Classes in this File | Line Coverage | Branch Coverage | Complexity | ||||
IsolationLevels |
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| 0.0;0 |
1 | package org.apache.ojb.broker.locking; | |
2 | ||
3 | /* Copyright 2002-2005 The Apache Software Foundation | |
4 | * | |
5 | * Licensed under the Apache License, Version 2.0 (the "License"); | |
6 | * you may not use this file except in compliance with the License. | |
7 | * You may obtain a copy of the License at | |
8 | * | |
9 | * http://www.apache.org/licenses/LICENSE-2.0 | |
10 | * | |
11 | * Unless required by applicable law or agreed to in writing, software | |
12 | * distributed under the License is distributed on an "AS IS" BASIS, | |
13 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. | |
14 | * See the License for the specific language governing permissions and | |
15 | * limitations under the License. | |
16 | */ | |
17 | ||
18 | /** | |
19 | * This interface defines the lock isolation level constants used by | |
20 | * OJB locking api. It contains numeric constants and literal constants | |
21 | * representing all known isolation levels. | |
22 | * <p/> | |
23 | * NOTE: The lock isolation levels are labeled like the database transaction level but | |
24 | * the definition of the levels is different - take care of that. | |
25 | * | |
26 | * @version $Id: IsolationLevels.java,v 1.1 2007-08-24 22:17:41 ewestfal Exp $ | |
27 | */ | |
28 | public interface IsolationLevels | |
29 | { | |
30 | /** | |
31 | * Numeric constant representing an no-op isolation level. | |
32 | * <p/> | |
33 | * The lock manager completely ignores locking. | |
34 | * <p/> | |
35 | * Allows:<br/> | |
36 | * all possible concurrent side-effects<br/> | |
37 | */ | |
38 | public final static int IL_NONE = -1; | |
39 | ||
40 | /** | |
41 | * Numeric constant representing the uncommited read isolation level. | |
42 | * <p/> | |
43 | * Obtaining two concurrent write locks on a given object is not | |
44 | * allowed. Obtaining read locks is allowed even if | |
45 | * another transaction is writing to that object | |
46 | * (Thats why this level is also called "dirty reads"). | |
47 | * <p/> | |
48 | * Allows:<br/> | |
49 | * Dirty Reads<br/> | |
50 | * Non-Repeatable Reads<br/> | |
51 | * Phantom Reads<br/> | |
52 | */ | |
53 | public final static int IL_READ_UNCOMMITTED = 2; | |
54 | ||
55 | /** | |
56 | * Numeric constant representing the commited read isolation level. | |
57 | * <p/> | |
58 | * Obtaining two concurrent write locks on a given object is not allowed. | |
59 | * Obtaining read locks is allowed only if there is no write lock on | |
60 | * the given object. | |
61 | * <p/> | |
62 | * Allows:<br/> | |
63 | * Non-Repeatable Reads<br/> | |
64 | * Phantom Reads<br/> | |
65 | */ | |
66 | public final static int IL_READ_COMMITTED = 3; | |
67 | ||
68 | /** | |
69 | * Numeric constant representing the repeatable read isolation level. | |
70 | * <p/> | |
71 | * As commited reads, but obtaining a write lock on an object that has | |
72 | * been locked for reading by another transaction is not allowed. | |
73 | * <p/> | |
74 | * Allows:<br/> | |
75 | * Phantom Reads<br/> | |
76 | */ | |
77 | public final static int IL_REPEATABLE_READ = 5; | |
78 | ||
79 | /** | |
80 | * Numeric constant representing the serializable transactions isolation level. | |
81 | * <p/> | |
82 | * As Repeatable Reads, but it is even not allowed to have multiple | |
83 | * read locks on a given object. | |
84 | * <p/> | |
85 | * Allows:<br/> | |
86 | * -<br/> | |
87 | */ | |
88 | public final static int IL_SERIALIZABLE = 7; | |
89 | ||
90 | /** | |
91 | * Numeric constant representing the optimistic locking isolation level. | |
92 | * <p/> | |
93 | * The lock manager does not perform any pessimistic locking action. Normally | |
94 | * it's not needed to declare this isolation level in persistent object metadata, | |
95 | * because OJB will automatically detect an enabled optimistic locking. | |
96 | * <br/> | |
97 | * NOTE: Usage of this isolation level needs an specific optimistic locking | |
98 | * declaration for the specified object. This declaration is <strong>not</strong> | |
99 | * automatically handled by OJB and need setting of configuration properties - see OJB docs. | |
100 | */ | |
101 | public final static int IL_OPTIMISTIC = 4; | |
102 | ||
103 | /** | |
104 | * Numeric constant representing the default isolation level used by | |
105 | * OJB - current used default level is {@link #IL_READ_UNCOMMITTED}. | |
106 | */ | |
107 | public final static int IL_DEFAULT = IL_READ_UNCOMMITTED; | |
108 | ||
109 | /** | |
110 | * Literal constant representing the uncommited read isolation level. | |
111 | */ | |
112 | public final static String LITERAL_IL_NONE = "none"; | |
113 | ||
114 | /** | |
115 | * Literal constant representing the uncommited read isolation level. | |
116 | */ | |
117 | public final static String LITERAL_IL_READ_UNCOMMITTED = "read-uncommitted"; | |
118 | ||
119 | /** | |
120 | * Literal constant representing the commited read isolation level. | |
121 | */ | |
122 | public final static String LITERAL_IL_READ_COMMITTED = "read-committed"; | |
123 | ||
124 | /** | |
125 | * Literal constant representing the repeatable read isolation level. | |
126 | */ | |
127 | public final static String LITERAL_IL_REPEATABLE_READ = "repeatable-read"; | |
128 | ||
129 | /** | |
130 | * Literal constant representing the serializable transactions isolation level. | |
131 | */ | |
132 | public final static String LITERAL_IL_SERIALIZABLE = "serializable"; | |
133 | ||
134 | /** | |
135 | * Literal constant representing the optimistic locking isolation level. | |
136 | */ | |
137 | public final static String LITERAL_IL_OPTIMISTIC = "optimistic"; | |
138 | } |