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    }