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1   /*
2    * Licensed to the Apache Software Foundation (ASF) under one or more
3    * contributor license agreements.  See the NOTICE file distributed with
4    * this work for additional information regarding copyright ownership.
5    * The ASF licenses this file to You under the Apache License, Version 2.0
6    * (the "License"); you may not use this file except in compliance with
7    * the License.  You may obtain a copy of the License at
8    *
9    *      http://www.apache.org/licenses/LICENSE-2.0
10   *
11   * Unless required by applicable law or agreed to in writing, software
12   * distributed under the License is distributed on an "AS IS" BASIS,
13   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14   * See the License for the specific language governing permissions and
15   * limitations under the License.
16   */
17  package org.apache.commons.pool2.proxy;
18  
19  import org.apache.commons.pool2.UsageTracking;
20  
21  import net.sf.cglib.proxy.Enhancer;
22  import net.sf.cglib.proxy.Factory;
23  
24  /**
25   * cglib is unmaintained and does not work well (or possibly at all?) in newer JDKs, particularly JDK17+; see https://github.com/cglib/cglib
26   * <p>
27   * Provides proxy objects using CGLib.
28   * </p>
29   *
30   * @param <T> type of the pooled object to be proxied
31   * @since 2.0
32   */
33  public class CglibProxySource<T> implements ProxySource<T> {
34  
35      private final Class<? extends T> superclass;
36  
37      /**
38       * Constructs a new proxy source for the given class.
39       *
40       * @param superclass The class to proxy
41       */
42      public CglibProxySource(final Class<? extends T> superclass) {
43          this.superclass = superclass;
44      }
45  
46      @SuppressWarnings("unchecked") // Case to T on return
47      @Override
48      public T createProxy(final T pooledObject, final UsageTracking<T> usageTracking) {
49          final Enhancer enhancer = new Enhancer();
50          enhancer.setSuperclass(superclass);
51  
52          final CglibProxyHandler<T> proxyInterceptor =
53                  new CglibProxyHandler<>(pooledObject, usageTracking);
54          enhancer.setCallback(proxyInterceptor);
55  
56          return (T) enhancer.create();
57      }
58  
59      @Override
60      public T resolveProxy(final T proxy) {
61          @SuppressWarnings("unchecked")
62          final
63          CglibProxyHandler<T> cglibProxyHandler =
64                  (CglibProxyHandler<T>) ((Factory) proxy).getCallback(0);
65          return cglibProxyHandler.disableProxy();
66      }
67  
68      /**
69       * @since 2.4.3
70       */
71      @Override
72      public String toString() {
73          final StringBuilder builder = new StringBuilder();
74          builder.append("CglibProxySource [superclass=");
75          builder.append(superclass);
76          builder.append("]");
77          return builder.toString();
78      }
79  }