2 * ============LICENSE_START=======================================================
4 * ================================================================================
5 * Copyright (C) 2017 AT&T Intellectual Property. All rights reserved.
6 * ================================================================================
7 * Licensed under the Apache License, Version 2.0 (the "License");
8 * you may not use this file except in compliance with the License.
9 * You may obtain a copy of the License at
11 * http://www.apache.org/licenses/LICENSE-2.0
13 * Unless required by applicable law or agreed to in writing, software
14 * distributed under the License is distributed on an "AS IS" BASIS,
15 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
16 * See the License for the specific language governing permissions and
17 * limitations under the License.
18 * ============LICENSE_END=========================================================
21 package org.onap.so.client.dmaap;
23 import java.util.ServiceLoader;
25 public class DmaapPropertiesLoader {
26 /* required to make ServiceLoader thread safe */
27 private static final ThreadLocal<ServiceLoader<DmaapProperties>> services = new ThreadLocal<ServiceLoader<DmaapProperties>>() {
29 protected ServiceLoader<DmaapProperties> initialValue() {
30 return ServiceLoader.load(DmaapProperties.class);
34 private DmaapPropertiesLoader() {
37 private static class Helper {
38 private static final DmaapPropertiesLoader INSTANCE = new DmaapPropertiesLoader();
41 public static DmaapPropertiesLoader getInstance() {
42 return Helper.INSTANCE;
44 public DmaapProperties getImpl() {
45 return this.getImpl(false);
47 public DmaapProperties getNewImpl() {
48 return this.getImpl(true);
50 private DmaapProperties getImpl(boolean forceNewInstance) {
52 ServiceLoader<DmaapProperties> loader = this.services.get();
53 for (DmaapProperties service : loader) {
54 if (forceNewInstance) {
56 return service.getClass().newInstance();
57 } catch (InstantiationException | IllegalAccessException e) {
58 /* all spi implementations must provide a public
59 * no argument constructor