    001// Copyright 2007 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.internal.services;
    016
    017import org.apache.tapestry5.annotations.Service;
    018import org.apache.tapestry5.ioc.AnnotationProvider;
    019import org.apache.tapestry5.ioc.ObjectLocator;
    020import org.apache.tapestry5.ioc.ObjectProvider;
    021
    022/**
    023 * Adds support for the {@link Service} annotation (which can be applied to fields or parameters), which is used to
    024 * disambiguate injection when multiple services implement the same service interface.
    025 */
    026public class ServiceAnnotationObjectProvider implements ObjectProvider
    027{
    028    public <T> T provide(Class<T> objectType, AnnotationProvider annotationProvider,
    029                         ObjectLocator locator)
    030    {
    031        Service annotation = annotationProvider.getAnnotation(Service.class);
    032
    033        if (annotation == null) return null;
    034
    035        return locator.getService(annotation.value(), objectType);
    036    }
    037
    038}