001/*
002 * Copyright 2002-2007 the original author or authors.
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 *      https://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 */
016
017package org.springframework.beans.factory.serviceloader;
018
019import java.util.Iterator;
020import java.util.ServiceLoader;
021
022import org.springframework.beans.factory.BeanClassLoaderAware;
023import org.springframework.lang.Nullable;
024
025/**
026 * {@link org.springframework.beans.factory.FactoryBean} that exposes the
027 * 'primary' service for the configured service class, obtained through
028 * the JDK 1.6 {@link java.util.ServiceLoader} facility.
029 *
030 * @author Juergen Hoeller
031 * @since 2.5
032 * @see java.util.ServiceLoader
033 */
034public class ServiceFactoryBean extends AbstractServiceLoaderBasedFactoryBean implements BeanClassLoaderAware {
035
036        @Override
037        protected Object getObjectToExpose(ServiceLoader<?> serviceLoader) {
038                Iterator<?> it = serviceLoader.iterator();
039                if (!it.hasNext()) {
040                        throw new IllegalStateException(
041                                        "ServiceLoader could not find service for type [" + getServiceType() + "]");
042                }
043                return it.next();
044        }
045
046        @Override
047        @Nullable
048        public Class<?> getObjectType() {
049                return getServiceType();
050        }
051
052}