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.spi.config.support;
17
18 import java.util.ArrayList;
19 import java.util.Collection;
20 import java.util.HashMap;
21 import java.util.Map;
22
23 import javax.annotation.CheckForNull;
24 import javax.annotation.concurrent.NotThreadSafe;
25
26 import de.smartics.properties.api.config.domain.ConfigurationException;
27 import de.smartics.properties.api.config.domain.PropertyProvider;
28 import de.smartics.properties.api.config.domain.key.ConfigurationKey;
29 import de.smartics.properties.api.core.domain.ConfigException;
30 import de.smartics.properties.spi.config.definition.DefinitionConfigParser;
31 import de.smartics.properties.spi.config.definition.DefinitionKeyHelper;
32 import de.smartics.properties.spi.config.definition.PropertiesDefinitionContext;
33 import de.smartics.util.lang.ClassPathContext;
34
35 /**
36 * Helper to provide multiple sources for any configurations found.
37 */
38 @NotThreadSafe
39 public final class MultiSourcePropertiesManager
40 {
41 // ********************************* Fields *********************************
42
43 // --- constants ------------------------------------------------------------
44
45 // --- members --------------------------------------------------------------
46
47 /**
48 * The additional properties added by other means than loading them from the
49 * class path.
50 */
51 private final Collection<PropertyProvider> rootPropertyProviders;
52
53 /**
54 * The flag indicates that configuration problems are not signaled by
55 * exceptions.
56 */
57 private final boolean lenient;
58
59 /**
60 * The dictionary to map a configuration key to a properties collection.
61 */
62 private final Map<ConfigurationKey, MultiSourceProperties> dictionary =
63 new HashMap<ConfigurationKey, MultiSourceProperties>();
64
65 /**
66 * The cache for property definition information loaded from
67 * {@value de.smartics.properties.api.core.domain.PropertiesContext#DEFINITION_FILE}
68 * or the default (which may be <code>null</code> if
69 * {@value de.smartics.properties.api.core.domain.PropertiesContext#META_INF_HOME}
70 * is absent).
71 * <p>
72 * The key is the path to the root folder that contains the
73 * <code>META-INF</code> folder for a given resource in form of a
74 * {@link ClassPathContext} instance.
75 * </p>
76 */
77 private final Map<ClassPathContext, DefinitionKeyHelper> definitionCache =
78 new HashMap<ClassPathContext, DefinitionKeyHelper>();
79
80 // ****************************** Initializer *******************************
81
82 // ****************************** Constructors ******************************
83
84 MultiSourcePropertiesManager(final boolean lenient,
85 final Collection<PropertyProvider> rootPropertyProviders)
86 {
87 this.lenient = lenient;
88 this.rootPropertyProviders = rootPropertyProviders;
89 }
90
91 // ****************************** Inner Classes *****************************
92
93 // ********************************* Methods ********************************
94
95 // --- init -----------------------------------------------------------------
96
97 // --- get&set --------------------------------------------------------------
98
99 // --- business -------------------------------------------------------------
100
101 MultiSourceProperties create(final ConfigurationKey key)
102 {
103 MultiSourceProperties allProperties = dictionary.get(key);
104 if (allProperties == null)
105 {
106 allProperties =
107 new MultiSourceProperties(key, lenient ? null
108 : new ArrayList<ConfigurationException>());
109 allProperties.addProviders(rootPropertyProviders);
110 dictionary.put(key, allProperties);
111 }
112
113 return allProperties;
114 }
115
116 void create()
117 {
118 for (final PropertyProvider provider : rootPropertyProviders)
119 {
120 final ConfigurationKey key = provider.getConfigurationKey();
121 MultiSourceProperties allProperties = dictionary.get(key);
122 if (allProperties == null)
123 {
124 allProperties =
125 new MultiSourceProperties(key, lenient ? null
126 : new ArrayList<ConfigurationException>());
127 allProperties.addProvider(provider);
128 dictionary.put(key, allProperties);
129 }
130 }
131 }
132
133 /**
134 * Returns the definition information for the given class loader.
135 *
136 * @param context the class loader and the root folder to read the
137 * <code>{@value de.smartics.properties.api.core.domain.PropertiesContext#DEFINITION_FILE_NAME}</code>
138 * .
139 * @return the definition helper if there is a
140 * <code>{@value de.smartics.properties.api.core.domain.PropertiesContext#DEFINITION_FILE_NAME}</code>
141 * or at least
142 * {@value de.smartics.properties.api.core.domain.PropertiesContext#META_INF_HOME}
143 * , <code>null</code> otherwise.
144 */
145 @CheckForNull
146 DefinitionKeyHelper getDefinition(final ClassPathContext context)
147 {
148 DefinitionKeyHelper definition = definitionCache.get(context);
149 if (definition == null)
150 {
151 final DefinitionConfigParser parser = new DefinitionConfigParser();
152 try
153 {
154 final PropertiesDefinitionContext definitionContext =
155 parser.parse(context);
156 definition = new DefinitionKeyHelper(definitionContext);
157 }
158 catch (final ConfigException e)
159 {
160 definition = new DefinitionKeyHelper();
161 }
162
163 definitionCache.put(context, definition);
164 }
165
166 return definition;
167 }
168
169 Collection<MultiSourceProperties> getProperties()
170 {
171 return dictionary.values();
172 }
173
174 // --- object basics --------------------------------------------------------
175
176 }