test/tck/ConcurrentLinkedQueueTest.java

/*
 * 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/publicdomain/zero/1.0/
 * Other contributors include Andrew Wright, Jeffrey Hayes,
 * Pat Fisher, Mike Judd.
 */

import java.util.Arrays;
import java.util.Collection;
import java.util.Iterator;
import java.util.NoSuchElementException;
import java.util.Queue;
import java.util.concurrent.ConcurrentLinkedQueue;

import junit.framework.Test;
import junit.framework.TestSuite;

public class ConcurrentLinkedQueueTest extends JSR166TestCase {

    public static void main(String[] args) {
        main(suite(), args);
    }

    public static Test suite() {
        return new TestSuite(ConcurrentLinkedQueueTest.class);
    }

    /**
     * Returns a new queue of given size containing consecutive
     * Integers 0 ... n.
     */
    private ConcurrentLinkedQueue<Integer> populatedQueue(int n) {
        ConcurrentLinkedQueue<Integer> q = new ConcurrentLinkedQueue<Integer>();
        assertTrue(q.isEmpty());
        for (int i = 0; i < n; ++i)
            assertTrue(q.offer(new Integer(i)));
        assertFalse(q.isEmpty());
        assertEquals(n, q.size());
        return q;
    }

    /**
     * new queue is empty
     */
    public void testConstructor1() {
        assertEquals(0, new ConcurrentLinkedQueue().size());
    }

    /**
     * Initializing from null Collection throws NPE
     */
    public void testConstructor3() {
        try {
            new ConcurrentLinkedQueue((Collection)null);
            shouldThrow();
        } catch (NullPointerException success) {}
    }

    /**
     * Initializing from Collection of null elements throws NPE
     */
    public void testConstructor4() {
        try {
            Integer[] ints = new Integer[SIZE];
            new ConcurrentLinkedQueue(Arrays.asList(ints));
            shouldThrow();
        } catch (NullPointerException success) {}
    }

    /**
     * Initializing from Collection with some null elements throws NPE
     */
    public void testConstructor5() {
        try {
            Integer[] ints = new Integer[SIZE];
            for (int i = 0; i < SIZE-1; ++i)
                ints[i] = new Integer(i);
            new ConcurrentLinkedQueue(Arrays.asList(ints));
            shouldThrow();
        } catch (NullPointerException success) {}
    }

    /**
     * Queue contains all elements of collection used to initialize
     */
    public void testConstructor6() {
        Integer[] ints = new Integer[SIZE];
        for (int i = 0; i < SIZE; ++i)
            ints[i] = new Integer(i);
        ConcurrentLinkedQueue q = new ConcurrentLinkedQueue(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() {
        ConcurrentLinkedQueue q = new ConcurrentLinkedQueue();
        assertTrue(q.isEmpty());
        q.add(one);
        assertFalse(q.isEmpty());
        q.add(two);
        q.remove();
        q.remove();
        assertTrue(q.isEmpty());
    }

    /**
     * size changes when elements added and removed
     */
    public void testSize() {
        ConcurrentLinkedQueue q = populatedQueue(SIZE);
        for (int i = 0; i < SIZE; ++i) {
            assertEquals(SIZE-i, q.size());
            q.remove();
        }
        for (int i = 0; i < SIZE; ++i) {
            assertEquals(i, q.size());
            q.add(new Integer(i));
        }
    }

    /**
     * offer(null) throws NPE
     */
    public void testOfferNull() {
        try {
            ConcurrentLinkedQueue q = new ConcurrentLinkedQueue();
            q.offer(null);
            shouldThrow();
        } catch (NullPointerException success) {}
    }

    /**
     * add(null) throws NPE
     */
    public void testAddNull() {
        try {
            ConcurrentLinkedQueue q = new ConcurrentLinkedQueue();
            q.add(null);
            shouldThrow();
        } catch (NullPointerException success) {}
    }

    /**
     * Offer returns true
     */
    public void testOffer() {
        ConcurrentLinkedQueue q = new ConcurrentLinkedQueue();
        assertTrue(q.offer(zero));
        assertTrue(q.offer(one));
    }

    /**
     * add returns true
     */
    public void testAdd() {
        ConcurrentLinkedQueue q = new ConcurrentLinkedQueue();
        for (int i = 0; i < SIZE; ++i) {
            assertEquals(i, q.size());
            assertTrue(q.add(new Integer(i)));
        }
    }

    /**
     * addAll(null) throws NPE
     */
    public void testAddAll1() {
        try {
            ConcurrentLinkedQueue q = new ConcurrentLinkedQueue();
            q.addAll(null);
            shouldThrow();
        } catch (NullPointerException success) {}
    }

    /**
     * addAll(this) throws IAE
     */
    public void testAddAllSelf() {
        try {
            ConcurrentLinkedQueue q = populatedQueue(SIZE);
            q.addAll(q);
            shouldThrow();
        } catch (IllegalArgumentException success) {}
    }

    /**
     * addAll of a collection with null elements throws NPE
     */
    public void testAddAll2() {
        try {
            ConcurrentLinkedQueue q = new ConcurrentLinkedQueue();
            Integer[] ints = new Integer[SIZE];
            q.addAll(Arrays.asList(ints));
            shouldThrow();
        } catch (NullPointerException success) {}
    }

    /**
     * addAll of a collection with any null elements throws NPE after
     * possibly adding some elements
     */
    public void testAddAll3() {
        try {
            ConcurrentLinkedQueue q = new ConcurrentLinkedQueue();
            Integer[] ints = new Integer[SIZE];
            for (int i = 0; i < SIZE-1; ++i)
                ints[i] = new Integer(i);
            q.addAll(Arrays.asList(ints));
            shouldThrow();
        } catch (NullPointerException success) {}
    }

    /**
     * Queue contains all elements, in traversal order, of successful addAll
     */
    public void testAddAll5() {
        Integer[] empty = new Integer[0];
        Integer[] ints = new Integer[SIZE];
        for (int i = 0; i < SIZE; ++i)
            ints[i] = new Integer(i);
        ConcurrentLinkedQueue q = new ConcurrentLinkedQueue();
        assertFalse(q.addAll(Arrays.asList(empty)));
        assertTrue(q.addAll(Arrays.asList(ints)));
        for (int i = 0; i < SIZE; ++i)
            assertEquals(ints[i], q.poll());
    }

    /**
     * poll succeeds unless empty
     */
    public void testPoll() {
        ConcurrentLinkedQueue q = populatedQueue(SIZE);
        for (int i = 0; i < SIZE; ++i) {
            assertEquals(i, q.poll());
        }
        assertNull(q.poll());
    }

    /**
     * peek returns next element, or null if empty
     */
    public void testPeek() {
        ConcurrentLinkedQueue q = populatedQueue(SIZE);
        for (int i = 0; i < SIZE; ++i) {
            assertEquals(i, q.peek());
            assertEquals(i, q.poll());
            assertTrue(q.peek() == null ||
                       !q.peek().equals(i));
        }
        assertNull(q.peek());
    }

    /**
     * element returns next element, or throws NSEE if empty
     */
    public void testElement() {
        ConcurrentLinkedQueue q = populatedQueue(SIZE);
        for (int i = 0; i < SIZE; ++i) {
            assertEquals(i, q.element());
            assertEquals(i, q.poll());
        }
        try {
            q.element();
            shouldThrow();
        } catch (NoSuchElementException success) {}
    }

    /**
     * remove removes next element, or throws NSEE if empty
     */
    public void testRemove() {
        ConcurrentLinkedQueue q = populatedQueue(SIZE);
        for (int i = 0; i < SIZE; ++i) {
            assertEquals(i, q.remove());
        }
        try {
            q.remove();
            shouldThrow();
        } catch (NoSuchElementException success) {}
    }

    /**
     * remove(x) removes x and returns true if present
     */
    public void testRemoveElement() {
        ConcurrentLinkedQueue q = populatedQueue(SIZE);
        for (int i = 1; i < SIZE; i += 2) {
            assertTrue(q.contains(i));
            assertTrue(q.remove(i));
            assertFalse(q.contains(i));
            assertTrue(q.contains(i-1));
        }
        for (int i = 0; i < SIZE; i += 2) {
            assertTrue(q.contains(i));
            assertTrue(q.remove(i));
            assertFalse(q.contains(i));
            assertFalse(q.remove(i+1));
            assertFalse(q.contains(i+1));
        }
        assertTrue(q.isEmpty());
    }

    /**
     * contains(x) reports true when elements added but not yet removed
     */
    public void testContains() {
        ConcurrentLinkedQueue q = populatedQueue(SIZE);
        for (int i = 0; i < SIZE; ++i) {
            assertTrue(q.contains(new Integer(i)));
            q.poll();
            assertFalse(q.contains(new Integer(i)));
        }
    }

    /**
     * clear removes all elements
     */
    public void testClear() {
        ConcurrentLinkedQueue q = populatedQueue(SIZE);
        q.clear();
        assertTrue(q.isEmpty());
        assertEquals(0, q.size());
        q.add(one);
        assertFalse(q.isEmpty());
        q.clear();
        assertTrue(q.isEmpty());
    }

    /**
     * containsAll(c) is true when c contains a subset of elements
     */
    public void testContainsAll() {
        ConcurrentLinkedQueue q = populatedQueue(SIZE);
        ConcurrentLinkedQueue p = new ConcurrentLinkedQueue();
        for (int i = 0; i < SIZE; ++i) {
            assertTrue(q.containsAll(p));
            assertFalse(p.containsAll(q));
            p.add(new Integer(i));
        }
        assertTrue(p.containsAll(q));
    }

    /**
     * retainAll(c) retains only those elements of c and reports true if change
     */
    public void testRetainAll() {
        ConcurrentLinkedQueue q = populatedQueue(SIZE);
        ConcurrentLinkedQueue p = populatedQueue(SIZE);
        for (int i = 0; i < SIZE; ++i) {
            boolean changed = q.retainAll(p);
            if (i == 0)
                assertFalse(changed);
            else
                assertTrue(changed);

            assertTrue(q.containsAll(p));
            assertEquals(SIZE-i, q.size());
            p.remove();
        }
    }

    /**
     * removeAll(c) removes only those elements of c and reports true if changed
     */
    public void testRemoveAll() {
        for (int i = 1; i < SIZE; ++i) {
            ConcurrentLinkedQueue q = populatedQueue(SIZE);
            ConcurrentLinkedQueue p = populatedQueue(i);
            assertTrue(q.removeAll(p));
            assertEquals(SIZE-i, q.size());
            for (int j = 0; j < i; ++j) {
                Integer x = (Integer)(p.remove());
                assertFalse(q.contains(x));
            }
        }
    }

    /**
     * toArray contains all elements in FIFO order
     */
    public void testToArray() {
        ConcurrentLinkedQueue q = populatedQueue(SIZE);
        Object[] o = q.toArray();
        for (int i = 0; i < o.length; i++)
            assertSame(o[i], q.poll());
    }

    /**
     * toArray(a) contains all elements in FIFO order
     */
    public void testToArray2() {
        ConcurrentLinkedQueue<Integer> q = populatedQueue(SIZE);
        Integer[] ints = new Integer[SIZE];
        Integer[] array = q.toArray(ints);
        assertSame(ints, array);
        for (int i = 0; i < ints.length; i++)
            assertSame(ints[i], q.poll());
    }

    /**
     * toArray(null) throws NullPointerException
     */
    public void testToArray_NullArg() {
        ConcurrentLinkedQueue q = populatedQueue(SIZE);
        try {
            q.toArray(null);
            shouldThrow();
        } catch (NullPointerException success) {}
    }

    /**
     * toArray(incompatible array type) throws ArrayStoreException
     */
    public void testToArray1_BadArg() {
        ConcurrentLinkedQueue q = populatedQueue(SIZE);
        try {
            q.toArray(new String[10]);
            shouldThrow();
        } catch (ArrayStoreException success) {}
    }

    /**
     * iterator iterates through all elements
     */
    public void testIterator() {
        ConcurrentLinkedQueue q = populatedQueue(SIZE);
        Iterator it = q.iterator();
        int i;
        for (i = 0; it.hasNext(); i++)
            assertTrue(q.contains(it.next()));
        assertEquals(i, SIZE);
        assertIteratorExhausted(it);
    }

    /**
     * iterator of empty collection has no elements
     */
    public void testEmptyIterator() {
        assertIteratorExhausted(new ConcurrentLinkedQueue().iterator());
    }

    /**
     * iterator ordering is FIFO
     */
    public void testIteratorOrdering() {
        final ConcurrentLinkedQueue q = new ConcurrentLinkedQueue();
        q.add(one);
        q.add(two);
        q.add(three);

        int k = 0;
        for (Iterator it = q.iterator(); it.hasNext();) {
            assertEquals(++k, it.next());
        }

        assertEquals(3, k);
    }

    /**
     * Modifications do not cause iterators to fail
     */
    public void testWeaklyConsistentIteration() {
        final ConcurrentLinkedQueue q = new ConcurrentLinkedQueue();
        q.add(one);
        q.add(two);
        q.add(three);

        for (Iterator it = q.iterator(); it.hasNext();) {
            q.remove();
            it.next();
        }

        assertEquals("queue should be empty again", 0, q.size());
    }

    /**
     * iterator.remove removes current element
     */
    public void testIteratorRemove() {
        final ConcurrentLinkedQueue q = new ConcurrentLinkedQueue();
        q.add(one);
        q.add(two);
        q.add(three);
        Iterator it = q.iterator();
        it.next();
        it.remove();
        it = q.iterator();
        assertSame(it.next(), two);
        assertSame(it.next(), three);
        assertFalse(it.hasNext());
    }

    /**
     * toString contains toStrings of elements
     */
    public void testToString() {
        ConcurrentLinkedQueue q = populatedQueue(SIZE);
        String s = q.toString();
        for (int i = 0; i < SIZE; ++i) {
            assertTrue(s.contains(String.valueOf(i)));
        }
    }

    /**
     * A deserialized serialized queue has same elements in same order
     */
    public void testSerialization() throws Exception {
        Queue x = populatedQueue(SIZE);
        Queue y = serialClone(x);

        assertNotSame(x, y);
        assertEquals(x.size(), y.size());
        assertEquals(x.toString(), y.toString());
        assertTrue(Arrays.equals(x.toArray(), y.toArray()));
        while (!x.isEmpty()) {
            assertFalse(y.isEmpty());
            assertEquals(x.remove(), y.remove());
        }
        assertTrue(y.isEmpty());
    }

    /**
     * remove(null), contains(null) always return false
     */
    public void testNeverContainsNull() {
        Collection<?>[] qs = {
            new ConcurrentLinkedQueue<Object>(),
            populatedQueue(2),
        };

        for (Collection<?> q : qs) {
            assertFalse(q.contains(null));
            assertFalse(q.remove(null));
        }
    }
}
Revision:	1.37
Committed:	Sat Apr 25 04:55:30 2015 UTC (9 years ago) by jsr166
Branch:	MAIN
Changes since 1.36:	+1 -1 lines
Log Message:	improve main methods; respect system properties; actually fail if a test fails
#	Content
1	/*
2	* Written by Doug Lea with assistance from members of JCP JSR-166
3	* Expert Group and released to the public domain, as explained at
4	* http://creativecommons.org/publicdomain/zero/1.0/
5	* Other contributors include Andrew Wright, Jeffrey Hayes,
6	* Pat Fisher, Mike Judd.
7	*/
8
9	import java.util.Arrays;
10	import java.util.Collection;
11	import java.util.Iterator;
12	import java.util.NoSuchElementException;
13	import java.util.Queue;
14	import java.util.concurrent.ConcurrentLinkedQueue;
15
16	import junit.framework.Test;
17	import junit.framework.TestSuite;
18
19	public class ConcurrentLinkedQueueTest extends JSR166TestCase {
20
21	public static void main(String[] args) {
22	main(suite(), args);
23	}
24
25	public static Test suite() {
26	return new TestSuite(ConcurrentLinkedQueueTest.class);
27	}
28
29	/**
30	* Returns a new queue of given size containing consecutive
31	* Integers 0 ... n.
32	*/
33	private ConcurrentLinkedQueue<Integer> populatedQueue(int n) {
34	ConcurrentLinkedQueue<Integer> q = new ConcurrentLinkedQueue<Integer>();
35	assertTrue(q.isEmpty());
36	for (int i = 0; i < n; ++i)
37	assertTrue(q.offer(new Integer(i)));
38	assertFalse(q.isEmpty());
39	assertEquals(n, q.size());
40	return q;
41	}
42
43	/**
44	* new queue is empty
45	*/
46	public void testConstructor1() {
47	assertEquals(0, new ConcurrentLinkedQueue().size());
48	}
49
50	/**
51	* Initializing from null Collection throws NPE
52	*/
53	public void testConstructor3() {
54	try {
55	new ConcurrentLinkedQueue((Collection)null);
56	shouldThrow();
57	} catch (NullPointerException success) {}
58	}
59
60	/**
61	* Initializing from Collection of null elements throws NPE
62	*/
63	public void testConstructor4() {
64	try {
65	Integer[] ints = new Integer[SIZE];
66	new ConcurrentLinkedQueue(Arrays.asList(ints));
67	shouldThrow();
68	} catch (NullPointerException success) {}
69	}
70
71	/**
72	* Initializing from Collection with some null elements throws NPE
73	*/
74	public void testConstructor5() {
75	try {
76	Integer[] ints = new Integer[SIZE];
77	for (int i = 0; i < SIZE-1; ++i)
78	ints[i] = new Integer(i);
79	new ConcurrentLinkedQueue(Arrays.asList(ints));
80	shouldThrow();
81	} catch (NullPointerException success) {}
82	}
83
84	/**
85	* Queue contains all elements of collection used to initialize
86	*/
87	public void testConstructor6() {
88	Integer[] ints = new Integer[SIZE];
89	for (int i = 0; i < SIZE; ++i)
90	ints[i] = new Integer(i);
91	ConcurrentLinkedQueue q = new ConcurrentLinkedQueue(Arrays.asList(ints));
92	for (int i = 0; i < SIZE; ++i)
93	assertEquals(ints[i], q.poll());
94	}
95
96	/**
97	* isEmpty is true before add, false after
98	*/
99	public void testEmpty() {
100	ConcurrentLinkedQueue q = new ConcurrentLinkedQueue();
101	assertTrue(q.isEmpty());
102	q.add(one);
103	assertFalse(q.isEmpty());
104	q.add(two);
105	q.remove();
106	q.remove();
107	assertTrue(q.isEmpty());
108	}
109
110	/**
111	* size changes when elements added and removed
112	*/
113	public void testSize() {
114	ConcurrentLinkedQueue q = populatedQueue(SIZE);
115	for (int i = 0; i < SIZE; ++i) {
116	assertEquals(SIZE-i, q.size());
117	q.remove();
118	}
119	for (int i = 0; i < SIZE; ++i) {
120	assertEquals(i, q.size());
121	q.add(new Integer(i));
122	}
123	}
124
125	/**
126	* offer(null) throws NPE
127	*/
128	public void testOfferNull() {
129	try {
130	ConcurrentLinkedQueue q = new ConcurrentLinkedQueue();
131	q.offer(null);
132	shouldThrow();
133	} catch (NullPointerException success) {}
134	}
135
136	/**
137	* add(null) throws NPE
138	*/
139	public void testAddNull() {
140	try {
141	ConcurrentLinkedQueue q = new ConcurrentLinkedQueue();
142	q.add(null);
143	shouldThrow();
144	} catch (NullPointerException success) {}
145	}
146
147	/**
148	* Offer returns true
149	*/
150	public void testOffer() {
151	ConcurrentLinkedQueue q = new ConcurrentLinkedQueue();
152	assertTrue(q.offer(zero));
153	assertTrue(q.offer(one));
154	}
155
156	/**
157	* add returns true
158	*/
159	public void testAdd() {
160	ConcurrentLinkedQueue q = new ConcurrentLinkedQueue();
161	for (int i = 0; i < SIZE; ++i) {
162	assertEquals(i, q.size());
163	assertTrue(q.add(new Integer(i)));
164	}
165	}
166
167	/**
168	* addAll(null) throws NPE
169	*/
170	public void testAddAll1() {
171	try {
172	ConcurrentLinkedQueue q = new ConcurrentLinkedQueue();
173	q.addAll(null);
174	shouldThrow();
175	} catch (NullPointerException success) {}
176	}
177
178	/**
179	* addAll(this) throws IAE
180	*/
181	public void testAddAllSelf() {
182	try {
183	ConcurrentLinkedQueue q = populatedQueue(SIZE);
184	q.addAll(q);
185	shouldThrow();
186	} catch (IllegalArgumentException success) {}
187	}
188
189	/**
190	* addAll of a collection with null elements throws NPE
191	*/
192	public void testAddAll2() {
193	try {
194	ConcurrentLinkedQueue q = new ConcurrentLinkedQueue();
195	Integer[] ints = new Integer[SIZE];
196	q.addAll(Arrays.asList(ints));
197	shouldThrow();
198	} catch (NullPointerException success) {}
199	}
200
201	/**
202	* addAll of a collection with any null elements throws NPE after
203	* possibly adding some elements
204	*/
205	public void testAddAll3() {
206	try {
207	ConcurrentLinkedQueue q = new ConcurrentLinkedQueue();
208	Integer[] ints = new Integer[SIZE];
209	for (int i = 0; i < SIZE-1; ++i)
210	ints[i] = new Integer(i);
211	q.addAll(Arrays.asList(ints));
212	shouldThrow();
213	} catch (NullPointerException success) {}
214	}
215
216	/**
217	* Queue contains all elements, in traversal order, of successful addAll
218	*/
219	public void testAddAll5() {
220	Integer[] empty = new Integer[0];
221	Integer[] ints = new Integer[SIZE];
222	for (int i = 0; i < SIZE; ++i)
223	ints[i] = new Integer(i);
224	ConcurrentLinkedQueue q = new ConcurrentLinkedQueue();
225	assertFalse(q.addAll(Arrays.asList(empty)));
226	assertTrue(q.addAll(Arrays.asList(ints)));
227	for (int i = 0; i < SIZE; ++i)
228	assertEquals(ints[i], q.poll());
229	}
230
231	/**
232	* poll succeeds unless empty
233	*/
234	public void testPoll() {
235	ConcurrentLinkedQueue q = populatedQueue(SIZE);
236	for (int i = 0; i < SIZE; ++i) {
237	assertEquals(i, q.poll());
238	}
239	assertNull(q.poll());
240	}
241
242	/**
243	* peek returns next element, or null if empty
244	*/
245	public void testPeek() {
246	ConcurrentLinkedQueue q = populatedQueue(SIZE);
247	for (int i = 0; i < SIZE; ++i) {
248	assertEquals(i, q.peek());
249	assertEquals(i, q.poll());
250	assertTrue(q.peek() == null \|\|
251	!q.peek().equals(i));
252	}
253	assertNull(q.peek());
254	}
255
256	/**
257	* element returns next element, or throws NSEE if empty
258	*/
259	public void testElement() {
260	ConcurrentLinkedQueue q = populatedQueue(SIZE);
261	for (int i = 0; i < SIZE; ++i) {
262	assertEquals(i, q.element());
263	assertEquals(i, q.poll());
264	}
265	try {
266	q.element();
267	shouldThrow();
268	} catch (NoSuchElementException success) {}
269	}
270
271	/**
272	* remove removes next element, or throws NSEE if empty
273	*/
274	public void testRemove() {
275	ConcurrentLinkedQueue q = populatedQueue(SIZE);
276	for (int i = 0; i < SIZE; ++i) {
277	assertEquals(i, q.remove());
278	}
279	try {
280	q.remove();
281	shouldThrow();
282	} catch (NoSuchElementException success) {}
283	}
284
285	/**
286	* remove(x) removes x and returns true if present
287	*/
288	public void testRemoveElement() {
289	ConcurrentLinkedQueue q = populatedQueue(SIZE);
290	for (int i = 1; i < SIZE; i += 2) {
291	assertTrue(q.contains(i));
292	assertTrue(q.remove(i));
293	assertFalse(q.contains(i));
294	assertTrue(q.contains(i-1));
295	}
296	for (int i = 0; i < SIZE; i += 2) {
297	assertTrue(q.contains(i));
298	assertTrue(q.remove(i));
299	assertFalse(q.contains(i));
300	assertFalse(q.remove(i+1));
301	assertFalse(q.contains(i+1));
302	}
303	assertTrue(q.isEmpty());
304	}
305
306	/**
307	* contains(x) reports true when elements added but not yet removed
308	*/
309	public void testContains() {
310	ConcurrentLinkedQueue q = populatedQueue(SIZE);
311	for (int i = 0; i < SIZE; ++i) {
312	assertTrue(q.contains(new Integer(i)));
313	q.poll();
314	assertFalse(q.contains(new Integer(i)));
315	}
316	}
317
318	/**
319	* clear removes all elements
320	*/
321	public void testClear() {
322	ConcurrentLinkedQueue q = populatedQueue(SIZE);
323	q.clear();
324	assertTrue(q.isEmpty());
325	assertEquals(0, q.size());
326	q.add(one);
327	assertFalse(q.isEmpty());
328	q.clear();
329	assertTrue(q.isEmpty());
330	}
331
332	/**
333	* containsAll(c) is true when c contains a subset of elements
334	*/
335	public void testContainsAll() {
336	ConcurrentLinkedQueue q = populatedQueue(SIZE);
337	ConcurrentLinkedQueue p = new ConcurrentLinkedQueue();
338	for (int i = 0; i < SIZE; ++i) {
339	assertTrue(q.containsAll(p));
340	assertFalse(p.containsAll(q));
341	p.add(new Integer(i));
342	}
343	assertTrue(p.containsAll(q));
344	}
345
346	/**
347	* retainAll(c) retains only those elements of c and reports true if change
348	*/
349	public void testRetainAll() {
350	ConcurrentLinkedQueue q = populatedQueue(SIZE);
351	ConcurrentLinkedQueue p = populatedQueue(SIZE);
352	for (int i = 0; i < SIZE; ++i) {
353	boolean changed = q.retainAll(p);
354	if (i == 0)
355	assertFalse(changed);
356	else
357	assertTrue(changed);
358
359	assertTrue(q.containsAll(p));
360	assertEquals(SIZE-i, q.size());
361	p.remove();
362	}
363	}
364
365	/**
366	* removeAll(c) removes only those elements of c and reports true if changed
367	*/
368	public void testRemoveAll() {
369	for (int i = 1; i < SIZE; ++i) {
370	ConcurrentLinkedQueue q = populatedQueue(SIZE);
371	ConcurrentLinkedQueue p = populatedQueue(i);
372	assertTrue(q.removeAll(p));
373	assertEquals(SIZE-i, q.size());
374	for (int j = 0; j < i; ++j) {
375	Integer x = (Integer)(p.remove());
376	assertFalse(q.contains(x));
377	}
378	}
379	}
380
381	/**
382	* toArray contains all elements in FIFO order
383	*/
384	public void testToArray() {
385	ConcurrentLinkedQueue q = populatedQueue(SIZE);
386	Object[] o = q.toArray();
387	for (int i = 0; i < o.length; i++)
388	assertSame(o[i], q.poll());
389	}
390
391	/**
392	* toArray(a) contains all elements in FIFO order
393	*/
394	public void testToArray2() {
395	ConcurrentLinkedQueue<Integer> q = populatedQueue(SIZE);
396	Integer[] ints = new Integer[SIZE];
397	Integer[] array = q.toArray(ints);
398	assertSame(ints, array);
399	for (int i = 0; i < ints.length; i++)
400	assertSame(ints[i], q.poll());
401	}
402
403	/**
404	* toArray(null) throws NullPointerException
405	*/
406	public void testToArray_NullArg() {
407	ConcurrentLinkedQueue q = populatedQueue(SIZE);
408	try {
409	q.toArray(null);
410	shouldThrow();
411	} catch (NullPointerException success) {}
412	}
413
414	/**
415	* toArray(incompatible array type) throws ArrayStoreException
416	*/
417	public void testToArray1_BadArg() {
418	ConcurrentLinkedQueue q = populatedQueue(SIZE);
419	try {
420	q.toArray(new String[10]);
421	shouldThrow();
422	} catch (ArrayStoreException success) {}
423	}
424
425	/**
426	* iterator iterates through all elements
427	*/
428	public void testIterator() {
429	ConcurrentLinkedQueue q = populatedQueue(SIZE);
430	Iterator it = q.iterator();
431	int i;
432	for (i = 0; it.hasNext(); i++)
433	assertTrue(q.contains(it.next()));
434	assertEquals(i, SIZE);
435	assertIteratorExhausted(it);
436	}
437
438	/**
439	* iterator of empty collection has no elements
440	*/
441	public void testEmptyIterator() {
442	assertIteratorExhausted(new ConcurrentLinkedQueue().iterator());
443	}
444
445	/**
446	* iterator ordering is FIFO
447	*/
448	public void testIteratorOrdering() {
449	final ConcurrentLinkedQueue q = new ConcurrentLinkedQueue();
450	q.add(one);
451	q.add(two);
452	q.add(three);
453
454	int k = 0;
455	for (Iterator it = q.iterator(); it.hasNext();) {
456	assertEquals(++k, it.next());
457	}
458
459	assertEquals(3, k);
460	}
461
462	/**
463	* Modifications do not cause iterators to fail
464	*/
465	public void testWeaklyConsistentIteration() {
466	final ConcurrentLinkedQueue q = new ConcurrentLinkedQueue();
467	q.add(one);
468	q.add(two);
469	q.add(three);
470
471	for (Iterator it = q.iterator(); it.hasNext();) {
472	q.remove();
473	it.next();
474	}
475
476	assertEquals("queue should be empty again", 0, q.size());
477	}
478
479	/**
480	* iterator.remove removes current element
481	*/
482	public void testIteratorRemove() {
483	final ConcurrentLinkedQueue q = new ConcurrentLinkedQueue();
484	q.add(one);
485	q.add(two);
486	q.add(three);
487	Iterator it = q.iterator();
488	it.next();
489	it.remove();
490	it = q.iterator();
491	assertSame(it.next(), two);
492	assertSame(it.next(), three);
493	assertFalse(it.hasNext());
494	}
495
496	/**
497	* toString contains toStrings of elements
498	*/
499	public void testToString() {
500	ConcurrentLinkedQueue q = populatedQueue(SIZE);
501	String s = q.toString();
502	for (int i = 0; i < SIZE; ++i) {
503	assertTrue(s.contains(String.valueOf(i)));
504	}
505	}
506
507	/**
508	* A deserialized serialized queue has same elements in same order
509	*/
510	public void testSerialization() throws Exception {
511	Queue x = populatedQueue(SIZE);
512	Queue y = serialClone(x);
513
514	assertNotSame(x, y);
515	assertEquals(x.size(), y.size());
516	assertEquals(x.toString(), y.toString());
517	assertTrue(Arrays.equals(x.toArray(), y.toArray()));
518	while (!x.isEmpty()) {
519	assertFalse(y.isEmpty());
520	assertEquals(x.remove(), y.remove());
521	}
522	assertTrue(y.isEmpty());
523	}
524
525	/**
526	* remove(null), contains(null) always return false
527	*/
528	public void testNeverContainsNull() {
529	Collection<?>[] qs = {
530	new ConcurrentLinkedQueue<Object>(),
531	populatedQueue(2),
532	};
533
534	for (Collection<?> q : qs) {
535	assertFalse(q.contains(null));
536	assertFalse(q.remove(null));
537	}
538	}
539	}