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1   /*
2    * Licensed to the Apache Software Foundation (ASF) under one
3    * or more contributor license agreements.  See the NOTICE file
4    * distributed with this work for additional information
5    * regarding copyright ownership.  The ASF licenses this file
6    * to you under the Apache License, Version 2.0 (the
7    * "License"); you may not use this file except in compliance
8    * with the License.  You may obtain a copy of the License at
9    *
10   *   https://www.apache.org/licenses/LICENSE-2.0
11   *
12   * Unless required by applicable law or agreed to in writing,
13   * software distributed under the License is distributed on an
14   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
15   * KIND, either express or implied.  See the License for the
16   * specific language governing permissions and limitations
17   * under the License.
18   */
19  package org.apache.bcel.util;
20  
21  import java.lang.ref.SoftReference;
22  import java.util.HashMap;
23  import java.util.Map;
24  
25  import org.apache.bcel.classfile.JavaClass;
26  
27  /**
28   * This repository is used in situations where a Class is created outside the realm of a ClassLoader. Classes are loaded
29   * from the file systems using the paths specified in the given class path. By default, this is the value returned by
30   * ClassPath.getClassPath(). This repository holds onto classes with SoftReferences, and will reload as needed, in cases
31   * where memory sizes are important.
32   *
33   * @see org.apache.bcel.Repository
34   */
35  public class MemorySensitiveClassPathRepository extends AbstractClassPathRepository {
36  
37      private final Map<String, SoftReference<JavaClass>> loadedClasses = new HashMap<>(); // CLASSNAME X JAVACLASS
38  
39      public MemorySensitiveClassPathRepository(final ClassPath path) {
40          super(path);
41      }
42  
43      /**
44       * Clear all entries from cache.
45       */
46      @Override
47      public void clear() {
48          loadedClasses.clear();
49      }
50  
51      /**
52       * Find an already defined (cached) JavaClass object by name.
53       */
54      @Override
55      public JavaClass findClass(final String className) {
56          final SoftReference<JavaClass> ref = loadedClasses.get(className);
57          return ref == null ? null : ref.get();
58      }
59  
60      /**
61       * Remove class from repository
62       */
63      @Override
64      public void removeClass(final JavaClass clazz) {
65          loadedClasses.remove(clazz.getClassName());
66      }
67  
68      /**
69       * Store a new JavaClass instance into this Repository.
70       */
71      @Override
72      public void storeClass(final JavaClass clazz) {
73          // Not calling super.storeClass because this subclass maintains the mapping.
74          loadedClasses.put(clazz.getClassName(), new SoftReference<>(clazz));
75          clazz.setRepository(this);
76      }
77  }