1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License. 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 package org.apache.commons.discovery.tools;
18
19 import java.util.Properties;
20
21 import org.apache.commons.discovery.resource.ClassLoaders;
22
23 /**
24 * Holder for a default class.
25 *
26 * Class may be specified by name (String) or class (Class).
27 * Using the holder complicates the users job, but minimized # of API's.
28 */
29 public class PropertiesHolder {
30
31 private Properties properties;
32
33 private final String propertiesFileName;
34
35 /**
36 * Creates a new {@code PropertiesHolder} instance given an
37 * already load {@code Properties} set.
38 *
39 * @param properties The already load {@code Properties} set
40 */
41 public PropertiesHolder(Properties properties) {
42 this.properties = properties;
43 this.propertiesFileName = null;
44 }
45
46 /**
47 * Creates a new {@code PropertiesHolder} instance given a
48 * property file name.
49 *
50 * @param propertiesFileName The property file name
51 */
52 public PropertiesHolder(String propertiesFileName) {
53 this.properties = null;
54 this.propertiesFileName = propertiesFileName;
55 }
56
57 /**
58 * Returns the {@code Properties} instance, loaded if necessary from {@code propertiesFileName}.
59 *
60 * @param spi Optional SPI (may be null).
61 * If provided, an attempt is made to load the
62 * property file as-per Class.getResource().
63 *
64 * @param loaders Used only if properties need to be loaded.
65 *
66 * @return The {@code Properties}, loaded if necessary.
67 */
68 public Properties getProperties(SPInterface<?> spi, ClassLoaders loaders) {
69 if (properties == null) {
70 properties = ResourceUtils.loadProperties(spi.getSPClass(), getPropertiesFileName(), loaders);
71 }
72 return properties;
73 }
74
75 /**
76 * Returns the property file name
77 *
78 * @return The property file name
79 */
80 public String getPropertiesFileName() {
81 return propertiesFileName;
82 }
83
84 }