src/com/vaadin/event/dd/acceptcriteria/ContainsDataFlavor.java


1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54

/*
@VaadinApache2LicenseForJavaFiles@
 */
/**
 * 
 */
package com.vaadin.event.dd.acceptcriteria;

import com.vaadin.event.Transferable;
import com.vaadin.event.dd.DragAndDropEvent;
import com.vaadin.terminal.PaintException;
import com.vaadin.terminal.PaintTarget;
import com.vaadin.terminal.gwt.client.ui.dd.VContainsDataFlavor;

/**
 * A Criterion that checks whether {@link Transferable} contains given data
 * flavor. The developer might for example accept the incoming data only if it
 * contains "Url" or "Text".
 * 
 * @since 6.3
 */
@ClientCriterion(VContainsDataFlavor.class)
public class ContainsDataFlavor extends ClientSideCriterion {

    private String dataFlavorId;

    /**
     * Constructs a new instance of {@link ContainsDataFlavor}.
     * 
     * @param dataFlawor
     *            the type of data that will be checked from
     *            {@link Transferable}
     */
    public ContainsDataFlavor(String dataFlawor) {
        dataFlavorId = dataFlawor;
    }

    @Override
    public void paintContent(PaintTarget target) throws PaintException {
        super.paintContent(target);
        target.addAttribute("p", dataFlavorId);
    }

    public boolean accept(DragAndDropEvent dragEvent) {
        return dragEvent.getTransferable().getDataFlavors()
                .contains(dataFlavorId);
    }

    @Override
    protected String getIdentifier() {
        // extending classes use client side implementation from this class
        return ContainsDataFlavor.class.getCanonicalName();
    }
}