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author | upstream source tree <ports@midipix.org> | 2015-03-15 20:14:05 -0400 |
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committer | upstream source tree <ports@midipix.org> | 2015-03-15 20:14:05 -0400 |
commit | 554fd8c5195424bdbcabf5de30fdc183aba391bd (patch) | |
tree | 976dc5ab7fddf506dadce60ae936f43f58787092 /libjava/classpath/java/rmi/server/RemoteObjectInvocationHandler.java | |
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Diffstat (limited to 'libjava/classpath/java/rmi/server/RemoteObjectInvocationHandler.java')
-rw-r--r-- | libjava/classpath/java/rmi/server/RemoteObjectInvocationHandler.java | 229 |
1 files changed, 229 insertions, 0 deletions
diff --git a/libjava/classpath/java/rmi/server/RemoteObjectInvocationHandler.java b/libjava/classpath/java/rmi/server/RemoteObjectInvocationHandler.java new file mode 100644 index 000000000..0cf4bca98 --- /dev/null +++ b/libjava/classpath/java/rmi/server/RemoteObjectInvocationHandler.java @@ -0,0 +1,229 @@ +/* RemoteObjectInvocationHandler.java -- RMI stub replacement. + Copyright (C) 2005 Free Software Foundation, Inc. + + This file is part of GNU Classpath. + + GNU Classpath is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 2, or (at your option) + any later version. + + GNU Classpath is distributed in the hope that it will be useful, but + WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + General Public License for more details. + + You should have received a copy of the GNU General Public License + along with GNU Classpath; see the file COPYING. If not, write to the + Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA + 02110-1301 USA. + + Linking this library statically or dynamically with other modules is + making a combined work based on this library. Thus, the terms and + conditions of the GNU General Public License cover the whole + combination. + + As a special exception, the copyright holders of this library give you + permission to link this library with independent modules to produce an + executable, regardless of the license terms of these independent + modules, and to copy and distribute the resulting executable under + terms of your choice, provided that you also meet, for each linked + independent module, the terms and conditions of the license of that + module. An independent module is a module which is not derived from + or based on this library. If you modify this library, you may extend + this exception to your version of the library, but you are not + obligated to do so. If you do not wish to do so, delete this + exception statement from your version. */ + + +package java.rmi.server; + +import gnu.java.rmi.server.RMIHashes; + +import java.io.Serializable; +import java.lang.reflect.InvocationHandler; +import java.lang.reflect.Method; +import java.lang.reflect.Proxy; +import java.rmi.Remote; +import java.rmi.RemoteException; +import java.rmi.UnexpectedException; +import java.rmi.registry.Registry; +import java.rmi.server.RemoteObject; +import java.rmi.server.RemoteRef; +import java.rmi.server.UnicastRemoteObject; +import java.util.Hashtable; + +/** + * Together with dynamic proxy instance, this class replaces the generated RMI + * stub (*_Stub) classes that (following 1.5 specification) should be no longer + * required. It is unusual to use the instances of this class directly in the + * user program. Such instances are automatically created and returned by + * {@link Registry} or {@link UnicastRemoteObject} methods if the remote + * reference is known but the corresponding stub class is not accessible. + * + * @see Registry#lookup + * + * @author Audrius Meskauskas (AudriusA@Bioinformatics.org) + */ +public class RemoteObjectInvocationHandler extends RemoteObject implements + InvocationHandler, Remote, Serializable +{ + /** + * Use the jdk 1.5 SUID for interoperability. + */ + static final long serialVersionUID = 2L; + + /** + * The RMI method hash codes, computed once as described in the section 8.3 + * of the Java Remote Method Invocation (RMI) Specification. + */ + static Hashtable methodHashCodes = new Hashtable(); + + /** + * The empty class array to define parameters of .hashCode and .toString. + */ + static final Class[] noArgsC = new Class[0]; + + /** + * The class array to define parameters of .equals + */ + static final Class[] anObjectC = new Class[] { Object.class }; + + /** + * The empty object array to replace null when no args are passed. + */ + static final Object[] noArgs = new Object[0]; + + /** + * Construct the remote invocation handler that forwards calls to the given + * remote object. + * + * @param reference the reference to the remote object where the method + * calls should be forwarded. + */ + public RemoteObjectInvocationHandler(RemoteRef reference) + { + super(reference); + } + + /** + * Invoke the remote method. When the known method is invoked on a created RMI + * stub proxy class, the call is delivered to this method and then transferred + * to the {@link RemoteRef#invoke(Remote, Method, Object[], long)} of the + * remote reference that was passed in constructor. The methods are handled as + * following: + * <ul> + * <li> The toString() method is delegated to the passed proxy instance.</li> + * <li>The .equals method only returns true if the passed object is an + * instance of proxy class and its invocation handler is equal to this + * invocation handles.</li> + * <li>The .hashCode returns the hashCode of this invocation handler (if the.</li> + * <li>All other methods are converted to remote calls and forwarded to the + * remote reference. </li> + * </ul> + * + * @param proxyInstance + * the instance of the proxy stub + * @param method + * the method being invoked + * @param parameters + * the method parameters + * @return the method return value, returned by RemoteRef.invoke + * @throws IllegalAccessException + * if the passed proxy instance does not implement Remote interface. + * @throws UnexpectedException + * if remote call throws some exception, not listed in the + * <code>throws</code> clause of the method being called. + * @throws Throwable + * that is thrown by remote call, if that exception is listend in + * the <code>throws</code> clause of the method being called. + */ + public Object invoke(Object proxyInstance, Method method, Object[] parameters) + throws Throwable + { + if (!(proxyInstance instanceof Remote)) + { + String name = proxyInstance == null ? "null" + : proxyInstance.getClass().getName(); + throw new IllegalAccessException(name + " does not implement " + + Remote.class.getName()); + } + + if (parameters == null) + parameters = noArgs; + + String name = method.getName(); + switch (name.charAt(0)) + { + case 'e': + if (parameters.length == 1 && name.equals("equals") + && method.getParameterTypes()[0].equals(Object.class)) + { + if (parameters[0] instanceof Proxy) + { + Object handler = Proxy.getInvocationHandler(parameters[0]); + if (handler == null) + return Boolean.FALSE; + else + return handler.equals(this) ? Boolean.TRUE : Boolean.FALSE; + } + else + return Boolean.FALSE; + } + break; + case 'h': + if (parameters.length == 0 && name.equals("hashCode")) + { + int hashC = Proxy.getInvocationHandler(proxyInstance).hashCode(); + return new Integer(hashC); + } + break; + case 't': + if (parameters.length == 0 && name.equals("toString")) + return "Proxy stub:"+ref.remoteToString(); + break; + default: + break; + } + + Long hash = (Long) methodHashCodes.get(method); + if (hash == null) + { + hash = new Long(RMIHashes.getMethodHash(method)); + methodHashCodes.put(method, hash); + } + + try + { + return getRef().invoke((Remote) proxyInstance, method, parameters, + hash.longValue()); + } + catch (RuntimeException exception) + { + // RuntimeException is always supported. + throw exception; + } + catch (RemoteException exception) + { + // All remote methods can throw RemoteException. + throw exception; + } + catch (Error exception) + { + throw exception; + } + catch (Exception exception) + { + Class[] exceptions = method.getExceptionTypes(); + Class exceptionClass = exception.getClass(); + + for (int i = 0; i < exceptions.length; i++) + { + if (exceptions[i].equals(exceptionClass)) + throw exception; + } + throw new UnexpectedException(method.getName(), exception); + } + } + +} |