001// Copyright 2011, 2012 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.def;
016
017
018/**
019 * Starting in Tapestry 5.3, contributions could be optional.
020 *
021 * @since 5.3
022 * @see org.apache.tapestry5.ioc.annotations.Optional
023 */
024public interface ContributionDef3 extends ContributionDef2
025{
026    /** Is this contribution optional, meaning it is not an error if the service to which the contribution is targetted
027     * does not exist.
028     */
029    boolean isOptional();
030}