8376434: Remove AppContext from awt ImageFetcher implementation

Reviewed-by: azvegint, aivanov

Author: prrace

src/java.desktop/share/classes/sun/awt/image/ImageFetcher.java

@@ -26,18 +26,13 @@
 package sun.awt.image;
 
 import java.util.Vector;
-import sun.awt.AppContext;
 
 /**
   * An ImageFetcher is a thread used to fetch ImageFetchable objects.
   * Once an ImageFetchable object has been fetched, the ImageFetcher
   * thread may also be used to animate it if necessary, via the
   * startingAnimation() / stoppingAnimation() methods.
   *
-  * There can be up to FetcherInfo.MAX_NUM_FETCHERS_PER_APPCONTEXT
-  * ImageFetcher threads for each AppContext.  A per-AppContext queue
-  * of ImageFetchables is used to track objects to fetch.
-  *
   * @author Jim Graham
   * @author Fred Ecks
   */
@@ -153,7 +148,6 @@ private static ImageFetchable nextImage() {
                         info.numWaiting++;
                         info.waitList.wait(end - now);
                     } catch (InterruptedException e) {
-                        // A normal occurrence as an AppContext is disposed
                         return null;
                     } finally {
                         info.numWaiting--;
@@ -280,28 +274,20 @@ private static void createFetchers(final FetcherInfo info) {
        // We need to instantiate a new ImageFetcher thread.
        // First, figure out which ThreadGroup we'll put the
        // new ImageFetcher into
-       final AppContext appContext = AppContext.getAppContext();
-       ThreadGroup threadGroup = appContext.getThreadGroup();
-       ThreadGroup fetcherThreadGroup;
-       if (threadGroup.getParent() != null) {
-           // threadGroup is not the root, so we proceed
-           fetcherThreadGroup = threadGroup;
-       } else {
-           // threadGroup is the root ("system") ThreadGroup.
-           // We instead want to use its child: the "main"
-           // ThreadGroup.  Thus, we start with the current
-           // ThreadGroup, and go up the tree until
-           // threadGroup.getParent().getParent() == null.
-           threadGroup = Thread.currentThread().getThreadGroup();
-           ThreadGroup parent = threadGroup.getParent();
-           while ((parent != null)
-                && (parent.getParent() != null)) {
-                threadGroup = parent;
-                parent = threadGroup.getParent();
-           }
-           fetcherThreadGroup = threadGroup;
+       // We don't want the root ("system") ThreadGroup.
+       // We instead want to use its child: the "main"
+       // ThreadGroup.  Thus, we start with the current
+       // ThreadGroup, and go up the tree until
+       // threadGroup.getParent().getParent() == null.
+       ThreadGroup threadGroup = Thread.currentThread().getThreadGroup();
+       ThreadGroup parent = threadGroup.getParent();
+       while ((parent != null)
+            && (parent.getParent() != null)) {
+            threadGroup = parent;
+            parent = threadGroup.getParent();
        }
-       final ThreadGroup fetcherGroup = fetcherThreadGroup;
+       final ThreadGroup fetcherGroup = threadGroup;
+
 
        for (int i = 0; i < info.fetchers.length; i++) {
            if (info.fetchers[i] == null) {
@@ -320,38 +306,27 @@ private static void createFetchers(final FetcherInfo info) {
 }
 
 /**
-  * The FetcherInfo class encapsulates the per-AppContext ImageFetcher
+  * The FetcherInfo class encapsulates the ImageFetcher
   * information.  This includes the array of ImageFetchers, as well as
   * the queue of ImageFetchable objects.
   */
 class FetcherInfo {
-    static final int MAX_NUM_FETCHERS_PER_APPCONTEXT = 4;
+    static final int MAX_NUM_FETCHERS = 4;
+    static final FetcherInfo FETCHER_INFO = new FetcherInfo();
 
     Thread[] fetchers;
     int numFetchers;
     int numWaiting;
     Vector<ImageFetchable> waitList;
 
     private FetcherInfo() {
-        fetchers = new Thread[MAX_NUM_FETCHERS_PER_APPCONTEXT];
+        fetchers = new Thread[MAX_NUM_FETCHERS];
         numFetchers = 0;
         numWaiting = 0;
         waitList = new Vector<>();
     }
 
-    /* The key to put()/get() the FetcherInfo into/from the AppContext. */
-    private static final Object FETCHER_INFO_KEY =
-                                        new StringBuffer("FetcherInfo");
-
     static FetcherInfo getFetcherInfo() {
-        AppContext appContext = AppContext.getAppContext();
-        synchronized(appContext) {
-            FetcherInfo info = (FetcherInfo)appContext.get(FETCHER_INFO_KEY);
-            if (info == null) {
-                info = new FetcherInfo();
-                appContext.put(FETCHER_INFO_KEY, info);
-            }
-            return info;
-        }
+        return FETCHER_INFO;
     }
 }