Java tutorial
/* * Copyright 2000-2018 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.acceptcriteria; import java.util.logging.Level; import java.util.logging.Logger; import com.vaadin.event.TransferableImpl; import com.vaadin.event.dd.DragAndDropEvent; import com.vaadin.server.PaintException; import com.vaadin.server.PaintTarget; import com.vaadin.ui.Component; /** * Client side criteria that checks if the drag source is one of the given * components. * * @since 6.3 */ @SuppressWarnings("serial") public class SourceIs extends ClientSideCriterion { private final Component[] components; public SourceIs(Component... component) { components = component; } @Override public void paintContent(PaintTarget target) throws PaintException { super.paintContent(target); int paintedComponents = 0; for (int i = 0; i < components.length; i++) { Component c = components[i]; if (c.isAttached()) { target.addAttribute("component" + paintedComponents++, c); } else { Logger.getLogger(SourceIs.class.getName()).log(Level.WARNING, "SourceIs component {0} at index {1} is not attached to the component hierachy and will thus be ignored", new Object[] { c.getClass().getName(), Integer.valueOf(i) }); } } target.addAttribute("c", paintedComponents); } @Override public boolean accept(DragAndDropEvent dragEvent) { if (dragEvent.getTransferable() instanceof TransferableImpl) { Component sourceComponent = dragEvent.getTransferable().getSourceComponent(); for (Component c : components) { if (c == sourceComponent) { return true; } } } return false; } }