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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.CompositeName;
13 import javax.naming.Context;
14 import javax.naming.Name;
15 import javax.naming.NameParser;
16 import javax.naming.spi.ResolveResult;
17
18 /***
19 * Abstract JNDI Context that can be inherited from to
20 * provide a particular type of Context.
21 *
22 * @author <a href="mailto:donaldp@apache.org">Peter Donald</a>
23 * @version $Revision: 1.2 $
24 */
25 public abstract class AbstractURLContext
26 extends AbstractContext
27 implements NameParser
28 {
29 protected final String m_scheme;
30
31 public AbstractURLContext( final String scheme, final Hashtable environment )
32 {
33 super( environment );
34 m_scheme = scheme;
35 }
36
37 public Name parse( final String name )
38 throws NamingException
39 {
40 return (new CompositeName().add( name ));
41 }
42
43 protected NameParser getNameParser()
44 throws NamingException
45 {
46 return this;
47 }
48
49 /***
50 * Helper method to bind
51 */
52 protected void bind( final Name name, final Object object, final boolean rebind )
53 throws NamingException
54 {
55 final ResolveResult resolveResult = getBaseURLContext( name, m_environment );
56 final Context context = (Context)resolveResult.getResolvedObj();
57
58 try
59 {
60 if( rebind )
61 {
62 context.rebind( resolveResult.getRemainingName(), object );
63 }
64 else
65 {
66 context.bind( resolveResult.getRemainingName(), object );
67 }
68 }
69 finally
70 {
71 context.close();
72 }
73 }
74
75 /***
76 * Create a Subcontext.
77 *
78 * @param name the name of subcontext
79 * @return the created context
80 * @exception NamingException if an error occurs (ie context exists, badly formated name etc)
81 */
82 public Context createSubcontext( final Name name )
83 throws NamingException
84 {
85 final ResolveResult resolveResult = getBaseURLContext( name, m_environment );
86 final Context context = (Context)resolveResult.getResolvedObj();
87
88 try
89 {
90 return context.createSubcontext( resolveResult.getRemainingName() );
91 }
92 finally
93 {
94 context.close();
95 }
96 }
97
98 public void destroySubcontext( final Name name )
99 throws NamingException
100 {
101 final ResolveResult resolveResult = getBaseURLContext( name, m_environment );
102 final Context context = (Context)resolveResult.getResolvedObj();
103
104 try
105 {
106 context.destroySubcontext( resolveResult.getRemainingName() );
107 }
108 finally
109 {
110 context.close();
111 }
112 }
113
114 public String getNameInNamespace()
115 throws NamingException
116 {
117 return "";
118 }
119
120 /***
121 * Enumerates the names bound in the named context.
122 *
123 * @param name the name of the context
124 * @return the enumeration
125 * @exception NamingException if an error occurs
126 */
127 public NamingEnumeration list( final Name name )
128 throws NamingException
129 {
130 final ResolveResult resolveResult = getBaseURLContext( name, m_environment );
131 final Context context = (Context)resolveResult.getResolvedObj();
132
133 try
134 {
135 return context.list( resolveResult.getRemainingName() );
136 }
137 finally
138 {
139 context.close();
140 }
141 }
142
143 /***
144 * Enumerates the names bound in the named context, along with the objects bound to them.
145 *
146 * @param name the name of the context
147 * @return the enumeration
148 * @exception NamingException if an error occurs
149 */
150 public NamingEnumeration listBindings( final Name name )
151 throws NamingException
152 {
153 final ResolveResult resolveResult = getBaseURLContext( name, m_environment );
154 final Context context = (Context)resolveResult.getResolvedObj();
155
156 try
157 {
158 return context.listBindings( resolveResult.getRemainingName() );
159 }
160 finally
161 {
162 context.close();
163 }
164 }
165
166 /***
167 * Get the object named.
168 *
169 * @param name the name
170 * @return the object
171 * @exception NamingException if an error occurs (ie object name is inavlid or unbound)
172 */
173 public Object lookup( final Name name )
174 throws NamingException
175 {
176 final ResolveResult resolveResult = getBaseURLContext( name, m_environment );
177 final Context context = (Context)resolveResult.getResolvedObj();
178
179 try
180 {
181 return context.lookup( resolveResult.getRemainingName() );
182 }
183 finally
184 {
185 context.close();
186 }
187 }
188
189 /***
190 * Unbind a object from a name.
191 *
192 * @param name the name
193 * @exception NamingException if an error occurs
194 */
195 public void unbind( final Name name )
196 throws NamingException
197 {
198 final ResolveResult resolveResult = getBaseURLContext( name, m_environment );
199 final Context context = (Context)resolveResult.getResolvedObj();
200
201 try
202 {
203 context.unbind( resolveResult.getRemainingName() );
204 }
205 finally
206 {
207 context.close();
208 }
209 }
210
211 protected ResolveResult getBaseURLContext( final Name name, final Hashtable environment )
212 throws NamingException
213 {
214 if( name.isEmpty() )
215 {
216 throw new InvalidNameException( "Unable to locate URLContext will empty name" );
217 }
218
219 final String nameString = name.toString();
220 int index = nameString.indexOf( ':' );
221
222 if( -1 == index )
223 {
224 throw new InvalidNameException( "Unable to build URLContext as it does not specify scheme" );
225 }
226
227 final String scheme = nameString.substring( 0, index );
228 final int end = getEndIndexOfURLPart( nameString, index + 1 );
229 final String urlPart = nameString.substring( index + 1, end );
230 final String namePart = nameString.substring( end );
231
232 if( !m_scheme.equals( scheme ) )
233 {
234 throw new InvalidNameException( "Bad Scheme use to build URLContext (" + scheme + "). " +
235 "Expected " + m_scheme );
236 }
237
238 final Context context = newContext( urlPart );
239
240 return new ResolveResult( context, new CompositeName( namePart ) );
241 }
242
243 /***
244 * Find end index of url part in string.
245 * Default implementation looks for
246 * //.../[name-part]
247 * ///[name-part]
248 * //... (no name part)
249 * [name-part]
250 *
251 * @param name the name
252 * @param index the index where "scheme:" ends
253 * @return the index where url ends
254 * @exception NamingException if an error occurs
255 */
256 protected int getEndIndexOfURLPart( final String name, final int index )
257 throws NamingException
258 {
259 int result = 0;
260
261
262 if( name.startsWith( "//", index ) )
263 {
264
265 int end = name.indexOf( "/", index + 2 );
266
267 if( -1 != end )
268 {
269 result = end;
270 }
271 else
272 {
273 result = name.length();
274 }
275 }
276
277 return result;
278 }
279
280 /***
281 * Return a new instance of the base context for a URL.
282 * This must be implemented in particular URLContext.
283 *
284 * @param urlPart the part of url string not including "scheme:"
285 * @return a base URLContext for urlPart
286 * @exception NamingException if an error occurs
287 */
288 protected abstract Context newContext( String urlPart )
289 throws NamingException;
290 }