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() {
        class Implementation implements CollectionImplementation {
            public Class<?> klazz() { return ConcurrentLinkedQueue.class; }
            public Collection emptyCollection() { return new ConcurrentLinkedQueue(); }
            public Object makeElement(int i) { return i; }
            public boolean isConcurrent() { return true; }
            public boolean permitsNulls() { return false; }
        }
        return newTestSuite(ConcurrentLinkedQueueTest.class,
                            CollectionTest.testSuite(new Implementation()));
    }

    /**
     * Returns a new queue of given size containing consecutive
     * Integers 0 ... n - 1.
     */
    private ConcurrentLinkedQueue<Integer> populatedQueue(int n) {
        ConcurrentLinkedQueue<Integer> q = new ConcurrentLinkedQueue<>();
        assertTrue(q.isEmpty());
        for (int i = 0; i < n; ++i)
            assertTrue(q.offer(new Integer(i)));
        assertFalse(q.isEmpty());
        assertEquals(n, q.size());
        assertEquals((Integer) 0, q.peek());
        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 {
            new ConcurrentLinkedQueue(Arrays.asList(new Integer[SIZE]));
            shouldThrow();
        } catch (NullPointerException success) {}
    }

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

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

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

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

    /**
     * addAll of a collection with any null elements throws NPE after
     * possibly adding some elements
     */
    public void testAddAll3() {
        ConcurrentLinkedQueue q = new ConcurrentLinkedQueue();
        Integer[] ints = new Integer[SIZE];
        for (int i = 0; i < SIZE - 1; ++i)
            ints[i] = new Integer(i);
        try {
            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:	1.43
Committed:	Wed Jan 4 06:09:58 2017 UTC (7 years, 4 months ago) by jsr166
Branch:	MAIN
Changes since 1.42:	+1 -1 lines
Log Message:	convert to Diamond
#	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	class Implementation implements CollectionImplementation {
27	public Class<?> klazz() { return ConcurrentLinkedQueue.class; }
28	public Collection emptyCollection() { return new ConcurrentLinkedQueue(); }
29	public Object makeElement(int i) { return i; }
30	public boolean isConcurrent() { return true; }
31	public boolean permitsNulls() { return false; }
32	}
33	return newTestSuite(ConcurrentLinkedQueueTest.class,
34	CollectionTest.testSuite(new Implementation()));
35	}
36
37	/**
38	* Returns a new queue of given size containing consecutive
39	* Integers 0 ... n - 1.
40	*/
41	private ConcurrentLinkedQueue<Integer> populatedQueue(int n) {
42	ConcurrentLinkedQueue<Integer> q = new ConcurrentLinkedQueue<>();
43	assertTrue(q.isEmpty());
44	for (int i = 0; i < n; ++i)
45	assertTrue(q.offer(new Integer(i)));
46	assertFalse(q.isEmpty());
47	assertEquals(n, q.size());
48	assertEquals((Integer) 0, q.peek());
49	return q;
50	}
51
52	/**
53	* new queue is empty
54	*/
55	public void testConstructor1() {
56	assertEquals(0, new ConcurrentLinkedQueue().size());
57	}
58
59	/**
60	* Initializing from null Collection throws NPE
61	*/
62	public void testConstructor3() {
63	try {
64	new ConcurrentLinkedQueue((Collection)null);
65	shouldThrow();
66	} catch (NullPointerException success) {}
67	}
68
69	/**
70	* Initializing from Collection of null elements throws NPE
71	*/
72	public void testConstructor4() {
73	try {
74	new ConcurrentLinkedQueue(Arrays.asList(new Integer[SIZE]));
75	shouldThrow();
76	} catch (NullPointerException success) {}
77	}
78
79	/**
80	* Initializing from Collection with some null elements throws NPE
81	*/
82	public void testConstructor5() {
83	Integer[] ints = new Integer[SIZE];
84	for (int i = 0; i < SIZE - 1; ++i)
85	ints[i] = new Integer(i);
86	try {
87	new ConcurrentLinkedQueue(Arrays.asList(ints));
88	shouldThrow();
89	} catch (NullPointerException success) {}
90	}
91
92	/**
93	* Queue contains all elements of collection used to initialize
94	*/
95	public void testConstructor6() {
96	Integer[] ints = new Integer[SIZE];
97	for (int i = 0; i < SIZE; ++i)
98	ints[i] = new Integer(i);
99	ConcurrentLinkedQueue q = new ConcurrentLinkedQueue(Arrays.asList(ints));
100	for (int i = 0; i < SIZE; ++i)
101	assertEquals(ints[i], q.poll());
102	}
103
104	/**
105	* isEmpty is true before add, false after
106	*/
107	public void testEmpty() {
108	ConcurrentLinkedQueue q = new ConcurrentLinkedQueue();
109	assertTrue(q.isEmpty());
110	q.add(one);
111	assertFalse(q.isEmpty());
112	q.add(two);
113	q.remove();
114	q.remove();
115	assertTrue(q.isEmpty());
116	}
117
118	/**
119	* size changes when elements added and removed
120	*/
121	public void testSize() {
122	ConcurrentLinkedQueue q = populatedQueue(SIZE);
123	for (int i = 0; i < SIZE; ++i) {
124	assertEquals(SIZE - i, q.size());
125	q.remove();
126	}
127	for (int i = 0; i < SIZE; ++i) {
128	assertEquals(i, q.size());
129	q.add(new Integer(i));
130	}
131	}
132
133	/**
134	* offer(null) throws NPE
135	*/
136	public void testOfferNull() {
137	ConcurrentLinkedQueue q = new ConcurrentLinkedQueue();
138	try {
139	q.offer(null);
140	shouldThrow();
141	} catch (NullPointerException success) {}
142	}
143
144	/**
145	* add(null) throws NPE
146	*/
147	public void testAddNull() {
148	ConcurrentLinkedQueue q = new ConcurrentLinkedQueue();
149	try {
150	q.add(null);
151	shouldThrow();
152	} catch (NullPointerException success) {}
153	}
154
155	/**
156	* Offer returns true
157	*/
158	public void testOffer() {
159	ConcurrentLinkedQueue q = new ConcurrentLinkedQueue();
160	assertTrue(q.offer(zero));
161	assertTrue(q.offer(one));
162	}
163
164	/**
165	* add returns true
166	*/
167	public void testAdd() {
168	ConcurrentLinkedQueue q = new ConcurrentLinkedQueue();
169	for (int i = 0; i < SIZE; ++i) {
170	assertEquals(i, q.size());
171	assertTrue(q.add(new Integer(i)));
172	}
173	}
174
175	/**
176	* addAll(null) throws NPE
177	*/
178	public void testAddAll1() {
179	ConcurrentLinkedQueue q = new ConcurrentLinkedQueue();
180	try {
181	q.addAll(null);
182	shouldThrow();
183	} catch (NullPointerException success) {}
184	}
185
186	/**
187	* addAll(this) throws IAE
188	*/
189	public void testAddAllSelf() {
190	ConcurrentLinkedQueue q = populatedQueue(SIZE);
191	try {
192	q.addAll(q);
193	shouldThrow();
194	} catch (IllegalArgumentException success) {}
195	}
196
197	/**
198	* addAll of a collection with null elements throws NPE
199	*/
200	public void testAddAll2() {
201	ConcurrentLinkedQueue q = new ConcurrentLinkedQueue();
202	try {
203	q.addAll(Arrays.asList(new Integer[SIZE]));
204	shouldThrow();
205	} catch (NullPointerException success) {}
206	}
207
208	/**
209	* addAll of a collection with any null elements throws NPE after
210	* possibly adding some elements
211	*/
212	public void testAddAll3() {
213	ConcurrentLinkedQueue q = new ConcurrentLinkedQueue();
214	Integer[] ints = new Integer[SIZE];
215	for (int i = 0; i < SIZE - 1; ++i)
216	ints[i] = new Integer(i);
217	try {
218	q.addAll(Arrays.asList(ints));
219	shouldThrow();
220	} catch (NullPointerException success) {}
221	}
222
223	/**
224	* Queue contains all elements, in traversal order, of successful addAll
225	*/
226	public void testAddAll5() {
227	Integer[] empty = new Integer[0];
228	Integer[] ints = new Integer[SIZE];
229	for (int i = 0; i < SIZE; ++i)
230	ints[i] = new Integer(i);
231	ConcurrentLinkedQueue q = new ConcurrentLinkedQueue();
232	assertFalse(q.addAll(Arrays.asList(empty)));
233	assertTrue(q.addAll(Arrays.asList(ints)));
234	for (int i = 0; i < SIZE; ++i)
235	assertEquals(ints[i], q.poll());
236	}
237
238	/**
239	* poll succeeds unless empty
240	*/
241	public void testPoll() {
242	ConcurrentLinkedQueue q = populatedQueue(SIZE);
243	for (int i = 0; i < SIZE; ++i) {
244	assertEquals(i, q.poll());
245	}
246	assertNull(q.poll());
247	}
248
249	/**
250	* peek returns next element, or null if empty
251	*/
252	public void testPeek() {
253	ConcurrentLinkedQueue q = populatedQueue(SIZE);
254	for (int i = 0; i < SIZE; ++i) {
255	assertEquals(i, q.peek());
256	assertEquals(i, q.poll());
257	assertTrue(q.peek() == null \|\|
258	!q.peek().equals(i));
259	}
260	assertNull(q.peek());
261	}
262
263	/**
264	* element returns next element, or throws NSEE if empty
265	*/
266	public void testElement() {
267	ConcurrentLinkedQueue q = populatedQueue(SIZE);
268	for (int i = 0; i < SIZE; ++i) {
269	assertEquals(i, q.element());
270	assertEquals(i, q.poll());
271	}
272	try {
273	q.element();
274	shouldThrow();
275	} catch (NoSuchElementException success) {}
276	}
277
278	/**
279	* remove removes next element, or throws NSEE if empty
280	*/
281	public void testRemove() {
282	ConcurrentLinkedQueue q = populatedQueue(SIZE);
283	for (int i = 0; i < SIZE; ++i) {
284	assertEquals(i, q.remove());
285	}
286	try {
287	q.remove();
288	shouldThrow();
289	} catch (NoSuchElementException success) {}
290	}
291
292	/**
293	* remove(x) removes x and returns true if present
294	*/
295	public void testRemoveElement() {
296	ConcurrentLinkedQueue q = populatedQueue(SIZE);
297	for (int i = 1; i < SIZE; i += 2) {
298	assertTrue(q.contains(i));
299	assertTrue(q.remove(i));
300	assertFalse(q.contains(i));
301	assertTrue(q.contains(i - 1));
302	}
303	for (int i = 0; i < SIZE; i += 2) {
304	assertTrue(q.contains(i));
305	assertTrue(q.remove(i));
306	assertFalse(q.contains(i));
307	assertFalse(q.remove(i + 1));
308	assertFalse(q.contains(i + 1));
309	}
310	assertTrue(q.isEmpty());
311	}
312
313	/**
314	* contains(x) reports true when elements added but not yet removed
315	*/
316	public void testContains() {
317	ConcurrentLinkedQueue q = populatedQueue(SIZE);
318	for (int i = 0; i < SIZE; ++i) {
319	assertTrue(q.contains(new Integer(i)));
320	q.poll();
321	assertFalse(q.contains(new Integer(i)));
322	}
323	}
324
325	/**
326	* clear removes all elements
327	*/
328	public void testClear() {
329	ConcurrentLinkedQueue q = populatedQueue(SIZE);
330	q.clear();
331	assertTrue(q.isEmpty());
332	assertEquals(0, q.size());
333	q.add(one);
334	assertFalse(q.isEmpty());
335	q.clear();
336	assertTrue(q.isEmpty());
337	}
338
339	/**
340	* containsAll(c) is true when c contains a subset of elements
341	*/
342	public void testContainsAll() {
343	ConcurrentLinkedQueue q = populatedQueue(SIZE);
344	ConcurrentLinkedQueue p = new ConcurrentLinkedQueue();
345	for (int i = 0; i < SIZE; ++i) {
346	assertTrue(q.containsAll(p));
347	assertFalse(p.containsAll(q));
348	p.add(new Integer(i));
349	}
350	assertTrue(p.containsAll(q));
351	}
352
353	/**
354	* retainAll(c) retains only those elements of c and reports true if change
355	*/
356	public void testRetainAll() {
357	ConcurrentLinkedQueue q = populatedQueue(SIZE);
358	ConcurrentLinkedQueue p = populatedQueue(SIZE);
359	for (int i = 0; i < SIZE; ++i) {
360	boolean changed = q.retainAll(p);
361	if (i == 0)
362	assertFalse(changed);
363	else
364	assertTrue(changed);
365
366	assertTrue(q.containsAll(p));
367	assertEquals(SIZE - i, q.size());
368	p.remove();
369	}
370	}
371
372	/**
373	* removeAll(c) removes only those elements of c and reports true if changed
374	*/
375	public void testRemoveAll() {
376	for (int i = 1; i < SIZE; ++i) {
377	ConcurrentLinkedQueue q = populatedQueue(SIZE);
378	ConcurrentLinkedQueue p = populatedQueue(i);
379	assertTrue(q.removeAll(p));
380	assertEquals(SIZE - i, q.size());
381	for (int j = 0; j < i; ++j) {
382	Integer x = (Integer)(p.remove());
383	assertFalse(q.contains(x));
384	}
385	}
386	}
387
388	/**
389	* toArray contains all elements in FIFO order
390	*/
391	public void testToArray() {
392	ConcurrentLinkedQueue q = populatedQueue(SIZE);
393	Object[] o = q.toArray();
394	for (int i = 0; i < o.length; i++)
395	assertSame(o[i], q.poll());
396	}
397
398	/**
399	* toArray(a) contains all elements in FIFO order
400	*/
401	public void testToArray2() {
402	ConcurrentLinkedQueue<Integer> q = populatedQueue(SIZE);
403	Integer[] ints = new Integer[SIZE];
404	Integer[] array = q.toArray(ints);
405	assertSame(ints, array);
406	for (int i = 0; i < ints.length; i++)
407	assertSame(ints[i], q.poll());
408	}
409
410	/**
411	* toArray(null) throws NullPointerException
412	*/
413	public void testToArray_NullArg() {
414	ConcurrentLinkedQueue q = populatedQueue(SIZE);
415	try {
416	q.toArray(null);
417	shouldThrow();
418	} catch (NullPointerException success) {}
419	}
420
421	/**
422	* toArray(incompatible array type) throws ArrayStoreException
423	*/
424	public void testToArray1_BadArg() {
425	ConcurrentLinkedQueue q = populatedQueue(SIZE);
426	try {
427	q.toArray(new String[10]);
428	shouldThrow();
429	} catch (ArrayStoreException success) {}
430	}
431
432	/**
433	* iterator iterates through all elements
434	*/
435	public void testIterator() {
436	ConcurrentLinkedQueue q = populatedQueue(SIZE);
437	Iterator it = q.iterator();
438	int i;
439	for (i = 0; it.hasNext(); i++)
440	assertTrue(q.contains(it.next()));
441	assertEquals(i, SIZE);
442	assertIteratorExhausted(it);
443	}
444
445	/**
446	* iterator of empty collection has no elements
447	*/
448	public void testEmptyIterator() {
449	assertIteratorExhausted(new ConcurrentLinkedQueue().iterator());
450	}
451
452	/**
453	* iterator ordering is FIFO
454	*/
455	public void testIteratorOrdering() {
456	final ConcurrentLinkedQueue q = new ConcurrentLinkedQueue();
457	q.add(one);
458	q.add(two);
459	q.add(three);
460
461	int k = 0;
462	for (Iterator it = q.iterator(); it.hasNext();) {
463	assertEquals(++k, it.next());
464	}
465
466	assertEquals(3, k);
467	}
468
469	/**
470	* Modifications do not cause iterators to fail
471	*/
472	public void testWeaklyConsistentIteration() {
473	final ConcurrentLinkedQueue q = new ConcurrentLinkedQueue();
474	q.add(one);
475	q.add(two);
476	q.add(three);
477
478	for (Iterator it = q.iterator(); it.hasNext();) {
479	q.remove();
480	it.next();
481	}
482
483	assertEquals("queue should be empty again", 0, q.size());
484	}
485
486	/**
487	* iterator.remove removes current element
488	*/
489	public void testIteratorRemove() {
490	final ConcurrentLinkedQueue q = new ConcurrentLinkedQueue();
491	q.add(one);
492	q.add(two);
493	q.add(three);
494	Iterator it = q.iterator();
495	it.next();
496	it.remove();
497	it = q.iterator();
498	assertSame(it.next(), two);
499	assertSame(it.next(), three);
500	assertFalse(it.hasNext());
501	}
502
503	/**
504	* toString contains toStrings of elements
505	*/
506	public void testToString() {
507	ConcurrentLinkedQueue q = populatedQueue(SIZE);
508	String s = q.toString();
509	for (int i = 0; i < SIZE; ++i) {
510	assertTrue(s.contains(String.valueOf(i)));
511	}
512	}
513
514	/**
515	* A deserialized serialized queue has same elements in same order
516	*/
517	public void testSerialization() throws Exception {
518	Queue x = populatedQueue(SIZE);
519	Queue y = serialClone(x);
520
521	assertNotSame(x, y);
522	assertEquals(x.size(), y.size());
523	assertEquals(x.toString(), y.toString());
524	assertTrue(Arrays.equals(x.toArray(), y.toArray()));
525	while (!x.isEmpty()) {
526	assertFalse(y.isEmpty());
527	assertEquals(x.remove(), y.remove());
528	}
529	assertTrue(y.isEmpty());
530	}
531
532	/**
533	* remove(null), contains(null) always return false
534	*/
535	public void testNeverContainsNull() {
536	Collection<?>[] qs = {
537	new ConcurrentLinkedQueue<Object>(),
538	populatedQueue(2),
539	};
540
541	for (Collection<?> q : qs) {
542	assertFalse(q.contains(null));
543	assertFalse(q.remove(null));
544	}
545	}
546	}