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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  /**
33   * A collection of utilities to workaround limitations of Java clone framework.
34   *
35   * @since 4.0
36   */
37  public class CloneUtils {
38  
39      /**
40       * @since 4.3
41       */
42      public static <T> T cloneObject(final T obj) throws CloneNotSupportedException {
43          if (obj == null) {
44              return null;
45          }
46          if (obj instanceof Cloneable) {
47              final Class<?> clazz = obj.getClass ();
48              final Method m;
49              try {
50                  m = clazz.getMethod("clone", (Class<?>[]) null);
51              } catch (final NoSuchMethodException ex) {
52                  throw new NoSuchMethodError(ex.getMessage());
53              }
54              try {
55                  @SuppressWarnings("unchecked") // OK because clone() preserves the class
56                  final T result = (T) m.invoke(obj, (Object []) null);
57                  return result;
58              } catch (final InvocationTargetException ex) {
59                  final Throwable cause = ex.getCause();
60                  if (cause instanceof CloneNotSupportedException) {
61                      throw ((CloneNotSupportedException) cause);
62                  } else {
63                      throw new Error("Unexpected exception", cause);
64                  }
65              } catch (final IllegalAccessException ex) {
66                  throw new IllegalAccessError(ex.getMessage());
67              }
68          } else {
69              throw new CloneNotSupportedException();
70          }
71      }
72  
73      public static Object clone(final Object obj) throws CloneNotSupportedException {
74          return cloneObject(obj);
75      }
76  
77      /**
78       * This class should not be instantiated.
79       */
80      private CloneUtils() {
81      }
82  
83  }