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 * https://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.i18n.I18n;
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 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 final 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 * Private constructor
52 */
53 private LdapApiServiceFactory()
54 {
55 }
56
57
58 /**
59 * Checks to see if the factory is initialized.
60 *
61 * @return true if initialized, false otherwise
62 */
63 public static boolean isInitialized()
64 {
65 return ldapCodecService != null;
66 }
67
68
69 /**
70 * Checks to see if the factory is using the standalone implementation.
71 *
72 * @return true if using the standalone implementation, false otherwise.
73 */
74 public static boolean isUsingStandaloneImplementation()
75 {
76 if ( !isInitialized() )
77 {
78 String msg = I18n.err( I18n.ERR_05200_NOT_INITIALIZED_YET );
79 LOG.error( msg );
80 throw new IllegalStateException( msg );
81 }
82
83 return usingStandaloneImplementation;
84 }
85
86
87 /**
88 * Gets the singleton instance of the LdapCodecService.
89 *
90 * @return a valid instance implementation based on environment and the
91 * availability of bindings.
92 */
93 public static LdapApiService getSingleton()
94 {
95 if ( ldapCodecService == null )
96 {
97 initialize( null );
98 }
99
100 return ldapCodecService;
101 }
102
103
104 /**
105 * Initialization can only take place once. There after an exception
106 * results.
107 *
108 * @param ldapCodecService The LDAP Codec Service to initialize with.
109 */
110 public static void initialize( LdapApiService ldapCodecService )
111 {
112 /*
113 * If the class member is already set we have problems.
114 */
115
116 if ( LdapApiServiceFactory.ldapCodecService != null )
117 {
118 String msg = I18n.err( I18n.ERR_05201_INSTANCE_ALREADY_SET, LdapApiServiceFactory.class.getName() );
119 LOG.error( msg );
120 throw new IllegalStateException( msg );
121 }
122
123 /*
124 * If the argument is null, then we attempt discovery
125 */
126
127 if ( ldapCodecService == null )
128 {
129 try
130 {
131 @SuppressWarnings("unchecked")
132 Class<? extends LdapApiService> serviceClass = ( Class<? extends LdapApiService> )
133 Class.forName( "org.apache.directory.api.ldap.codec.standalone.StandaloneLdapApiService" );
134 LdapApiServiceFactory.ldapCodecService = serviceClass.newInstance();
135 usingStandaloneImplementation = true;
136 }
137 catch ( Exception e )
138 {
139 LOG.error( I18n.err( I18n.ERR_05202_FAILED_TO_INSTANCIATE, e.getMessage() ) );
140 }
141 }
142 else
143 {
144 usingStandaloneImplementation = false;
145 LdapApiServiceFactory.ldapCodecService = ldapCodecService;
146 }
147 }
148 }