JDK8/Java8源码在线阅读
/*
* Copyright (c) 2009, 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
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package javax.swing;
import sun.awt.AWTAccessor;
import javax.swing.plaf.LayerUI;
import javax.swing.border.Border;
import javax.accessibility.*;
import java.awt.*;
import java.awt.event.*;
import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.util.ArrayList;
import java.security.AccessController;
import java.security.PrivilegedAction;
/**
* {@code JLayer} is a universal decorator for Swing components
* which enables you to implement various advanced painting effects as well as
* receive notifications of all {@code AWTEvent}s generated within its borders.
* <p>
* {@code JLayer} delegates the handling of painting and input events to a
* {@link javax.swing.plaf.LayerUI} object, which performs the actual decoration.
* <p>
* The custom painting implemented in the {@code LayerUI} and events notification
* work for the JLayer itself and all its subcomponents.
* This combination enables you to enrich existing components
* by adding new advanced functionality such as temporary locking of a hierarchy,
* data tips for compound components, enhanced mouse scrolling etc and so on.
* <p>
* {@code JLayer} is a good solution if you only need to do custom painting
* over compound component or catch input events from its subcomponents.
* <pre>
* import javax.swing.*;
* import javax.swing.plaf.LayerUI;
* import java.awt.*;
*
* public class JLayerSample {
*
* private static JLayer<JComponent> createLayer() {
* // This custom layerUI will fill the layer with translucent green
* // and print out all mouseMotion events generated within its borders
* LayerUI<JComponent> layerUI = new LayerUI<JComponent>() {
*
* public void paint(Graphics g, JComponent c) {
* // paint the layer as is
* super.paint(g, c);
* // fill it with the translucent green
* g.setColor(new Color(0, 128, 0, 128));
* g.fillRect(0, 0, c.getWidth(), c.getHeight());
* }
*
* public void installUI(JComponent c) {
* super.installUI(c);
* // enable mouse motion events for the layer's subcomponents
* ((JLayer) c).setLayerEventMask(AWTEvent.MOUSE_MOTION_EVENT_MASK);
* }
*
* public void uninstallUI(JComponent c) {
* super.uninstallUI(c);
* // reset the layer event mask
* ((JLayer) c).setLayerEventMask(0);
* }
*
* // overridden method which catches MouseMotion events
* public void eventDispatched(AWTEvent e, JLayer<? extends JComponent> l) {
* System.out.println("AWTEvent detected: " + e);
* }
* };
* // create a component to be decorated with the layer
* JPanel panel = new JPanel();
* panel.add(new JButton("JButton"));
*
* // create the layer for the panel using our custom layerUI
* return new JLayer<JComponent>(panel, layerUI);
* }
*
* private static void createAndShowGUI() {
* final JFrame frame = new JFrame();
* frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
*
* // work with the layer as with any other Swing component
* frame.add(createLayer());
*
* frame.setSize(200, 200);
* frame.setLocationRelativeTo(null);
* frame.setVisible(true);
* }
*
* public static void main(String[] args) throws Exception {
* SwingUtilities.invokeAndWait(new Runnable() {
* public void run() {
* createAndShowGUI();
* }
* });
* }
* }
* </pre>
*
* <b>Note:</b> {@code JLayer} doesn't support the following methods:
* <ul>
* <li>{@link Container#add(java.awt.Component)}</li>
* <li>{@link Container#add(String, java.awt.Component)}</li>
* <li>{@link Container#add(java.awt.Component, int)}</li>
* <li>{@link Container#add(java.awt.Component, Object)}</li>
* <li>{@link Container#add(java.awt.Component, Object, int)}</li>
* </ul>
* using any of of them will cause {@code UnsupportedOperationException} to be thrown,
* to add a component to {@code JLayer}
* use {@link #setView(Component)} or {@link #setGlassPane(JPanel)}.
*
* @param <V> the type of {@code JLayer}'s view component
*
* @see #JLayer(Component)
* @see #setView(Component)
* @see #getView()
* @see javax.swing.plaf.LayerUI
* @see #JLayer(Component, LayerUI)
* @see #setUI(javax.swing.plaf.LayerUI)
* @see #getUI()
* @since 1.7
*
* @author Alexander Potochkin
*/
public final class JLayer<V extends Component>
extends JComponent
implements Scrollable, PropertyChangeListener, Accessible {
private V view;
// this field is necessary because JComponent.ui is transient
// when layerUI is serializable
private LayerUI<? super V> layerUI;
private JPanel glassPane;
private long eventMask;
private transient boolean isPainting;
private transient boolean isPaintingImmediately;
private static final LayerEventController eventController =
new LayerEventController();
/**
* Creates a new {@code JLayer} object with a {@code null} view component
* and default {@link javax.swing.plaf.LayerUI}.
*
* @see #setView
* @see #setUI
*/
public JLayer() {
this(null);
}
/**
* Creates a new {@code JLayer} object
* with default {@link javax.swing.plaf.LayerUI}.
*
* @param view the component to be decorated by this {@code JLayer}
*
* @see #setUI
*/
public JLayer(V view) {
this(view, new LayerUI<V>());
}
/**
* Creates a new {@code JLayer} object with the specified view component
* and {@link javax.swing.plaf.LayerUI} object.
*
* @param view the component to be decorated
* @param ui the {@link javax.swing.plaf.LayerUI} delegate
* to be used by this {@code JLayer}
*/
public JLayer(V view, LayerUI<V> ui) {
setGlassPane(createGlassPane());
setView(view);
setUI(ui);
}
/**
* Returns the {@code JLayer}'s view component or {@code null}.
* <br>This is a bound property.
*
* @return the {@code JLayer}'s view component
* or {@code null} if none exists
*
* @see #setView(Component)
*/
public V getView() {
return view;
}
/**
* Sets the {@code JLayer}'s view component, which can be {@code null}.
* <br>This is a bound property.
*
* @param view the view component for this {@code JLayer}
*
* @see #getView()
*/
public void setView(V view) {
Component oldView = getView();
if (oldView != null) {
super.remove(oldView);
}
if (view != null) {
super.addImpl(view, null, getComponentCount());
}
this.view = view;
firePropertyChange("view", oldView, view);
revalidate();
repaint();
}
/**
* Sets the {@link javax.swing.plaf.LayerUI} which will perform painting
* and receive input events for this {@code JLayer}.
*
* @param ui the {@link javax.swing.plaf.LayerUI} for this {@code JLayer}
*/
public void setUI(LayerUI<? super V> ui) {
this.layerUI = ui;
super.setUI(ui);
}
/**
* Returns the {@link javax.swing.plaf.LayerUI} for this {@code JLayer}.
*
* @return the {@code LayerUI} for this {@code JLayer}
*/
public LayerUI<? super V> getUI() {
return layerUI;
}
/**
* Returns the {@code JLayer}'s glassPane component or {@code null}.
* <br>This is a bound property.
*
* @return the {@code JLayer}'s glassPane component
* or {@code null} if none exists
*
* @see #setGlassPane(JPanel)
*/
public JPanel getGlassPane() {
return glassPane;
}
/**
* Sets the {@code JLayer}'s glassPane component, which can be {@code null}.
* <br>This is a bound property.
*
* @param glassPane the glassPane component of this {@code JLayer}
*
* @see #getGlassPane()
*/
public void setGlassPane(JPanel glassPane) {
Component oldGlassPane = getGlassPane();
boolean isGlassPaneVisible = false;
if (oldGlassPane != null) {
isGlassPaneVisible = oldGlassPane.isVisible();
super.remove(oldGlassPane);
}
if (glassPane != null) {
AWTAccessor.getComponentAccessor().setMixingCutoutShape(glassPane,
new Rectangle());
glassPane.setVisible(isGlassPaneVisible);
super.addImpl(glassPane, null, 0);
}
this.glassPane = glassPane;
firePropertyChange("glassPane", oldGlassPane, glassPane);
revalidate();
repaint();
}
/**
* Called by the constructor methods to create a default {@code glassPane}.
* By default this method creates a new JPanel with visibility set to true
* and opacity set to false.
*
* @return the default {@code glassPane}
*/
public JPanel createGlassPane() {
return new DefaultLayerGlassPane();
}
/**
* Sets the layout manager for this container. This method is
* overridden to prevent the layout manager from being set.
* <p>Note: If {@code mgr} is non-{@code null}, this
* method will throw an exception as layout managers are not supported on
* a {@code JLayer}.
*
* @param mgr the specified layout manager
* @exception IllegalArgumentException this method is not supported
*/
public void setLayout(LayoutManager mgr) {
if (mgr != null) {
throw new IllegalArgumentException("JLayer.setLayout() not supported");
}
}
/**
* A non-{@code null} border, or non-zero insets, isn't supported, to prevent the geometry
* of this component from becoming complex enough to inhibit
* subclassing of {@code LayerUI} class. To create a {@code JLayer} with a border,
* add it to a {@code JPanel} that has a border.
* <p>Note: If {@code border} is non-{@code null}, this
* method will throw an exception as borders are not supported on
* a {@code JLayer}.
*
* @param border the {@code Border} to set
* @exception IllegalArgumentException this method is not supported
*/
public void setBorder(Border border) {
if (border != null) {
throw new IllegalArgumentException("JLayer.setBorder() not supported");
}
}
/**
* This method is not supported by {@code JLayer}
* and always throws {@code UnsupportedOperationException}
*
* @throws UnsupportedOperationException this method is not supported
*
* @see #setView(Component)
* @see #setGlassPane(JPanel)
*/
protected void addImpl(Component comp, Object constraints, int index) {
throw new UnsupportedOperationException(
"Adding components to JLayer is not supported, " +
"use setView() or setGlassPane() instead");
}
/**
* {@inheritDoc}
*/
public void remove(Component comp) {
if (comp == null) {
super.remove(comp);
} else if (comp == getView()) {
setView(null);
} else if (comp == getGlassPane()) {
setGlassPane(null);
} else {
super.remove(comp);
}
}
/**
* {@inheritDoc}
*/
public void removeAll() {
if (view != null) {
setView(null);
}
if (glassPane != null) {
setGlassPane(null);
}
}
/**
* Always returns {@code true} to cause painting to originate from {@code JLayer},
* or one of its ancestors.
*
* @return true
* @see JComponent#isPaintingOrigin()
*/
protected boolean isPaintingOrigin() {
return true;
}
/**
* Delegates its functionality to the
* {@link javax.swing.plaf.LayerUI#paintImmediately(int, int, int, int, JLayer)} method,
* if {@code LayerUI} is set.
*
* @param x the x value of the region to be painted
* @param y the y value of the region to be painted
* @param w the width of the region to be painted
* @param h the height of the region to be painted
*/
public void paintImmediately(int x, int y, int w, int h) {
if (!isPaintingImmediately && getUI() != null) {
isPaintingImmediately = true;
try {
getUI().paintImmediately(x, y, w, h, this);
} finally {
isPaintingImmediately = false;
}
} else {
super.paintImmediately(x, y, w, h);
}
}
/**
* Delegates all painting to the {@link javax.swing.plaf.LayerUI} object.
*
* @param g the {@code Graphics} to render to
*/
public void paint(Graphics g) {
if (!isPainting) {
isPainting = true;
try {
super.paintComponent(g);
} finally {
isPainting = false;
}
} else {
super.paint(g);
}
}
/**
* This method is empty, because all painting is done by
* {@link #paint(Graphics)} and
* {@link javax.swing.plaf.LayerUI#update(Graphics, JComponent)} methods
*/
protected void paintComponent(Graphics g) {
}
/**
* The {@code JLayer} overrides the default implementation of
* this method (in {@code JComponent}) to return {@code false}.
* This ensures
* that the drawing machinery will call the {@code JLayer}'s
* {@code paint}
* implementation rather than messaging the {@code JLayer}'s
* children directly.
*
* @return false
*/
public boolean isOptimizedDrawingEnabled() {
return false;
}
/**
* {@inheritDoc}
*/
public void propertyChange(PropertyChangeEvent evt) {
if (getUI() != null) {
getUI().applyPropertyChange(evt, this);
}
}
/**
* Enables the events from JLayer and <b>all its descendants</b>
* defined by the specified event mask parameter
* to be delivered to the
* {@link LayerUI#eventDispatched(AWTEvent, JLayer)} method.
* <p>
* Events are delivered provided that {@code LayerUI} is set
* for this {@code JLayer} and the {@code JLayer}
* is displayable.
* <p>
* The following example shows how to correctly use this method
* in the {@code LayerUI} implementations:
* <pre>
* public void installUI(JComponent c) {
* super.installUI(c);
* JLayer l = (JLayer) c;
* // this LayerUI will receive only key and focus events
* l.setLayerEventMask(AWTEvent.KEY_EVENT_MASK | AWTEvent.FOCUS_EVENT_MASK);
* }
*
* public void uninstallUI(JComponent c) {
* super.uninstallUI(c);
* JLayer l = (JLayer) c;
* // JLayer must be returned to its initial state
* l.setLayerEventMask(0);
* }
* </pre>
*
* By default {@code JLayer} receives no events and its event mask is {@code 0}.
*
* @param layerEventMask the bitmask of event types to receive
*
* @see #getLayerEventMask()
* @see LayerUI#eventDispatched(AWTEvent, JLayer)
* @see Component#isDisplayable()
*/
public void setLayerEventMask(long layerEventMask) {
long oldEventMask = getLayerEventMask();
this.eventMask = layerEventMask;
firePropertyChange("layerEventMask", oldEventMask, layerEventMask);
if (layerEventMask != oldEventMask) {
disableEvents(oldEventMask);
enableEvents(eventMask);
if (isDisplayable()) {
eventController.updateAWTEventListener(
oldEventMask, layerEventMask);
}
}
}
/**
* Returns the bitmap of event mask to receive by this {@code JLayer}
* and its {@code LayerUI}.
* <p>
* It means that {@link javax.swing.plaf.LayerUI#eventDispatched(AWTEvent, JLayer)} method
* will only receive events that match the event mask.
* <p>
* By default {@code JLayer} receives no events.
*
* @return the bitmask of event types to receive for this {@code JLayer}
*/
public long getLayerEventMask() {
return eventMask;
}
/**
* Delegates its functionality to the {@link javax.swing.plaf.LayerUI#updateUI(JLayer)} method,
* if {@code LayerUI} is set.
*/
public void updateUI() {
if (getUI() != null) {
getUI().updateUI(this);
}
}
/**
* Returns the preferred size of the viewport for a view component.
* <p>
* If the view component of this layer implements {@link Scrollable}, this method delegates its
* implementation to the view component.
*
* @return the preferred size of the viewport for a view component
*
* @see Scrollable
*/
public Dimension getPreferredScrollableViewportSize() {
if (getView() instanceof Scrollable) {
return ((Scrollable)getView()).getPreferredScrollableViewportSize();
}
return getPreferredSize();
}
/**
* Returns a scroll increment, which is required for components
* that display logical rows or columns in order to completely expose
* one block of rows or columns, depending on the value of orientation.
* <p>
* If the view component of this layer implements {@link Scrollable}, this method delegates its
* implementation to the view component.
*
* @return the "block" increment for scrolling in the specified direction
*
* @see Scrollable
*/
public int getScrollableBlockIncrement(Rectangle visibleRect,
int orientation, int direction) {
if (getView() instanceof Scrollable) {
return ((Scrollable)getView()).getScrollableBlockIncrement(visibleRect,
orientation, direction);
}
return (orientation == SwingConstants.VERTICAL) ? visibleRect.height :
visibleRect.width;
}
/**
* Returns {@code false} to indicate that the height of the viewport does not
* determine the height of the layer, unless the preferred height
* of the layer is smaller than the height of the viewport.
* <p>
* If the view component of this layer implements {@link Scrollable}, this method delegates its
* implementation to the view component.
*
* @return whether the layer should track the height of the viewport
*
* @see Scrollable
*/
public boolean getScrollableTracksViewportHeight() {
if (getView() instanceof Scrollable) {
return ((Scrollable)getView()).getScrollableTracksViewportHeight();
}
return false;
}
/**
* Returns {@code false} to indicate that the width of the viewport does not
* determine the width of the layer, unless the preferred width
* of the layer is smaller than the width of the viewport.
* <p>
* If the view component of this layer implements {@link Scrollable}, this method delegates its
* implementation to the view component.
*
* @return whether the layer should track the width of the viewport
*
* @see Scrollable
*/
public boolean getScrollableTracksViewportWidth() {
if (getView() instanceof Scrollable) {
return ((Scrollable)getView()).getScrollableTracksViewportWidth();
}
return false;
}
/**
* Returns a scroll increment, which is required for components
* that display logical rows or columns in order to completely expose
* one new row or column, depending on the value of orientation.
* Ideally, components should handle a partially exposed row or column
* by returning the distance required to completely expose the item.
* <p>
* Scrolling containers, like {@code JScrollPane}, will use this method
* each time the user requests a unit scroll.
* <p>
* If the view component of this layer implements {@link Scrollable}, this method delegates its
* implementation to the view component.
*
* @return The "unit" increment for scrolling in the specified direction.
* This value should always be positive.
*
* @see Scrollable
*/
public int getScrollableUnitIncrement(Rectangle visibleRect, int orientation,
int direction) {
if (getView() instanceof Scrollable) {
return ((Scrollable) getView()).getScrollableUnitIncrement(
visibleRect, orientation, direction);
}
return 1;
}
private void readObject(ObjectInputStream s)
throws IOException, ClassNotFoundException {
s.defaultReadObject();
if (layerUI != null) {
setUI(layerUI);
}
if (eventMask != 0) {
eventController.updateAWTEventListener(0, eventMask);
}
}
/**
* {@inheritDoc}
*/
public void addNotify() {
super.addNotify();
eventController.updateAWTEventListener(0, eventMask);
}
/**
* {@inheritDoc}
*/
public void removeNotify() {
super.removeNotify();
eventController.updateAWTEventListener(eventMask, 0);
}
/**
* Delegates its functionality to the {@link javax.swing.plaf.LayerUI#doLayout(JLayer)} method,
* if {@code LayerUI} is set.
*/
public void doLayout() {
if (getUI() != null) {
getUI().doLayout(this);
}
}
/**
* Gets the AccessibleContext associated with this {@code JLayer}.
*
* @return the AccessibleContext associated with this {@code JLayer}.
*/
public AccessibleContext getAccessibleContext() {
if (accessibleContext == null) {
accessibleContext = new AccessibleJComponent() {
public AccessibleRole getAccessibleRole() {
return AccessibleRole.PANEL;
}
};
}
return accessibleContext;
}
/**
* static AWTEventListener to be shared with all AbstractLayerUIs
*/
private static class LayerEventController implements AWTEventListener {
private ArrayList<Long> layerMaskList =
new ArrayList<Long>();
private long currentEventMask;
private static final long ACCEPTED_EVENTS =
AWTEvent.COMPONENT_EVENT_MASK |
AWTEvent.CONTAINER_EVENT_MASK |
AWTEvent.FOCUS_EVENT_MASK |
AWTEvent.KEY_EVENT_MASK |
AWTEvent.MOUSE_WHEEL_EVENT_MASK |
AWTEvent.MOUSE_MOTION_EVENT_MASK |
AWTEvent.MOUSE_EVENT_MASK |
AWTEvent.INPUT_METHOD_EVENT_MASK |
AWTEvent.HIERARCHY_EVENT_MASK |
AWTEvent.HIERARCHY_BOUNDS_EVENT_MASK;
@SuppressWarnings("unchecked")
public void eventDispatched(AWTEvent event) {
Object source = event.getSource();
if (source instanceof Component) {
Component component = (Component) source;
while (component != null) {
if (component instanceof JLayer) {
JLayer l = (JLayer) component;
LayerUI ui = l.getUI();
if (ui != null &&
isEventEnabled(l.getLayerEventMask(), event.getID()) &&
(!(event instanceof InputEvent) || !((InputEvent)event).isConsumed())) {
ui.eventDispatched(event, l);
}
}
component = component.getParent();
}
}
}
private void updateAWTEventListener(long oldEventMask, long newEventMask) {
if (oldEventMask != 0) {
layerMaskList.remove(oldEventMask);
}
if (newEventMask != 0) {
layerMaskList.add(newEventMask);
}
long combinedMask = 0;
for (Long mask : layerMaskList) {
combinedMask |= mask;
}
// filter out all unaccepted events
combinedMask &= ACCEPTED_EVENTS;
if (combinedMask == 0) {
removeAWTEventListener();
} else if (getCurrentEventMask() != combinedMask) {
removeAWTEventListener();
addAWTEventListener(combinedMask);
}
currentEventMask = combinedMask;
}
private long getCurrentEventMask() {
return currentEventMask;
}
private void addAWTEventListener(final long eventMask) {
AccessController.doPrivileged(new PrivilegedAction<Void>() {
public Void run() {
Toolkit.getDefaultToolkit().
addAWTEventListener(LayerEventController.this, eventMask);
return null;
}
});
}
private void removeAWTEventListener() {
AccessController.doPrivileged(new PrivilegedAction<Void>() {
public Void run() {
Toolkit.getDefaultToolkit().
removeAWTEventListener(LayerEventController.this);
return null;
}
});
}
private boolean isEventEnabled(long eventMask, int id) {
return (((eventMask & AWTEvent.COMPONENT_EVENT_MASK) != 0 &&
id >= ComponentEvent.COMPONENT_FIRST &&
id <= ComponentEvent.COMPONENT_LAST)
|| ((eventMask & AWTEvent.CONTAINER_EVENT_MASK) != 0 &&
id >= ContainerEvent.CONTAINER_FIRST &&
id <= ContainerEvent.CONTAINER_LAST)
|| ((eventMask & AWTEvent.FOCUS_EVENT_MASK) != 0 &&
id >= FocusEvent.FOCUS_FIRST &&
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