Coverage Summary for Class: LongAddables (com.google.common.hash)

1 /*
2  * Copyright (C) 2012 The Guava Authors
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except
5  * in compliance with the License. You may obtain a copy of the License at
6  *
7  * http://www.apache.org/licenses/LICENSE-2.0
8  *
9  * Unless required by applicable law or agreed to in writing, software distributed under the License
10  * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
11  * or implied. See the License for the specific language governing permissions and limitations under
12  * the License.
13  */
14 
15 package com.google.common.hash;
16 
17 import com.google.common.base.Supplier;
18 import java.util.concurrent.atomic.AtomicLong;
19 
20 /**
21  * Source of {@link LongAddable} objects that deals with GWT, Unsafe, and all that.
22  *
23  * @author Louis Wasserman
24  */
25 @ElementTypesAreNonnullByDefault
26 final class LongAddables {
27   private static final Supplier<LongAddable> SUPPLIER;
28 
29   static {
30     Supplier<LongAddable> supplier;
31     try {
32       new LongAdder(); // trigger static initialization of the LongAdder class, which may fail
33       supplier =
34           new Supplier<LongAddable>() {
35             @Override
36             public LongAddable get() {
37               return new LongAdder();
38             }
39           };
40     } catch (Throwable t) { // we really want to catch *everything*
41       supplier =
42           new Supplier<LongAddable>() {
43             @Override
44             public LongAddable get() {
45               return new PureJavaLongAddable();
46             }
47           };
48     }
49     SUPPLIER = supplier;
50   }
51 
52   public static LongAddable create() {
53     return SUPPLIER.get();
54   }
55 
56   private static final class PureJavaLongAddable extends AtomicLong implements LongAddable {
57     @Override
58     public void increment() {
59       getAndIncrement();
60     }
61 
62     @Override
63     public void add(long x) {
64       getAndAdd(x);
65     }
66 
67     @Override
68     public long sum() {
69       return get();
70     }
71   }
72 }