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| 1 | +/* | |
| 2 | + * Copyright (c) 2003, 2005, 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 | +package java.rmi.server; | |
| 26 | + | |
| 27 | +import java.io.InvalidObjectException; | |
| 28 | +import java.lang.reflect.InvocationHandler; | |
| 29 | +import java.lang.reflect.Method; | |
| 30 | +import java.lang.reflect.Proxy; | |
| 31 | +import java.rmi.Remote; | |
| 32 | +import java.rmi.UnexpectedException; | |
| 33 | +import java.rmi.activation.Activatable; | |
| 34 | +import java.util.Map; | |
| 35 | +import java.util.WeakHashMap; | |
| 36 | +import sun.rmi.server.Util; | |
| 37 | +import sun.rmi.server.WeakClassHashMap; | |
| 38 | + | |
| 39 | +/** | |
| 40 | + * An implementation of the <code>InvocationHandler</code> interface for | |
| 41 | + * use with Java Remote Method Invocation (Java RMI). This invocation | |
| 42 | + * handler can be used in conjunction with a dynamic proxy instance as a | |
| 43 | + * replacement for a pregenerated stub class. | |
| 44 | + * | |
| 45 | + * <p>Applications are not expected to use this class directly. A remote | |
| 46 | + * object exported to use a dynamic proxy with {@link UnicastRemoteObject} | |
| 47 | + * or {@link Activatable} has an instance of this class as that proxy's | |
| 48 | + * invocation handler. | |
| 49 | + * | |
| 50 | + * @author Ann Wollrath | |
| 51 | + * @since 1.5 | |
| 52 | + **/ | |
| 53 | +public class RemoteObjectInvocationHandler | |
| 54 | + extends RemoteObject | |
| 55 | + implements InvocationHandler | |
| 56 | +{ | |
| 57 | + private static final long serialVersionUID = 2L; | |
| 58 | + | |
| 59 | + /** | |
| 60 | + * A weak hash map, mapping classes to weak hash maps that map | |
| 61 | + * method objects to method hashes. | |
| 62 | + **/ | |
| 63 | + private static final MethodToHash_Maps methodToHash_Maps = | |
| 64 | + new MethodToHash_Maps(); | |
| 65 | + | |
| 66 | + /** | |
| 67 | + * Creates a new <code>RemoteObjectInvocationHandler</code> constructed | |
| 68 | + * with the specified <code>RemoteRef</code>. | |
| 69 | + * | |
| 70 | + * @param ref the remote ref | |
| 71 | + * | |
| 72 | + * @throws NullPointerException if <code>ref</code> is <code>null</code> | |
| 73 | + **/ | |
| 74 | + public RemoteObjectInvocationHandler(RemoteRef ref) { | |
| 75 | + super(ref); | |
| 76 | + if (ref == null) { | |
| 77 | + throw new NullPointerException(); | |
| 78 | + } | |
| 79 | + } | |
| 80 | + | |
| 81 | + /** | |
| 82 | + * Processes a method invocation made on the encapsulating | |
| 83 | + * proxy instance, <code>proxy</code>, and returns the result. | |
| 84 | + * | |
| 85 | + * <p><code>RemoteObjectInvocationHandler</code> implements this method | |
| 86 | + * as follows: | |
| 87 | + * | |
| 88 | + * <p>If <code>method</code> is one of the following methods, it | |
| 89 | + * is processed as described below: | |
| 90 | + * | |
| 91 | + * <ul> | |
| 92 | + * | |
| 93 | + * <li>{@link Object#hashCode Object.hashCode}: Returns the hash | |
| 94 | + * code value for the proxy. | |
| 95 | + * | |
| 96 | + * <li>{@link Object#equals Object.equals}: Returns <code>true</code> | |
| 97 | + * if the argument (<code>args[0]</code>) is an instance of a dynamic | |
| 98 | + * proxy class and this invocation handler is equal to the invocation | |
| 99 | + * handler of that argument, and returns <code>false</code> otherwise. | |
| 100 | + * | |
| 101 | + * <li>{@link Object#toString Object.toString}: Returns a string | |
| 102 | + * representation of the proxy. | |
| 103 | + * </ul> | |
| 104 | + * | |
| 105 | + * <p>Otherwise, a remote call is made as follows: | |
| 106 | + * | |
| 107 | + * <ul> | |
| 108 | + * <li>If <code>proxy</code> is not an instance of the interface | |
| 109 | + * {@link Remote}, then an {@link IllegalArgumentException} is thrown. | |
| 110 | + * | |
| 111 | + * <li>Otherwise, the {@link RemoteRef#invoke invoke} method is invoked | |
| 112 | + * on this invocation handler's <code>RemoteRef</code>, passing | |
| 113 | + * <code>proxy</code>, <code>method</code>, <code>args</code>, and the | |
| 114 | + * method hash (defined in section 8.3 of the "Java Remote Method | |
| 115 | + * Invocation (RMI) Specification") for <code>method</code>, and the | |
| 116 | + * result is returned. | |
| 117 | + * | |
| 118 | + * <li>If an exception is thrown by <code>RemoteRef.invoke</code> and | |
| 119 | + * that exception is a checked exception that is not assignable to any | |
| 120 | + * exception in the <code>throws</code> clause of the method | |
| 121 | + * implemented by the <code>proxy</code>'s class, then that exception | |
| 122 | + * is wrapped in an {@link UnexpectedException} and the wrapped | |
| 123 | + * exception is thrown. Otherwise, the exception thrown by | |
| 124 | + * <code>invoke</code> is thrown by this method. | |
| 125 | + * </ul> | |
| 126 | + * | |
| 127 | + * <p>The semantics of this method are unspecified if the | |
| 128 | + * arguments could not have been produced by an instance of some | |
| 129 | + * valid dynamic proxy class containing this invocation handler. | |
| 130 | + * | |
| 131 | + * @param proxy the proxy instance that the method was invoked on | |
| 132 | + * @param method the <code>Method</code> instance corresponding to the | |
| 133 | + * interface method invoked on the proxy instance | |
| 134 | + * @param args an array of objects containing the values of the | |
| 135 | + * arguments passed in the method invocation on the proxy instance, or | |
| 136 | + * <code>null</code> if the method takes no arguments | |
| 137 | + * @return the value to return from the method invocation on the proxy | |
| 138 | + * instance | |
| 139 | + * @throws Throwable the exception to throw from the method invocation | |
| 140 | + * on the proxy instance | |
| 141 | + **/ | |
| 142 | + public Object invoke(Object proxy, Method method, Object[] args) | |
| 143 | + throws Throwable | |
| 144 | + { | |
| 145 | + if (method.getDeclaringClass() == Object.class) { | |
| 146 | + return invokeObjectMethod(proxy, method, args); | |
| 147 | + } else { | |
| 148 | + return invokeRemoteMethod(proxy, method, args); | |
| 149 | + } | |
| 150 | + } | |
| 151 | + | |
| 152 | + /** | |
| 153 | + * Handles java.lang.Object methods. | |
| 154 | + **/ | |
| 155 | + private Object invokeObjectMethod(Object proxy, | |
| 156 | + Method method, | |
| 157 | + Object[] args) | |
| 158 | + { | |
| 159 | + String name = method.getName(); | |
| 160 | + | |
| 161 | + if (name.equals("hashCode")) { | |
| 162 | + return hashCode(); | |
| 163 | + | |
| 164 | + } else if (name.equals("equals")) { | |
| 165 | + Object obj = args[0]; | |
| 166 | + return | |
| 167 | + proxy == obj || | |
| 168 | + (obj != null && | |
| 169 | + Proxy.isProxyClass(obj.getClass()) && | |
| 170 | + equals(Proxy.getInvocationHandler(obj))); | |
| 171 | + | |
| 172 | + } else if (name.equals("toString")) { | |
| 173 | + return proxyToString(proxy); | |
| 174 | + | |
| 175 | + } else { | |
| 176 | + throw new IllegalArgumentException( | |
| 177 | + "unexpected Object method: " + method); | |
| 178 | + } | |
| 179 | + } | |
| 180 | + | |
| 181 | + /** | |
| 182 | + * Handles remote methods. | |
| 183 | + **/ | |
| 184 | + private Object invokeRemoteMethod(Object proxy, | |
| 185 | + Method method, | |
| 186 | + Object[] args) | |
| 187 | + throws Exception | |
| 188 | + { | |
| 189 | + try { | |
| 190 | + if (!(proxy instanceof Remote)) { | |
| 191 | + throw new IllegalArgumentException( | |
| 192 | + "proxy not Remote instance"); | |
| 193 | + } | |
| 194 | + return ref.invoke((Remote) proxy, method, args, | |
| 195 | + getMethodHash(method)); | |
| 196 | + } catch (Exception e) { | |
| 197 | + if (!(e instanceof RuntimeException)) { | |
| 198 | + Class<?> cl = proxy.getClass(); | |
| 199 | + try { | |
| 200 | + method = cl.getMethod(method.getName(), | |
| 201 | + method.getParameterTypes()); | |
| 202 | + } catch (NoSuchMethodException nsme) { | |
| 203 | + throw (IllegalArgumentException) | |
| 204 | + new IllegalArgumentException().initCause(nsme); | |
| 205 | + } | |
| 206 | + Class<?> thrownType = e.getClass(); | |
| 207 | + for (Class<?> declaredType : method.getExceptionTypes()) { | |
| 208 | + if (declaredType.isAssignableFrom(thrownType)) { | |
| 209 | + throw e; | |
| 210 | + } | |
| 211 | + } | |
| 212 | + e = new UnexpectedException("unexpected exception", e); | |
| 213 | + } | |
| 214 | + throw e; | |
| 215 | + } | |
| 216 | + } | |
| 217 | + | |
| 218 | + /** | |
| 219 | + * Returns a string representation for a proxy that uses this invocation | |
| 220 | + * handler. | |
| 221 | + **/ | |
| 222 | + private String proxyToString(Object proxy) { | |
| 223 | + Class<?>[] interfaces = proxy.getClass().getInterfaces(); | |
| 224 | + if (interfaces.length == 0) { | |
| 225 | + return "Proxy[" + this + "]"; | |
| 226 | + } | |
| 227 | + String iface = interfaces[0].getName(); | |
| 228 | + if (iface.equals("java.rmi.Remote") && interfaces.length > 1) { | |
| 229 | + iface = interfaces[1].getName(); | |
| 230 | + } | |
| 231 | + int dot = iface.lastIndexOf('.'); | |
| 232 | + if (dot >= 0) { | |
| 233 | + iface = iface.substring(dot + 1); | |
| 234 | + } | |
| 235 | + return "Proxy[" + iface + "," + this + "]"; | |
| 236 | + } | |
| 237 | + | |
| 238 | + /** | |
| 239 | + * @throws InvalidObjectException unconditionally | |
| 240 | + **/ | |
| 241 | + private void readObjectNoData() throws InvalidObjectException { | |
| 242 | + throw new InvalidObjectException("no data in stream; class: " + | |
| 243 | + this.getClass().getName()); | |
| 244 | + } | |
| 245 | + | |
| 246 | + /** | |
| 247 | + * Returns the method hash for the specified method. Subsequent calls | |
| 248 | + * to "getMethodHash" passing the same method argument should be faster | |
| 249 | + * since this method caches internally the result of the method to | |
| 250 | + * method hash mapping. The method hash is calculated using the | |
| 251 | + * "computeMethodHash" method. | |
| 252 | + * | |
| 253 | + * @param method the remote method | |
| 254 | + * @return the method hash for the specified method | |
| 255 | + */ | |
| 256 | + private static long getMethodHash(Method method) { | |
| 257 | + return methodToHash_Maps.get(method.getDeclaringClass()).get(method); | |
| 258 | + } | |
| 259 | + | |
| 260 | + /** | |
| 261 | + * A weak hash map, mapping classes to weak hash maps that map | |
| 262 | + * method objects to method hashes. | |
| 263 | + **/ | |
| 264 | + private static class MethodToHash_Maps | |
| 265 | + extends WeakClassHashMap<Map<Method,Long>> | |
| 266 | + { | |
| 267 | + MethodToHash_Maps() {} | |
| 268 | + | |
| 269 | + protected Map<Method,Long> computeValue(Class<?> remoteClass) { | |
| 270 | + return new WeakHashMap<Method,Long>() { | |
| 271 | + public synchronized Long get(Object key) { | |
| 272 | + Long hash = super.get(key); | |
| 273 | + if (hash == null) { | |
| 274 | + Method method = (Method) key; | |
| 275 | + hash = Util.computeMethodHash(method); | |
| 276 | + put(method, hash); | |
| 277 | + } | |
| 278 | + return hash; | |
| 279 | + } | |
| 280 | + }; | |
| 281 | + } | |
| 282 | + } | |
| 283 | +} | |