1   package org.apache.bcel.util;
2   
3   /* ====================================================================
4    * The Apache Software License, Version 1.1
5    *
6    * Copyright (c) 2001 The Apache Software Foundation.  All rights
7    * reserved.
8    *
9    * Redistribution and use in source and binary forms, with or without
10   * modification, are permitted provided that the following conditions
11   * are met:
12   *
13   * 1. Redistributions of source code must retain the above copyright
14   *    notice, this list of conditions and the following disclaimer.
15   *
16   * 2. Redistributions in binary form must reproduce the above copyright
17   *    notice, this list of conditions and the following disclaimer in
18   *    the documentation and/or other materials provided with the
19   *    distribution.
20   *
21   * 3. The end-user documentation included with the redistribution,
22   *    if any, must include the following acknowledgment:
23   *       "This product includes software developed by the
24   *        Apache Software Foundation (http://www.apache.org/)."
25   *    Alternately, this acknowledgment may appear in the software itself,
26   *    if and wherever such third-party acknowledgments normally appear.
27   *
28   * 4. The names "Apache" and "Apache Software Foundation" and
29   *    "Apache BCEL" must not be used to endorse or promote products
30   *    derived from this software without prior written permission. For
31   *    written permission, please contact apache@apache.org.
32   *
33   * 5. Products derived from this software may not be called "Apache",
34   *    "Apache BCEL", nor may "Apache" appear in their name, without
35   *    prior written permission of the Apache Software Foundation.
36   *
37   * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
38   * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
39   * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
40   * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
41   * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
42   * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
43   * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
44   * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
45   * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
46   * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
47   * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
48   * SUCH DAMAGE.
49   * ====================================================================
50   *
51   * This software consists of voluntary contributions made by many
52   * individuals on behalf of the Apache Software Foundation.  For more
53   * information on the Apache Software Foundation, please see
54   * <http://www.apache.org/>.
55   */
56  
57  import java.io.*;
58  
59  import java.util.Map;
60  import java.util.HashMap;
61  
62  import org.apache.bcel.classfile.*;
63  
64  /***
65   * This repository is used in situations where a Class is created
66   * outside the realm of a ClassLoader. Classes are loaded from
67   * the file systems using the paths specified in the given
68   * class path. By default, this is the value returned by
69   * ClassPath.getClassPath().
70   * <br>
71   * It is designed to be used as a singleton, however it
72   * can also be used with custom classpaths.
73   *
74  /**
75   * Abstract definition of a class repository. Instances may be used
76   * to load classes from different sources and may be used in the
77   * Repository.setRepository method.
78   *
79   * @see org.apache.bcel.Repository
80   *
81   * @version $Id: SyntheticRepository.java,v 1.6 2002/11/10 18:30:05 mdahm Exp $
82   * @author <A HREF="mailto:markus.dahm@berlin.de">M. Dahm</A>
83   * @author David Dixon-Peugh
84   */
85  public class SyntheticRepository implements Repository {
86    private static final String DEFAULT_PATH = ClassPath.getClassPath();
87  
88    private static HashMap _instances = new HashMap(); // CLASSPATH X REPOSITORY
89  
90    private ClassPath _path = null;
91    private HashMap   _loadedClasses = new HashMap(); // CLASSNAME X JAVACLASS
92  
93    private SyntheticRepository(ClassPath path) {
94      _path = path;
95    }
96  
97    public static SyntheticRepository getInstance() {
98      return getInstance(ClassPath.SYSTEM_CLASS_PATH);
99    }
100 
101   public static SyntheticRepository getInstance(ClassPath classPath) {
102     SyntheticRepository rep = (SyntheticRepository)_instances.get(classPath);
103 
104     if(rep == null) {
105       rep = new SyntheticRepository(classPath);
106       _instances.put(classPath, rep);
107     }
108 
109     return rep;
110   }
111 
112   /***
113    * Store a new JavaClass instance into this Repository.
114    */
115   public void storeClass(JavaClass clazz) {
116     _loadedClasses.put(clazz.getClassName(), clazz);
117     clazz.setRepository(this);
118  }
119 
120   /***
121    * Remove class from repository
122    */
123   public void removeClass(JavaClass clazz) {
124     _loadedClasses.remove(clazz.getClassName());
125   }
126 
127   /***
128    * Find an already defined (cached) JavaClass object by name.
129    */
130   public JavaClass findClass(String className) {
131     return (JavaClass)_loadedClasses.get(className);
132   }
133 
134   /***
135    * Load a JavaClass object for the given class name using
136    * the CLASSPATH environment variable.
137    */
138   public JavaClass loadClass(String className) 
139     throws ClassNotFoundException
140   {
141     if(className == null || className.equals("")) {
142       throw new IllegalArgumentException("Invalid class name " + className);
143     }
144 
145     className = className.replace('/', '.'); // Just in case, canonical form
146 
147     try {
148       return loadClass(_path.getInputStream(className), className);
149     } catch(IOException e) {
150       throw new ClassNotFoundException("Exception while looking for class " + 
151 				       className + ": " + e.toString());
152     }
153   }
154 
155   /***
156    * Try to find class source via getResourceAsStream().
157    * @see Class
158    * @return JavaClass object for given runtime class
159    */
160   public JavaClass loadClass(Class clazz) throws ClassNotFoundException {
161     String className = clazz.getName();
162     String name      = className;
163     int    i         = name.lastIndexOf('.');
164 
165     if(i > 0) {
166       name = name.substring(i + 1);
167     }
168 
169     return loadClass(clazz.getResourceAsStream(name + ".class"), className);
170   }
171 
172   private JavaClass loadClass(InputStream is, String className)
173     throws ClassNotFoundException
174   {
175     JavaClass clazz = findClass(className);
176 
177     if(clazz != null) { 
178       return clazz;
179     }
180 
181     try {
182       if(is != null) {
183 	ClassParser parser = new ClassParser(is, className);
184 	clazz = parser.parse();
185 	
186 	storeClass(clazz);
187 	
188 	return clazz;
189       }
190     } catch(IOException e) {
191       throw new ClassNotFoundException("Exception while looking for class " + 
192 				       className + ": " + e.toString());
193     }
194 
195     throw new ClassNotFoundException("SyntheticRepository could not load " +
196 				     className);    
197   }
198 
199   /*** Clear all entries from cache.
200    */
201   public void clear() {
202     _loadedClasses.clear();
203   }
204 }
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