1 /*
2 * Copyright (C) 2011 The Guava Authors
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
17 package com.google.common.cache;
18
19 import com.google.common.annotations.Beta;
20 import com.google.common.annotations.GwtCompatible;
21
22 import java.util.Iterator;
23 import java.util.Map;
24 import java.util.concurrent.ConcurrentMap;
25
26 /**
27 * The reason why a cached entry was removed.
28 *
29 * @author Charles Fry
30 * @since 10.0
31 */
32 @Beta
33 @GwtCompatible
34 public enum RemovalCause {
35 /**
36 * The entry was manually removed by the user. This can result from the user invoking
37 * {@link Cache#invalidate}, {@link Cache#invalidateAll(Iterable)}, {@link Cache#invalidateAll()},
38 * {@link Map#remove}, {@link ConcurrentMap#remove}, or {@link Iterator#remove}.
39 */
40 EXPLICIT {
41 @Override
42 boolean wasEvicted() {
43 return false;
44 }
45 },
46
47 /**
48 * The entry itself was not actually removed, but its value was replaced by the user. This can
49 * result from the user invoking {@link Cache#put}, {@link LoadingCache#refresh}, {@link Map#put},
50 * {@link Map#putAll}, {@link ConcurrentMap#replace(Object, Object)}, or
51 * {@link ConcurrentMap#replace(Object, Object, Object)}.
52 */
53 REPLACED {
54 @Override
55 boolean wasEvicted() {
56 return false;
57 }
58 },
59
60 /**
61 * The entry was removed automatically because its key or value was garbage-collected. This
62 * can occur when using {@link CacheBuilder#weakKeys}, {@link CacheBuilder#weakValues}, or
63 * {@link CacheBuilder#softValues}.
64 */
65 COLLECTED {
66 @Override
67 boolean wasEvicted() {
68 return true;
69 }
70 },
71
72 /**
73 * The entry's expiration timestamp has passed. This can occur when using
74 * {@link CacheBuilder#expireAfterWrite} or {@link CacheBuilder#expireAfterAccess}.
75 */
76 EXPIRED {
77 @Override
78 boolean wasEvicted() {
79 return true;
80 }
81 },
82
83 /**
84 * The entry was evicted due to size constraints. This can occur when using
85 * {@link CacheBuilder#maximumSize} or {@link CacheBuilder#maximumWeight}.
86 */
87 SIZE {
88 @Override
89 boolean wasEvicted() {
90 return true;
91 }
92 };
93
94 /**
95 * Returns {@code true} if there was an automatic removal due to eviction (the cause is neither
96 * {@link #EXPLICIT} nor {@link #REPLACED}).
97 */
98 abstract boolean wasEvicted();
99 }