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1 package org.objectweb.celtix.configuration;
2
3 import java.io.BufferedReader  ;
4 import java.io.InputStream ;
5 import java.io.InputStreamReader ;
6
7
8 public final class ConfigurationBuilderFactory {
9 private static final String DEFAULT_CONFIGURATION_BUILDER_CLASSNAME =
10 "org.objectweb.celtix.bus.configuration.CeltixConfigurationBuilder";
11 private static ConfigurationBuilder theBuilder;
12
13 private ConfigurationBuilderFactory() {
14 }
15
16 public static ConfigurationBuilder getBuilder() {
17 return getBuilder(null);
18 }
19 public static void clearBuilder() {
20 theBuilder = null;
21 }
22
23 public static ConfigurationBuilder getBuilder(ClassLoader classLoader) {
24
25 if (null == theBuilder) {
26 String builderClass = getBuilderClass(classLoader);
27
28
30 theBuilder = createBuilder(builderClass, selectClassLoader(classLoader));
31 }
32 return theBuilder;
33 }
34
35 private static ConfigurationBuilder createBuilder(String className, ClassLoader classLoader) {
36
37 Class <? extends ConfigurationBuilder> builderClass;
38 try {
39 builderClass = Class.forName(className, true, classLoader)
40 .asSubclass(ConfigurationBuilder.class);
41 return builderClass.newInstance();
42 } catch (Exception ex) {
43 throw new ConfigurationException(ex);
44 }
45 }
46
47 private static ClassLoader selectClassLoader(ClassLoader classLoader) {
48 ClassLoader ret = classLoader;
49 if (null == classLoader) {
50 ret = ConfigurationBuilderFactory.class.getClassLoader();
51 }
52 return ret;
53 }
54
55 private static String getBuilderClass(ClassLoader classLoader) throws ConfigurationException {
56
57 String builderClass = null;
58
59 builderClass = System.getProperty(ConfigurationBuilder.CONFIGURATION_BUILDER_CLASS_PROPERTY);
61 if (isValidBuilderClass(builderClass)) {
62 return builderClass;
63 }
64
65 try {
66 String serviceId = "META-INF/services/"
68 + ConfigurationBuilder.CONFIGURATION_BUILDER_CLASS_PROPERTY;
69 InputStream is = null;
70
71 if (classLoader == null) {
72 classLoader = Thread.currentThread().getContextClassLoader();
73 }
74
75 if (classLoader == null) {
76 is = ClassLoader.getSystemResourceAsStream(serviceId);
77 } else {
78 is = classLoader.getResourceAsStream(serviceId);
79 }
80 if (is != null) {
81 BufferedReader rd = new BufferedReader (new InputStreamReader (is, "UTF-8"));
82 builderClass = rd.readLine();
83 rd.close();
84 }
85 if (isValidBuilderClass(builderClass)) {
86 return builderClass;
87 }
88
89 builderClass = DEFAULT_CONFIGURATION_BUILDER_CLASSNAME;
91 return builderClass;
92 } catch (Exception ex) {
93 throw new ConfigurationException(ex);
94 }
95 }
96
97 private static boolean isValidBuilderClass(String builderClassName) {
98 return builderClassName != null && !"".equals(builderClassName);
99 }
100
101 }
102 |
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