1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one
3 * or more contributor license agreements. See the NOTICE file
4 * distributed with this work for additional information
5 * regarding copyright ownership. The ASF licenses this file
6 * to you under the Apache License, Version 2.0 (the
7 * "License"); you may not use this file except in compliance
8 * with the License. You may obtain a copy of the License at
9 *
10 * http://www.apache.org/licenses/LICENSE-2.0
11 *
12 * Unless required by applicable law or agreed to in writing,
13 * software distributed under the License is distributed on an
14 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
15 * KIND, either express or implied. See the License for the
16 * specific language governing permissions and limitations
17 * under the License.
18 *
19 */
20 package org.apache.directory.api.ldap.codec.api;
21
22
23 import org.apache.directory.api.ldap.codec.osgi.DefaultLdapCodecService;
24 import org.slf4j.Logger;
25 import org.slf4j.LoggerFactory;
26
27
28 /**
29 * A factory that allows callers a means to get a handle on an LdapCodecService
30 * implementation regardless of the environment in which they're accessing it.
31 * In an OSGi environment, the BundleActivator binds the LdapCodecService
32 * class member forever to the {@link DefaultLdapCodecService}. If in
33 *
34 * In a standard standalone mode, the Bundle
35 *
36 * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
37 */
38 public class LdapApiServiceFactory
39 {
40 /** Logger for this class */
41 private static final Logger LOG = LoggerFactory.getLogger( LdapApiServiceFactory.class );
42
43 /** The LdapCodecService singleton bound to this factory */
44 private static LdapApiService ldapCodecService;
45
46 /** Whether or not the standalone implementation is being used */
47 private static boolean usingStandaloneImplementation;
48
49
50 /**
51 * Checks to see if the factory is initialized.
52 *
53 * @return true if initialized, false otherwise
54 */
55 public static boolean isInitialized()
56 {
57 return ldapCodecService != null;
58 }
59
60
61 /**
62 * Checks to see if the factory is using the standalone implementation.
63 *
64 * @return true if using the standalone implementation, false otherwise.
65 */
66 public static boolean isUsingStandaloneImplementation()
67 {
68 if ( !isInitialized() )
69 {
70 String msg = "Not initialized yet!";
71 LOG.error( msg );
72 throw new IllegalStateException( msg );
73 }
74
75 return usingStandaloneImplementation;
76 }
77
78
79 /**
80 * Gets the singleton instance of the LdapCodecService.
81 *
82 * @return a valid instance implementation based on environment and the
83 * availability of bindings.
84 */
85 public static LdapApiService getSingleton()
86 {
87 if ( ldapCodecService == null )
88 {
89 initialize( null );
90 }
91
92 return ldapCodecService;
93 }
94
95
96 /**
97 * Initialization can only take place once. There after an exception
98 * results.
99 *
100 * @param ldapCodecService The LDAP Codec Service to initialize with.
101 */
102 public static void initialize( LdapApiService ldapCodecService )
103 {
104 /*
105 * If the class member is already set we have problems.
106 */
107
108 if ( LdapApiServiceFactory.ldapCodecService != null )
109 {
110 StringBuilder sb = new StringBuilder( "The LdapCodecService is already set to an instance of " );
111 sb.append( LdapApiServiceFactory.class.getName() );
112 LOG.error( sb.toString() );
113 throw new IllegalStateException( sb.toString() );
114 }
115
116 /*
117 * If the argument is null, then we attempt discovery
118 */
119
120 if ( ldapCodecService == null )
121 {
122 try
123 {
124 @SuppressWarnings("unchecked")
125 Class<? extends LdapApiService> serviceClass = ( Class<? extends LdapApiService> )
126 Class.forName( "org.apache.directory.api.ldap.codec.standalone.StandaloneLdapApiService" );
127 LdapApiServiceFactory.ldapCodecService = serviceClass.newInstance();
128 usingStandaloneImplementation = true;
129 }
130 catch ( Exception e )
131 {
132 LOG.error( "Failed to instantiate a viable instance, instantiating new instance of ", e );
133 }
134 }
135 else
136 {
137 usingStandaloneImplementation = false;
138 LdapApiServiceFactory.ldapCodecService = ldapCodecService;
139 }
140 }
141 }