package io.ebeaninternal.server.lib;


import java.util.concurrent.ThreadFactory;
import java.util.concurrent.atomic.AtomicInteger;

ThreadFactory for Daemon threads.

Daemon threads do not stop a JVM stopping. If an application only has Daemon
threads left it will shutdown.


In using Daemon threads you need to either not care about being interrupted
on shutdown or register with the JVM shutdown hook to perform a nice shutdown
of the daemon threads etc.

Author:
rbygrave/**
 * ThreadFactory for Daemon threads.
 * <p>
 * Daemon threads do not stop a JVM stopping. If an application only has Daemon
 * threads left it will shutdown.
 * </p>
 * <p>
 * In using Daemon threads you need to either not care about being interrupted
 * on shutdown or register with the JVM shutdown hook to perform a nice shutdown
 * of the daemon threads etc.
 * </p>
 *
 * @author rbygrave
 */
public class DaemonThreadFactory implements ThreadFactory {

  private static final AtomicInteger poolNumber = new AtomicInteger(1);

  private final ThreadGroup group;

  private final AtomicInteger threadNumber = new AtomicInteger(1);

  private final String namePrefix;

  public DaemonThreadFactory(String namePrefix) {
    SecurityManager s = System.getSecurityManager();
    this.group = (s != null) ? s.getThreadGroup() : Thread.currentThread().getThreadGroup();
    this.namePrefix = namePrefix != null ? namePrefix : "pool-" + poolNumber.getAndIncrement() + "-thread-";
  }

  @Override
  public Thread newThread(Runnable r) {

    Thread t = new Thread(group, r, namePrefix + threadNumber.getAndIncrement(), 0);

    t.setDaemon(true);

    if (t.getPriority() != Thread.NORM_PRIORITY) {
      t.setPriority(Thread.NORM_PRIORITY);
    }

    return t;
  }
}