Include a message when a task is rejected from an executor.

Browser folks have been seeing this exception in their logcat logs
and it would be handy to give them some insight on why the pool
rejected the task.

Change-Id: I7257b3b174e6e2342e63238a542095bb3f7845f2
http://b/issue?id=3023092

2 files changed, 43 insertions, 1 deletions

diff --git a/luni/src/main/java/java/util/concurrent/ThreadPoolExecutor.java b/luni/src/main/java/java/util/concurrent/ThreadPoolExecutor.java
index 9bddc8d..7efa78b 100644
--- a/luni/src/main/java/java/util/concurrent/ThreadPoolExecutor.java
+++ b/luni/src/main/java/java/util/concurrent/ThreadPoolExecutor.java
@@ -1947,7 +1947,20 @@ public class ThreadPoolExecutor extends AbstractExecutorService {
          * @throws RejectedExecutionException always.
          */
         public void rejectedExecution(Runnable r, ThreadPoolExecutor e) {
-            throw new RejectedExecutionException();
+            // BEGIN android-changed
+            //     provide diagnostic messaging for a common exception
+
+            // a message is helpful even if it isn't created atomically
+            int queueSize = e.getQueue().size();
+            int remainingCapacity = e.getQueue().remainingCapacity();
+            String message = "pool=" + e.getPoolSize() + "/" + e.maximumPoolSize
+                    + ", queue=" + queueSize;
+            if (remainingCapacity != Integer.MAX_VALUE) {
+                message += "/" + (queueSize + remainingCapacity);
+            }
+            throw new RejectedExecutionException(message);
+
+            // END android-changed
         }
     }
 
diff --git a/luni/src/test/java/tests/api/java/util/concurrent/ThreadPoolExecutorTest.java b/luni/src/test/java/tests/api/java/util/concurrent/ThreadPoolExecutorTest.java
index 9b7fcac..b706185 100755
--- a/luni/src/test/java/tests/api/java/util/concurrent/ThreadPoolExecutorTest.java
+++ b/luni/src/test/java/tests/api/java/util/concurrent/ThreadPoolExecutorTest.java
@@ -1479,4 +1479,33 @@ public class ThreadPoolExecutorTest extends JSR166TestCase {
         }
     }
 
+    // BEGIN android-added
+    /** http://b/3046427 */
+    public void testRejected() {
+        BlockingQueue<Runnable> queue = new LinkedBlockingQueue<Runnable>(2);
+        ExecutorService executor = new ThreadPoolExecutor(0, 2, 1, TimeUnit.SECONDS, queue);
+        executor.submit(new Sleeper()); // thread #1
+        executor.submit(new Sleeper()); // thread #2
+        executor.submit(new Sleeper()); // queue #1
+        executor.submit(new Sleeper()); // queue #2
+        try {
+            executor.submit(new Sleeper());
+            fail();
+        } catch (RejectedExecutionException expected) {
+            System.out.println(expected.getMessage());
+            assertNotNull(expected.getMessage());
+        }
+        executor.shutdown();
+    }
+
+    static class Sleeper implements Runnable {
+        public void run() {
+            try {
+                Thread.sleep(1000);
+            } catch (InterruptedException e) {
+                e.printStackTrace();
+            }
+        }
+    }
+    // END android-added
 }