+/*
+ * Copyright (c) 2018. Developed by Hedgecode.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.hedgecode.chess.service;
+
+import java.util.Iterator;
+import java.util.ServiceLoader;
+
+import org.hedgecode.chess.domain.Adapter;
+import org.hedgecode.chess.domain.EtudeAdapter;
+import org.hedgecode.chess.dto.EtudeDTO;
+import org.hedgecode.chess.persistence.PersistenceManager;
+
+/**
+ * Service Provider Interface (SPI) Registry.
+ *
+ * @author Dmitry Samoshin aka gotty
+ */
+public final class ServiceRegistry {
+
+ private ServiceRegistry() {
+ }
+
+ public static <ServiceType> Iterator<ServiceType> providers(Class<ServiceType> serviceClass) {
+ final Iterator<ServiceType> providers = ServiceLoader.load(serviceClass).iterator();
+
+ if (!providers.hasNext()) {
+ throw new ServiceRegistryException("service.provider.not.found", serviceClass.getName());
+ }
+
+ return providers;
+ }
+
+ public static <ServiceType> ServiceType singleProvider(Class<ServiceType> serviceClass) {
+ final Iterator<ServiceType> providers = providers(serviceClass);
+
+ ServiceType provider = providers.next();
+ if (providers.hasNext()) {
+ throw new ServiceRegistryException("service.too.many.providers", serviceClass.getName());
+ }
+
+ return provider;
+ }
+
+ public static <AdapterType extends Adapter, TargetType> AdapterType singleAdapter(
+ Class<AdapterType> adapterClass,
+ Class<TargetType> targetClass)
+ {
+ AdapterType targetAdapter = null;
+
+ final Iterator<AdapterType> providers = providers(adapterClass);
+
+ while (providers.hasNext()) {
+ AdapterType adapter = providers.next();
+ if (adapter.getTargetClass().equals(targetClass)) {
+ if (targetAdapter != null)
+ throw new ServiceRegistryException(
+ "service.too.many.adapters", adapterClass.getName(), targetClass.getName()
+ );
+ targetAdapter = adapter;
+ }
+ }
+ if (targetAdapter == null)
+ throw new ServiceRegistryException(
+ "service.adapter.not.found", adapterClass.getName(), targetClass.getName()
+ );
+
+ return targetAdapter;
+ }
+
+
+ public static void main(String... args) {
+
+ AuthorService as = ServiceRegistry.singleProvider(AuthorService.class);
+ System.out.println(as);
+ PersistenceManager pm = ServiceRegistry.singleProvider(PersistenceManager.class);
+ System.out.println(pm);
+ EtudeAdapter ea = ServiceRegistry.singleAdapter(EtudeAdapter.class, EtudeDTO.class);
+ System.out.println(ea);
+
+ }
+
+}
git.hedgecode.org / chesshog.git / commitdiff