com.sencha.gxt.dnd.core.client.StatusProxy.java Source code

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Here is the source code for com.sencha.gxt.dnd.core.client.StatusProxy.java

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/**
 * Sencha GXT 4.0.0 - Sencha for GWT
 * Copyright (c) 2006-2015, Sencha Inc.
 *
 * licensing@sencha.com
 * http://www.sencha.com/products/gxt/license/
 *
 * ================================================================================
 * Open Source License
 * ================================================================================
 * This version of Sencha GXT is licensed under the terms of the Open Source GPL v3
 * license. You may use this license only if you are prepared to distribute and
 * share the source code of your application under the GPL v3 license:
 * http://www.gnu.org/licenses/gpl.html
 *
 * If you are NOT prepared to distribute and share the source code of your
 * application under the GPL v3 license, other commercial and oem licenses
 * are available for an alternate download of Sencha GXT.
 *
 * Please see the Sencha GXT Licensing page at:
 * http://www.sencha.com/products/gxt/license/
 *
 * For clarification or additional options, please contact:
 * licensing@sencha.com
 * ================================================================================
 *
 *
 * ================================================================================
 * Disclaimer
 * ================================================================================
 * THIS SOFTWARE IS DISTRIBUTED "AS-IS" WITHOUT ANY WARRANTIES, CONDITIONS AND
 * REPRESENTATIONS WHETHER EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION THE
 * IMPLIED WARRANTIES AND CONDITIONS OF MERCHANTABILITY, MERCHANTABLE QUALITY,
 * FITNESS FOR A PARTICULAR PURPOSE, DURABILITY, NON-INFRINGEMENT, PERFORMANCE AND
 * THOSE ARISING BY STATUTE OR FROM CUSTOM OR USAGE OF TRADE OR COURSE OF DEALING.
 * ================================================================================
 */
package com.sencha.gxt.dnd.core.client;

import com.google.gwt.core.client.GWT;
import com.google.gwt.dom.client.Element;
import com.google.gwt.resources.client.ImageResource;
import com.google.gwt.safehtml.shared.SafeHtml;
import com.google.gwt.safehtml.shared.SafeHtmlBuilder;
import com.sencha.gxt.core.client.dom.XDOM;
import com.sencha.gxt.widget.core.client.Component;

/**
 * A custom widget used to display the status of the drag operation and
 * information about the data being dragged. The widget is displayed next to the
 * cursor as the user drags data.
 */
public class StatusProxy extends Component {

    public interface StatusProxyAppearance {

        void render(SafeHtmlBuilder builder);

        void setStatus(Element parent, boolean allowed);

        void setStatus(Element parent, ImageResource icon);

        void update(Element parent, SafeHtml html);

    }

    private static final StatusProxy instance = GWT.create(StatusProxy.class);

    /**
     * Returns the singleton instance.
     * 
     * @return the status proxy
     */
    public static StatusProxy get() {
        return instance;
    }

    private boolean status;
    private final StatusProxyAppearance appearance;

    protected StatusProxy() {
        this(GWT.<StatusProxyAppearance>create(StatusProxyAppearance.class));
    }

    protected StatusProxy(StatusProxyAppearance appearance) {
        this.appearance = appearance;
        SafeHtmlBuilder builder = new SafeHtmlBuilder();
        appearance.render(builder);
        setElement((Element) XDOM.create(builder.toSafeHtml()));
        setStatus(false);

        setShadow(true);
    }

    public StatusProxyAppearance getAppearance() {
        return appearance;
    }

    /**
     * Returns true if the drop is allowed.
     * 
     * @return the status
     */
    public boolean getStatus() {
        return status;
    }

    /**
     * Updates the proxy's visual element to indicate the status of whether or not
     * drop is allowed over the current target element.
     * 
     * @param allowed true for the standard ok icon, false for standard no icon
     */
    public void setStatus(boolean allowed) {
        appearance.setStatus(getElement(), allowed);
        this.status = allowed;
    }

    /**
     * Updates the proxy's visual element to indicate the status of whether or not
     * drop is allowed over the current target element.
     * 
     * @param allowed drop is allowed
     * @param icon icon to display
     */
    public void setStatus(boolean allowed, ImageResource icon) {
        appearance.setStatus(getElement(), icon);
        this.status = allowed;
    }

    /**
     * Updates the contents of the ghost element.
     * 
     * @param html the html that will replace the current contents of the ghost
     *          element
     */
    public void update(SafeHtml html) {
        appearance.update(getElement(), html);
    }

}