# CompositeMethodInstance.java

    /*
     * Copyright (c) 2008, Rickard Öberg. All Rights Reserved.
     *
     * Licensed under the Apache License, Version 2.0 (the "License");
     * you may not use this file except in compliance with the License.
     * You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0
     * Unless required by applicable law or agreed to in writing, software
     * distributed under the License is distributed on an "AS IS" BASIS,
     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     * See the License for the specific language governing permissions and
     * limitations under the License.
     *
     */

    package org.qi4j.runtime.composite;

    import java.lang.reflect.InvocationHandler;
    import java.lang.reflect.Method;

    /**
     * JAVADOC
     */
    public final class CompositeMethodInstance
    {
        private final InvocationHandler invoker;
        private final FragmentInvocationHandler mixinInvoker;
        private final Method method;
        private final int methodIdx;

        private CompositeMethodInstance next;

        public CompositeMethodInstance( InvocationHandler invoker,
                                        FragmentInvocationHandler mixinInvoker,
                                        Method method, int methodIdx
        )
        {
            this.invoker = invoker;
            this.method = method;
            this.mixinInvoker = mixinInvoker;
            this.methodIdx = methodIdx;
        }

        public Method method()
        {
            return method;
        }

        public Object getMixinFrom( Object[] mixins )
        {
            return mixins[ methodIdx ];
        }

        public Object invoke( Object composite, Object[] params, Object mixin )
            throws Throwable
        {
            mixinInvoker.setFragment( mixin );

            try
            {
                return invoker.invoke( composite, method, params );
            }
            finally
            {
                mixinInvoker.setFragment( null );
            }
        }

        public CompositeMethodInstance getNext()
        {
            return next;
        }

        public void setNext( CompositeMethodInstance next )
        {
            this.next = next;
        }
    }