1 /*

     2  * Copyright (c) 2009, 2010, 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.  Oracle designates this

     8  * particular file as subject to the "Classpath" exception as provided

     9  * by Oracle in the LICENSE file that accompanied this code.

    10  *

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

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

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

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

    15  * accompanied this code).

    16  *

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

    18  * 2 along with this work; if not, write to the Free Software Foundation,

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

    20  *

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

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

    23  * questions.

    24  */

    25 

    26 package sun.misc;

    27 

    28 import java.io.File;

    29 import java.io.IOException;

    30 import java.net.URLStreamHandlerFactory;

    31 import sun.misc.URLClassPath;

    32 

    33 /**

    34  * BootClassLoaderHook defines an interface for a hook to inject

    35  * into the bootstrap class loader.

    36  *

    37  * With jkernel now removed, no hook is set

    38  */

    39 public abstract class BootClassLoaderHook {

    40     private static BootClassLoaderHook bootLoaderHook = null;

    41     public static synchronized BootClassLoaderHook getHook() {

    42         return bootLoaderHook;

    43     }

    44 

    45     public static synchronized void setHook(BootClassLoaderHook hook) {

    46         if (!VM.isBooted()) {

    47             throw new InternalError("hook can only be set after VM is booted");

    48         }

    49         if (bootLoaderHook != null) {

    50             throw new InternalError("hook should not be reinitialized");

    51         }

    52         bootLoaderHook = hook;

    53     }

    54 

    55     protected BootClassLoaderHook() {

    56     }

    57 

    58     /**

    59      * A method to be invoked before a class loader loads

    60      * a bootstrap class.

    61      *

    62      * @param classname the binary name of the class

    63      */

    64     public static void preLoadClass(String classname) {

    65         BootClassLoaderHook hook = getHook();

    66         if (hook != null) {

    67             hook.loadBootstrapClass(classname);

    68         }

    69     }

    70 

    71     /**

    72      * A method to be invoked before a class loader loads

    73      * a resource.

    74      *

    75      * @param resourcename the resource name

    76      */

    77     public static void preLoadResource(String resourcename) {

    78         BootClassLoaderHook hook = getHook();

    79         if (hook != null) {

    80             hook.getBootstrapResource(resourcename);

    81         }

    82     }

    83 

    84     /**

    85      * A method to be invoked before a library is loaded.

    86      *

    87      * @param libname the name of the library

    88      */

    89     public static void preLoadLibrary(String libname) {

    90         BootClassLoaderHook hook = getHook();

    91         if (hook != null) {

    92             hook.loadLibrary(libname);

    93         }

    94     }

    95 

    96     /**

    97      * Returns a pathname of a JAR or class that the hook loads

    98      * per this loadClass request; or null.

    99      *

   100      * @param classname the binary name of the class

   101      */

   102     public abstract String loadBootstrapClass(String className);

   103 

   104     /**

   105      * Returns a pathname of a resource file that the hook loads

   106      * per this getResource request; or null.

   107      *

   108      * @param resourceName the resource name

   109      */

   110     public abstract String getBootstrapResource(String resourceName);

   111 

   112     /**

   113      * Returns true if the hook successfully performs an operation per

   114      * this loadLibrary request; or false if it fails.

   115      *

   116      * @param libname the name of the library

   117      */

   118     public abstract boolean loadLibrary(String libname);

   119 

   120     /**

   121      * Returns a bootstrap class path constructed by the hook.

   122      *

   123      * @param bcp VM's bootstrap class path

   124      * @param factory Launcher's URL stream handler

   125      */

   126     public abstract URLClassPath getBootstrapClassPath(URLClassPath bcp,

   127             URLStreamHandlerFactory factory);

   128 

   129     /**

   130      * Returns true if the current thread is in the process of doing

   131      * a prefetching operation.

   132      */

   133     public abstract boolean isCurrentThreadPrefetching();

   134 

   135     /**

   136      * Returns true if the hook successfully prefetches the specified file.

   137      *

   138      * @param name a platform independent pathname

   139      */

   140     public abstract boolean prefetchFile(String name);

   141 }