--- jsr166/src/jsr166e/CompletableFuture.java	2013/01/02 14:13:12	1.1
+++ jsr166/src/jsr166e/CompletableFuture.java	2013/01/02 18:20:16	1.3
@@ -403,7 +403,7 @@ public class CompletableFuture<T> implem
         }
         public final boolean exec() {
             CompletableFuture<Void> d; Throwable ex;
-            if ((d = this.dst) != null) {
+            if ((d = this.dst) != null && d.result == null) {
                 try {
                     fn.run();
                     ex = null;
@@ -425,7 +425,7 @@ public class CompletableFuture<T> implem
         }
         public final boolean exec() {
             CompletableFuture<U> d; U u; Throwable ex;
-            if ((d = this.dst) != null) {
+            if ((d = this.dst) != null && d.result == null) {
                 try {
                     u = fn.get();
                     ex = null;
@@ -450,7 +450,7 @@ public class CompletableFuture<T> implem
         }
         public final boolean exec() {
             CompletableFuture<U> d; U u; Throwable ex;
-            if ((d = this.dst) != null) {
+            if ((d = this.dst) != null && d.result == null) {
                 try {
                     u = fn.apply(arg);
                     ex = null;
@@ -477,7 +477,7 @@ public class CompletableFuture<T> implem
         }
         public final boolean exec() {
             CompletableFuture<V> d; V v; Throwable ex;
-            if ((d = this.dst) != null) {
+            if ((d = this.dst) != null && d.result == null) {
                 try {
                     v = fn.apply(arg1, arg2);
                     ex = null;
@@ -502,7 +502,7 @@ public class CompletableFuture<T> implem
         }
         public final boolean exec() {
             CompletableFuture<Void> d; Throwable ex;
-            if ((d = this.dst) != null) {
+            if ((d = this.dst) != null && d.result == null) {
                 try {
                     fn.accept(arg);
                     ex = null;
@@ -528,7 +528,7 @@ public class CompletableFuture<T> implem
         }
         public final boolean exec() {
             CompletableFuture<Void> d; Throwable ex;
-            if ((d = this.dst) != null) {
+            if ((d = this.dst) != null && d.result == null) {
                 try {
                     fn.accept(arg1, arg2);
                     ex = null;
@@ -2644,7 +2644,7 @@ public class CompletableFuture<T> implem
      * completed. This method is designed for use only in error
      * recovery actions, and even in such situations may result in
      * ongoing dependent completions using established versus
-     * overwritten values.
+     * overwritten outcomes.
      *
      * @param value the completion value
      */
@@ -2653,6 +2653,22 @@ public class CompletableFuture<T> implem
         postComplete();
     }
 
+    /**
+     * Forcibly causes subsequent invocations of method get() and
+     * related methods to throw the given exception, whether or not
+     * already completed. This method is designed for use only in
+     * recovery actions, and even in such situations may result in
+     * ongoing dependent completions using established versus
+     * overwritten outcomes.
+     *
+     * @param ex the exception
+     */
+    public void obtrudeException(Throwable ex) {
+        if (ex == null) throw new NullPointerException();
+        result = new AltResult(ex);
+        postComplete();
+    }
+
     // Unsafe mechanics
     private static final sun.misc.Unsafe UNSAFE;
     private static final long RESULT;