AnnotatedModuleReader


1   // Copyright 2007 The Apache Software Foundation
2   //
3   // Licensed under the Apache License, Version 2.0 (the "License");
4   // you may not use this file except in compliance with the License.
5   // You may obtain a copy of the License at
6   //
7   //     http://www.apache.org/licenses/LICENSE-2.0
8   //
9   // Unless required by applicable law or agreed to in writing, software
10  // distributed under the License is distributed on an "AS IS" BASIS,
11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12  // See the License for the specific language governing permissions and
13  // limitations under the License.
14  
15  package org.apache.hivemind.annotations;
16  
17  import org.apache.commons.logging.Log;
18  import org.apache.commons.logging.LogFactory;
19  import org.apache.hivemind.ApplicationRuntimeException;
20  import org.apache.hivemind.ClassResolver;
21  import org.apache.hivemind.ErrorHandler;
22  import org.apache.hivemind.HiveMind;
23  import org.apache.hivemind.annotations.internal.AnnotatedModuleProcessor;
24  import org.apache.hivemind.definition.RegistryDefinition;
25  import org.apache.hivemind.impl.DefaultClassResolver;
26  import org.apache.hivemind.impl.DefaultErrorHandler;
27  
28  /**
29   * Reads a annotated hivemind module into a {@link RegistryDefinition}. Thus
30   * the defined services configurations and contributions are added to the
31   * registry.
32   * The class delegates the work to {@link AnnotatedModuleProcessor}
33   * 
34   * @author Achim Huegen
35   */
36  public class AnnotatedModuleReader
37  {
38      private static final Log LOG = LogFactory.getLog(AnnotatedModuleReader.class);
39  
40      private RegistryDefinition _registryDefinition;
41  
42      private AnnotatedModuleProcessor _processor;
43  
44      private ErrorHandler _errorHandler;
45  
46      private ClassResolver _classResolver;
47  
48      /**
49       * @param registryDefinition  the registry definition to which the modules are added.
50       */
51      public AnnotatedModuleReader(RegistryDefinition registryDefinition)
52      {
53          this(registryDefinition, new DefaultClassResolver(), new DefaultErrorHandler());
54      }
55  
56      /**
57       * @param registryDefinition  the registry definition to which the modules are added.
58       * @param classResolver  the {@link ClassResolver} used to resolve all classes referenced from 
59       *          elements inside this module.
60       * @param errorHandler  errorHandler used for handling recoverable errors
61       */
62      public AnnotatedModuleReader(RegistryDefinition registryDefinition, ClassResolver classResolver,
63              ErrorHandler errorHandler)
64      {
65          _registryDefinition = registryDefinition;
66          _classResolver = classResolver;
67          _errorHandler = errorHandler;
68          _processor = new AnnotatedModuleProcessor(_registryDefinition, _classResolver, _errorHandler);
69      }
70  
71      /**
72       * Reads an annotated module specified by its classname. The module must have a no
73       * argument constructor.
74       * 
75       * @param moduleClassName  class name of the module
76       */
77      public void readModule(String   moduleClassName)
78      {
79          Class   moduleClass = findModuleInClassResolver(moduleClassName);
80          readModule(moduleClass);
81      }
82  
83      /**
84       * Reads an annotated module.
85       * 
86       * @param moduleClass  class of the module
87       */
88      public void readModule(Class   moduleClass)
89      {
90          try
91          {
92              _processor.processModule(moduleClass);
93          }
94          catch (RuntimeException   ex)
95          {
96              _errorHandler.error(LOG, ex.getMessage(), HiveMind.getLocation(ex), ex);
97          }
98      }
99      
100     private Class   findModuleInClassResolver(String   type)
101     {
102         Class   result = _classResolver.checkForClass(type);
103 
104         if (result == null)
105             throw new ApplicationRuntimeException(AnnotationsMessages.unableToFindModuleClass(
106                     type, _classResolver));
107 
108         return result;
109     }
110 
111 }
112
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