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.openecomp.core.logging.api;
23 import java.util.Iterator;
24 import java.util.ServiceLoader;
27 * Contains common functionality for factories used in the logging framework. <p>In order to use the
28 * factory, a particular (e.g. framework-specific) implementation of a service must be configured as
29 * described in <a href="http://docs.oracle.com/javase/8/docs/api/java/util/ServiceLoader.html">java.util.ServiceLoader</a>).</p>
31 * @see java.util.ServiceLoader
33 public class BaseFactory {
35 protected static <T> T locateService(Class<T> clazz) throws Exception {
38 ServiceLoader<T> loader = ServiceLoader.load(clazz);
39 Iterator<T> iterator = loader.iterator();
40 if (iterator.hasNext()) {
42 service = iterator.next();
43 if (iterator.hasNext()) {
44 System.err.println(String.format("Warning! Configured more than one implementation of %s",
51 throw new IllegalArgumentException(
52 (String.format("No implementations configured for %s", clazz.getName())));