src/java.desktop/share/classes/sun/awt/NullComponentPeer.java

/*
 * Copyright (c) 2000, 2020, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * 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.
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 * 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
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package sun.awt;

import java.awt.AWTException;
import java.awt.BufferCapabilities;
import java.awt.Color;
import java.awt.Component;
import java.awt.Cursor;
import java.awt.Dimension;
import java.awt.Event;
import java.awt.Font;
import java.awt.FontMetrics;
import java.awt.Graphics;
import java.awt.GraphicsConfiguration;
import java.awt.Image;
import java.awt.Insets;
import java.awt.Point;
import java.awt.Rectangle;
import java.awt.event.FocusEvent.Cause;
import java.awt.event.PaintEvent;
import java.awt.image.ColorModel;
import java.awt.image.VolatileImage;
import java.awt.peer.CanvasPeer;
import java.awt.peer.ComponentPeer;
import java.awt.peer.ContainerPeer;
import java.awt.peer.LightweightPeer;
import java.awt.peer.PanelPeer;

import sun.java2d.pipe.Region;

/**
 * Implements the LightweightPeer interface for use in lightweight components
 * that have no native window associated with them.  This gets created by
 * default in Component so that Component and Container can be directly
 * extended to create useful components written entirely in java.  These
 * components must be hosted somewhere higher up in the component tree by a
 * native container (such as a Frame).
 *
 * This implementation provides no useful semantics and serves only as a
 * marker.  One could provide alternative implementations in java that do
 * something useful for some of the other peer interfaces to minimize the
 * native code.
 *
 * This was renamed from java.awt.LightweightPeer (a horrible and confusing
 * name) and moved from java.awt.Toolkit into sun.awt as a public class in
 * its own file.
 *
 * @author Timothy Prinzing
 * @author Michael Martak
 */
public class NullComponentPeer implements LightweightPeer,
    CanvasPeer, PanelPeer {

    public boolean isObscured() {
        return false;
    }

    public boolean canDetermineObscurity() {
        return false;
    }

    public boolean isFocusable() {
        return false;
    }

    public void setVisible(boolean b) {
    }

    public void show() {
    }

    public void hide() {
    }

    public void setEnabled(boolean b) {
    }

    public void enable() {
    }

    public void disable() {
    }

    public void paint(Graphics g) {
    }

    public void repaint(long tm, int x, int y, int width, int height) {
    }

    public void print(Graphics g) {
    }

    public void setBounds(int x, int y, int width, int height, int op) {
    }

    public void reshape(int x, int y, int width, int height) {
    }

    public void coalescePaintEvent(PaintEvent e) {
    }

    @SuppressWarnings("deprecation")
    public boolean handleEvent(Event e) {
        return false;
    }

    public void handleEvent(java.awt.AWTEvent arg0) {
    }

    public Dimension getPreferredSize() {
        return new Dimension(1,1);
    }

    public Dimension getMinimumSize() {
        return new Dimension(1,1);
    }

    public ColorModel getColorModel() {
        return null;
    }

    public Graphics getGraphics() {
        return null;
    }

    public GraphicsConfiguration getGraphicsConfiguration() {
        return null;
    }

    public FontMetrics  getFontMetrics(Font font) {
        return null;
    }

    public void dispose() {
    // no native code
    }

    public void setForeground(Color c) {
    }

    public void setBackground(Color c) {
    }

    public void setFont(Font f) {
    }

    public void updateCursorImmediately() {
    }

    public void setCursor(Cursor cursor) {
    }

    public boolean requestFocus
        (Component lightweightChild, boolean temporary,
         boolean focusedWindowChangeAllowed, long time, Cause cause) {
        return false;
    }

    public Image createImage(int width, int height) {
        return null;
    }

    public Dimension preferredSize() {
        return getPreferredSize();
    }

    public Dimension minimumSize() {
        return getMinimumSize();
    }

    public Point getLocationOnScreen() {
        return new Point(0,0);
    }

    public Insets getInsets() {
        return insets();
    }

    public void beginValidate() {
    }

    public void endValidate() {
    }

    public Insets insets() {
        return new Insets(0, 0, 0, 0);
    }

    public boolean isPaintPending() {
        return false;
    }

    public boolean handlesWheelScrolling() {
        return false;
    }

    public VolatileImage createVolatileImage(int width, int height) {
        return null;
    }

    public void beginLayout() {
    }

    public void endLayout() {
    }

    public void createBuffers(int numBuffers, BufferCapabilities caps)
        throws AWTException {
        throw new AWTException(
            "Page-flipping is not allowed on a lightweight component");
    }
    public Image getBackBuffer() {
        throw new IllegalStateException(
            "Page-flipping is not allowed on a lightweight component");
    }
    public void flip(int x1, int y1, int x2, int y2,
                     BufferCapabilities.FlipContents flipAction)
    {
        throw new IllegalStateException(
            "Page-flipping is not allowed on a lightweight component");
    }
    public void destroyBuffers() {
    }

    /**
     * @see java.awt.peer.ComponentPeer#isReparentSupported
     */
    public boolean isReparentSupported() {
        return false;
    }

    /**
     * @see java.awt.peer.ComponentPeer#reparent
     */
    public void reparent(ContainerPeer newNativeParent) {
        throw new UnsupportedOperationException();
    }

    public void layout() {
    }

    public Rectangle getBounds() {
        return new Rectangle(0, 0, 0, 0);
    }


    /**
      * Applies the shape to the native component window.
      * @since 1.7
      */
    public void applyShape(Region shape) {
    }

    /**
     * Lowers this component at the bottom of the above HW peer. If the above parameter
     * is null then the method places this component at the top of the Z-order.
     */
    public void setZOrder(ComponentPeer above) {
    }

    public boolean updateGraphicsData(GraphicsConfiguration gc) {
        return false;
    }

    public GraphicsConfiguration getAppropriateGraphicsConfiguration(
                        GraphicsConfiguration gc)
    {
        return gc;
    }
}