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34 package org.relaxng.datatype.helpers;
35
36 import org.relaxng.datatype.DatatypeLibraryFactory;
37 import org.relaxng.datatype.DatatypeLibrary;
38 import java.util.Enumeration  ;
39 import java.util.NoSuchElementException ;
40 import java.util.Vector ;
41 import java.io.Reader ;
42 import java.io.InputStream ;
43 import java.io.InputStreamReader ;
44 import java.io.BufferedReader ;
45 import java.io.IOException ;
46 import java.io.UnsupportedEncodingException ;
47 import java.net.URL ;
48
49
56 public class DatatypeLibraryLoader implements DatatypeLibraryFactory {
57 private final Service service = new Service(DatatypeLibraryFactory.class);
58
59 public DatatypeLibrary createDatatypeLibrary(String uri) {
60 for (Enumeration e = service.getProviders();
61 e.hasMoreElements();) {
62 DatatypeLibraryFactory factory
63 = (DatatypeLibraryFactory)e.nextElement();
64 DatatypeLibrary library = factory.createDatatypeLibrary(uri);
65 if (library != null)
66 return library;
67 }
68 return null;
69 }
70
71 private static class Service {
72 private final Class serviceClass;
73 private final Enumeration configFiles;
74 private Enumeration classNames = null;
75 private final Vector providers = new Vector ();
76 private Loader loader;
77
78 private class ProviderEnumeration implements Enumeration {
79 private int nextIndex = 0;
80
81 public boolean hasMoreElements() {
82 return nextIndex < providers.size() || moreProviders();
83 }
84
85 public Object nextElement() {
86 try {
87 return providers.elementAt(nextIndex++);
88 }
89 catch (ArrayIndexOutOfBoundsException e) {
90 throw new NoSuchElementException ();
91 }
92 }
93 }
94
95 private static class Singleton implements Enumeration {
96 private Object obj;
97 private Singleton(Object obj) {
98 this.obj = obj;
99 }
100
101 public boolean hasMoreElements() {
102 return obj != null;
103 }
104
105 public Object nextElement() {
106 if (obj == null)
107 throw new NoSuchElementException ();
108 Object tem = obj;
109 obj = null;
110 return tem;
111 }
112 }
113
114 private static class Loader {
116 Enumeration getResources(String resName) {
117 ClassLoader cl = Loader.class.getClassLoader();
118 URL url;
119 if (cl == null)
120 url = ClassLoader.getSystemResource(resName);
121 else
122 url = cl.getResource(resName);
123 return new Singleton(url);
124 }
125
126 Class loadClass(String name) throws ClassNotFoundException {
127 return Class.forName(name);
128 }
129 }
130
131 private static class Loader2 extends Loader {
133 private ClassLoader cl;
134
135 Loader2() {
136 cl = Loader2.class.getClassLoader();
137 ClassLoader clt = Thread.currentThread().getContextClassLoader();
142 for (ClassLoader tem = clt; tem != null; tem = tem.getParent())
143 if (tem == cl) {
144 cl = clt;
145 break;
146 }
147 }
148
149 Enumeration getResources(String resName) {
150 try {
151 Enumeration resources = cl.getResources(resName);
152 if (resources.hasMoreElements())
153 return resources;
154 return new Singleton(cl.getResource(resName));
157 }
158 catch (IOException e) {
159 return new Singleton(null);
160 }
161 }
162
163 Class loadClass(String name) throws ClassNotFoundException {
164 return Class.forName(name, true, cl);
165 }
166 }
167
168 public Service(Class cls) {
169 try {
170 loader = new Loader2();
171 }
172 catch (NoSuchMethodError e) {
173 loader = new Loader();
174 }
175 serviceClass = cls;
176 String resName = "META-INF/services/" + serviceClass.getName();
177 configFiles = loader.getResources(resName);
178 }
179
180 public Enumeration getProviders() {
181 return new ProviderEnumeration();
182 }
183
184 synchronized private boolean moreProviders() {
185 for (;;) {
186 while (classNames == null) {
187 if (!configFiles.hasMoreElements())
188 return false;
189 classNames = parseConfigFile((URL )configFiles.nextElement());
190 }
191 while (classNames.hasMoreElements()) {
192 String className = (String )classNames.nextElement();
193 try {
194 Class cls = loader.loadClass(className);
195 Object obj = cls.newInstance();
196 if (serviceClass.isInstance(obj)) {
197 providers.addElement(obj);
198 return true;
199 }
200 }
201 catch (ClassNotFoundException e) { }
202 catch (InstantiationException e) { }
203 catch (IllegalAccessException e) { }
204 catch (LinkageError e) { }
205 }
206 classNames = null;
207 }
208 }
209
210 private static final int START = 0;
211 private static final int IN_NAME = 1;
212 private static final int IN_COMMENT = 2;
213
214 private static Enumeration parseConfigFile(URL url) {
215 try {
216 InputStream in = url.openStream();
217 Reader r;
218 try {
219 r = new InputStreamReader (in, "UTF-8");
220 }
221 catch (UnsupportedEncodingException e) {
222 r = new InputStreamReader (in, "UTF8");
223 }
224 r = new BufferedReader (r);
225 Vector tokens = new Vector ();
226 StringBuffer tokenBuf = new StringBuffer ();
227 int state = START;
228 for (;;) {
229 int n = r.read();
230 if (n < 0)
231 break;
232 char c = (char)n;
233 switch (c) {
234 case '\r':
235 case '\n':
236 state = START;
237 break;
238 case ' ':
239 case '\t':
240 break;
241 case '#':
242 state = IN_COMMENT;
243 break;
244 default:
245 if (state != IN_COMMENT) {
246 state = IN_NAME;
247 tokenBuf.append(c);
248 }
249 break;
250 }
251 if (tokenBuf.length() != 0 && state != IN_NAME) {
252 tokens.addElement(tokenBuf.toString());
253 tokenBuf.setLength(0);
254 }
255 }
256 if (tokenBuf.length() != 0)
257 tokens.addElement(tokenBuf.toString());
258 return tokens.elements();
259 }
260 catch (IOException e) {
261 return null;
262 }
263 }
264 }
265
266 }
267
268 |
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