ScalaEntityManager and context for higher order functions

src/main/scala/net/liftmodules/transaction/TransactionContext.scala

@@ -80,6 +80,11 @@ trait TransactionMonad {
    */
   def getEntityManager: EntityManager = TransactionContext.getEntityManager
 
+  /**
+   * Returns the current EntityManager as ScalaEntityManager.
+   */
+  def getScalaEntityManager: ScalaEntityManager = TransactionContext.getScalaEntityManager
+
   /**
    * Checks if an EntityManager exists in current context.
    */
@@ -122,6 +127,16 @@ trait TransactionMonad {
  *   query.getSingleResult
  * }
  * </pre>
+ * Example usage 3:
+ * <pre>
+ * def findUserByName(name: String) = TransactionContext.required { ctx =>
+ *   // transactional stuff
+ *   ctx.getScalaentityManager
+ *      .createQuery[User]("select u from User u where u.name = :name")
+ *      .setParams("name" -> "fred")
+ *      .findOne
+ * }
+ * </pre>
  *
  * @author <a href="http://jonasboner.com">Jonas Bon&#233;r</a>
  */
@@ -168,6 +183,16 @@ object TransactionContext extends TransactionProtocol with Loggable {
     override def filter(f: TransactionMonad => Boolean): TransactionMonad = this
   }
 
+  def required[T](body: TransactionMonad => T): T = for (ctx <- Required) yield { body(ctx) }
+
+  def requiresNew[T](body: TransactionMonad => T): T = for (ctx <- RequiresNew) yield { body(ctx) }
+
+  def supports[T](body: TransactionMonad => T): T = for (ctx <- Supports) yield { body(ctx) }
+
+  def mandatory[T](body: TransactionMonad => T): T = for (ctx <- Mandatory) yield { body(ctx) }
+
+  def never[T](body: => T): T = for (ctx <- Mandatory) yield { body }
+
   private[transaction] def setRollbackOnly = current.setRollbackOnly
 
   private[transaction] def isRollbackOnly = current.isRollbackOnly
@@ -178,6 +203,8 @@ object TransactionContext extends TransactionProtocol with Loggable {
 
   private[transaction] def getEntityManager: EntityManager = current.getEntityManager
 
+  private[transaction] def getScalaEntityManager: ScalaEntityManager = current
+
   private[transaction] def closeEntityManager = current.closeEntityManager
 
   private[this] def current = stack.value