Lift Framework example source code file (RequestVarEM.scala)

This example Lift Framework source code file (RequestVarEM.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

entitymanager, requestvarem, requestvarem, scalaemfactory, scalaemfactory, scalaentitymanager, scalaentitymanager, transientrequestvar, transientrequestvar

The Lift Framework RequestVarEM.scala source code

/*
 * Copyright 2006-2011 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 jpa

import javax.persistence.EntityManager

import net.liftweb.http.TransientRequestVar

import org.scala_libs.jpa.{ScalaEMFactory, ScalaEntityManager}

/**
 * This trait provides specific functionality for the Lift web framework
 * by using a Lift <code>RequestVar to hold the underlying EM. This
 * allows you to use a singleton for EM access. You must mix in some
 * other class to provide the actual ScalaEMFactory functionality.
 * Example usage would be:
 *
 * <p>
 * <code>
 * object Model extends LocalEMF("test") with RequestVarEM
 * </code>
 * </p>
 *
 * @author Derek Chen-Becker
 */
trait RequestVarEM extends ScalaEntityManager with ScalaEMFactory {
  /**
   * Provides the request var that holds the underlying <code>EntityManager
   * for each request.
   */
  object emVar extends TransientRequestVar[EntityManager](openEM()) {
    this.registerGlobalCleanupFunc(ignore => closeEM(this.is))

    override def __nameSalt = net.liftweb.util.Helpers.randomString(10)
  }

  // Must be provided to properly implement ScalaEntityManager
  protected def em = emVar.is
  val factory = this

  /**
   * Returns the current underlying <code>EntityManager. Generally
   * you shouldn't need to do this unless you're using some very
   * advanced or propietary functionality on the EM.
   *
   * @return The underlying EM
   */
  def getUnderlying : EntityManager = em
}