MethodCallContributionConstructor


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.internal;
16  
17  import java.lang.reflect.Method  ;
18  
19  import org.apache.hivemind.ApplicationRuntimeException;
20  import org.apache.hivemind.Location;
21  import org.apache.hivemind.definition.Contribution;
22  import org.apache.hivemind.definition.ContributionContext;
23  
24  /**
25   * Contributes to a configuration point by passing the configuration container
26   * to a method defined in an annotated module by use of the {@link Contribution} annotation. 
27   * 
28   * @author Achim Huegen
29   */
30  public class MethodCallContributionConstructor implements
31          Contribution
32  {
33      private Method   _templateMethod;
34  
35      private ModuleInstanceProvider _moduleInstanceProvider;
36  
37      private Location _location;
38  
39      public MethodCallContributionConstructor(Location location, Method   factoryMethod,
40              ModuleInstanceProvider moduleInstanceProvider)
41      {
42          _location = location;
43          _templateMethod = factoryMethod;
44          _moduleInstanceProvider = moduleInstanceProvider;
45      }
46  
47      public Location getLocation()
48      {
49          return _location;
50      }
51  
52      public void contribute(ContributionContext context)
53      {
54          try
55          {
56              if (_templateMethod.getParameterTypes().length == 0) {
57                  Object   result = _templateMethod.invoke(_moduleInstanceProvider.getModuleInstance());
58                  // a null contribution means: nothing to contribute. This happens for example
59                  // in configuration point definitions 
60                  if (result != null) {
61                      context.mergeContribution(result);
62                  }
63              } else if (_templateMethod.getParameterTypes().length == 1) {
64                  Object  [] params = new Object  [] {context.getConfigurationData()}; 
65                  _templateMethod.invoke(_moduleInstanceProvider.getModuleInstance(), params);
66              } else {
67                  // TODO: Throw Exception
68              }
69          }
70          catch (Exception   ex)
71          {
72              throw new ApplicationRuntimeException(ex.getMessage(), getLocation(), ex);
73          }
74          
75      }
76  
77  }
78
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