001// Copyright 2007, 2009, 2011 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.annotations; 016 017import org.apache.tapestry5.ioc.def.ServiceDef; 018 019import java.lang.annotation.Documented; 020import java.lang.annotation.Retention; 021import java.lang.annotation.Target; 022 023import static java.lang.annotation.ElementType.METHOD; 024import static java.lang.annotation.ElementType.TYPE; 025import static java.lang.annotation.RetentionPolicy.RUNTIME; 026 027/** 028 * Used to define one or more {@linkplain ServiceDef#getMarkers() marker annotations} for a service implementation. This 029 * allows for injection based on the combination of type and marker interface. These marker interfaces should not have 030 * any values. The mere presence of the marker annotation is all that is needed. 031 * <p/> 032 * When applied to a module class, this sets the default markers for all services within the module. Markers are 033 * additive, so a Marker annotation on the implementation class and/or specified with {@link 034 * org.apache.tapestry5.ioc.ServiceBindingOptions#withMarker(Class[])} will accumulate; a service may have any number of 035 * markers. Generally one or two is enough. 036 * 037 * @see org.apache.tapestry5.ioc.ObjectLocator#getService(Class, Class[]) 038 */ 039@Target( 040 {TYPE, METHOD}) 041@Retention(RUNTIME) 042@Documented 043@UseWith({AnnotationUseContext.SERVICE, AnnotationUseContext.MODULE}) 044public @interface Marker 045{ 046 /** 047 * The type of annotation (which will be present at the injection point). 048 */ 049 Class[] value(); 050}