    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}