    001    // Copyright 2006, 2009 The Apache Software Foundation
    002    //
    003    // Licensed under the Apache License, Version 2.0 (the "License");
    004    // you may not use this file except in compliance with the License.
    005    // You may obtain a copy of the License at
    006    //
    007    //     http://www.apache.org/licenses/LICENSE-2.0
    008    //
    009    // Unless required by applicable law or agreed to in writing, software
    010    // distributed under the License is distributed on an "AS IS" BASIS,
    011    // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    012    // See the License for the specific language governing permissions and
    013    // limitations under the License.
    014
    015    package org.apache.tapestry5.ioc;
    016
    017    /**
    018     * A service decorator is derived from a {@link org.apache.tapestry5.ioc.def.DecoratorDef} and is responsible for
    019     * building an interceptor around an existing implementation (called the "delegate").
    020     *
    021     * @see org.apache.tapestry5.ioc.ServiceAdvisor
    022     */
    023    public interface ServiceDecorator
    024    {
    025        /**
    026         * Creates a new interceptor object implementing the same service interface as the delegate object.
    027         *
    028         * @param delegate an existing object implementing the service interface.
    029         * @return a new object implementing the same service interface, or delegate or null if the decorator chooses not to
    030         *         create a new interceptor.
    031         */
    032        Object createInterceptor(Object delegate);
    033    }