aboutsummaryrefslogtreecommitdiff
path: root/guava-tests/test/com/google/common/collect/InternersTest.java
blob: cfa14b892244acb89322378242a2bd2444ee0bb9 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
/*
 * Copyright (C) 2007 The Guava Authors
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.google.common.collect;

import com.google.common.base.Function;
import com.google.common.collect.Interners.InternerImpl;
import com.google.common.collect.MapMakerInternalMap.Strength;
import com.google.common.testing.GcFinalization;
import com.google.common.testing.NullPointerTester;
import java.lang.ref.WeakReference;
import junit.framework.TestCase;

/**
 * Unit test for {@link Interners}.
 *
 * @author Kevin Bourrillion
 */
public class InternersTest extends TestCase {

  public void testStrong_simplistic() {
    String canonical = "a";
    String not = new String("a");

    Interner<String> pool = Interners.newStrongInterner();
    assertSame(canonical, pool.intern(canonical));
    assertSame(canonical, pool.intern(not));
  }

  public void testStrong_null() {
    Interner<String> pool = Interners.newStrongInterner();
    try {
      pool.intern(null);
      fail();
    } catch (NullPointerException ok) {
    }
  }

  public void testStrong_builder() {
    int concurrencyLevel = 42;
    Interner<Object> interner =
        Interners.newBuilder().strong().concurrencyLevel(concurrencyLevel).build();
    InternerImpl<Object> internerImpl = (InternerImpl<Object>) interner;
    assertEquals(Strength.STRONG, internerImpl.map.keyStrength());
  }

  public void testWeak_simplistic() {
    String canonical = "a";
    String not = new String("a");

    Interner<String> pool = Interners.newWeakInterner();
    assertSame(canonical, pool.intern(canonical));
    assertSame(canonical, pool.intern(not));
  }

  public void testWeak_null() {
    Interner<String> pool = Interners.newWeakInterner();
    try {
      pool.intern(null);
      fail();
    } catch (NullPointerException ok) {
    }
  }

  public void testWeak_builder() {
    int concurrencyLevel = 42;
    Interner<Object> interner =
        Interners.newBuilder().weak().concurrencyLevel(concurrencyLevel).build();
    InternerImpl<Object> internerImpl = (InternerImpl<Object>) interner;
    assertEquals(Strength.WEAK, internerImpl.map.keyStrength());
    assertEquals(concurrencyLevel, internerImpl.map.concurrencyLevel);
  }


  public void testWeak_afterGC() throws InterruptedException {
    Integer canonical = new Integer(5);
    Integer not = new Integer(5);

    Interner<Integer> pool = Interners.newWeakInterner();
    assertSame(canonical, pool.intern(canonical));

    WeakReference<Integer> signal = new WeakReference<>(canonical);
    canonical = null; // Hint to the JIT that canonical is unreachable

    GcFinalization.awaitClear(signal);
    assertSame(not, pool.intern(not));
  }

  public void testAsFunction_simplistic() {
    String canonical = "a";
    String not = new String("a");

    Function<String, String> internerFunction =
        Interners.asFunction(Interners.<String>newStrongInterner());

    assertSame(canonical, internerFunction.apply(canonical));
    assertSame(canonical, internerFunction.apply(not));
  }

  public void testNullPointerExceptions() {
    new NullPointerTester().testAllPublicStaticMethods(Interners.class);
  }

  public void testConcurrencyLevel_Zero() {
    Interners.InternerBuilder builder = Interners.newBuilder();
    try {
      builder.concurrencyLevel(0);
      fail();
    } catch (IllegalArgumentException expected) {
    }
  }

  public void testConcurrencyLevel_Negative() {
    Interners.InternerBuilder builder = Interners.newBuilder();
    try {
      builder.concurrencyLevel(-42);
      fail();
    } catch (IllegalArgumentException expected) {
    }
  }
}