src/share/classes/sun/applet/AppletImageRef.java

*** 1,7 ****
  /*
!  * Copyright (c) 1996, 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
--- 1,7 ----
  /*
!  * Copyright (c) 1995, 2014, 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
*** 25,54 ****
  
  package sun.applet;
  
  import java.awt.Toolkit;
  import java.awt.Image;
  import sun.awt.image.URLImageSource;
  import java.net.URL;
  
! class AppletImageRef extends sun.misc.Ref {
      URL url;
  
      /**
       * Create the Ref
       */
      AppletImageRef(URL url) {
          this.url = url;
      }
  
!     public void flush() {
!         super.flush();
      }
  
      /**
       * Reconsitute the image.  Only called when the ref has been flushed.
       */
!     public Object reconstitute() {
          Image img = Toolkit.getDefaultToolkit().createImage(new URLImageSource(url));
          return img;
      }
  }
--- 25,98 ----
  
  package sun.applet;
  
  import java.awt.Toolkit;
  import java.awt.Image;
+ import java.lang.ref.SoftReference;
  import sun.awt.image.URLImageSource;
  import java.net.URL;
  
! class AppletImageRef {
!     private SoftReference<Image> soft = null;
! 
      URL url;
  
      /**
+      * Returns a pointer to the object referenced by this Ref.  If the object
+      * has been thrown away by the garbage collector, it will be
+      * reconstituted. This method does everything necessary to ensure that the garbage
+      * collector throws things away in Least Recently Used(LRU) order.  Applications should
+      * never override this method. The get() method effectively caches calls to
+      * reconstitute().
+      */
+     public synchronized Image get() {
+         Image t = check();
+         if (t == null) {
+             t = reconstitute();
+             setThing(t);
+         }
+         return t;
+     }
+ 
+     /**
       * Create the Ref
       */
      AppletImageRef(URL url) {
          this.url = url;
      }
  
!     /**
!      * Flushes the cached object.  Forces the next invocation of get() to
!      * invoke reconstitute().
!      */
!     public synchronized void flush() {
!         SoftReference s = soft;
!         if (s != null) s.clear();
!         soft = null;
!     }
! 
!     /**
!      * Sets the thing to the specified object.
!      * @param thing the specified object
!      */
!     public synchronized void setThing(Object thing) {
!         flush();
!         soft = new SoftReference(thing);
!     }
! 
!     /**
!      * Checks to see what object is being pointed at by this Ref and returns it.
!      */
!     public synchronized Image check() {
!         SoftReference<Image> s = soft;
!         if (s == null) return null;
!         return s.get();
      }
  
      /**
       * Reconsitute the image.  Only called when the ref has been flushed.
       */
!     public Image reconstitute() {
          Image img = Toolkit.getDefaultToolkit().createImage(new URLImageSource(url));
          return img;
      }
  }