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.io.BufferedInputStream;
19 import java.io.IOException;
20 import java.io.InputStream;
21 import java.util.Properties;
22
23 import org.apache.commons.io.IOUtils;
24
25 import de.smartics.properties.api.config.domain.ConfigurationLoadingException;
26 import de.smartics.properties.api.config.domain.key.ConfigurationKey;
27
28 /**
29 * Simple utilities class to help on dealing with properties.
30 */
31 public final class PropertiesHelper
32 {
33 // ********************************* Fields *********************************
34
35 // --- constants ------------------------------------------------------------
36
37 // --- members --------------------------------------------------------------
38
39 /**
40 * The key to the configuration to load properties for.
41 */
42 private final ConfigurationKey<?> key;
43
44 // ****************************** Initializer *******************************
45
46 // ****************************** Constructors ******************************
47
48 /**
49 * Default constructor.
50 *
51 * @param key the key to the configuration to load properties for.
52 */
53 public PropertiesHelper(final ConfigurationKey<?> key)
54 {
55 this.key = key;
56 }
57
58 // ****************************** Inner Classes *****************************
59
60 // ********************************* Methods ********************************
61
62 // --- init -----------------------------------------------------------------
63
64 // --- get&set --------------------------------------------------------------
65
66 // --- business -------------------------------------------------------------
67
68 /**
69 * Reads the properties from the thread context class path location.
70 *
71 * @param resourceId the resource on the class path to read.
72 * @return the properties from the class path.
73 */
74 public Properties readProperties(final String resourceId)
75 {
76 final ClassLoader loader = Thread.currentThread().getContextClassLoader();
77 return readProperties(loader, resourceId);
78 }
79
80 /**
81 * Reads the properties from the given class path location.
82 *
83 * @param classLoader the class loader to access the resource.
84 * @param resourceId the resource on the class path to read.
85 * @return the properties from the class path.
86 */
87 public Properties readProperties(final ClassLoader classLoader,
88 final String resourceId)
89 {
90 final InputStream input = classLoader.getResourceAsStream(resourceId);
91 return readProperties(resourceId, input);
92 }
93
94 /**
95 * Reads the properties from the given stream.
96 * <p>
97 * Closes the stream after the properties are read.
98 * </p>
99 *
100 * @param resourceId the identifier of the stream. Used for error reporting.
101 * @param input the stream to read from.
102 * @return the properties from the stream.
103 */
104 public Properties readProperties(final String resourceId,
105 final InputStream input)
106 {
107 final BufferedInputStream bin = new BufferedInputStream(input);
108 try
109 {
110 final Properties properties = new Properties();
111 properties.load(bin);
112 return properties;
113 }
114 catch (final IOException e)
115 {
116 throw new ConfigurationLoadingException(e, key, resourceId);
117 }
118 finally
119 {
120 IOUtils.closeQuietly(bin);
121 }
122 }
123
124 // --- object basics --------------------------------------------------------
125
126 }