001 /**
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements. See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License. You may obtain a copy of the License at
008 *
009 * http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017
018 package org.apache.activemq.jndi;
019
020 import java.io.Serializable;
021 import java.util.Collections;
022 import java.util.HashMap;
023 import java.util.Hashtable;
024 import java.util.Iterator;
025 import java.util.Map;
026 import javax.naming.Binding;
027 import javax.naming.CompositeName;
028 import javax.naming.Context;
029 import javax.naming.LinkRef;
030 import javax.naming.Name;
031 import javax.naming.NameClassPair;
032 import javax.naming.NameNotFoundException;
033 import javax.naming.NameParser;
034 import javax.naming.NamingEnumeration;
035 import javax.naming.NamingException;
036 import javax.naming.NotContextException;
037 import javax.naming.OperationNotSupportedException;
038 import javax.naming.Reference;
039 import javax.naming.spi.NamingManager;
040 import org.slf4j.Logger;
041 import org.slf4j.LoggerFactory;
042
043 /**
044 * A read-only Context <p/> This version assumes it and all its subcontext are
045 * read-only and any attempt to modify (e.g. through bind) will result in an
046 * OperationNotSupportedException. Each Context in the tree builds a cache of
047 * the entries in all sub-contexts to optimise the performance of lookup.
048 * </p>
049 * <p>
050 * This implementation is intended to optimise the performance of lookup(String)
051 * to about the level of a HashMap get. It has been observed that the scheme
052 * resolution phase performed by the JVM takes considerably longer, so for
053 * optimum performance lookups should be coded like:
054 * </p>
055 * <code>
056 * Context componentContext = (Context)new InitialContext().lookup("java:comp");
057 * String envEntry = (String) componentContext.lookup("env/myEntry");
058 * String envEntry2 = (String) componentContext.lookup("env/myEntry2");
059 * </code>
060 *
061 * $Date: 2005/08/27 03:52:39 $
062 */
063 @SuppressWarnings("unchecked")
064 public class ReadOnlyContext implements Context, Serializable {
065 private static final Logger LOG = LoggerFactory.getLogger(ReadOnlyContext.class);
066 public static final String SEPARATOR = "/";
067 protected static final NameParser NAME_PARSER = new NameParserImpl();
068 private static final long serialVersionUID = -5754338187296859149L;
069
070 protected final Hashtable<String, Object> environment; // environment for this context
071 protected final Map<String, Object> bindings; // bindings at my level
072 protected final Map<String, Object> treeBindings; // all bindings under me
073
074 private boolean frozen;
075 private String nameInNamespace = "";
076
077 public ReadOnlyContext() {
078 environment = new Hashtable<String, Object>();
079 bindings = new HashMap<String, Object>();
080 treeBindings = new HashMap<String, Object>();
081 }
082
083 public ReadOnlyContext(Hashtable env) {
084 if (env == null) {
085 this.environment = new Hashtable<String, Object>();
086 } else {
087 this.environment = new Hashtable<String, Object>(env);
088 }
089 this.bindings = Collections.EMPTY_MAP;
090 this.treeBindings = Collections.EMPTY_MAP;
091 }
092
093 public ReadOnlyContext(Hashtable environment, Map<String, Object> bindings) {
094 if (environment == null) {
095 this.environment = new Hashtable<String, Object>();
096 } else {
097 this.environment = new Hashtable<String, Object>(environment);
098 }
099 this.bindings = new HashMap<String, Object>();
100 treeBindings = new HashMap<String, Object>();
101 if (bindings != null) {
102 for (Map.Entry<String, Object> binding : bindings.entrySet()) {
103 try {
104 internalBind(binding.getKey(), binding.getValue());
105 } catch (Throwable e) {
106 LOG.error("Failed to bind " + binding.getKey() + "=" + binding.getValue(), e);
107 }
108 }
109 }
110 frozen = true;
111 }
112
113 public ReadOnlyContext(Hashtable environment, Map bindings, String nameInNamespace) {
114 this(environment, bindings);
115 this.nameInNamespace = nameInNamespace;
116 }
117
118 protected ReadOnlyContext(ReadOnlyContext clone, Hashtable env) {
119 this.bindings = clone.bindings;
120 this.treeBindings = clone.treeBindings;
121 this.environment = new Hashtable<String, Object>(env);
122 }
123
124 protected ReadOnlyContext(ReadOnlyContext clone, Hashtable<String, Object> env, String nameInNamespace) {
125 this(clone, env);
126 this.nameInNamespace = nameInNamespace;
127 }
128
129 public void freeze() {
130 frozen = true;
131 }
132
133 boolean isFrozen() {
134 return frozen;
135 }
136
137 /**
138 * internalBind is intended for use only during setup or possibly by
139 * suitably synchronized superclasses. It binds every possible lookup into a
140 * map in each context. To do this, each context strips off one name segment
141 * and if necessary creates a new context for it. Then it asks that context
142 * to bind the remaining name. It returns a map containing all the bindings
143 * from the next context, plus the context it just created (if it in fact
144 * created it). (the names are suitably extended by the segment originally
145 * lopped off).
146 *
147 * @param name
148 * @param value
149 * @return
150 * @throws javax.naming.NamingException
151 */
152 protected Map<String, Object> internalBind(String name, Object value) throws NamingException {
153 assert name != null && name.length() > 0;
154 assert !frozen;
155
156 Map<String, Object> newBindings = new HashMap<String, Object>();
157 int pos = name.indexOf('/');
158 if (pos == -1) {
159 if (treeBindings.put(name, value) != null) {
160 throw new NamingException("Something already bound at " + name);
161 }
162 bindings.put(name, value);
163 newBindings.put(name, value);
164 } else {
165 String segment = name.substring(0, pos);
166 assert segment != null;
167 assert !segment.equals("");
168 Object o = treeBindings.get(segment);
169 if (o == null) {
170 o = newContext();
171 treeBindings.put(segment, o);
172 bindings.put(segment, o);
173 newBindings.put(segment, o);
174 } else if (!(o instanceof ReadOnlyContext)) {
175 throw new NamingException("Something already bound where a subcontext should go");
176 }
177 ReadOnlyContext readOnlyContext = (ReadOnlyContext)o;
178 String remainder = name.substring(pos + 1);
179 Map<String, Object> subBindings = readOnlyContext.internalBind(remainder, value);
180 for (Iterator iterator = subBindings.entrySet().iterator(); iterator.hasNext();) {
181 Map.Entry entry = (Map.Entry)iterator.next();
182 String subName = segment + "/" + (String)entry.getKey();
183 Object bound = entry.getValue();
184 treeBindings.put(subName, bound);
185 newBindings.put(subName, bound);
186 }
187 }
188 return newBindings;
189 }
190
191 protected ReadOnlyContext newContext() {
192 return new ReadOnlyContext();
193 }
194
195 public Object addToEnvironment(String propName, Object propVal) throws NamingException {
196 return environment.put(propName, propVal);
197 }
198
199 public Hashtable<String, Object> getEnvironment() throws NamingException {
200 return (Hashtable<String, Object>)environment.clone();
201 }
202
203 public Object removeFromEnvironment(String propName) throws NamingException {
204 return environment.remove(propName);
205 }
206
207 public Object lookup(String name) throws NamingException {
208 if (name.length() == 0) {
209 return this;
210 }
211 Object result = treeBindings.get(name);
212 if (result == null) {
213 result = bindings.get(name);
214 }
215 if (result == null) {
216 int pos = name.indexOf(':');
217 if (pos > 0) {
218 String scheme = name.substring(0, pos);
219 Context ctx = NamingManager.getURLContext(scheme, environment);
220 if (ctx == null) {
221 throw new NamingException("scheme " + scheme + " not recognized");
222 }
223 return ctx.lookup(name);
224 } else {
225 // Split out the first name of the path
226 // and look for it in the bindings map.
227 CompositeName path = new CompositeName(name);
228
229 if (path.size() == 0) {
230 return this;
231 } else {
232 String first = path.get(0);
233 Object obj = bindings.get(first);
234 if (obj == null) {
235 throw new NameNotFoundException(name);
236 } else if (obj instanceof Context && path.size() > 1) {
237 Context subContext = (Context)obj;
238 obj = subContext.lookup(path.getSuffix(1));
239 }
240 return obj;
241 }
242 }
243 }
244 if (result instanceof LinkRef) {
245 LinkRef ref = (LinkRef)result;
246 result = lookup(ref.getLinkName());
247 }
248 if (result instanceof Reference) {
249 try {
250 result = NamingManager.getObjectInstance(result, null, null, this.environment);
251 } catch (NamingException e) {
252 throw e;
253 } catch (Exception e) {
254 throw (NamingException)new NamingException("could not look up : " + name).initCause(e);
255 }
256 }
257 if (result instanceof ReadOnlyContext) {
258 String prefix = getNameInNamespace();
259 if (prefix.length() > 0) {
260 prefix = prefix + SEPARATOR;
261 }
262 result = new ReadOnlyContext((ReadOnlyContext)result, environment, prefix + name);
263 }
264 return result;
265 }
266
267 public Object lookup(Name name) throws NamingException {
268 return lookup(name.toString());
269 }
270
271 public Object lookupLink(String name) throws NamingException {
272 return lookup(name);
273 }
274
275 public Name composeName(Name name, Name prefix) throws NamingException {
276 Name result = (Name)prefix.clone();
277 result.addAll(name);
278 return result;
279 }
280
281 public String composeName(String name, String prefix) throws NamingException {
282 CompositeName result = new CompositeName(prefix);
283 result.addAll(new CompositeName(name));
284 return result.toString();
285 }
286
287 public NamingEnumeration list(String name) throws NamingException {
288 Object o = lookup(name);
289 if (o == this) {
290 return new ListEnumeration();
291 } else if (o instanceof Context) {
292 return ((Context)o).list("");
293 } else {
294 throw new NotContextException();
295 }
296 }
297
298 public NamingEnumeration listBindings(String name) throws NamingException {
299 Object o = lookup(name);
300 if (o == this) {
301 return new ListBindingEnumeration();
302 } else if (o instanceof Context) {
303 return ((Context)o).listBindings("");
304 } else {
305 throw new NotContextException();
306 }
307 }
308
309 public Object lookupLink(Name name) throws NamingException {
310 return lookupLink(name.toString());
311 }
312
313 public NamingEnumeration list(Name name) throws NamingException {
314 return list(name.toString());
315 }
316
317 public NamingEnumeration listBindings(Name name) throws NamingException {
318 return listBindings(name.toString());
319 }
320
321 public void bind(Name name, Object obj) throws NamingException {
322 throw new OperationNotSupportedException();
323 }
324
325 public void bind(String name, Object obj) throws NamingException {
326 throw new OperationNotSupportedException();
327 }
328
329 public void close() throws NamingException {
330 // ignore
331 }
332
333 public Context createSubcontext(Name name) throws NamingException {
334 throw new OperationNotSupportedException();
335 }
336
337 public Context createSubcontext(String name) throws NamingException {
338 throw new OperationNotSupportedException();
339 }
340
341 public void destroySubcontext(Name name) throws NamingException {
342 throw new OperationNotSupportedException();
343 }
344
345 public void destroySubcontext(String name) throws NamingException {
346 throw new OperationNotSupportedException();
347 }
348
349 public String getNameInNamespace() throws NamingException {
350 return nameInNamespace;
351 }
352
353 public NameParser getNameParser(Name name) throws NamingException {
354 return NAME_PARSER;
355 }
356
357 public NameParser getNameParser(String name) throws NamingException {
358 return NAME_PARSER;
359 }
360
361 public void rebind(Name name, Object obj) throws NamingException {
362 throw new OperationNotSupportedException();
363 }
364
365 public void rebind(String name, Object obj) throws NamingException {
366 throw new OperationNotSupportedException();
367 }
368
369 public void rename(Name oldName, Name newName) throws NamingException {
370 throw new OperationNotSupportedException();
371 }
372
373 public void rename(String oldName, String newName) throws NamingException {
374 throw new OperationNotSupportedException();
375 }
376
377 public void unbind(Name name) throws NamingException {
378 throw new OperationNotSupportedException();
379 }
380
381 public void unbind(String name) throws NamingException {
382 throw new OperationNotSupportedException();
383 }
384
385 private abstract class LocalNamingEnumeration implements NamingEnumeration {
386 private final Iterator i = bindings.entrySet().iterator();
387
388 public boolean hasMore() throws NamingException {
389 return i.hasNext();
390 }
391
392 public boolean hasMoreElements() {
393 return i.hasNext();
394 }
395
396 protected Map.Entry getNext() {
397 return (Map.Entry)i.next();
398 }
399
400 public void close() throws NamingException {
401 }
402 }
403
404 private class ListEnumeration extends LocalNamingEnumeration {
405 ListEnumeration() {
406 }
407
408 public Object next() throws NamingException {
409 return nextElement();
410 }
411
412 public Object nextElement() {
413 Map.Entry entry = getNext();
414 return new NameClassPair((String)entry.getKey(), entry.getValue().getClass().getName());
415 }
416 }
417
418 private class ListBindingEnumeration extends LocalNamingEnumeration {
419 ListBindingEnumeration() {
420 }
421
422 public Object next() throws NamingException {
423 return nextElement();
424 }
425
426 public Object nextElement() {
427 Map.Entry entry = getNext();
428 return new Binding((String)entry.getKey(), entry.getValue());
429 }
430 }
431 }