/*

 * Copyright (c) 2010, 2013, 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.

 */

/*

 * This file is available under and governed by the GNU General Public

 * License version 2 only, as published by the Free Software Foundation.

 * However, the following notice accompanied the original version of this

 * file, and Oracle licenses the original version of this file under the BSD

 * license:

 */

/*

   Copyright 2009-2013 Attila Szegedi

*/

package jdk.dynalink.beans;

import java.lang.invoke.MethodHandle;

import java.lang.invoke.MethodHandles;

import jdk.dynalink.CallSiteDescriptor;

import jdk.dynalink.NamedOperation;

import jdk.dynalink.Operation;

import jdk.dynalink.StandardNamespace;

import jdk.dynalink.StandardOperation;

import jdk.dynalink.linker.GuardedInvocation;

import jdk.dynalink.linker.LinkRequest;

import jdk.dynalink.linker.LinkerServices;

import jdk.dynalink.linker.TypeBasedGuardingDynamicLinker;

import jdk.dynalink.linker.support.Guards;

/**

 * Simple linker that implements the {@link StandardOperation#CALL} operation

 * for {@link DynamicMethod} objects - the objects returned by

 * {@link StandardOperation#GET} on {@link StandardNamespace#METHOD} namespace through

 * {@link AbstractJavaLinker}.

 */

class DynamicMethodLinker implements TypeBasedGuardingDynamicLinker {

    @Override

    public boolean canLinkType(final Class<?> type) {

        return DynamicMethod.class.isAssignableFrom(type);

    }

    @Override

    public GuardedInvocation getGuardedInvocation(final LinkRequest linkRequest, final LinkerServices linkerServices) {

        final Object receiver = linkRequest.getReceiver();

        if(!(receiver instanceof DynamicMethod)) {

            return null;

        }

        final DynamicMethod dynMethod = (DynamicMethod)receiver;

        final boolean constructor = dynMethod.isConstructor();

        final MethodHandle invocation;

        final CallSiteDescriptor desc = linkRequest.getCallSiteDescriptor();

        final Operation op = NamedOperation.getBaseOperation(desc.getOperation());

        if (op == StandardOperation.CALL && !constructor) {

            invocation = dynMethod.getInvocation(desc.changeMethodType(

                    desc.getMethodType().dropParameterTypes(0, 1)), linkerServices);

        } else if (op == StandardOperation.NEW && constructor) {

            final MethodHandle ctorInvocation = dynMethod.getInvocation(desc, linkerServices);

            if(ctorInvocation == null) {

                return null;

            }

            // Insert null for StaticClass parameter

            invocation = MethodHandles.insertArguments(ctorInvocation, 0, (Object)null);

        } else {

            return null;

        }

        if (invocation != null) {

            return new GuardedInvocation(MethodHandles.dropArguments(invocation, 0,

                desc.getMethodType().parameterType(0)), Guards.getIdentityGuard(receiver));

        }

        return null;

    }

}