Play Framework/Scala example source code file (HttpExecutionContext.scala)

This example Play Framework source code file (HttpExecutionContext.scala) is included in my "Source Code Warehouse" project. The intent of this project is to help you more easily find Play Framework (and Scala) source code examples by using tags.

All credit for the original source code belongs to Play Framework; I'm just trying to make examples easier to find. (For my Scala work, see my Scala examples and tutorials.)

Play Framework tags/keywords

classloader, concurrent, core, executioncontext, executioncontextexecutor, fixme, httpexecutioncontext, make, mvc, play, play framework, runnable, si-7383, throwable

The HttpExecutionContext.scala Play Framework example source code

/*
 * Copyright (C) 2009-2013 Typesafe Inc. <http://www.typesafe.com>
 */
package play.core.j

import play.mvc.Http
import scala.concurrent.{ ExecutionContext, ExecutionContextExecutor }

object HttpExecutionContext {

  /**
   * Create an HttpExecutionContext with values from the current thread.
   */
  def fromThread(delegate: ExecutionContext): ExecutionContextExecutor =
    new HttpExecutionContext(Thread.currentThread().getContextClassLoader(), Http.Context.current.get(), delegate)

  /**
   * Create an ExecutionContext that will, when prepared, be created with values from that thread.
   */
  def unprepared(delegate: ExecutionContext) = new ExecutionContext {
    def execute(runnable: Runnable) = delegate.execute(runnable) // FIXME: Make calling this an error once SI-7383 is fixed
    def reportFailure(t: Throwable) = delegate.reportFailure(t)
    override def prepare(): ExecutionContext = fromThread(delegate)
  }
}

/**
 * Manages execution to ensure that the given context ClassLoader and Http.Context are set correctly
 * in the current thread. Actual execution is performed by a delegate ExecutionContext.
 */
class HttpExecutionContext(contextClassLoader: ClassLoader, httpContext: Http.Context, delegate: ExecutionContext) extends ExecutionContextExecutor {
  def execute(runnable: Runnable) = delegate.execute(new Runnable {
    def run() {
      val thread = Thread.currentThread()
      val oldContextClassLoader = thread.getContextClassLoader()
      val oldHttpContext = Http.Context.current.get()
      thread.setContextClassLoader(contextClassLoader)
      Http.Context.current.set(httpContext)
      try {
        runnable.run()
      } finally {
        thread.setContextClassLoader(oldContextClassLoader)
        Http.Context.current.set(oldHttpContext)
      }
    }
  })
  def reportFailure(t: Throwable) = delegate.reportFailure(t)
}