    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
    015    package org.apache.tapestry5.internal.services;
    016
    017    import org.apache.tapestry5.annotations.Service;
    018    import org.apache.tapestry5.ioc.AnnotationProvider;
    019    import org.apache.tapestry5.ioc.ObjectLocator;
    020    import 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     */
    026    public 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    }