1/*
2 * Copyright (C) 2016 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License
15 */
16
17package libcore.java.util;
18
19import java.util.Collection;
20import java.util.ConcurrentModificationException;
21import java.util.function.Predicate;
22import java.util.function.Supplier;
23
24import static junit.framework.Assert.assertTrue;
25import static junit.framework.Assert.fail;
26
27/**
28 * Tests behavior common to all implementations of {@link Collection#removeIf(Predicate)}.
29 */
30public class RemoveIfTester {
31
32    private static final Predicate<Integer> isEven = x -> x % 2 == 0;
33    private static final Predicate<Integer> isOdd = isEven.negate();
34
35    public static void runBasicRemoveIfTests(Supplier<Collection<Integer>> supp) {
36        Collection<Integer> integers = supp.get();
37        for (int h = 0; h < 100; ++h) {
38            // Insert some ordered integers.
39            integers.add(h);
40        }
41
42        integers.removeIf(isEven);
43        Integer prev = null;
44        for (Integer i : integers) {
45            assertTrue(i % 2 != 0);
46            if (prev != null) {
47                assertTrue(prev <= i);
48            }
49            prev = i;
50        }
51
52        integers.removeIf(isOdd);
53        assertTrue(integers.isEmpty());
54    }
55
56    public static void runBasicRemoveIfTestsUnordered(Supplier<Collection<Integer>> supp) {
57        Collection<Integer> integers = supp.get();
58        for (int h = 0; h < 100; ++h) {
59            // Insert a bunch of arbitrary integers.
60            integers.add((h >>> 2) ^ (h >>> 5) ^ (h >>> 11) ^ (h >>> 17));
61        }
62
63        integers.removeIf(isEven);
64        for (Integer i : integers) {
65            assertTrue(i % 2 != 0);
66        }
67
68        integers.removeIf(isOdd);
69        assertTrue(integers.isEmpty());
70    }
71
72    /**
73     * Removing from an empty collection should not fail.
74     */
75    public static void runRemoveIfOnEmpty(Supplier<Collection<Integer>> supp) {
76        supp.get().removeIf(x -> {
77            fail();
78            return false;
79        });
80    }
81
82    public static void testRemoveIfNPE(Supplier<Collection<Integer>> supp) {
83        try {
84            supp.get().removeIf(null);
85            fail();
86        } catch (NullPointerException expected) {}
87    }
88
89    public static void testRemoveIfCME(Supplier<Collection<Integer>> supp) {
90        Collection<Integer> c = supp.get();
91        c.add(0);
92
93        try {
94            c.removeIf(x -> {c.add(42); return true;});
95            fail();
96        } catch (ConcurrentModificationException expected) {
97        }
98    }
99}
100