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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   */
18  package org.apache.bcel.util;
19  
20  import java.io.IOException;
21  import java.io.InputStream;
22  import java.util.HashMap;
23  import java.util.Map;
24  
25  import org.apache.bcel.classfile.ClassParser;
26  import org.apache.bcel.classfile.JavaClass;
27  
28  /**
29   * This repository is used in situations where a Class is created outside the realm of a ClassLoader. Classes are loaded from the file systems using the paths
30   * specified in the given class path. By default, this is the value returned by ClassPath.getClassPath(). <br>
31   *
32   * @see org.apache.bcel.Repository
33   */
34  public class ClassPathRepository implements Repository {
35  
36      private ClassPath _path = null;
37      private final Map<String, JavaClass> _loadedClasses = new HashMap<>(); // CLASSNAME X JAVACLASS
38  
39      public ClassPathRepository(final ClassPath path) {
40          _path = path;
41      }
42  
43      /**
44       * Store a new JavaClass instance into this Repository.
45       */
46      @Override
47      public void storeClass(final JavaClass clazz) {
48          _loadedClasses.put(clazz.getClassName(), clazz);
49          clazz.setRepository(this);
50      }
51  
52      /**
53       * Remove class from repository
54       */
55      @Override
56      public void removeClass(final JavaClass clazz) {
57          _loadedClasses.remove(clazz.getClassName());
58      }
59  
60      /**
61       * Find an already defined (cached) JavaClass object by name.
62       */
63      @Override
64      public JavaClass findClass(final String className) {
65          return _loadedClasses.get(className);
66      }
67  
68      /**
69       * Find a JavaClass object by name. If it is already in this Repository, the Repository version is returned. Otherwise, the Repository's classpath is
70       * searched for the class (and it is added to the Repository if found).
71       *
72       * @param className
73       *            the name of the class
74       * @return the JavaClass object
75       * @throws ClassNotFoundException
76       *             if the class is not in the Repository, and could not be found on the classpath
77       */
78      @Override
79      public JavaClass loadClass(String className) throws ClassNotFoundException {
80          if ((className == null) || className.isEmpty()) {
81              throw new IllegalArgumentException("Invalid class name " + className);
82          }
83          className = className.replace('/', '.'); // Just in case, canonical form
84          final JavaClass clazz = findClass(className);
85          if (clazz != null) {
86              return clazz;
87          }
88          try {
89              return loadClass(_path.getInputStream(className), className);
90          } catch (final IOException e) {
91              throw new ClassNotFoundException("Exception while looking for class " + className + ": " + e, e);
92          }
93      }
94  
95      /**
96       * Find the JavaClass object for a runtime Class object. If a class with the same name is already in this Repository, the Repository version is returned.
97       * Otherwise, getResourceAsStream() is called on the Class object to find the class's representation. If the representation is found, it is added to the
98       * Repository.
99       *
100      * @see Class
101      * @param clazz
102      *            the runtime Class object
103      * @return JavaClass object for given runtime class
104      * @throws ClassNotFoundException
105      *             if the class is not in the Repository, and its representation could not be found
106      */
107     @Override
108     public JavaClass loadClass(final Class<?> clazz) throws ClassNotFoundException {
109         final String className = clazz.getName();
110         final JavaClass repositoryClass = findClass(className);
111         if (repositoryClass != null) {
112             return repositoryClass;
113         }
114         String name = className;
115         final int i = name.lastIndexOf('.');
116         if (i > 0) {
117             name = name.substring(i + 1);
118         }
119         JavaClass cls = null;
120         try (InputStream clsStream = clazz.getResourceAsStream(name + ".class")) {
121             return cls = loadClass(clsStream, className);
122         } catch (final IOException e) {
123             return cls;
124         }
125     }
126 
127     private JavaClass loadClass(final InputStream is, final String className) throws ClassNotFoundException {
128         try {
129             if (is != null) {
130                 final ClassParser parser = new ClassParser(is, className);
131                 final JavaClass clazz = parser.parse();
132                 storeClass(clazz);
133                 return clazz;
134             }
135         } catch (final IOException e) {
136             throw new ClassNotFoundException("Exception while looking for class " + className + ": " + e, e);
137         } finally {
138             if (is != null) {
139                 try {
140                     is.close();
141                 } catch (final IOException e) {
142                     // ignored
143                 }
144             }
145         }
146         throw new ClassNotFoundException("SyntheticRepository could not load " + className);
147     }
148 
149     /**
150      * ClassPath associated with the Repository.
151      */
152     @Override
153     public ClassPath getClassPath() {
154         return _path;
155     }
156 
157     /**
158      * Clear all entries from cache.
159      */
160     @Override
161     public void clear() {
162         _loadedClasses.clear();
163     }
164 }