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/* * Copyright (c) 2005, 2011, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation.  Oracle designates this * particular file as subject to the "Classpath" exception as provided * by Oracle in the LICENSE file that accompanied this code. * * This code 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 * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. */ package com.sun.script.util; import javax.script.*;import java.lang.reflect.*;import java.security.*; /* * java.lang.reflect.Proxy based interface implementor. This is meant * to be used to implement Invocable.getInterface. * * @author Mike Grogan * @since 1.6 */public class InterfaceImplementor {     private Invocable engine;     /** Creates a new instance of Invocable */    public InterfaceImplementor(Invocable engine) {        this.engine = engine;    }     private final class InterfaceImplementorInvocationHandler                        implements InvocationHandler {        private Object thiz;        private AccessControlContext accCtxt;         public InterfaceImplementorInvocationHandler(Object thiz,            AccessControlContext accCtxt) {            this.thiz = thiz;            this.accCtxt = accCtxt;        }         public Object invoke(Object proxy , Method method, Object[] args)        throws java.lang.Throwable {            // give chance to convert input args            args = convertArguments(method, args);            Object result;            final Method m = method;            final Object[] a = args;            result = AccessController.doPrivileged(new PrivilegedExceptionAction<Object>() {                public Object run() throws Exception {                    if (thiz == null) {                        return engine.invokeFunction(m.getName(), a);                    } else {                        return engine.invokeMethod(thiz, m.getName(), a);                    }                }            }, accCtxt);            // give chance to convert the method result            return convertResult(method, result);        }    }     public <T> T getInterface(Object thiz, Class<T> iface)    throws ScriptException {        if (iface == null || !iface.isInterface()) {            throw new IllegalArgumentException("interface Class expected");        }        if (! isImplemented(thiz, iface)) {            return null;        }        AccessControlContext accCtxt = AccessController.getContext();        return iface.cast(Proxy.newProxyInstance(iface.getClassLoader(),            new Class[]{iface},            new InterfaceImplementorInvocationHandler(thiz, accCtxt)));    }     protected boolean isImplemented(Object thiz, Class<?> iface) {        return true;    }     // called to convert method result after invoke    protected Object convertResult(Method method, Object res)                                   throws ScriptException {        // default is identity conversion        return res;    }     // called to convert method arguments before invoke    protected Object[] convertArguments(Method method, Object[] args)                                      throws ScriptException {        // default is identity conversion        return args;    }}