|
1 package org.objectweb.celtix;
2
3
4 import java.io.BufferedReader  ;
5 import java.io.InputStream ;
6 import java.io.InputStreamReader ;
7 import java.util.Map ;
8 import org.objectweb.celtix.configuration.CommandLineOption;
9
10
13 public final class BusFactory {
14
15 private static final CommandLineOption BUS_CLASS_OPT;
16 private static final String DEFAULT_BUS_CLASSNAME = "org.objectweb.celtix.bus.busimpl.CeltixBus";
17 private static BusFactory theInstance;
18
19 static {
20 BUS_CLASS_OPT = new CommandLineOption("-BUSclass");
21 }
22
23 private BusFactory() {
24 }
25
26 public static BusFactory getInstance() {
27 synchronized (BusFactory.class) {
28 if (null == theInstance) {
29 theInstance = new BusFactory();
30 }
31 }
32 return theInstance;
33 }
34
35 public Bus getBus(String [] args,
36 Map <String , Object > properties,
37 ClassLoader classLoader) throws BusException {
38
39
42 String busClass = getBusClass(args, properties, classLoader);
43
44
46 return createBus(busClass, selectClassLoader(classLoader), args, properties);
47 }
48
49 private ClassLoader selectClassLoader(ClassLoader classLoader) {
50 ClassLoader ret = classLoader;
51 if (null == classLoader) {
52 ret = BusFactory.class.getClassLoader();
53 }
54 return ret;
55 }
56
57 private static Bus createBus(String className,
58 ClassLoader classLoader,
59 String [] args,
60 Map <String , Object > properties) throws BusException {
61
62 Class <? extends Bus> busClass;
63 try {
64 busClass = Class.forName(className, true, classLoader).asSubclass(Bus.class);
65 Bus bus = busClass.newInstance();
66 bus.initialize(args, properties);
67 return bus;
68 } catch (Exception ex) {
69 throw new BusException(ex);
70 }
71 }
72
73 String getBusClass(String [] args, Map <String , Object > properties, ClassLoader classLoader)
74 throws BusException {
75
76 String busClass = null;
77
78 BUS_CLASS_OPT.initialize(args);
80 busClass = (String )BUS_CLASS_OPT.getValue();
81 if (isValidBusClass(busClass)) {
82 return busClass;
83 }
84
85 busClass = (String )properties.get(Bus.BUS_CLASS_PROPERTY);
87 if (isValidBusClass(busClass)) {
88 return busClass;
89 }
90
91 busClass = System.getProperty(Bus.BUS_CLASS_PROPERTY);
93 if (isValidBusClass(busClass)) {
94 return busClass;
95 }
96
97 try {
98 String serviceId = "META-INF/services/" + Bus.BUS_CLASS_PROPERTY;
100 InputStream is = null;
101
102 if (classLoader == null) {
103 classLoader = Thread.currentThread().getContextClassLoader();
104 }
105
106 if (classLoader == null) {
107 is = ClassLoader.getSystemResourceAsStream(serviceId);
108 } else {
109 is = classLoader.getResourceAsStream(serviceId);
110 }
111 if (is != null) {
112 BufferedReader rd = new BufferedReader (new InputStreamReader (is, "UTF-8"));
113 busClass = rd.readLine();
114 rd.close();
115 }
116 if (isValidBusClass(busClass)) {
117 return busClass;
118 }
119
120 busClass = DEFAULT_BUS_CLASSNAME;
122 return busClass;
123 } catch (Exception ex) {
124 throw new BusException(ex);
125 }
126 }
127
128 private boolean isValidBusClass(String busClassName) {
129 return busClassName != null && !"".equals(busClassName);
130 }
131
132 }
133 |
Popular Tags |
Java API By Example, From Geeks To Geeks.