Java example source code file (LightweightFrame.java)

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Java - Java tags/keywords

awt, container, frame, framepeer, graphics, image, lightweightframe, override, runtimeexception, suntoolkit, suppresswarnings

The LightweightFrame.java Java example source code

/*
 * Copyright (c) 2013, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

package sun.awt;

import java.awt.Container;
import java.awt.Frame;
import java.awt.Graphics;
import java.awt.Image;
import java.awt.MenuBar;
import java.awt.MenuComponent;
import java.awt.Toolkit;
import java.awt.peer.FramePeer;

/**
 * The class provides basic functionality for a lightweight frame
 * implementation. A subclass is expected to provide painting to an
 * offscreen image and access to it. Thus it can be used for lightweight
 * embedding.
 *
 * @author Artem Ananiev
 * @author Anton Tarasov
 */
@SuppressWarnings("serial")
public abstract class LightweightFrame extends Frame {

    /**
     * Constructs a new, initially invisible {@code LightweightFrame}
     * instance.
     */
    public LightweightFrame() {
        setUndecorated(true);
        setResizable(true);
        setEnabled(true);
    }

    /**
     * Blocks introspection of a parent window by this child.
     *
     * @return null
     */
    @Override public final Container getParent() { return null; }

    @Override public Graphics getGraphics() { return null; }

    @Override public final boolean isResizable() { return true; }

    // Block modification of any frame attributes, since they aren't
    // applicable for a lightweight frame.

    @Override public final void setTitle(String title) {}
    @Override public final void setIconImage(Image image) {}
    @Override public final void setIconImages(java.util.List<? extends Image> icons) {}
    @Override public final void setMenuBar(MenuBar mb) {}
    @Override public final void setResizable(boolean resizable) {}
    @Override public final void remove(MenuComponent m) {}
    @Override public final void toFront() {}
    @Override public final void toBack() {}

    @Override public void addNotify() {
        synchronized (getTreeLock()) {
            if (getPeer() == null) {
                SunToolkit stk = (SunToolkit)Toolkit.getDefaultToolkit();
                try {
                    setPeer(stk.createLightweightFrame(this));
                } catch (Exception e) {
                    throw new RuntimeException(e);
                }
            }
            super.addNotify();
        }
    }

    private void setPeer(final FramePeer p) {
        AWTAccessor.getComponentAccessor().setPeer(this, p);
    }

    /**
     * Requests the peer to emulate activation or deactivation of the
     * frame. Peers should override this method if they are to implement
     * this functionality.
     *
     * @param activate if <code>true, activates the frame;
     *                 otherwise, deactivates the frame
     */
    public void emulateActivation(boolean activate) {
        ((FramePeer)getPeer()).emulateActivation(activate);
    }

    /**
     * Delegates the focus grab action to the client (embedding) application.
     * The method is called by the AWT grab machinery.
     *
     * @see SunToolkit#grab(java.awt.Window)
     */
    public abstract void grabFocus();

    /**
     * Delegates the focus ungrab action to the client (embedding) application.
     * The method is called by the AWT grab machinery.
     *
     * @see SunToolkit#ungrab(java.awt.Window)
     */
    public abstract void ungrabFocus();
}