/*

 * Copyright (c) 2019, 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.

 *

 * 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 test;

import java.lang.invoke.MethodHandle;

import java.lang.invoke.MethodHandles;

import java.lang.invoke.MethodHandles.Lookup;

import java.lang.invoke.MethodType;

import java.lang.reflect.InvocationTargetException;

import java.lang.reflect.Method;

import java.util.Comparator;

/*

 * java.util.Comparator is in java.base.  MyComparator is a Comparator

 * subclass and it's in a different module.

 *

 * Test findSpecial and unreflectSpecial with Comparator and MyComparator

 * as the special caller.

 */

public class FindSpecial {

    private static final Lookup LOOKUP = MethodHandles.lookup();

    public static void main(String... args) throws Throwable {

        findSpecialTest();

        unreflectSpecialTest();

        reflectMethodInvoke();

    }

    static void findSpecialTest() throws Throwable {

        Method m = Comparator.class.getMethod("reversed");

        MethodType mt = MethodType.methodType(m.getReturnType(), m.getParameterTypes());

        // refc and specialCaller are both in java.base

        MethodHandle mh = LOOKUP.findSpecial(Comparator.class, m.getName(), mt, Comparator.class);

        // refc in java.base, specialCaller in this module

        MethodHandle mh1 = LOOKUP.findSpecial(m.getDeclaringClass(), m.getName(), mt,

                                                MyComparator.class);

        Comparator<Object> cmp = new MyComparator();

        // invokespecial to invoke Comparator::reversed.

        Object o = mh.invoke(cmp);

        Object o1 = mh1.invoke(cmp);

    }

    static void unreflectSpecialTest() throws Throwable {

        Method m = Comparator.class.getMethod("reversed");

        // refc and specialCaller are both in java.base

        MethodHandle mh = LOOKUP.unreflectSpecial(m, Comparator.class);

        // refc in java.base, specialCaller in this module

        MethodHandle mh1 = LOOKUP.unreflectSpecial(m, MyComparator.class);

        Comparator<Object> cmp = new MyComparator();

        // invokespecial to invoke Comparator::reversed.

        Object o = mh.invoke(cmp);

        Object o1 = mh1.invoke(cmp);

    }

    static void reflectMethodInvoke() throws Throwable {

        Method m = Comparator.class.getMethod("reversed");

        try {

            // invokevirtual dispatch

            Object o = m.invoke(new MyComparator());

            throw new RuntimeException("should throw an exception");

        } catch (InvocationTargetException e) {

            if (!(e.getCause() instanceof Error &&

                  e.getCause().getMessage().equals("should not reach here"))) {

                throw e.getCause();

            }

        }

    }

    static class MyComparator implements Comparator<Object> {

        public int compare(Object o1, Object o2) {

            return 0;

        }

        @Override

        public Comparator<Object> reversed() {

            throw new Error("should not reach here");

        }

    }

}