Source for javax.management.loading.ClassLoaderRepository

   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:    */
  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:    */
 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:    */
 135:   Class<?> loadClassWithout(ClassLoader exclude, String name)
 136:     throws ClassNotFoundException;
 137: 
 138: }