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.resolve;
17
18 import javax.annotation.concurrent.ThreadSafe;
19
20 import de.smartics.properties.api.config.domain.ConfigurationProperties;
21 import de.smartics.properties.api.core.domain.PropertyDescriptorRegistry;
22
23 /**
24 * Property value resolver implementation using commons-jexl.
25 *
26 * @impl the implementation is thread safe since it only provides read access to
27 * the wrapped configuration. If the configuration is accessed by other
28 * threads, it is not.
29 */
30 @ThreadSafe
31 public final class SimplePropertyValueResolver implements PropertyValueResolver
32 {
33 // ********************************* Fields *********************************
34
35 // --- constants ------------------------------------------------------------
36
37 // --- members --------------------------------------------------------------
38
39 /**
40 * The execution context for the Jexl engine providing access to other
41 * properties.
42 *
43 * @serial
44 */
45 private final ResolveContext context;
46
47 // ****************************** Initializer *******************************
48
49 // ****************************** Constructors ******************************
50
51 /**
52 * Default constructor.
53 *
54 * @param registry the registry to resolve property descriptors.
55 * @param config the configuration to resolve place holders in property
56 * values.
57 */
58 public SimplePropertyValueResolver(final PropertyDescriptorRegistry registry,
59 final ConfigurationProperties config)
60 {
61 this.context = new ConfigurationPropertiesResolveContext(registry, config);
62 }
63
64 // ****************************** Inner Classes *****************************
65
66 // ********************************* Methods ********************************
67
68 // --- init -----------------------------------------------------------------
69
70 // --- get&set --------------------------------------------------------------
71
72 // --- business -------------------------------------------------------------
73
74 /**
75 * {@inheritDoc}
76 *
77 * @see de.smartics.properties.spi.config.resolve.PropertyValueResolver#resolve(java.lang.String)
78 */
79 @Override
80 public String resolve(final String expression)
81 throws ResolveConfigurationException
82 {
83 try
84 {
85 final Resolver resolver = new Resolver(context);
86 final String resolved = resolver.resolve(expression);
87
88 return resolved;
89 }
90 catch (final RuntimeException e)
91 {
92 throw new ResolveConfigurationException(e, context.getKey(), expression);
93 }
94 }
95
96 // --- object basics --------------------------------------------------------
97
98 }