JDK8/Java8源码在线阅读
/*
* Copyright (c) 1997, 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 javax.swing;
import java.awt.*;
import java.awt.image.*;
import java.beans.ConstructorProperties;
import java.beans.Transient;
import java.net.URL;
import java.io.Serializable;
import java.io.ObjectOutputStream;
import java.io.ObjectInputStream;
import java.io.IOException;
import java.util.Locale;
import javax.accessibility.*;
import sun.awt.AppContext;
import java.lang.reflect.Field;
import java.security.*;
/**
* An implementation of the Icon interface that paints Icons
* from Images. Images that are created from a URL, filename or byte array
* are preloaded using MediaTracker to monitor the loaded state
* of the image.
*
* <p>
* For further information and examples of using image icons, see
* <a href="https://docs.oracle.com/javase/tutorial/uiswing/components/icon.html">How to Use Icons</a>
* in <em>The Java Tutorial.</em>
*
* <p>
* <strong>Warning:</strong>
* Serialized objects of this class will not be compatible with
* future Swing releases. The current serialization support is
* appropriate for short term storage or RMI between applications running
* the same version of Swing. As of 1.4, support for long term storage
* of all JavaBeans™
* has been added to the <code>java.beans</code> package.
* Please see {@link java.beans.XMLEncoder}.
*
* @author Jeff Dinkins
* @author Lynn Monsanto
*/
public class ImageIcon implements Icon, Serializable, Accessible {
/* Keep references to the filename and location so that
* alternate persistence schemes have the option to archive
* images symbolically rather than including the image data
* in the archive.
*/
transient private String filename;
transient private URL location;
transient Image image;
transient int loadStatus = 0;
ImageObserver imageObserver;
String description = null;
/**
* Do not use this shared component, which is used to track image loading.
* It is left for backward compatibility only.
* @deprecated since 1.8
*/
@Deprecated
protected final static Component component;
/**
* Do not use this shared media tracker, which is used to load images.
* It is left for backward compatibility only.
* @deprecated since 1.8
*/
@Deprecated
protected final static MediaTracker tracker;
static {
component = AccessController.doPrivileged(new PrivilegedAction<Component>() {
public Component run() {
try {
final Component component = createNoPermsComponent();
// 6482575 - clear the appContext field so as not to leak it
Field appContextField =
Component.class.getDeclaredField("appContext");
appContextField.setAccessible(true);
appContextField.set(component, null);
return component;
} catch (Throwable e) {
// We don't care about component.
// So don't prevent class initialisation.
e.printStackTrace();
return null;
}
}
});
tracker = new MediaTracker(component);
}
private static Component createNoPermsComponent() {
// 7020198 - set acc field to no permissions and no subject
// Note, will have appContext set.
return AccessController.doPrivileged(
new PrivilegedAction<Component>() {
public Component run() {
return new Component() {
};
}
},
new AccessControlContext(new ProtectionDomain[]{
new ProtectionDomain(null, null)
})
);
}
/**
* Id used in loading images from MediaTracker.
*/
private static int mediaTrackerID;
private final static Object TRACKER_KEY = new StringBuilder("TRACKER_KEY");
int width = -1;
int height = -1;
/**
* Creates an ImageIcon from the specified file. The image will
* be preloaded by using MediaTracker to monitor the loading state
* of the image.
* @param filename the name of the file containing the image
* @param description a brief textual description of the image
* @see #ImageIcon(String)
*/
public ImageIcon(String filename, String description) {
image = Toolkit.getDefaultToolkit().getImage(filename);
if (image == null) {
return;
}
this.filename = filename;
this.description = description;
loadImage(image);
}
/**
* Creates an ImageIcon from the specified file. The image will
* be preloaded by using MediaTracker to monitor the loading state
* of the image. The specified String can be a file name or a
* file path. When specifying a path, use the Internet-standard
* forward-slash ("/") as a separator.
* (The string is converted to an URL, so the forward-slash works
* on all systems.)
* For example, specify:
* <pre>
* new ImageIcon("images/myImage.gif") </pre>
* The description is initialized to the <code>filename</code> string.
*
* @param filename a String specifying a filename or path
* @see #getDescription
*/
@ConstructorProperties({"description"})
public ImageIcon (String filename) {
this(filename, filename);
}
/**
* Creates an ImageIcon from the specified URL. The image will
* be preloaded by using MediaTracker to monitor the loaded state
* of the image.
* @param location the URL for the image
* @param description a brief textual description of the image
* @see #ImageIcon(String)
*/
public ImageIcon(URL location, String description) {
image = Toolkit.getDefaultToolkit().getImage(location);
if (image == null) {
return;
}
this.location = location;
this.description = description;
loadImage(image);
}
/**
* Creates an ImageIcon from the specified URL. The image will
* be preloaded by using MediaTracker to monitor the loaded state
* of the image.
* The icon's description is initialized to be
* a string representation of the URL.
* @param location the URL for the image
* @see #getDescription
*/
public ImageIcon (URL location) {
this(location, location.toExternalForm());
}
/**
* Creates an ImageIcon from the image.
* @param image the image
* @param description a brief textual description of the image
*/
public ImageIcon(Image image, String description) {
this(image);
this.description = description;
}
/**
* Creates an ImageIcon from an image object.
* If the image has a "comment" property that is a string,
* then the string is used as the description of this icon.
* @param image the image
* @see #getDescription
* @see java.awt.Image#getProperty
*/
public ImageIcon (Image image) {
this.image = image;
Object o = image.getProperty("comment", imageObserver);
if (o instanceof String) {
description = (String) o;
}
loadImage(image);
}
/**
* Creates an ImageIcon from an array of bytes which were
* read from an image file containing a supported image format,
* such as GIF, JPEG, or (as of 1.3) PNG.
* Normally this array is created
* by reading an image using Class.getResourceAsStream(), but
* the byte array may also be statically stored in a class.
*
* @param imageData an array of pixels in an image format supported
* by the AWT Toolkit, such as GIF, JPEG, or (as of 1.3) PNG
* @param description a brief textual description of the image
* @see java.awt.Toolkit#createImage
*/
public ImageIcon (byte[] imageData, String description) {
this.image = Toolkit.getDefaultToolkit().createImage(imageData);
if (image == null) {
return;
}
this.description = description;
loadImage(image);
}
/**
* Creates an ImageIcon from an array of bytes which were
* read from an image file containing a supported image format,
* such as GIF, JPEG, or (as of 1.3) PNG.
* Normally this array is created
* by reading an image using Class.getResourceAsStream(), but
* the byte array may also be statically stored in a class.
* If the resulting image has a "comment" property that is a string,
* then the string is used as the description of this icon.
*
* @param imageData an array of pixels in an image format supported by
* the AWT Toolkit, such as GIF, JPEG, or (as of 1.3) PNG
* @see java.awt.Toolkit#createImage
* @see #getDescription
* @see java.awt.Image#getProperty
*/
public ImageIcon (byte[] imageData) {
this.image = Toolkit.getDefaultToolkit().createImage(imageData);
if (image == null) {
return;
}
Object o = image.getProperty("comment", imageObserver);
if (o instanceof String) {
description = (String) o;
}
loadImage(image);
}
/**
* Creates an uninitialized image icon.
*/
public ImageIcon() {
}
/**
* Loads the image, returning only when the image is loaded.
* @param image the image
*/
protected void loadImage(Image image) {
MediaTracker mTracker = getTracker();
synchronized(mTracker) {
int id = getNextID();
mTracker.addImage(image, id);
try {
mTracker.waitForID(id, 0);
} catch (InterruptedException e) {
System.out.println("INTERRUPTED while loading Image");
}
loadStatus = mTracker.statusID(id, false);
mTracker.removeImage(image, id);
width = image.getWidth(imageObserver);
height = image.getHeight(imageObserver);
}
}
/**
* Returns an ID to use with the MediaTracker in loading an image.
*/
private int getNextID() {
synchronized(getTracker()) {
return ++mediaTrackerID;
}
}
/**
* Returns the MediaTracker for the current AppContext, creating a new
* MediaTracker if necessary.
*/
private MediaTracker getTracker() {
Object trackerObj;
AppContext ac = AppContext.getAppContext();
// Opt: Only synchronize if trackerObj comes back null?
// If null, synchronize, re-check for null, and put new tracker
synchronized(ac) {
trackerObj = ac.get(TRACKER_KEY);
if (trackerObj == null) {
Component comp = new Component() {};
trackerObj = new MediaTracker(comp);
ac.put(TRACKER_KEY, trackerObj);
}
}
return (MediaTracker) trackerObj;
}
/**
* Returns the status of the image loading operation.
* @return the loading status as defined by java.awt.MediaTracker
* @see java.awt.MediaTracker#ABORTED
* @see java.awt.MediaTracker#ERRORED
* @see java.awt.MediaTracker#COMPLETE
*/
public int getImageLoadStatus() {
return loadStatus;
}
/**
* Returns this icon's <code>Image</code>.
* @return the <code>Image</code> object for this <code>ImageIcon</code>
*/
@Transient
public Image getImage() {
return image;
}
/**
* Sets the image displayed by this icon.
* @param image the image
*/
public void setImage(Image image) {
this.image = image;
loadImage(image);
}
/**
* Gets the description of the image. This is meant to be a brief
* textual description of the object. For example, it might be
* presented to a blind user to give an indication of the purpose
* of the image.
* The description may be null.
*
* @return a brief textual description of the image
*/
public String getDescription() {
return description;
}
/**
* Sets the description of the image. This is meant to be a brief
* textual description of the object. For example, it might be
* presented to a blind user to give an indication of the purpose
* of the image.
* @param description a brief textual description of the image
*/
public void setDescription(String description) {
this.description = description;
}
/**
* Paints the icon.
* The top-left corner of the icon is drawn at
* the point (<code>x</code>, <code>y</code>)
* in the coordinate space of the graphics context <code>g</code>.
* If this icon has no image observer,
* this method uses the <code>c</code> component
* as the observer.
*
* @param c the component to be used as the observer
* if this icon has no image observer
* @param g the graphics context
* @param x the X coordinate of the icon's top-left corner
* @param y the Y coordinate of the icon's top-left corner
*/
public synchronized void paintIcon(Component c, Graphics g, int x, int y) {
if(imageObserver == null) {
g.drawImage(image, x, y, c);
} else {
g.drawImage(image, x, y, imageObserver);
}
}
/**
* Gets the width of the icon.
*
* @return the width in pixels of this icon
*/
public int getIconWidth() {
return width;
}
/**
* Gets the height of the icon.
*
* @return the height in pixels of this icon
*/
public int getIconHeight() {
return height;
}
/**
* Sets the image observer for the image. Set this
* property if the ImageIcon contains an animated GIF, so
* the observer is notified to update its display.
* For example:
* <pre>
* icon = new ImageIcon(...)
* button.setIcon(icon);
* icon.setImageObserver(button);
* </pre>
*
* @param observer the image observer
*/
public void setImageObserver(ImageObserver observer) {
imageObserver = observer;
}
/**
* Returns the image observer for the image.
*
* @return the image observer, which may be null
*/
@Transient
public ImageObserver getImageObserver() {
return imageObserver;
}
/**
* Returns a string representation of this image.
*
* @return a string representing this image
*/
public String toString() {
if (description != null) {
return description;
}
return super.toString();
}
private void readObject(ObjectInputStream s)
throws ClassNotFoundException, IOException
{
s.defaultReadObject();
int w = s.readInt();
int h = s.readInt();
int[] pixels = (int[])(s.readObject());
if (pixels != null) {
Toolkit tk = Toolkit.getDefaultToolkit();
ColorModel cm = ColorModel.getRGBdefault();
image = tk.createImage(new MemoryImageSource(w, h, cm, pixels, 0, w));
loadImage(image);
}
}
private void writeObject(ObjectOutputStream s)
throws IOException
{
s.defaultWriteObject();
int w = getIconWidth();
int h = getIconHeight();
int[] pixels = image != null? new int[w * h] : null;
if (image != null) {
try {
PixelGrabber pg = new PixelGrabber(image, 0, 0, w, h, pixels, 0, w);
pg.grabPixels();
if ((pg.getStatus() & ImageObserver.ABORT) != 0) {
throw new IOException("failed to load image contents");
}
}
catch (InterruptedException e) {
throw new IOException("image load interrupted");
}
}
s.writeInt(w);
s.writeInt(h);
s.writeObject(pixels);
}
/**
* --- Accessibility Support ---
*/
private AccessibleImageIcon accessibleContext = null;
/**
* Gets the AccessibleContext associated with this ImageIcon.
* For image icons, the AccessibleContext takes the form of an
* AccessibleImageIcon.
* A new AccessibleImageIcon instance is created if necessary.
*
* @return an AccessibleImageIcon that serves as the
* AccessibleContext of this ImageIcon
* @beaninfo
* expert: true
* description: The AccessibleContext associated with this ImageIcon.
* @since 1.3
*/
public AccessibleContext getAccessibleContext() {
if (accessibleContext == null) {
accessibleContext = new AccessibleImageIcon();
}
return accessibleContext;
}
/**
* This class implements accessibility support for the
* <code>ImageIcon</code> class. It provides an implementation of the
* Java Accessibility API appropriate to image icon user-interface
* elements.
* <p>
* <strong>Warning:</strong>
* Serialized objects of this class will not be compatible with
* future Swing releases. The current serialization support is
* appropriate for short term storage or RMI between applications running
* the same version of Swing. As of 1.4, support for long term storage
* of all JavaBeans™
* has been added to the <code>java.beans</code> package.
* Please see {@link java.beans.XMLEncoder}.
* @since 1.3
*/
protected class AccessibleImageIcon extends AccessibleContext
implements AccessibleIcon, Serializable {
/*
* AccessibleContest implementation -----------------
*/
/**
* Gets the role of this object.
*
* @return an instance of AccessibleRole describing the role of the
* object
* @see AccessibleRole
*/
public AccessibleRole getAccessibleRole() {
return AccessibleRole.ICON;
}
/**
* Gets the state of this object.
*
* @return an instance of AccessibleStateSet containing the current
* state set of the object
* @see AccessibleState
*/
public AccessibleStateSet getAccessibleStateSet() {
return null;
}
/**
* Gets the Accessible parent of this object. If the parent of this
* object implements Accessible, this method should simply return
* getParent().
*
* @return the Accessible parent of this object -- can be null if this
* object does not have an Accessible parent
*/
public Accessible getAccessibleParent() {
return null;
}
/**
* Gets the index of this object in its accessible parent.
*
* @return the index of this object in its parent; -1 if this
* object does not have an accessible parent.
* @see #getAccessibleParent
*/
public int getAccessibleIndexInParent() {
return -1;
}
/**
* Returns the number of accessible children in the object. If all
* of the children of this object implement Accessible, than this
* method should return the number of children of this object.
*
* @return the number of accessible children in the object.
*/
public int getAccessibleChildrenCount() {
/**代码未完, 请加载全部代码(NowJava.com).**/
关注时代Java
关注时代Java