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
015package 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 */
023public 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}