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1   /*
2    * ====================================================================
3    * Licensed to the Apache Software Foundation (ASF) under one
4    * or more contributor license agreements.  See the NOTICE file
5    * distributed with this work for additional information
6    * regarding copyright ownership.  The ASF licenses this file
7    * to you under the Apache License, Version 2.0 (the
8    * "License"); you may not use this file except in compliance
9    * with the License.  You may obtain a copy of the License at
10   *
11   *   http://www.apache.org/licenses/LICENSE-2.0
12   *
13   * Unless required by applicable law or agreed to in writing,
14   * software distributed under the License is distributed on an
15   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
16   * KIND, either express or implied.  See the License for the
17   * specific language governing permissions and limitations
18   * under the License.
19   * ====================================================================
20   *
21   * This software consists of voluntary contributions made by many
22   * individuals on behalf of the Apache Software Foundation.  For more
23   * information on the Apache Software Foundation, please see
24   * <http://www.apache.org/>.
25   *
26   */
27  package org.apache.http.client.utils;
28  
29  import java.lang.reflect.InvocationTargetException;
30  import java.lang.reflect.Method;
31  
32  import org.apache.http.annotation.Immutable;
33  
34  /**
35   * A collection of utilities to workaround limitations of Java clone framework.
36   *
37   * @since 4.0
38   */
39  @Immutable
40  public class CloneUtils {
41  
42      /**
43       * @since 4.3
44       */
45      public static <T> T cloneObject(final T obj) throws CloneNotSupportedException {
46          if (obj == null) {
47              return null;
48          }
49          if (obj instanceof Cloneable) {
50              final Class<?> clazz = obj.getClass ();
51              final Method m;
52              try {
53                  m = clazz.getMethod("clone", (Class<?>[]) null);
54              } catch (final NoSuchMethodException ex) {
55                  throw new NoSuchMethodError(ex.getMessage());
56              }
57              try {
58                  @SuppressWarnings("unchecked") // OK because clone() preserves the class
59                  final T result = (T) m.invoke(obj, (Object []) null);
60                  return result;
61              } catch (final InvocationTargetException ex) {
62                  final Throwable cause = ex.getCause();
63                  if (cause instanceof CloneNotSupportedException) {
64                      throw ((CloneNotSupportedException) cause);
65                  } else {
66                      throw new Error("Unexpected exception", cause);
67                  }
68              } catch (final IllegalAccessException ex) {
69                  throw new IllegalAccessError(ex.getMessage());
70              }
71          } else {
72              throw new CloneNotSupportedException();
73          }
74      }
75  
76      public static Object clone(final Object obj) throws CloneNotSupportedException {
77          return cloneObject(obj);
78      }
79  
80      /**
81       * This class should not be instantiated.
82       */
83      private CloneUtils() {
84      }
85  
86  }