src/java.base/share/classes/java/nio/channels/spi/AbstractSelectableChannel.java

rev 48757 : [mq]: nio-cleanup

@@ -1,7 +1,7 @@
 /*
- * Copyright (c) 2000, 2013, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2000, 2018, 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

@@ -24,11 +24,18 @@
  */
 
 package java.nio.channels.spi;
 
 import java.io.IOException;
-import java.nio.channels.*;
+import java.nio.channels.CancelledKeyException;
+import java.nio.channels.ClosedChannelException;
+import java.nio.channels.ClosedSelectorException;
+import java.nio.channels.IllegalBlockingModeException;
+import java.nio.channels.IllegalSelectorException;
+import java.nio.channels.SelectableChannel;
+import java.nio.channels.SelectionKey;
+import java.nio.channels.Selector;
 
 
 /**
  * Base implementation class for selectable channels.
  *

@@ -65,12 +72,12 @@
     private final Object keyLock = new Object();
 
     // Lock for registration and configureBlocking operations
     private final Object regLock = new Object();
 
-    // Blocking mode, protected by regLock
-    boolean blocking = true;
+    // Blocking mode, need regLock to change;
+    private volatile boolean nonBlocking;
 
     /**
      * Initializes a new instance of this class.
      *
      * @param  provider

@@ -195,11 +202,11 @@
         synchronized (regLock) {
             if (!isOpen())
                 throw new ClosedChannelException();
             if ((ops & ~validOps()) != 0)
                 throw new IllegalArgumentException();
-            if (blocking)
+            if (isBlocking())
                 throw new IllegalBlockingModeException();
             SelectionKey k = findKey(sel);
             if (k != null) {
                 k.interestOps(ops);
                 k.attach(att);

@@ -262,13 +269,11 @@
 
 
     // -- Blocking --
 
     public final boolean isBlocking() {
-        synchronized (regLock) {
-            return blocking;
-        }
+        return !nonBlocking;
     }
 
     public final Object blockingLock() {
         return regLock;
     }

@@ -285,16 +290,17 @@
         throws IOException
     {
         synchronized (regLock) {
             if (!isOpen())
                 throw new ClosedChannelException();
-            if (blocking == block)
-                return this;
+            boolean blocking = !nonBlocking;
+            if (block != blocking) {
             if (block && haveValidKeys())
                 throw new IllegalBlockingModeException();
             implConfigureBlocking(block);
-            blocking = block;
+                nonBlocking = !block;
+            }
         }
         return this;
     }
 
     /**