DefaultConstructionProxyFactory


1   /**
2    * Copyright (C) 2006 Google Inc.
3    *
4    * Licensed under the Apache License, Version 2.0 (the "License");
5    * you may not use this file except in compliance with the License.
6    * You may obtain a copy of the License at
7    *
8    * http://www.apache.org/licenses/LICENSE-2.0
9    *
10   * Unless required by applicable law or agreed to in writing, software
11   * distributed under the License is distributed on an "AS IS" BASIS,
12   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13   * See the License for the specific language governing permissions and
14   * limitations under the License.
15   */
16  
17  package com.google.inject;
18  
19  import com.google.inject.util.GuiceFastClass;
20  import com.google.inject.util.Objects;
21  import java.lang.reflect.Constructor  ;
22  import java.lang.reflect.InvocationTargetException  ;
23  import java.lang.reflect.Modifier  ;
24  import net.sf.cglib.reflect.FastClass;
25  import net.sf.cglib.reflect.FastConstructor;
26  
27  /**
28   * Default {@link ConstructionProxyFactory} implementation. Simply invokes the
29   * constructor. Can be reused by other {@code ConstructionProxyFactory}
30   * implementations.
31   *
32   * @author crazybob@google.com (Bob Lee)
33   */
34  class DefaultConstructionProxyFactory implements ConstructionProxyFactory {
35  
36    public <T> ConstructionProxy<T> get(final Constructor  <T> constructor) {
37      // We can't use FastConstructor if the constructor is private or protected.
38      if (Modifier.isPrivate(constructor.getModifiers())
39          || Modifier.isProtected(constructor.getModifiers())) {
40        constructor.setAccessible(true);
41        return new ConstructionProxy<T>() {
42          public T newInstance(Object  ... arguments) throws
43              InvocationTargetException   {
44            Objects.assertNoNulls(arguments);
45            try {
46              return constructor.newInstance(arguments);
47            }
48            catch (InstantiationException   e) {
49              throw new RuntimeException  (e);
50            }
51            catch (IllegalAccessException   e) {
52              throw new AssertionError  (e);
53            }
54          }
55        };
56      }
57  
58      Class  <T> classToConstruct = constructor.getDeclaringClass();
59      FastClass fastClass = GuiceFastClass.create(classToConstruct);
60      final FastConstructor fastConstructor
61          = fastClass.getConstructor(constructor);
62      return new ConstructionProxy<T>() {
63        @SuppressWarnings  ("unchecked")
64        public T newInstance(Object  ... arguments)
65            throws InvocationTargetException   {
66          Objects.assertNoNulls(arguments);
67          return (T) fastConstructor.newInstance(arguments);
68        }
69      };
70    }
71  }
72
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