core/src/main/java/org/jclouds/logging/LoggingModules.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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.jclouds.logging;

import static com.google.common.collect.Iterables.find;

import java.util.NoSuchElementException;
import java.util.ServiceLoader;

import org.jclouds.logging.config.LoggingModule;
import org.jclouds.logging.jdk.config.JDKLoggingModule;

import com.google.common.base.Predicates;

/**
 * The LoggingModules class provides static methods for accessing
 * loggingModules.
 */
public class LoggingModules {

   /**
    * Returns the {@link LoggingModule}s located on the classpath via
    * {@link java.util.ServiceLoader}.
    * 
    */
   private static Iterable<LoggingModule> fromServiceLoader() {
      return ServiceLoader.load(LoggingModule.class);
   }

   /**
    * all available {@link LoggingModule}s
    */
   public static Iterable<LoggingModule> all() {
      return fromServiceLoader();
   }

   /**
    * the first available {@link LoggingModule}s from
    * {@link java.util.ServiceLoader} or {@link JDKLoggingModule}
    */
   public static LoggingModule firstOrJDKLoggingModule() {
      try {
         return find(ServiceLoader.load(LoggingModule.class),
               Predicates.not(Predicates.instanceOf(JDKLoggingModule.class)));
      } catch (NoSuchElementException e) {
         return new JDKLoggingModule();
      }
   }
}