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 {
            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:	1.38
Committed:	Fri May 15 18:21:19 2015 UTC (9 years ago) by jsr166
Branch:	MAIN
Changes since 1.37:	+14 -16 lines
Log Message:	try/catch block scope hygiene
#	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	new ConcurrentLinkedQueue(Arrays.asList(new Integer[SIZE]));
66	shouldThrow();
67	} catch (NullPointerException success) {}
68	}
69
70	/**
71	* Initializing from Collection with some null elements throws NPE
72	*/
73	public void testConstructor5() {
74	Integer[] ints = new Integer[SIZE];
75	for (int i = 0; i < SIZE-1; ++i)
76	ints[i] = new Integer(i);
77	try {
78	new ConcurrentLinkedQueue(Arrays.asList(ints));
79	shouldThrow();
80	} catch (NullPointerException success) {}
81	}
82
83	/**
84	* Queue contains all elements of collection used to initialize
85	*/
86	public void testConstructor6() {
87	Integer[] ints = new Integer[SIZE];
88	for (int i = 0; i < SIZE; ++i)
89	ints[i] = new Integer(i);
90	ConcurrentLinkedQueue q = new ConcurrentLinkedQueue(Arrays.asList(ints));
91	for (int i = 0; i < SIZE; ++i)
92	assertEquals(ints[i], q.poll());
93	}
94
95	/**
96	* isEmpty is true before add, false after
97	*/
98	public void testEmpty() {
99	ConcurrentLinkedQueue q = new ConcurrentLinkedQueue();
100	assertTrue(q.isEmpty());
101	q.add(one);
102	assertFalse(q.isEmpty());
103	q.add(two);
104	q.remove();
105	q.remove();
106	assertTrue(q.isEmpty());
107	}
108
109	/**
110	* size changes when elements added and removed
111	*/
112	public void testSize() {
113	ConcurrentLinkedQueue q = populatedQueue(SIZE);
114	for (int i = 0; i < SIZE; ++i) {
115	assertEquals(SIZE-i, q.size());
116	q.remove();
117	}
118	for (int i = 0; i < SIZE; ++i) {
119	assertEquals(i, q.size());
120	q.add(new Integer(i));
121	}
122	}
123
124	/**
125	* offer(null) throws NPE
126	*/
127	public void testOfferNull() {
128	ConcurrentLinkedQueue q = new ConcurrentLinkedQueue();
129	try {
130	q.offer(null);
131	shouldThrow();
132	} catch (NullPointerException success) {}
133	}
134
135	/**
136	* add(null) throws NPE
137	*/
138	public void testAddNull() {
139	ConcurrentLinkedQueue q = new ConcurrentLinkedQueue();
140	try {
141	q.add(null);
142	shouldThrow();
143	} catch (NullPointerException success) {}
144	}
145
146	/**
147	* Offer returns true
148	*/
149	public void testOffer() {
150	ConcurrentLinkedQueue q = new ConcurrentLinkedQueue();
151	assertTrue(q.offer(zero));
152	assertTrue(q.offer(one));
153	}
154
155	/**
156	* add returns true
157	*/
158	public void testAdd() {
159	ConcurrentLinkedQueue q = new ConcurrentLinkedQueue();
160	for (int i = 0; i < SIZE; ++i) {
161	assertEquals(i, q.size());
162	assertTrue(q.add(new Integer(i)));
163	}
164	}
165
166	/**
167	* addAll(null) throws NPE
168	*/
169	public void testAddAll1() {
170	ConcurrentLinkedQueue q = new ConcurrentLinkedQueue();
171	try {
172	q.addAll(null);
173	shouldThrow();
174	} catch (NullPointerException success) {}
175	}
176
177	/**
178	* addAll(this) throws IAE
179	*/
180	public void testAddAllSelf() {
181	ConcurrentLinkedQueue q = populatedQueue(SIZE);
182	try {
183	q.addAll(q);
184	shouldThrow();
185	} catch (IllegalArgumentException success) {}
186	}
187
188	/**
189	* addAll of a collection with null elements throws NPE
190	*/
191	public void testAddAll2() {
192	ConcurrentLinkedQueue q = new ConcurrentLinkedQueue();
193	try {
194	q.addAll(Arrays.asList(new Integer[SIZE]));
195	shouldThrow();
196	} catch (NullPointerException success) {}
197	}
198
199	/**
200	* addAll of a collection with any null elements throws NPE after
201	* possibly adding some elements
202	*/
203	public void testAddAll3() {
204	ConcurrentLinkedQueue q = new ConcurrentLinkedQueue();
205	Integer[] ints = new Integer[SIZE];
206	for (int i = 0; i < SIZE-1; ++i)
207	ints[i] = new Integer(i);
208	try {
209	q.addAll(Arrays.asList(ints));
210	shouldThrow();
211	} catch (NullPointerException success) {}
212	}
213
214	/**
215	* Queue contains all elements, in traversal order, of successful addAll
216	*/
217	public void testAddAll5() {
218	Integer[] empty = new Integer[0];
219	Integer[] ints = new Integer[SIZE];
220	for (int i = 0; i < SIZE; ++i)
221	ints[i] = new Integer(i);
222	ConcurrentLinkedQueue q = new ConcurrentLinkedQueue();
223	assertFalse(q.addAll(Arrays.asList(empty)));
224	assertTrue(q.addAll(Arrays.asList(ints)));
225	for (int i = 0; i < SIZE; ++i)
226	assertEquals(ints[i], q.poll());
227	}
228
229	/**
230	* poll succeeds unless empty
231	*/
232	public void testPoll() {
233	ConcurrentLinkedQueue q = populatedQueue(SIZE);
234	for (int i = 0; i < SIZE; ++i) {
235	assertEquals(i, q.poll());
236	}
237	assertNull(q.poll());
238	}
239
240	/**
241	* peek returns next element, or null if empty
242	*/
243	public void testPeek() {
244	ConcurrentLinkedQueue q = populatedQueue(SIZE);
245	for (int i = 0; i < SIZE; ++i) {
246	assertEquals(i, q.peek());
247	assertEquals(i, q.poll());
248	assertTrue(q.peek() == null \|\|
249	!q.peek().equals(i));
250	}
251	assertNull(q.peek());
252	}
253
254	/**
255	* element returns next element, or throws NSEE if empty
256	*/
257	public void testElement() {
258	ConcurrentLinkedQueue q = populatedQueue(SIZE);
259	for (int i = 0; i < SIZE; ++i) {
260	assertEquals(i, q.element());
261	assertEquals(i, q.poll());
262	}
263	try {
264	q.element();
265	shouldThrow();
266	} catch (NoSuchElementException success) {}
267	}
268
269	/**
270	* remove removes next element, or throws NSEE if empty
271	*/
272	public void testRemove() {
273	ConcurrentLinkedQueue q = populatedQueue(SIZE);
274	for (int i = 0; i < SIZE; ++i) {
275	assertEquals(i, q.remove());
276	}
277	try {
278	q.remove();
279	shouldThrow();
280	} catch (NoSuchElementException success) {}
281	}
282
283	/**
284	* remove(x) removes x and returns true if present
285	*/
286	public void testRemoveElement() {
287	ConcurrentLinkedQueue q = populatedQueue(SIZE);
288	for (int i = 1; i < SIZE; i += 2) {
289	assertTrue(q.contains(i));
290	assertTrue(q.remove(i));
291	assertFalse(q.contains(i));
292	assertTrue(q.contains(i-1));
293	}
294	for (int i = 0; i < SIZE; i += 2) {
295	assertTrue(q.contains(i));
296	assertTrue(q.remove(i));
297	assertFalse(q.contains(i));
298	assertFalse(q.remove(i+1));
299	assertFalse(q.contains(i+1));
300	}
301	assertTrue(q.isEmpty());
302	}
303
304	/**
305	* contains(x) reports true when elements added but not yet removed
306	*/
307	public void testContains() {
308	ConcurrentLinkedQueue q = populatedQueue(SIZE);
309	for (int i = 0; i < SIZE; ++i) {
310	assertTrue(q.contains(new Integer(i)));
311	q.poll();
312	assertFalse(q.contains(new Integer(i)));
313	}
314	}
315
316	/**
317	* clear removes all elements
318	*/
319	public void testClear() {
320	ConcurrentLinkedQueue q = populatedQueue(SIZE);
321	q.clear();
322	assertTrue(q.isEmpty());
323	assertEquals(0, q.size());
324	q.add(one);
325	assertFalse(q.isEmpty());
326	q.clear();
327	assertTrue(q.isEmpty());
328	}
329
330	/**
331	* containsAll(c) is true when c contains a subset of elements
332	*/
333	public void testContainsAll() {
334	ConcurrentLinkedQueue q = populatedQueue(SIZE);
335	ConcurrentLinkedQueue p = new ConcurrentLinkedQueue();
336	for (int i = 0; i < SIZE; ++i) {
337	assertTrue(q.containsAll(p));
338	assertFalse(p.containsAll(q));
339	p.add(new Integer(i));
340	}
341	assertTrue(p.containsAll(q));
342	}
343
344	/**
345	* retainAll(c) retains only those elements of c and reports true if change
346	*/
347	public void testRetainAll() {
348	ConcurrentLinkedQueue q = populatedQueue(SIZE);
349	ConcurrentLinkedQueue p = populatedQueue(SIZE);
350	for (int i = 0; i < SIZE; ++i) {
351	boolean changed = q.retainAll(p);
352	if (i == 0)
353	assertFalse(changed);
354	else
355	assertTrue(changed);
356
357	assertTrue(q.containsAll(p));
358	assertEquals(SIZE-i, q.size());
359	p.remove();
360	}
361	}
362
363	/**
364	* removeAll(c) removes only those elements of c and reports true if changed
365	*/
366	public void testRemoveAll() {
367	for (int i = 1; i < SIZE; ++i) {
368	ConcurrentLinkedQueue q = populatedQueue(SIZE);
369	ConcurrentLinkedQueue p = populatedQueue(i);
370	assertTrue(q.removeAll(p));
371	assertEquals(SIZE-i, q.size());
372	for (int j = 0; j < i; ++j) {
373	Integer x = (Integer)(p.remove());
374	assertFalse(q.contains(x));
375	}
376	}
377	}
378
379	/**
380	* toArray contains all elements in FIFO order
381	*/
382	public void testToArray() {
383	ConcurrentLinkedQueue q = populatedQueue(SIZE);
384	Object[] o = q.toArray();
385	for (int i = 0; i < o.length; i++)
386	assertSame(o[i], q.poll());
387	}
388
389	/**
390	* toArray(a) contains all elements in FIFO order
391	*/
392	public void testToArray2() {
393	ConcurrentLinkedQueue<Integer> q = populatedQueue(SIZE);
394	Integer[] ints = new Integer[SIZE];
395	Integer[] array = q.toArray(ints);
396	assertSame(ints, array);
397	for (int i = 0; i < ints.length; i++)
398	assertSame(ints[i], q.poll());
399	}
400
401	/**
402	* toArray(null) throws NullPointerException
403	*/
404	public void testToArray_NullArg() {
405	ConcurrentLinkedQueue q = populatedQueue(SIZE);
406	try {
407	q.toArray(null);
408	shouldThrow();
409	} catch (NullPointerException success) {}
410	}
411
412	/**
413	* toArray(incompatible array type) throws ArrayStoreException
414	*/
415	public void testToArray1_BadArg() {
416	ConcurrentLinkedQueue q = populatedQueue(SIZE);
417	try {
418	q.toArray(new String[10]);
419	shouldThrow();
420	} catch (ArrayStoreException success) {}
421	}
422
423	/**
424	* iterator iterates through all elements
425	*/
426	public void testIterator() {
427	ConcurrentLinkedQueue q = populatedQueue(SIZE);
428	Iterator it = q.iterator();
429	int i;
430	for (i = 0; it.hasNext(); i++)
431	assertTrue(q.contains(it.next()));
432	assertEquals(i, SIZE);
433	assertIteratorExhausted(it);
434	}
435
436	/**
437	* iterator of empty collection has no elements
438	*/
439	public void testEmptyIterator() {
440	assertIteratorExhausted(new ConcurrentLinkedQueue().iterator());
441	}
442
443	/**
444	* iterator ordering is FIFO
445	*/
446	public void testIteratorOrdering() {
447	final ConcurrentLinkedQueue q = new ConcurrentLinkedQueue();
448	q.add(one);
449	q.add(two);
450	q.add(three);
451
452	int k = 0;
453	for (Iterator it = q.iterator(); it.hasNext();) {
454	assertEquals(++k, it.next());
455	}
456
457	assertEquals(3, k);
458	}
459
460	/**
461	* Modifications do not cause iterators to fail
462	*/
463	public void testWeaklyConsistentIteration() {
464	final ConcurrentLinkedQueue q = new ConcurrentLinkedQueue();
465	q.add(one);
466	q.add(two);
467	q.add(three);
468
469	for (Iterator it = q.iterator(); it.hasNext();) {
470	q.remove();
471	it.next();
472	}
473
474	assertEquals("queue should be empty again", 0, q.size());
475	}
476
477	/**
478	* iterator.remove removes current element
479	*/
480	public void testIteratorRemove() {
481	final ConcurrentLinkedQueue q = new ConcurrentLinkedQueue();
482	q.add(one);
483	q.add(two);
484	q.add(three);
485	Iterator it = q.iterator();
486	it.next();
487	it.remove();
488	it = q.iterator();
489	assertSame(it.next(), two);
490	assertSame(it.next(), three);
491	assertFalse(it.hasNext());
492	}
493
494	/**
495	* toString contains toStrings of elements
496	*/
497	public void testToString() {
498	ConcurrentLinkedQueue q = populatedQueue(SIZE);
499	String s = q.toString();
500	for (int i = 0; i < SIZE; ++i) {
501	assertTrue(s.contains(String.valueOf(i)));
502	}
503	}
504
505	/**
506	* A deserialized serialized queue has same elements in same order
507	*/
508	public void testSerialization() throws Exception {
509	Queue x = populatedQueue(SIZE);
510	Queue y = serialClone(x);
511
512	assertNotSame(x, y);
513	assertEquals(x.size(), y.size());
514	assertEquals(x.toString(), y.toString());
515	assertTrue(Arrays.equals(x.toArray(), y.toArray()));
516	while (!x.isEmpty()) {
517	assertFalse(y.isEmpty());
518	assertEquals(x.remove(), y.remove());
519	}
520	assertTrue(y.isEmpty());
521	}
522
523	/**
524	* remove(null), contains(null) always return false
525	*/
526	public void testNeverContainsNull() {
527	Collection<?>[] qs = {
528	new ConcurrentLinkedQueue<Object>(),
529	populatedQueue(2),
530	};
531
532	for (Collection<?> q : qs) {
533	assertFalse(q.contains(null));
534	assertFalse(q.remove(null));
535	}
536	}
537	}