1 /* ClassLoaderRepository.java -- Represents a collection of class loadersx. 2 Copyright (C) 2006 Free Software Foundation, Inc. 3 4 This file is part of GNU Classpath. 5 6 GNU Classpath is free software; you can redistribute it and/or modify 7 it under the terms of the GNU General Public License as published by 8 the Free Software Foundation; either version 2, or (at your option) 9 any later version. 10 11 GNU Classpath is distributed in the hope that it will be useful, but 12 WITHOUT ANY WARRANTY; without even the implied warranty of 13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 14 General Public License for more details. 15 16 You should have received a copy of the GNU General Public License 17 along with GNU Classpath; see the file COPYING. If not, write to the 18 Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 19 02110-1301 USA. 20 21 Linking this library statically or dynamically with other modules is 22 making a combined work based on this library. Thus, the terms and 23 conditions of the GNU General Public License cover the whole 24 combination. 25 26 As a special exception, the copyright holders of this library give you 27 permission to link this library with independent modules to produce an 28 executable, regardless of the license terms of these independent 29 modules, and to copy and distribute the resulting executable under 30 terms of your choice, provided that you also meet, for each linked 31 independent module, the terms and conditions of the license of that 32 module. An independent module is a module which is not derived from 33 or based on this library. If you modify this library, you may extend 34 this exception to your version of the library, but you are not 35 obligated to do so. If you do not wish to do so, delete this 36 exception statement from your version. */ 37 38 package javax.management.loading; 39 40 /** 41 * Implementations of this interface maintain a list of 42 * {@link ClassLoader}s for use by the management servers, 43 * allowing classes to be loaded by the first {@link ClassLoader} 44 * that will do so. A class loader is added to the list 45 * whenever a {@link ClassLoader} instance is registered with 46 * the management server, and it does not implement the 47 * {@link PrivateClassLoader} interface. They are removed when 48 * unregistered. The first class loader in the list is always 49 * the one which was used to load the management server itself. 50 * 51 * @author Andrew John Hughes (gnu_andrew@member.fsf.org) 52 * @since 1.5 53 * @see MBeanServerFactory 54 */ 55 public interface ClassLoaderRepository 56 { 57 58 /** 59 * Attempts to load the given class using class loaders 60 * supplied by the list. The {@link ClassLoader#loadClass(String)} 61 * method of each class loader is called. If the method 62 * returns successfully, then the returned {@link Class} instance 63 * is returned. If a {@link ClassNotFoundException} is thrown, 64 * then the next loader is tried. Any other exception thrown 65 * by the method is passed back to the caller. This method 66 * throws a {@link ClassNotFoundException} itself if all the 67 * class loaders listed prove fruitless. 68 * 69 * @param name the name of the class to load. 70 * @return the loaded class. 71 * @throws ClassNotFoundException if all the class loaders fail 72 * to load the class. 73 */ loadClass(String name)74 Class<?> loadClass(String name) 75 throws ClassNotFoundException; 76 77 /** 78 * <p> 79 * Attempts to load the given class using class loaders 80 * supplied by the list, stopping when the specified 81 * loader is reached. The {@link ClassLoader#loadClass(String)} 82 * method of each class loader is called. If the method 83 * returns successfully, then the returned {@link Class} instance 84 * is returned. If a {@link ClassNotFoundException} is thrown, 85 * then the next loader is tried. Any other exception thrown 86 * by the method is passed back to the caller. This method 87 * throws a {@link ClassNotFoundException} itself if all the 88 * class loaders listed prove fruitless. 89 * </p> 90 * <p> 91 * This method is usually used by the class loader specified 92 * by the <code>stop</code> argument to load classes using the 93 * loaders that appear before it in the list. By stopping when 94 * the loader is reached, the deadlock that occurs when the loader 95 * is merely skipped is avoided. 96 * </p> 97 * 98 * @param stop the class loader at which to stop, or <code>null</code> 99 * to obtain the same behaviour as {@link #loadClass(String)}. 100 * @param name the name of the class to load. 101 * @return the loaded class. 102 * @throws ClassNotFoundException if all the class loaders fail 103 * to load the class. 104 */ loadClassBefore(ClassLoader stop, String name)105 Class<?> loadClassBefore(ClassLoader stop, String name) 106 throws ClassNotFoundException; 107 108 /** 109 * <p> 110 * Attempts to load the given class using class loaders 111 * supplied by the list, excluding the one specified. 112 * The {@link ClassLoader#loadClass(String)} 113 * method of each class loader is called. If the method 114 * returns successfully, then the returned {@link Class} instance 115 * is returned. If a {@link ClassNotFoundException} is thrown, 116 * then the next loader is tried. Any other exception thrown 117 * by the method is passed back to the caller. This method 118 * throws a {@link ClassNotFoundException} itself if all the 119 * class loaders listed prove fruitless. 120 * </p> 121 * <p> 122 * Note that this method may deadlock if called simultaneously 123 * by two class loaders in the list. 124 * {@link loadClassBefore(ClassLoader, String)} should be used 125 * in preference to this method to avoid this. 126 * </p> 127 * 128 * @param exclude the class loader to exclude, or <code>null</code> 129 * to obtain the same behaviour as {@link #loadClass(String)}. 130 * @param name the name of the class to load. 131 * @return the loaded class. 132 * @throws ClassNotFoundException if all the class loaders fail 133 * to load the class. 134 */ loadClassWithout(ClassLoader exclude, String name)135 Class<?> loadClassWithout(ClassLoader exclude, String name) 136 throws ClassNotFoundException; 137 138 } 139