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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 | } | ||