com.vaadin.event.dd.DragSource Maven / Gradle / Ivy
/*
* Copyright 2000-2014 Vaadin Ltd.
*
* Licensed under the Apache License, Version 2.0 (the "License"); you may not
* use this file except in compliance with the License. You may obtain a copy of
* the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations under
* the License.
*/
package com.vaadin.event.dd;
import java.util.Map;
import com.vaadin.event.Transferable;
import com.vaadin.event.dd.acceptcriteria.AcceptCriterion;
import com.vaadin.ui.Component;
import com.vaadin.ui.Tree;
/**
* DragSource is a {@link Component} that builds a {@link Transferable} for a
* drag and drop operation.
*
* In Vaadin the drag and drop operation practically starts from client side
* component. The client side component initially defines the data that will be
* present in {@link Transferable} object on server side. If the server side
* counterpart of the component implements this interface, terminal
* implementation lets it create the {@link Transferable} instance from the raw
* client side "seed data". This way server side implementation may translate or
* extend the data that will be available for {@link DropHandler}.
*
* @since 6.3
*
*/
public interface DragSource extends Component {
/**
* DragSource may convert data added by client side component to meaningful
* values for server side developer or add other data based on it.
*
*
* For example Tree converts item identifiers to generated string keys for
* the client side. Vaadin developer don't and can't know anything about
* these generated keys, only about item identifiers. When tree node is
* dragged client puts that key to {@link Transferable}s client side
* counterpart. In {@link Tree#getTransferable(Map)} the key is converted
* back to item identifier that the server side developer can use.
*
*
* @since 6.3
* @param rawVariables
* the data that client side initially included in
* {@link Transferable}s client side counterpart.
* @return the {@link Transferable} instance that will be passed to
* {@link DropHandler} (and/or {@link AcceptCriterion})
*/
public Transferable getTransferable(Map rawVariables);
}