1 /*
2 * Copyright 2012-2013 smartics, Kronseder & Reiner GmbH
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 package de.smartics.properties.core.services;
17
18
19 /**
20 * Provides means to change the default configuration name. Usually the
21 * extension configuration to use is determined by boot properties found on the
22 * classpath. This is correct for applications that only use one configuration.
23 * This is not true for administration applications that switch their
24 * configurations at runtime.
25 * <p>
26 * Switching is done by adding the configuration name to lookup to the
27 * thread-local context. This implementation is an easy to use wrapper.
28 * </p>
29 */
30 public final class ThreadLocalAdminRuntime implements AdminRuntime
31 {
32 // ********************************* Fields *********************************
33
34 // --- constants ------------------------------------------------------------
35
36 /**
37 * The thread-local storage.
38 */
39 private static final ThreadLocal<ThreadLocalAdminRuntime> LOCAL =
40 new ThreadLocal<ThreadLocalAdminRuntime>()
41 {
42 @Override
43 protected ThreadLocalAdminRuntime initialValue()
44 {
45 return new ThreadLocalAdminRuntime();
46 }
47 };
48
49 // --- members --------------------------------------------------------------
50
51 /**
52 * The name of the selected configuration. May be <code>null</code>, if no
53 * configuration is selected. In this case the configuration name found in the
54 * boot properties is used.
55 */
56 private volatile String configurationName;
57
58 // ****************************** Initializer *******************************
59
60 // ****************************** Constructors ******************************
61
62 /**
63 * Default constructor.
64 */
65 public ThreadLocalAdminRuntime()
66 {
67 }
68
69 // ****************************** Inner Classes *****************************
70
71 // ********************************* Methods ********************************
72
73 // --- init -----------------------------------------------------------------
74
75 // --- get&set --------------------------------------------------------------
76
77 @Override
78 public String getConfigurationName()
79 {
80 return configurationName;
81 }
82
83 /**
84 * Sets the name of the selected configuration. May be <code>null</code>, if
85 * no configuration is selected. In this case the configuration name found in
86 * the boot properties is used.
87 *
88 * @param configurationName the name of the selected configuration.
89 */
90 public static void setConfigurationName(final String configurationName)
91 {
92 final ThreadLocalAdminRuntime instance = LOCAL.get();
93 instance.configurationName = configurationName;
94 }
95
96 // --- business -------------------------------------------------------------
97
98 /**
99 * Returns the thread-locally stored instance.
100 *
101 * @return the thread-locally stored instance.
102 */
103 public static AdminRuntime getInstance()
104 {
105 return LOCAL.get();
106 }
107
108 /**
109 * Delegates to {@link ThreadLocal#remove()}.
110 */
111 public static void remove()
112 {
113 LOCAL.remove();
114 }
115
116 // --- object basics --------------------------------------------------------
117
118 @Override
119 public String toString()
120 {
121 final StringBuilder buffer = new StringBuilder(32);
122
123 buffer.append(configurationName);
124
125 return buffer.toString();
126 }
127 }