Lift Framework example source code file (LAPinger.scala)

This example Lift Framework source code file (LAPinger.scala) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Lift Framework tags/keywords

actorpinger, boolean, long, pingerexception, pingerexception, scheduledfuture, string, string, tf, thread, thread, threadfactory, threading, threads, unit, unit

The Lift Framework LAPinger.scala source code

/*
 * Copyright 2007-2011 WorldWide Conferencing, LLC
 *
 * Licensed 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 net.liftweb
package actor

import java.util.concurrent._

/**
 * Rules for dealing with thread pools, both in lift-actor and
 * in lift-util
 */
object ThreadPoolRules {
  /**
   * When threads are created in the thread factories, should
   * they null the context class loader.  By default false,
   * but it you set it to true, Tomcat complains less about stuff.
   * Must be set in the first line of Boot.scala
   */
  @volatile var nullContextClassLoader: Boolean = false
}

/**
 * The ActorPing object schedules an actor to be ping-ed with a given message at specific intervals.
 * The schedule methods return a ScheduledFuture object which can be cancelled if necessary
 */
object LAPinger {

  /**The underlying <code>java.util.concurrent.ScheduledExecutor */
  private var service = Executors.newSingleThreadScheduledExecutor(TF)

  /**
   * Re-create the underlying <code>SingleThreadScheduledExecutor
   */
  def restart: Unit = synchronized {
    if ((service eq null) || service.isShutdown)
      service = Executors.newSingleThreadScheduledExecutor(TF)
  }

  /**
   * Shut down the underlying <code>SingleThreadScheduledExecutor
   */
  def shutdown: Unit = synchronized {
    service.shutdown
  }

  /**
   * Schedules the sending of a message to occur after the specified delay.
   *
   * @return a <code>ScheduledFuture which sends the msg to
   * the <code>to Actor after the specified TimeSpan delay.
   */
  def schedule[T](to: SpecializedLiftActor[T], msg: T, delay: Long): ScheduledFuture[Unit] = {
    val r = new Callable[Unit] {
      def call: Unit = {
        to ! msg
      }
    }
    try {
      service.schedule(r, delay, TimeUnit.MILLISECONDS)
    } catch {
      case e: RejectedExecutionException => throw PingerException(msg + " could not be scheduled on " + to, e)
    }
  }

}

/**
 * Exception thrown if a ping can't be scheduled.
 */
case class PingerException(msg: String, e: Throwable) extends RuntimeException(msg, e)

private object TF extends ThreadFactory {
  val threadFactory = Executors.defaultThreadFactory()

  def newThread(r: Runnable): Thread = {
    val d: Thread = threadFactory.newThread(r)
    d setName "ActorPinger"
    d setDaemon true
    if (ThreadPoolRules.nullContextClassLoader) {
      d setContextClassLoader null
    }
    d
  }
}