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8 package org.apache.avalon.excalibur.naming;
9
10 import java.util.Hashtable;
11 import javax.naming.*;
12 import javax.naming.Context;
13
14 /***
15 * Abstract JNDI Context that can be inherited from to
16 * provide a particular type of Context.
17 *
18 * @author <a href="mailto:donaldp@apache.org">Peter Donald</a>
19 * @version $Revision: 1.2 $
20 */
21 public abstract class AbstractContext
22 implements Context
23 {
24 protected Hashtable m_environment;
25
26 public AbstractContext()
27 {
28 this( new Hashtable() );
29 }
30
31 public AbstractContext( final Hashtable environment )
32 {
33 m_environment = environment;
34 }
35
36 protected abstract NameParser getNameParser()
37 throws NamingException;
38
39 /***
40 * Add a key-value pair to environment
41 *
42 * @param key the key
43 * @param value the value
44 * @return the value
45 */
46 public Object addToEnvironment( final String key, final Object value )
47 throws NamingException
48 {
49 if( null == m_environment ) m_environment = new Hashtable( 5, 0.75f );
50 return m_environment.put( key, value );
51 }
52
53 /***
54 * Release resources associated with context.
55 *
56 */
57 public void close()
58 {
59 m_environment = null;
60 }
61
62 protected boolean isSelf( final Name name )
63 {
64 return ( name.isEmpty() || name.get( 0 ).equals( "" ) );
65 }
66
67 /***
68 * Bind an object to a name.
69 *
70 * @param name the name to bind to
71 * @param object the object
72 * @exception NamingException if an error occurs such as bad name or invalid binding
73 */
74 public void bind( final String name, final Object object )
75 throws NamingException
76 {
77 bind( getNameParser().parse( name ), object );
78 }
79
80 /***
81 * Bind an object to a name.
82 *
83 * @param name the name to bind to
84 * @param object the object
85 * @exception NamingException if an error occurs such as bad name or invalid binding
86 */
87 public void bind( final Name name, final Object object )
88 throws NamingException
89 {
90 bind( name, object, false );
91 }
92
93 /***
94 * Helper method to bind
95 */
96 protected abstract void bind( Name name, Object object, boolean rebind )
97 throws NamingException;
98
99 /***
100 * Compose a name form a name and a prefix.
101 *
102 * @param name the name
103 * @param prefix the prefix
104 * @return the composed name
105 * @exception NamingException if a badly formatted name for context
106 */
107 public String composeName( final String name, final String prefix )
108 throws NamingException
109 {
110 final NameParser nameParser = getNameParser();
111 final Name result =
112 composeName( nameParser.parse( name ), nameParser.parse( prefix ) );
113 return result.toString();
114 }
115
116 /***
117 * Compose a name form a name and a prefix.
118 *
119 * @param name the name
120 * @param prefix the prefix
121 * @return the composed name
122 * @exception NamingException if a badly formatted name for context
123 */
124 public Name composeName( final Name name, final Name prefix )
125 throws NamingException
126 {
127 final Name result = (Name)(prefix.clone());
128 result.addAll( name );
129 return result;
130 }
131
132 /***
133 * Create a Subcontext.
134 *
135 * @param name the name of subcontext
136 * @return the created context
137 * @exception NamingException if an error occurs (ie context exists, badly formated name etc)
138 */
139 public Context createSubcontext( final String name )
140 throws NamingException
141 {
142 return createSubcontext( getNameParser().parse( name ) );
143 }
144
145 /***
146 * Destroy a Subcontext.
147 *
148 * @param name the name of subcontext to destroy
149 * @exception NamingException if an error occurs such as malformed name or
150 * context not exiting or not empty
151 */
152 public void destroySubcontext( final String name )
153 throws NamingException
154 {
155 destroySubcontext( getNameParser().parse( name ) );
156 }
157
158 /***
159 * Return a copy of environment.
160 *
161 * @return the environment
162 */
163 public Hashtable getEnvironment()
164 throws NamingException
165 {
166 if( null == m_environment ) return new Hashtable( 3, 0.75f );
167 else return (Hashtable)m_environment.clone();
168 }
169
170 /***
171 * Get the NameParser for the named context.
172 *
173 * @param name
174 * @return the NameParser
175 * @exception NamingException if an error occurs
176 */
177 public NameParser getNameParser( final String name )
178 throws NamingException
179 {
180 return getNameParser( getNameParser().parse( name ) );
181 }
182
183 /***
184 * Get the NameParser for the named context.
185 *
186 * @param name
187 * @return the NameParser
188 * @exception NamingException if an error occurs
189 */
190 public NameParser getNameParser( final Name name )
191 throws NamingException
192 {
193 if( name.isEmpty() )
194 {
195 return getNameParser();
196 }
197
198 Object object = lookup( name );
199 if( !(object instanceof Context) )
200 {
201 object = lookup( getPathName( name ) );
202 }
203
204 final Context context = (Context)object;
205 final NameParser parser = context.getNameParser( "" );
206 context.close();
207 return parser;
208 }
209
210 /***
211 * Enumerates the names bound in the named context, along with the objects bound to them.
212 *
213 * @param name the name of the context
214 * @return the enumeration
215 * @exception NamingException if an error occurs
216 */
217 public NamingEnumeration list( final String name )
218 throws NamingException
219 {
220 return list( getNameParser().parse( name ) );
221 }
222
223 /***
224 * Enumerates the names bound in the named context, along with the objects bound to them.
225 *
226 * @param name the name of the context
227 * @return the enumeration
228 * @exception NamingException if an error occurs
229 */
230 public NamingEnumeration listBindings( final String name )
231 throws NamingException
232 {
233 return listBindings( getNameParser().parse( name ) );
234 }
235
236 /***
237 * Get the object named.
238 *
239 * @param name the name
240 * @return the object
241 * @exception NamingException if an error occurs (ie object name is inavlid or unbound)
242 */
243 public Object lookup( final String name )
244 throws NamingException
245 {
246 return lookup( getNameParser().parse( name ) );
247 }
248
249 /***
250 * Get the object named following all links.
251 *
252 * @param name the name
253 * @return the object
254 * @exception NamingException if an error occurs (ie object name is inavlid or unbound)
255 */
256 public Object lookupLink( final String name )
257 throws NamingException
258 {
259 return lookupLink( getNameParser().parse( name ) );
260 }
261
262 /***
263 * Get the object named following all links.
264 *
265 * @param name the name
266 * @return the object
267 * @exception NamingException if an error occurs (ie object name is inavlid or unbound)
268 */
269 public Object lookupLink( final Name name )
270 throws NamingException
271 {
272 return lookup( name );
273 }
274
275 /***
276 * Binds a name to an object, overwriting any existing binding.
277 *
278 * @param name the name
279 * @param object the object
280 * @exception NamingException if an error occurs
281 */
282 public void rebind( final String name, final Object object )
283 throws NamingException
284 {
285 rebind( getNameParser().parse( name ), object );
286 }
287
288 /***
289 * Binds a name to an object, overwriting any existing binding.
290 *
291 * @param name the name
292 * @param object the object
293 * @exception NamingException if an error occurs
294 */
295 public void rebind( final Name name, final Object object )
296 throws NamingException
297 {
298 bind( name, object, true );
299 }
300
301 /***
302 * Remove a key-value pair form environment and return it.
303 *
304 * @param key the key
305 * @return the value
306 */
307 public Object removeFromEnvironment( final String key )
308 throws NamingException
309 {
310 if( null == m_environment ) return null;
311 return m_environment.remove( key );
312 }
313
314 /***
315 * Rename a already bound object
316 *
317 * @param oldName the old name
318 * @param newName the new name
319 * @exception NamingException if an error occurs
320 */
321 public void rename( final String oldName, final String newName )
322 throws NamingException
323 {
324 rename( getNameParser().parse( oldName ), getNameParser().parse( newName ) );
325 }
326
327 public void rename( final Name oldName, final Name newName )
328 throws NamingException
329 {
330 if( isSelf( oldName ) || isSelf( newName ) )
331 {
332 throw new InvalidNameException( "Failed to rebind self" );
333 }
334 else if( oldName.equals( newName ) )
335 {
336 throw new InvalidNameException( "Failed to rebind identical names" );
337 }
338
339 bind( newName, lookup( oldName ) );
340 unbind( oldName );
341 }
342
343 /***
344 * Unbind a object from a name.
345 *
346 * @param name the name
347 * @exception NamingException if an error occurs
348 */
349 public void unbind( final String name )
350 throws NamingException
351 {
352 unbind( getNameParser().parse( name ) );
353 }
354
355 /***
356 * Get name components minus leaf name component.
357 *
358 * @param name the name elements leading up to last element
359 * @return the name
360 * @exception NamingException if an error occurs
361 */
362 protected Name getPathName( final Name name )
363 throws NamingException
364 {
365 return name.getPrefix( name.size() - 1 );
366 }
367
368 /***
369 * Get leaf name component from specified Name object.
370 *
371 * @param name a value of type 'Name'
372 * @return a value of type 'Name'
373 * @exception NamingException if an error occurs
374 */
375 protected Name getLeafName( final Name name )
376 throws NamingException
377 {
378 return name.getSuffix( name.size() - 1 );
379 }
380 }