--- jsr166/src/test/tck/DelayQueueTest.java	2003/09/07 20:39:11	1.2
+++ jsr166/src/test/tck/DelayQueueTest.java	2010/08/25 00:07:03	1.31
@@ -1,57 +1,52 @@
 /*
- * Written by members of JCP JSR-166 Expert Group and released to the
- * public domain. Use, modify, and redistribute this code in any way
- * without acknowledgement. Other contributors include Andrew Wright,
- * Jeffrey Hayes, Pat Fischer, Mike Judd.
+ * Written by Doug Lea with assistance from members of JCP JSR-166
+ * Expert Group and released to the public domain, as explained at
+ * http://creativecommons.org/licenses/publicdomain
+ * Other contributors include Andrew Wright, Jeffrey Hayes,
+ * Pat Fisher, Mike Judd.
  */
 
 import junit.framework.*;
 import java.util.*;
+import static java.util.concurrent.TimeUnit.MILLISECONDS;
 import java.util.concurrent.*;
 
-public class DelayQueueTest extends TestCase {
-
-    private static final int N = 10;
-    private static final long SHORT_DELAY_MS = 100; 
-    private static final long MEDIUM_DELAY_MS = 1000;
-    private static final long LONG_DELAY_MS = 10000; 
-    private static final int NOCAP = Integer.MAX_VALUE;
-
+public class DelayQueueTest extends JSR166TestCase {
     public static void main(String[] args) {
-	junit.textui.TestRunner.run (suite());	
+        junit.textui.TestRunner.run(suite());
     }
 
     public static Test suite() {
-	return new TestSuite(DelayQueueTest.class);
+        return new TestSuite(DelayQueueTest.class);
     }
 
-    // Most Q/BQ tests use Pseudodelays, where delays are all elapsed
-    // (so, no blocking solely for delays) but are still ordered
+    private static final int NOCAP = Integer.MAX_VALUE;
 
-    static class PDelay implements Delayed { 
+    /**
+     * A delayed implementation for testing.
+     * Most tests use Pseudodelays, where delays are all elapsed
+     * (so, no blocking solely for delays) but are still ordered
+     */
+    static class PDelay implements Delayed {
         int pseudodelay;
         PDelay(int i) { pseudodelay = Integer.MIN_VALUE + i; }
-        public int compareTo(Object y) {
+        public int compareTo(PDelay y) {
             int i = pseudodelay;
-            int j = ((PDelay)y).pseudodelay;
+            int j = y.pseudodelay;
             if (i < j) return -1;
             if (i > j) return 1;
             return 0;
         }
 
-        public int compareTo(PDelay y) {
-            int i = pseudodelay;
-            int j = ((PDelay)y).pseudodelay;
-            if (i < j) return -1;
-            if (i > j) return 1;
-            return 0;
+        public int compareTo(Delayed y) {
+            return compareTo((PDelay)y);
         }
 
         public boolean equals(Object other) {
-            return ((PDelay)other).pseudodelay == pseudodelay;
+            return equals((PDelay)other);
         }
         public boolean equals(PDelay other) {
-            return ((PDelay)other).pseudodelay == pseudodelay;
+            return other.pseudodelay == pseudodelay;
         }
 
 
@@ -68,70 +63,121 @@ public class DelayQueueTest extends Test
     }
 
 
+    /**
+     * Delayed implementation that actually delays
+     */
+    static class NanoDelay implements Delayed {
+        long trigger;
+        NanoDelay(long i) {
+            trigger = System.nanoTime() + i;
+        }
+        public int compareTo(NanoDelay y) {
+            long i = trigger;
+            long j = y.trigger;
+            if (i < j) return -1;
+            if (i > j) return 1;
+            return 0;
+        }
+
+        public int compareTo(Delayed y) {
+            return compareTo((NanoDelay)y);
+        }
+
+        public boolean equals(Object other) {
+            return equals((NanoDelay)other);
+        }
+        public boolean equals(NanoDelay other) {
+            return other.trigger == trigger;
+        }
+
+        public long getDelay(TimeUnit unit) {
+            long n = trigger - System.nanoTime();
+            return unit.convert(n, TimeUnit.NANOSECONDS);
+        }
+
+        public long getTriggerTime() {
+            return trigger;
+        }
+
+        public String toString() {
+            return String.valueOf(trigger);
+        }
+    }
 
 
     /**
      * Create a queue of given size containing consecutive
      * PDelays 0 ... n.
      */
-    private DelayQueue fullQueue(int n) {
+    private DelayQueue populatedQueue(int n) {
         DelayQueue q = new DelayQueue();
         assertTrue(q.isEmpty());
-	for(int i = n-1; i >= 0; i-=2)
-	    assertTrue(q.offer(new PDelay(i)));
-	for(int i = (n & 1); i < n; i+=2)
-	    assertTrue(q.offer(new PDelay(i)));
+        for (int i = n-1; i >= 0; i-=2)
+            assertTrue(q.offer(new PDelay(i)));
+        for (int i = (n & 1); i < n; i+=2)
+            assertTrue(q.offer(new PDelay(i)));
         assertFalse(q.isEmpty());
         assertEquals(NOCAP, q.remainingCapacity());
-	assertEquals(n, q.size());
+        assertEquals(n, q.size());
         return q;
     }
- 
-    public void testConstructor1(){
+
+    /**
+     * A new queue has unbounded capacity
+     */
+    public void testConstructor1() {
         assertEquals(NOCAP, new DelayQueue().remainingCapacity());
     }
 
-    public void testConstructor3(){
-
+    /**
+     * Initializing from null Collection throws NPE
+     */
+    public void testConstructor3() {
         try {
             DelayQueue q = new DelayQueue(null);
-            fail("Cannot make from null collection");
-        }
-        catch (NullPointerException success) {}
+            shouldThrow();
+        } catch (NullPointerException success) {}
     }
 
-    public void testConstructor4(){
+    /**
+     * Initializing from Collection of null elements throws NPE
+     */
+    public void testConstructor4() {
         try {
-            PDelay[] ints = new PDelay[N];
+            PDelay[] ints = new PDelay[SIZE];
             DelayQueue q = new DelayQueue(Arrays.asList(ints));
-            fail("Cannot make with null elements");
-        }
-        catch (NullPointerException success) {}
+            shouldThrow();
+        } catch (NullPointerException success) {}
     }
 
-    public void testConstructor5(){
+    /**
+     * Initializing from Collection with some null elements throws NPE
+     */
+    public void testConstructor5() {
         try {
-            PDelay[] ints = new PDelay[N];
-            for (int i = 0; i < N-1; ++i)
+            PDelay[] ints = new PDelay[SIZE];
+            for (int i = 0; i < SIZE-1; ++i)
                 ints[i] = new PDelay(i);
             DelayQueue q = new DelayQueue(Arrays.asList(ints));
-            fail("Cannot make with null elements");
-        }
-        catch (NullPointerException success) {}
+            shouldThrow();
+        } catch (NullPointerException success) {}
     }
 
-    public void testConstructor6(){
-        try {
-            PDelay[] ints = new PDelay[N];
-            for (int i = 0; i < N; ++i)
-                ints[i] = new PDelay(i);
-            DelayQueue q = new DelayQueue(Arrays.asList(ints));
-            for (int i = 0; i < N; ++i)
-                assertEquals(ints[i], q.poll());
-        }
-        finally {}
+    /**
+     * Queue contains all elements of collection used to initialize
+     */
+    public void testConstructor6() {
+        PDelay[] ints = new PDelay[SIZE];
+        for (int i = 0; i < SIZE; ++i)
+            ints[i] = new PDelay(i);
+        DelayQueue q = new DelayQueue(Arrays.asList(ints));
+        for (int i = 0; i < SIZE; ++i)
+            assertEquals(ints[i], q.poll());
     }
 
+    /**
+     * isEmpty is true before add, false after
+     */
     public void testEmpty() {
         DelayQueue q = new DelayQueue();
         assertTrue(q.isEmpty());
@@ -144,371 +190,419 @@ public class DelayQueueTest extends Test
         assertTrue(q.isEmpty());
     }
 
-    public void testRemainingCapacity(){
-        DelayQueue q = fullQueue(N);
-        for (int i = 0; i < N; ++i) {
+    /**
+     * remainingCapacity does not change when elements added or removed,
+     * but size does
+     */
+    public void testRemainingCapacity() {
+        DelayQueue q = populatedQueue(SIZE);
+        for (int i = 0; i < SIZE; ++i) {
             assertEquals(NOCAP, q.remainingCapacity());
-            assertEquals(N-i, q.size());
+            assertEquals(SIZE-i, q.size());
             q.remove();
         }
-        for (int i = 0; i < N; ++i) {
+        for (int i = 0; i < SIZE; ++i) {
             assertEquals(NOCAP, q.remainingCapacity());
             assertEquals(i, q.size());
             q.add(new PDelay(i));
         }
     }
 
-    public void testOfferNull(){
-	try {
+    /**
+     * offer(null) throws NPE
+     */
+    public void testOfferNull() {
+        try {
             DelayQueue q = new DelayQueue();
             q.offer(null);
-            fail("should throw NPE");
-        } catch (NullPointerException success) { }   
+            shouldThrow();
+        } catch (NullPointerException success) {}
     }
 
+    /**
+     * add(null) throws NPE
+     */
+    public void testAddNull() {
+        try {
+            DelayQueue q = new DelayQueue();
+            q.add(null);
+            shouldThrow();
+        } catch (NullPointerException success) {}
+    }
+
+    /**
+     * offer non-null succeeds
+     */
     public void testOffer() {
         DelayQueue q = new DelayQueue();
         assertTrue(q.offer(new PDelay(0)));
         assertTrue(q.offer(new PDelay(1)));
     }
 
-    public void testAdd(){
+    /**
+     * add succeeds
+     */
+    public void testAdd() {
         DelayQueue q = new DelayQueue();
-        for (int i = 0; i < N; ++i) {
+        for (int i = 0; i < SIZE; ++i) {
             assertEquals(i, q.size());
             assertTrue(q.add(new PDelay(i)));
         }
     }
 
-    public void testAddAll1(){
+    /**
+     * addAll(null) throws NPE
+     */
+    public void testAddAll1() {
         try {
             DelayQueue q = new DelayQueue();
             q.addAll(null);
-            fail("Cannot add null collection");
-        }
-        catch (NullPointerException success) {}
+            shouldThrow();
+        } catch (NullPointerException success) {}
+    }
+
+
+    /**
+     * addAll(this) throws IAE
+     */
+    public void testAddAllSelf() {
+        try {
+            DelayQueue q = populatedQueue(SIZE);
+            q.addAll(q);
+            shouldThrow();
+        } catch (IllegalArgumentException success) {}
     }
-    public void testAddAll2(){
+
+    /**
+     * addAll of a collection with null elements throws NPE
+     */
+    public void testAddAll2() {
         try {
             DelayQueue q = new DelayQueue();
-            PDelay[] ints = new PDelay[N];
+            PDelay[] ints = new PDelay[SIZE];
             q.addAll(Arrays.asList(ints));
-            fail("Cannot add null elements");
-        }
-        catch (NullPointerException success) {}
+            shouldThrow();
+        } catch (NullPointerException success) {}
     }
-    public void testAddAll3(){
+    /**
+     * addAll of a collection with any null elements throws NPE after
+     * possibly adding some elements
+     */
+    public void testAddAll3() {
         try {
             DelayQueue q = new DelayQueue();
-            PDelay[] ints = new PDelay[N];
-            for (int i = 0; i < N-1; ++i)
+            PDelay[] ints = new PDelay[SIZE];
+            for (int i = 0; i < SIZE-1; ++i)
                 ints[i] = new PDelay(i);
             q.addAll(Arrays.asList(ints));
-            fail("Cannot add null elements");
-        }
-        catch (NullPointerException success) {}
+            shouldThrow();
+        } catch (NullPointerException success) {}
     }
 
-    public void testAddAll5(){
-        try {
-            PDelay[] empty = new PDelay[0];
-            PDelay[] ints = new PDelay[N];
-            for (int i = N-1; i >= 0; --i)
-                ints[i] = new PDelay(i);
-            DelayQueue q = new DelayQueue();
-            assertFalse(q.addAll(Arrays.asList(empty)));
-            assertTrue(q.addAll(Arrays.asList(ints)));
-            for (int i = 0; i < N; ++i)
-                assertEquals(ints[i], q.poll());
-        }
-        finally {}
+    /**
+     * Queue contains all elements of successful addAll
+     */
+    public void testAddAll5() {
+        PDelay[] empty = new PDelay[0];
+        PDelay[] ints = new PDelay[SIZE];
+        for (int i = SIZE-1; i >= 0; --i)
+            ints[i] = new PDelay(i);
+        DelayQueue q = new DelayQueue();
+        assertFalse(q.addAll(Arrays.asList(empty)));
+        assertTrue(q.addAll(Arrays.asList(ints)));
+        for (int i = 0; i < SIZE; ++i)
+            assertEquals(ints[i], q.poll());
     }
 
+    /**
+     * put(null) throws NPE
+     */
      public void testPutNull() {
-	try {
+        try {
             DelayQueue q = new DelayQueue();
             q.put(null);
-            fail("put should throw NPE");
-        } 
-        catch (NullPointerException success){
-	}   
+            shouldThrow();
+        } catch (NullPointerException success) {}
      }
 
+    /**
+     * all elements successfully put are contained
+     */
      public void testPut() {
-         try {
-             DelayQueue q = new DelayQueue();
-             for (int i = 0; i < N; ++i) {
-                 PDelay I = new PDelay(i);
-                 q.put(I);
-                 assertTrue(q.contains(I));
-             }
-             assertEquals(N, q.size());
+         DelayQueue q = new DelayQueue();
+         for (int i = 0; i < SIZE; ++i) {
+             PDelay I = new PDelay(i);
+             q.put(I);
+             assertTrue(q.contains(I));
          }
-         finally {
-        }
+         assertEquals(SIZE, q.size());
     }
 
-    public void testPutWithTake() {
+    /**
+     * put doesn't block waiting for take
+     */
+    public void testPutWithTake() throws InterruptedException {
         final DelayQueue q = new DelayQueue();
-        Thread t = new Thread(new Runnable() {
-                public void run(){
-                    int added = 0;
-                    try {
-                        q.put(new PDelay(0));
-                        ++added;
-                        q.put(new PDelay(0));
-                        ++added;
-                        q.put(new PDelay(0));
-                        ++added;
-                        q.put(new PDelay(0));
-                        ++added;
-                        assertTrue(added == 4);
-                    } finally {
-                    }
-                }
-            });
-        try {
-            t.start();
-            Thread.sleep(SHORT_DELAY_MS);
-            q.take();
-            t.interrupt();
-            t.join();
-        } catch (Exception e){
-            fail("Unexpected exception");
-        }
+        Thread t = new Thread(new CheckedRunnable() {
+            public void realRun() {
+                q.put(new PDelay(0));
+                q.put(new PDelay(0));
+                q.put(new PDelay(0));
+                q.put(new PDelay(0));
+            }});
+
+        t.start();
+        Thread.sleep(SHORT_DELAY_MS);
+        q.take();
+        t.interrupt();
+        t.join();
     }
 
-    public void testTimedOffer() {
+    /**
+     * timed offer does not time out
+     */
+    public void testTimedOffer() throws InterruptedException {
         final DelayQueue q = new DelayQueue();
-        Thread t = new Thread(new Runnable() {
-                public void run(){
-                    try {
-                        q.put(new PDelay(0));
-                        q.put(new PDelay(0));
-                        assertTrue(q.offer(new PDelay(0), SHORT_DELAY_MS/2, TimeUnit.MILLISECONDS));
-                        assertTrue(q.offer(new PDelay(0), LONG_DELAY_MS, TimeUnit.MILLISECONDS));
-                    } finally { }
-                }
-            });
-        
-        try {
-            t.start();
-            Thread.sleep(SHORT_DELAY_MS);
-            t.interrupt();
-            t.join();
-        } catch (Exception e){
-            fail("Unexpected exception");
-        }
+        Thread t = new Thread(new CheckedRunnable() {
+            public void realRun() throws InterruptedException {
+                q.put(new PDelay(0));
+                q.put(new PDelay(0));
+                assertTrue(q.offer(new PDelay(0), SHORT_DELAY_MS, MILLISECONDS));
+                assertTrue(q.offer(new PDelay(0), LONG_DELAY_MS, MILLISECONDS));
+            }});
+
+        t.start();
+        Thread.sleep(SMALL_DELAY_MS);
+        t.interrupt();
+        t.join();
     }
 
-    public void testTake(){
-	try {
-            DelayQueue q = fullQueue(N);
-            for (int i = 0; i < N; ++i) {
-                assertEquals(new PDelay(i), ((PDelay)q.take()));
-            }
-        } catch (InterruptedException e){
-	    fail("Unexpected exception");
-	}   
+    /**
+     * take retrieves elements in priority order
+     */
+    public void testTake() throws InterruptedException {
+        DelayQueue q = populatedQueue(SIZE);
+        for (int i = 0; i < SIZE; ++i) {
+            assertEquals(new PDelay(i), ((PDelay)q.take()));
+        }
     }
 
-    public void testTakeFromEmpty() {
+    /**
+     * take blocks interruptibly when empty
+     */
+    public void testTakeFromEmpty() throws InterruptedException {
         final DelayQueue q = new DelayQueue();
-        Thread t = new Thread(new Runnable() {
-                public void run(){
-                    try {
-                        q.take();
-			fail("Should block");
-                    } catch (InterruptedException success){ }                
-                }
-            });
-        try {
-            t.start();
-            Thread.sleep(SHORT_DELAY_MS);
-            t.interrupt();
-            t.join();
-        } catch (Exception e){
-            fail("Unexpected exception");
-        }
+        Thread t = new ThreadShouldThrow(InterruptedException.class) {
+            public void realRun() throws InterruptedException {
+                q.take();
+            }};
+
+        t.start();
+        Thread.sleep(SHORT_DELAY_MS);
+        t.interrupt();
+        t.join();
     }
 
-    public void testBlockingTake(){
-        Thread t = new Thread(new Runnable() {
-                public void run() {
-                    try {
-                        DelayQueue q = fullQueue(N);
-                        for (int i = 0; i < N; ++i) {
-                            assertEquals(new PDelay(i), ((PDelay)q.take()));
-                        }
-                        q.take();
-                        fail("take should block");
-                    } catch (InterruptedException success){
-                    }   
-                }});
+    /**
+     * Take removes existing elements until empty, then blocks interruptibly
+     */
+    public void testBlockingTake() throws InterruptedException {
+        final DelayQueue q = populatedQueue(SIZE);
+        Thread t = new Thread(new CheckedRunnable() {
+            public void realRun() throws InterruptedException {
+                for (int i = 0; i < SIZE; ++i) {
+                    assertEquals(new PDelay(i), ((PDelay)q.take()));
+                }
+                try {
+                    q.take();
+                    shouldThrow();
+                } catch (InterruptedException success) {}
+            }});
+
         t.start();
-        try { 
-           Thread.sleep(SHORT_DELAY_MS); 
-           t.interrupt();
-           t.join();
-        }
-        catch (InterruptedException ie) {
-	    fail("Unexpected exception");
-        }
+        Thread.sleep(SHORT_DELAY_MS);
+        t.interrupt();
+        t.join();
     }
 
 
-    public void testPoll(){
-        DelayQueue q = fullQueue(N);
-        for (int i = 0; i < N; ++i) {
+    /**
+     * poll succeeds unless empty
+     */
+    public void testPoll() {
+        DelayQueue q = populatedQueue(SIZE);
+        for (int i = 0; i < SIZE; ++i) {
             assertEquals(new PDelay(i), ((PDelay)q.poll()));
         }
-	assertNull(q.poll());
+        assertNull(q.poll());
     }
 
-    public void testTimedPoll0() {
-        try {
-            DelayQueue q = fullQueue(N);
-            for (int i = 0; i < N; ++i) {
-                assertEquals(new PDelay(i), ((PDelay)q.poll(0, TimeUnit.MILLISECONDS)));
-            }
-            assertNull(q.poll(0, TimeUnit.MILLISECONDS));
-        } catch (InterruptedException e){
-	    fail("Unexpected exception");
-	}   
+    /**
+     * timed pool with zero timeout succeeds when non-empty, else times out
+     */
+    public void testTimedPoll0() throws InterruptedException {
+        DelayQueue q = populatedQueue(SIZE);
+        for (int i = 0; i < SIZE; ++i) {
+            assertEquals(new PDelay(i), ((PDelay)q.poll(0, MILLISECONDS)));
+        }
+        assertNull(q.poll(0, MILLISECONDS));
     }
 
-    public void testTimedPoll() {
-        try {
-            DelayQueue q = fullQueue(N);
-            for (int i = 0; i < N; ++i) {
-                assertEquals(new PDelay(i), ((PDelay)q.poll(SHORT_DELAY_MS, TimeUnit.MILLISECONDS)));
-            }
-            assertNull(q.poll(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
-        } catch (InterruptedException e){
-	    fail("Unexpected exception");
-	}   
-    }
-
-    public void testInterruptedTimedPoll(){
-        Thread t = new Thread(new Runnable() {
-                public void run() {
-                    try {
-                        DelayQueue q = fullQueue(N);
-                        for (int i = 0; i < N; ++i) {
-                            assertEquals(new PDelay(i), ((PDelay)q.poll(SHORT_DELAY_MS, TimeUnit.MILLISECONDS)));
-                        }
-                        assertNull(q.poll(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
-                    } catch (InterruptedException success){
-                    }   
-                }});
-        t.start();
-        try { 
-           Thread.sleep(SHORT_DELAY_MS); 
-           t.interrupt();
-           t.join();
-        }
-        catch (InterruptedException ie) {
-	    fail("Unexpected exception");
+    /**
+     * timed pool with nonzero timeout succeeds when non-empty, else times out
+     */
+    public void testTimedPoll() throws InterruptedException {
+        DelayQueue q = populatedQueue(SIZE);
+        for (int i = 0; i < SIZE; ++i) {
+            assertEquals(new PDelay(i), ((PDelay)q.poll(SHORT_DELAY_MS, MILLISECONDS)));
         }
+        assertNull(q.poll(SHORT_DELAY_MS, MILLISECONDS));
     }
 
-    public void testTimedPollWithOffer(){
-        final DelayQueue q = new DelayQueue();
-        Thread t = new Thread(new Runnable() {
-                public void run(){
-                    try {
-                        assertNull(q.poll(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
-                        q.poll(LONG_DELAY_MS, TimeUnit.MILLISECONDS);
-                        q.poll(LONG_DELAY_MS, TimeUnit.MILLISECONDS);
-			fail("Should block");
-                    } catch (InterruptedException success) { }                
+    /**
+     * Interrupted timed poll throws InterruptedException instead of
+     * returning timeout status
+     */
+    public void testInterruptedTimedPoll() throws InterruptedException {
+        Thread t = new Thread(new CheckedRunnable() {
+            public void realRun() throws InterruptedException {
+                DelayQueue q = populatedQueue(SIZE);
+                for (int i = 0; i < SIZE; ++i) {
+                    assertEquals(new PDelay(i), ((PDelay)q.poll(SHORT_DELAY_MS, MILLISECONDS)));
                 }
-            });
-        try {
-            t.start();
-            Thread.sleep(SHORT_DELAY_MS * 2);
-            assertTrue(q.offer(new PDelay(0), SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
-            t.interrupt();
-            t.join();
-        } catch (Exception e){
-            fail("Unexpected exception");
-        }
-    }  
-
-
-    public void testPeek(){
-        DelayQueue q = fullQueue(N);
-        for (int i = 0; i < N; ++i) {
+                try {
+                    q.poll(SMALL_DELAY_MS, MILLISECONDS);
+                    shouldThrow();
+                } catch (InterruptedException success) {}
+            }});
+
+        t.start();
+        Thread.sleep(SHORT_DELAY_MS);
+        t.interrupt();
+        t.join();
+    }
+
+    /**
+     *  timed poll before a delayed offer fails; after offer succeeds;
+     *  on interruption throws
+     */
+    public void testTimedPollWithOffer() throws InterruptedException {
+        final DelayQueue q = new DelayQueue();
+        final PDelay pdelay = new PDelay(0);
+        Thread t = new Thread(new CheckedRunnable() {
+            public void realRun() throws InterruptedException {
+                assertNull(q.poll(SHORT_DELAY_MS, MILLISECONDS));
+                assertSame(pdelay, q.poll(LONG_DELAY_MS, MILLISECONDS));
+                try {
+                    q.poll(LONG_DELAY_MS, MILLISECONDS);
+                    shouldThrow();
+                } catch (InterruptedException success) {}
+            }});
+
+        t.start();
+        Thread.sleep(SMALL_DELAY_MS);
+        assertTrue(q.offer(pdelay, SHORT_DELAY_MS, MILLISECONDS));
+        t.interrupt();
+        t.join();
+    }
+
+
+    /**
+     * peek returns next element, or null if empty
+     */
+    public void testPeek() {
+        DelayQueue q = populatedQueue(SIZE);
+        for (int i = 0; i < SIZE; ++i) {
             assertEquals(new PDelay(i), ((PDelay)q.peek()));
-            q.poll();
-            assertTrue(q.peek() == null ||
-                       i != ((PDelay)q.peek()).intValue());
+            assertEquals(new PDelay(i), ((PDelay)q.poll()));
+            if (q.isEmpty())
+                assertNull(q.peek());
+            else
+                assertFalse(new PDelay(i).equals(q.peek()));
         }
-	assertNull(q.peek());
+        assertNull(q.peek());
     }
 
-    public void testElement(){
-        DelayQueue q = fullQueue(N);
-        for (int i = 0; i < N; ++i) {
+    /**
+     * element returns next element, or throws NSEE if empty
+     */
+    public void testElement() {
+        DelayQueue q = populatedQueue(SIZE);
+        for (int i = 0; i < SIZE; ++i) {
             assertEquals(new PDelay(i), ((PDelay)q.element()));
             q.poll();
         }
         try {
             q.element();
-            fail("no such element");
-        }
-        catch (NoSuchElementException success) {}
+            shouldThrow();
+        } catch (NoSuchElementException success) {}
     }
 
-    public void testRemove(){
-        DelayQueue q = fullQueue(N);
-        for (int i = 0; i < N; ++i) {
+    /**
+     * remove removes next element, or throws NSEE if empty
+     */
+    public void testRemove() {
+        DelayQueue q = populatedQueue(SIZE);
+        for (int i = 0; i < SIZE; ++i) {
             assertEquals(new PDelay(i), ((PDelay)q.remove()));
         }
         try {
             q.remove();
-            fail("remove should throw");
-        } catch (NoSuchElementException success){
-	}   
+            shouldThrow();
+        } catch (NoSuchElementException success) {}
     }
 
-    public void testRemoveElement(){
-        DelayQueue q = fullQueue(N);
-        for (int i = 1; i < N; i+=2) {
+    /**
+     * remove(x) removes x and returns true if present
+     */
+    public void testRemoveElement() {
+        DelayQueue q = populatedQueue(SIZE);
+        for (int i = 1; i < SIZE; i+=2) {
             assertTrue(q.remove(new PDelay(i)));
         }
-        for (int i = 0; i < N; i+=2) {
+        for (int i = 0; i < SIZE; i+=2) {
             assertTrue(q.remove(new PDelay(i)));
             assertFalse(q.remove(new PDelay(i+1)));
         }
         assertTrue(q.isEmpty());
     }
-	
-    public void testContains(){
-        DelayQueue q = fullQueue(N);
-        for (int i = 0; i < N; ++i) {
+
+    /**
+     * contains(x) reports true when elements added but not yet removed
+     */
+    public void testContains() {
+        DelayQueue q = populatedQueue(SIZE);
+        for (int i = 0; i < SIZE; ++i) {
             assertTrue(q.contains(new PDelay(i)));
             q.poll();
             assertFalse(q.contains(new PDelay(i)));
         }
     }
 
-    public void testClear(){
-        DelayQueue q = fullQueue(N);
+    /**
+     * clear removes all elements
+     */
+    public void testClear() {
+        DelayQueue q = populatedQueue(SIZE);
         q.clear();
         assertTrue(q.isEmpty());
         assertEquals(0, q.size());
         assertEquals(NOCAP, q.remainingCapacity());
-        q.add(new PDelay(1));
+        PDelay x = new PDelay(1);
+        q.add(x);
         assertFalse(q.isEmpty());
+        assertTrue(q.contains(x));
         q.clear();
         assertTrue(q.isEmpty());
     }
 
-    public void testContainsAll(){
-        DelayQueue q = fullQueue(N);
+    /**
+     * containsAll(c) is true when c contains a subset of elements
+     */
+    public void testContainsAll() {
+        DelayQueue q = populatedQueue(SIZE);
         DelayQueue p = new DelayQueue();
-        for (int i = 0; i < N; ++i) {
+        for (int i = 0; i < SIZE; ++i) {
             assertTrue(q.containsAll(p));
             assertFalse(p.containsAll(q));
             p.add(new PDelay(i));
@@ -516,10 +610,13 @@ public class DelayQueueTest extends Test
         assertTrue(p.containsAll(q));
     }
 
-    public void testRetainAll(){
-        DelayQueue q = fullQueue(N);
-        DelayQueue p = fullQueue(N);
-        for (int i = 0; i < N; ++i) {
+    /**
+     * retainAll(c) retains only those elements of c and reports true if changed
+     */
+    public void testRetainAll() {
+        DelayQueue q = populatedQueue(SIZE);
+        DelayQueue p = populatedQueue(SIZE);
+        for (int i = 0; i < SIZE; ++i) {
             boolean changed = q.retainAll(p);
             if (i == 0)
                 assertFalse(changed);
@@ -527,17 +624,20 @@ public class DelayQueueTest extends Test
                 assertTrue(changed);
 
             assertTrue(q.containsAll(p));
-            assertEquals(N-i, q.size());
+            assertEquals(SIZE-i, q.size());
             p.remove();
         }
     }
 
-    public void testRemoveAll(){
-        for (int i = 1; i < N; ++i) {
-            DelayQueue q = fullQueue(N);
-            DelayQueue p = fullQueue(i);
+    /**
+     * removeAll(c) removes only those elements of c and reports true if changed
+     */
+    public void testRemoveAll() {
+        for (int i = 1; i < SIZE; ++i) {
+            DelayQueue q = populatedQueue(SIZE);
+            DelayQueue p = populatedQueue(i);
             assertTrue(q.removeAll(p));
-            assertEquals(N-i, q.size());
+            assertEquals(SIZE-i, q.size());
             for (int j = 0; j < i; ++j) {
                 PDelay I = (PDelay)(p.remove());
                 assertFalse(q.contains(I));
@@ -545,72 +645,77 @@ public class DelayQueueTest extends Test
         }
     }
 
-    /*
-    public void testEqualsAndHashCode(){
-        DelayQueue q1 = fullQueue(N);
-        DelayQueue q2 = fullQueue(N);
-        assertTrue(q1.equals(q2));
-        assertTrue(q2.equals(q1));
-        assertEquals(q1.hashCode(), q2.hashCode());
-        q1.remove();
-        assertFalse(q1.equals(q2));
-        assertFalse(q2.equals(q1));
-        assertFalse(q1.hashCode() == q2.hashCode());
-        q2.remove();
-        assertTrue(q1.equals(q2));
-        assertTrue(q2.equals(q1));
-        assertEquals(q1.hashCode(), q2.hashCode());
-    }
-    */
-
-    public void testToArray(){
-        DelayQueue q = fullQueue(N);
-	Object[] o = q.toArray();
+    /**
+     * toArray contains all elements
+     */
+    public void testToArray() throws InterruptedException {
+        DelayQueue q = populatedQueue(SIZE);
+        Object[] o = q.toArray();
         Arrays.sort(o);
-	try {
-	for(int i = 0; i < o.length; i++)
-	    assertEquals(o[i], q.take());
-	} catch (InterruptedException e){
-	    fail("Unexpected exception");
-	}    
+        for (int i = 0; i < o.length; i++)
+            assertEquals(o[i], q.take());
     }
 
-    public void testToArray2(){
-        DelayQueue q = fullQueue(N);
-	PDelay[] ints = new PDelay[N];
-	ints = (PDelay[])q.toArray(ints);
+    /**
+     * toArray(a) contains all elements
+     */
+    public void testToArray2() throws InterruptedException {
+        DelayQueue q = populatedQueue(SIZE);
+        PDelay[] ints = new PDelay[SIZE];
+        ints = (PDelay[])q.toArray(ints);
         Arrays.sort(ints);
-	try {
-	    for(int i = 0; i < ints.length; i++)
-		assertEquals(ints[i], q.take());
-	} catch (InterruptedException e){
-	    fail("Unexpected exception");
-	}    
-    }
-    
-    public void testIterator(){
-        DelayQueue q = fullQueue(N);
+        for (int i = 0; i < ints.length; i++)
+            assertEquals(ints[i], q.take());
+    }
+
+
+    /**
+     * toArray(null) throws NPE
+     */
+    public void testToArray_BadArg() {
+        DelayQueue q = populatedQueue(SIZE);
+        try {
+            Object o[] = q.toArray(null);
+            shouldThrow();
+        } catch (NullPointerException success) {}
+    }
+
+    /**
+     * toArray with incompatible array type throws CCE
+     */
+    public void testToArray1_BadArg() {
+        DelayQueue q = populatedQueue(SIZE);
+        try {
+            Object o[] = q.toArray(new String[10]);
+            shouldThrow();
+        } catch (ArrayStoreException success) {}
+    }
+
+    /**
+     * iterator iterates through all elements
+     */
+    public void testIterator() {
+        DelayQueue q = populatedQueue(SIZE);
         int i = 0;
-	Iterator it = q.iterator();
-        while(it.hasNext()) {
+        Iterator it = q.iterator();
+        while (it.hasNext()) {
             assertTrue(q.contains(it.next()));
             ++i;
         }
-        assertEquals(i, N);
+        assertEquals(i, SIZE);
     }
 
-    public void testIteratorRemove () {
-
+    /**
+     * iterator.remove removes current element
+     */
+    public void testIteratorRemove() {
         final DelayQueue q = new DelayQueue();
-
         q.add(new PDelay(2));
         q.add(new PDelay(1));
         q.add(new PDelay(3));
-
         Iterator it = q.iterator();
         it.next();
         it.remove();
-
         it = q.iterator();
         assertEquals(it.next(), new PDelay(2));
         assertEquals(it.next(), new PDelay(3));
@@ -618,115 +723,195 @@ public class DelayQueueTest extends Test
     }
 
 
-    public void testToString(){
-        DelayQueue q = fullQueue(N);
+    /**
+     * toString contains toStrings of elements
+     */
+    public void testToString() {
+        DelayQueue q = populatedQueue(SIZE);
         String s = q.toString();
-        for (int i = 0; i < N; ++i) {
-            assertTrue(s.indexOf(String.valueOf(i)) >= 0);
+        for (int i = 0; i < SIZE; ++i) {
+            assertTrue(s.indexOf(String.valueOf(Integer.MIN_VALUE+i)) >= 0);
         }
-    }        
+    }
 
+    /**
+     * offer transfers elements across Executor tasks
+     */
     public void testPollInExecutor() {
-
         final DelayQueue q = new DelayQueue();
-
         ExecutorService executor = Executors.newFixedThreadPool(2);
+        executor.execute(new CheckedRunnable() {
+            public void realRun() throws InterruptedException {
+                assertNull(q.poll());
+                assertTrue(null != q.poll(MEDIUM_DELAY_MS, MILLISECONDS));
+                assertTrue(q.isEmpty());
+            }});
+
+        executor.execute(new CheckedRunnable() {
+            public void realRun() throws InterruptedException {
+                Thread.sleep(SHORT_DELAY_MS);
+                q.put(new PDelay(1));
+            }});
 
-        executor.execute(new Runnable() {
-            public void run() {
-                assertNull("poll should fail", q.poll());
-                try {
-                    assertTrue(null != q.poll(MEDIUM_DELAY_MS * 2, TimeUnit.MILLISECONDS));
-                    assertTrue(q.isEmpty());
-                }
-                catch (InterruptedException e) {
-                    fail("should not be interrupted");
-                }
-            }
-        });
-
-        executor.execute(new Runnable() {
-            public void run() {
-                try {
-                    Thread.sleep(MEDIUM_DELAY_MS);
-                    q.put(new PDelay(1));
-                }
-                catch (InterruptedException e) {
-                    fail("should not be interrupted");
-                }
-            }
-        });
-        
-        executor.shutdown();
-
+        joinPool(executor);
     }
 
-    static class NanoDelay implements Delayed { 
-        long trigger;
-        NanoDelay(long i) { 
-            trigger = System.nanoTime() + i;
+
+    /**
+     * Delayed actions do not occur until their delay elapses
+     */
+    public void testDelay() throws InterruptedException {
+        DelayQueue q = new DelayQueue();
+        NanoDelay[] elements = new NanoDelay[SIZE];
+        for (int i = 0; i < SIZE; ++i) {
+            elements[i] = new NanoDelay(1000000000L + 1000000L * (SIZE - i));
         }
-        public int compareTo(Object y) {
-            long i = trigger;
-            long j = ((NanoDelay)y).trigger;
-            if (i < j) return -1;
-            if (i > j) return 1;
-            return 0;
+        for (int i = 0; i < SIZE; ++i) {
+            q.add(elements[i]);
         }
 
-        public int compareTo(NanoDelay y) {
-            long i = trigger;
-            long j = ((NanoDelay)y).trigger;
-            if (i < j) return -1;
-            if (i > j) return 1;
-            return 0;
+        long last = 0;
+        for (int i = 0; i < SIZE; ++i) {
+            NanoDelay e = (NanoDelay)(q.take());
+            long tt = e.getTriggerTime();
+            assertTrue(tt <= System.nanoTime());
+            if (i != 0)
+                assertTrue(tt >= last);
+            last = tt;
         }
+    }
 
-        public boolean equals(Object other) {
-            return ((NanoDelay)other).trigger == trigger;
-        }
-        public boolean equals(NanoDelay other) {
-            return ((NanoDelay)other).trigger == trigger;
-        }
+    /**
+     * peek of a non-empty queue returns non-null even if not expired
+     */
+    public void testPeekDelayed() {
+        DelayQueue q = new DelayQueue();
+        q.add(new NanoDelay(Long.MAX_VALUE));
+        assert(q.peek() != null);
+    }
 
-        public long getDelay(TimeUnit unit) {
-            long n = trigger - System.nanoTime();
-            return unit.convert(n, TimeUnit.NANOSECONDS);
-        }
 
-        public long getTriggerTime() {
-            return trigger;
-        }
+    /**
+     * poll of a non-empty queue returns null if no expired elements.
+     */
+    public void testPollDelayed() {
+        DelayQueue q = new DelayQueue();
+        q.add(new NanoDelay(Long.MAX_VALUE));
+        assertNull(q.poll());
+    }
 
-        public String toString() {
-            return String.valueOf(trigger);
-        }
+    /**
+     * timed poll of a non-empty queue returns null if no expired elements.
+     */
+    public void testTimedPollDelayed() throws InterruptedException {
+        DelayQueue q = new DelayQueue();
+        q.add(new NanoDelay(LONG_DELAY_MS * 1000000L));
+        assertNull(q.poll(SHORT_DELAY_MS, MILLISECONDS));
+    }
+
+    /**
+     * drainTo(null) throws NPE
+     */
+    public void testDrainToNull() {
+        DelayQueue q = populatedQueue(SIZE);
+        try {
+            q.drainTo(null);
+            shouldThrow();
+        } catch (NullPointerException success) {}
+    }
+
+    /**
+     * drainTo(this) throws IAE
+     */
+    public void testDrainToSelf() {
+        DelayQueue q = populatedQueue(SIZE);
+        try {
+            q.drainTo(q);
+            shouldThrow();
+        } catch (IllegalArgumentException success) {}
     }
 
-    public void testDelay() {
+    /**
+     * drainTo(c) empties queue into another collection c
+     */
+    public void testDrainTo() {
         DelayQueue q = new DelayQueue();
-        NanoDelay[] elements = new NanoDelay[N];
-        for (int i = 0; i < N; ++i) {
-            elements[i] = new NanoDelay(1000000000L + 1000000L * (N - i));
-        }
-        for (int i = 0; i < N; ++i) {
-            q.add(elements[i]);
-        }
+        PDelay[] elems = new PDelay[SIZE];
+        for (int i = 0; i < SIZE; ++i) {
+            elems[i] = new PDelay(i);
+            q.add(elems[i]);
+        }
+        ArrayList l = new ArrayList();
+        q.drainTo(l);
+        assertEquals(q.size(), 0);
+        for (int i = 0; i < SIZE; ++i)
+            assertEquals(l.get(i), elems[i]);
+        q.add(elems[0]);
+        q.add(elems[1]);
+        assertFalse(q.isEmpty());
+        assertTrue(q.contains(elems[0]));
+        assertTrue(q.contains(elems[1]));
+        l.clear();
+        q.drainTo(l);
+        assertEquals(q.size(), 0);
+        assertEquals(l.size(), 2);
+        for (int i = 0; i < 2; ++i)
+            assertEquals(l.get(i), elems[i]);
+    }
 
+    /**
+     * drainTo empties queue
+     */
+    public void testDrainToWithActivePut() throws InterruptedException {
+        final DelayQueue q = populatedQueue(SIZE);
+        Thread t = new Thread(new CheckedRunnable() {
+            public void realRun() {
+                q.put(new PDelay(SIZE+1));
+            }});
+
+        t.start();
+        ArrayList l = new ArrayList();
+        q.drainTo(l);
+        assertTrue(l.size() >= SIZE);
+        t.join();
+        assertTrue(q.size() + l.size() >= SIZE);
+    }
+
+    /**
+     * drainTo(null, n) throws NPE
+     */
+    public void testDrainToNullN() {
+        DelayQueue q = populatedQueue(SIZE);
         try {
-            long last = 0;
-            for (int i = 0; i < N; ++i) {
-                NanoDelay e = (NanoDelay)(q.take());
-                long tt = e.getTriggerTime();
-                assertTrue(tt <= System.nanoTime());
-                if (i != 0) 
-                    assertTrue(tt >= last);
-                last = tt;
-            }
-        }
-        catch(InterruptedException ie) {
-            fail("Unexpected Exception");
+            q.drainTo(null, 0);
+            shouldThrow();
+        } catch (NullPointerException success) {}
+    }
+
+    /**
+     * drainTo(this, n) throws IAE
+     */
+    public void testDrainToSelfN() {
+        DelayQueue q = populatedQueue(SIZE);
+        try {
+            q.drainTo(q, 0);
+            shouldThrow();
+        } catch (IllegalArgumentException success) {}
+    }
+
+    /**
+     * drainTo(c, n) empties first max {n, size} elements of queue into c
+     */
+    public void testDrainToN() {
+        for (int i = 0; i < SIZE + 2; ++i) {
+            DelayQueue q = populatedQueue(SIZE);
+            ArrayList l = new ArrayList();
+            q.drainTo(l, i);
+            int k = (i < SIZE)? i : SIZE;
+            assertEquals(q.size(), SIZE-k);
+            assertEquals(l.size(), k);
         }
     }
 
+
 }