001// Copyright 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 java.lang.annotation.Documented; 018import java.lang.annotation.Retention; 019import java.lang.annotation.Target; 020 021import static java.lang.annotation.ElementType.METHOD; 022import static java.lang.annotation.RetentionPolicy.RUNTIME; 023 024/** 025 * Marks a service contribution method within a module as being optional: it is not an error if the contribution does not match against an actual service. In that case, the 026 * method will simply never be invoked. 027 * 028 * @see Contribute 029 * @since 5.3 030 */ 031@Target(METHOD) 032@Retention(RUNTIME) 033@Documented 034@UseWith(AnnotationUseContext.MODULE) 035public @interface Optional 036{ 037}