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 }