01: /**
02: * Copyright (C) 2006 Google Inc.
03: *
04: * Licensed under the Apache License, Version 2.0 (the "License");
05: * you may not use this file except in compliance with the License.
06: * You may obtain a copy of the License at
07: *
08: * http://www.apache.org/licenses/LICENSE-2.0
09: *
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: */package com.google.inject.util;
16:
17: /**
18: * Reference type. Used to specify what type of reference to keep to a
19: * referent.
20: *
21: * @see java.lang.ref.Reference
22: * @author crazybob@google.com (Bob Lee)
23: */
24: public enum ReferenceType {
25:
26: /**
27: * Prevents referent from being reclaimed by the garbage collector.
28: */
29: STRONG,
30:
31: /**
32: * Referent reclaimed in an LRU fashion when the VM runs low on memory and
33: * no strong references exist.
34: *
35: * @see java.lang.ref.SoftReference
36: */
37: SOFT,
38:
39: /**
40: * Referent reclaimed when no strong or soft references exist.
41: *
42: * @see java.lang.ref.WeakReference
43: */
44: WEAK,
45:
46: /**
47: * Similar to weak references except the garbage collector doesn't actually
48: * reclaim the referent. More flexible alternative to finalization.
49: *
50: * @see java.lang.ref.PhantomReference
51: */
52: PHANTOM;
53: }
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