourceFile.getName());
		//
		// Check if the target domain exists
		//
		if (Files.exists(dest)) {
			//
			// Prompt the user
			//
			Notification.show("A policy file with that name already exists in that directory.", Notification.Type.ERROR_MESSAGE);
		} else {
			//
			// Go ahead and rename it
			//
			this.renamePolicyFile(sourceFile, dest.toFile(), targetFile);
		}
	}
}
 

import com.vaadin.event.Transferable; //导入依赖的package包/类
@Override
public void drop(final DragAndDropEvent event) {
    TargetDetails targetDetails = event.getTargetDetails();
    Transferable transferable = event.getTransferable();

    MouseEventDetails mouseEventDetails = MouseEventDetails.deSerialize((String) targetDetails.getData("mouseEvent"));
    Integer absoluteLeft = (Integer) targetDetails.getData("absoluteLeft");
    Integer absoluteTop = (Integer) targetDetails.getData("absoluteTop");

    diagram.drop(
            mouseEventDetails.getClientX() - absoluteLeft,
            mouseEventDetails.getClientY() - absoluteTop,
            (String) transferable.getData("component-type")
            );
}
 

import com.vaadin.event.Transferable; //导入依赖的package包/类
private Component createDragEntry(final ToolbarItem item) {
    Entry entry = new Entry(item);
    DragAndDropWrapper drag = new DragAndDropWrapper(entry) {
        @Override
        public Transferable getTransferable(final Map<String, Object> variables) {
            variables.put("component-type", item.getName());
            return super.getTransferable(variables);
        }
    };
    drag.setSizeUndefined();
    drag.setDragStartMode(DragStartMode.COMPONENT);
    return drag;
}
 

import com.vaadin.event.Transferable; //导入依赖的package包/类
private void initTree() {
	this.setSizeFull();
	this.setImmediate(true);
	this.setSelectable(true);
	this.addItemClickListener(this);
	this.addContainerProperty("", String.class, null);
	this.addContainerProperty(ACTIONS, HorizontalLayout.class, null	);
	this.addItem(new Object[] {TOOL, getActionLayout(false, false, TOOL)}, TOOL);
	this.setItemDescriptionGenerator(new ItemDescriptionGenerator() {
		private static final long serialVersionUID = -1913286695570843896L;

		@Override
		public String generateDescription(Component source, Object itemId,
				Object propertyId) {
			String description = "Show all ";
			if(itemId.equals(TOOL))
				description += "elements";
			else if (itemId.equals(INPUTS))
				description += "inputs";
			else if (itemId.equals(OUTPUTS))
				description += "outputs";
			else if (itemId.equals(PARAMETERS))
				description += "parameters";
			else
				return null;
			return description;
		}
	});
	this.setCollapsed(TOOL, false);
	String[] rootToolElements = new String[] {INPUTS, OUTPUTS, PARAMETERS};
	for(String element : rootToolElements) {
		this.addItem(new Object[] {element, getActionLayout(true, false, element)}, element);
		this.setParent(element, TOOL);
		this.setCollapsed(element, false);
	}
	this.setDragMode(TableDragMode.ROW);
	this.setDropHandler(new DropHandler() {
		private static final long serialVersionUID = -4415321436294383112L;

		@Override
		public AcceptCriterion getAcceptCriterion() {
			return new Or(Tree.TargetItemAllowsChildren.get(), new Not(VerticalLocationIs.MIDDLE));
		}
		
		@Override
		public void drop(DragAndDropEvent event) {
            final Transferable t = event.getTransferable();
            if (t.getSourceComponent() != TreeToolEditor.this
                    || !(t instanceof DataBoundTransferable)) {
                return;
            }

            final AbstractSelectTargetDetails dropData = ((AbstractSelectTargetDetails) event.getTargetDetails());

            final Object sourceItemId = ((DataBoundTransferable) t).getItemId();
            final Object targetItemId = dropData.getItemIdOver();
            final VerticalDropLocation location = dropData.getDropLocation();

            moveNode(sourceItemId, targetItemId, location);
		}
	});

}