001// Copyright 2004, 2005 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.hivemind;
016
017import java.util.List;
018
019import org.apache.hivemind.internal.Module;
020
021/**
022 * Interface defining an interceptor factory, an object that can create
023 * an interceptor.  Interceptors are objects that implement a particular
024 * interface, adding logic before or after invoking methods on a wrapped
025 * object (implementing the same instance).
026 * 
027 * <p>
028 * Implementations must be stateless and multi-threaded. 
029 * An interceptor may only be applied once to any single service.
030 * The factory will only be invoked once for any single service (even in the case
031 * of non-standard service models such as threaded and pooled).
032 *
033 * @author Howard Lewis Ship
034 */
035public interface ServiceInterceptorFactory
036{
037    /**
038      * Creates an interceptor and pushes it onto the interceptor stack.
039      */
040    public void createInterceptor(InterceptorStack stack, Module invokingModule, List parameters);
041}