2 * Copyright © 2016-2017 European Support Limited
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
8 * http://www.apache.org/licenses/LICENSE-2.0
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
17 package org.openecomp.sdc.logging.api;
19 import org.openecomp.sdc.logging.spi.LoggerCreationService;
20 import org.openecomp.sdc.logging.spi.LoggingContextService;
21 import org.openecomp.sdc.logging.spi.LoggingServiceProvider;
23 import java.util.Iterator;
24 import java.util.Optional;
25 import java.util.ServiceLoader;
28 * <p>Binds to a concrete implementation of logging services.</p>
29 * <p>In order to use the factory, a particular (e.g. framework-specific) implementation of a service must be
30 * configured as described in
31 * <a href="http://docs.oracle.com/javase/8/docs/api/java/util/ServiceLoader.html">java.util.ServiceLoader</a>).</p>
38 // No advanced logging can be used here because we don't know
39 // which underlying implementation will be used
40 @SuppressWarnings({"UseOfSystemOutOrSystemErr", "squid:S106"})
43 private static final LoggingServiceProvider PROVIDER = lookupProvider();
45 private ServiceBinder() {
46 // prevent instantiation
49 private static LoggingServiceProvider lookupProvider() {
51 ServiceLoader<LoggingServiceProvider> loader = ServiceLoader.load(LoggingServiceProvider.class);
52 Iterator<LoggingServiceProvider> iterator = loader.iterator();
54 if (!iterator.hasNext()) {
55 System.err.printf("[ERROR] No provider configured for logging services %s. "
56 + "Default implementation will be used.\n", LoggingServiceProvider.class.getName());
62 LoggingServiceProvider provider = iterator.next();
63 if (!iterator.hasNext()) {
67 Logger logger = provider.getLogger(ServiceBinder.class);
68 if (logger.isWarnEnabled()) {
69 logger.warn("More than one provider for logging services {} found",
70 LoggingServiceProvider.class.getName());
75 } catch (Exception e) {
76 // don't fail if the provider cannot be instantiated
77 e.printStackTrace(System.err);
82 static Optional<LoggingContextService> getContextServiceBinding() {
83 return Optional.ofNullable(PROVIDER);
86 static Optional<LoggerCreationService> getCreationServiceBinding() {
87 return Optional.ofNullable(PROVIDER);