/*
    * 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.apache.logging.log4j.core.util;
  
  import java.util.concurrent.ThreadFactory;
  import java.util.concurrent.atomic.AtomicInteger;
  
  /**
   * Creates {@link Log4jThread}s.
   * 
   * @since 2.7
   */
  public class Log4jThreadFactory implements ThreadFactory {
  
      private static final String PREFIX = "TF-";
  
      /**
       * Creates a new daemon thread factory.
       * 
       * @param threadFactoryName
       *            The thread factory name.
       * @return a new daemon thread factory.
       */
      public static Log4jThreadFactory createDaemonThreadFactory(final String threadFactoryName) {
          return new Log4jThreadFactory(threadFactoryName, true, Thread.NORM_PRIORITY);
      }
  
      /**
       * Creates a new thread factory.
       * 
       * @param threadFactoryName
       *            The thread factory name.
       * @return a new daemon thread factory.
       */
      public static Log4jThreadFactory createThreadFactory(final String threadFactoryName) {
          return new Log4jThreadFactory(threadFactoryName, false, Thread.NORM_PRIORITY);
      }
  
      private static final AtomicInteger FACTORY_NUMBER = new AtomicInteger(1);
      private static final AtomicInteger THREAD_NUMBER = new AtomicInteger(1);
      private final boolean daemon;
      private final ThreadGroup group;
      private final int priority;
      private final String threadNamePrefix;
  
      /**
       * Constructs an initialized thread factory.
       * 
       * @param threadFactoryName
       *            The thread factory name.
       * @param daemon
       *            Whether to create daemon threads.
       * @param priority
       *            The thread priority.
       */
      public Log4jThreadFactory(final String threadFactoryName, final boolean daemon, final int priority) {
          this.threadNamePrefix = PREFIX + FACTORY_NUMBER.getAndIncrement() + "-" + threadFactoryName + "-";
          this.daemon = daemon;
          this.priority = priority;
          final SecurityManager securityManager = System.getSecurityManager();
          this.group = securityManager != null ? securityManager.getThreadGroup()
                  : Thread.currentThread().getThreadGroup();
      }
  
      @Override
      public Thread newThread(final Runnable runnable) {
          // Log4jThread prefixes names with "Log4j2-".
          final Thread thread = new Log4jThread(group, runnable, threadNamePrefix + THREAD_NUMBER.getAndIncrement(), 0);
          if (thread.isDaemon() != daemon) {
              thread.setDaemon(daemon);
          }
          if (thread.getPriority() != priority) {
              thread.setPriority(priority);
          }
          return thread;
      }
  
  }