1 /*

     2  * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.

     3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

     4  *

     5  * This code is free software; you can redistribute it and/or modify it

     6  * under the terms of the GNU General Public License version 2 only, as

     7  * published by the Free Software Foundation.

     8  *

     9  * This code is distributed in the hope that it will be useful, but WITHOUT

    10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

    11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

    12  * version 2 for more details (a copy is included in the LICENSE file that

    13  * accompanied this code).

    14  *

    15  * You should have received a copy of the GNU General Public License version

    16  * 2 along with this work; if not, write to the Free Software Foundation,

    17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

    18  *

    19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

    20  * or visit www.oracle.com if you need additional information or have any

    21  * questions.

    22  */

    23 

    24 package nsk.share;

    25 

    26 import java.io.*;

    27 

    28 /**

    29  * The <code>CustomClassLoader</code> class is used in <code>ClassUnloader</code>.

    30  *

    31  * <p>This class loader can load classes and notify <code>ClassUnloader</code>

    32  * about own finalization to make sure that all loaded classes have been unloaded.

    33  *

    34  * <p>By default this class loader loads class from .class file located in directory

    35  * specified with <code>setClassPath()</code> method. To use any other technique

    36  * of class loading one should implement derived class, which would override

    37  * <code>findClass</code> method.

    38  *

    39  * @see nsk.share.ClassUnloader

    40  *

    41  * @see #setClassPath(String)

    42  * @see #findClass(String)

    43  */

    44 public class CustomClassLoader extends ClassLoader {

    45 

    46     private ClassUnloader classUnloader;

    47     protected String classPath;

    48 

    49     /**

    50      * Initializes a newly created <code>CustomClassloader</code> object

    51      * not yet linked with any <code>ClassUnloader</code> object.

    52      *

    53      */

    54     public CustomClassLoader() {

    55         super(CustomClassLoader.class.getClassLoader());

    56         this.classUnloader = null;

    57     }

    58 

    59     /**

    60      * Initializes a newly created <code>CustomClassloader</code> object

    61      * linked with specified <code>ClassUnloader</code> object.

    62      *

    63      * @param classUnloader an instance of <code>ClassUnloader</code>

    64      */

    65     public CustomClassLoader(ClassUnloader classUnloader) {

    66         super(CustomClassLoader.class.getClassLoader());

    67         this.classUnloader = classUnloader;

    68     }

    69 

    70     /**

    71      * Links this class loader with specified <code>ClassUnloader</code> object.

    72      *

    73      * @param classUnloader an instance of <code>ClassUnloader</code>

    74      */

    75     public void setClassUnloader(ClassUnloader classUnloader) {

    76         this.classUnloader = classUnloader;

    77     }

    78 

    79     /**

    80      * Specifies path to .class file location.

    81      *

    82      * @param classPath a path to .class file location

    83      */

    84     public void setClassPath(String classPath) {

    85         this.classPath = classPath;

    86     }

    87 

    88     /**

    89      * Finds and loads class for specified class name.

    90      * This method loads class from .class file located in a directory

    91      * previously specified by <code>setClassPath()</code>.

    92      *

    93      * @param name The name of the class.

    94      *

    95      * @throws ClassNotFoundException if no .class file found

    96      *          for specified class name

    97      *

    98      * @see #setClassPath(String)

    99      */

   100     protected synchronized Class findClass(String name) throws ClassNotFoundException {

   101         java.nio.file.Path path = ClassFileFinder.findClassFile(name, classPath);

   102         if (path == null) {

   103             throw new ClassNotFoundException(name);

   104         }

   105         String classFileName = path.toString();

   106 

   107         FileInputStream in;

   108         try {

   109             in = new FileInputStream(classFileName);

   110             if (in == null) {

   111                 throw new ClassNotFoundException(classFileName);

   112             }

   113         } catch (FileNotFoundException e) {

   114             throw new ClassNotFoundException(classFileName, e);

   115         }

   116 

   117         int len;

   118         byte data[];

   119         try {

   120             len = in.available();

   121             data = new byte[len];

   122             for (int total = 0; total < data.length; ) {

   123                 total += in.read(data, total, data.length - total);

   124             }

   125         } catch (IOException e) {

   126             throw new ClassNotFoundException(classFileName, e);

   127         } finally {

   128             try {

   129                 in.close();

   130             } catch (IOException e) {

   131                 throw new ClassNotFoundException(classFileName, e);

   132             }

   133         }

   134 

   135         return defineClass(name, data, 0, data.length);

   136     }

   137 

   138     /**

   139      * Notifies <code>ClassUnloader</code> about finalization.

   140      */

   141     protected void finalize() throws Throwable {

   142 

   143         // notify ClassUnloader about finalization

   144         if (classUnloader != null) {

   145             classUnloader.finalized = true;

   146         }

   147 

   148         super.finalize();

   149     }

   150 }