Lift Framework example source code file (HasManyThrough.scala)

This example Lift Framework source code file (HasManyThrough.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

empty, from, from, hashset, list, mappedfield, mapper, metamapper, nil, nil, seq, seq, through, through

The Lift Framework HasManyThrough.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 mapper

import collection.mutable.HashSet
import util.FatLazy
import common._

class HasManyThrough[From <: KeyedMapper[ThroughType, From],
                     To <: Mapper[To],
                     Through <: Mapper[Through],
                     ThroughType <: Any](
                      owner: From,
                      otherSingleton: MetaMapper[To],
                      through: MetaMapper[Through],
                      throughFromField: MappedField[ThroughType, Through],
                      throughToField: MappedField[ThroughType, Through])
  extends LifecycleCallbacks {
  private var theSetList: Seq[ThroughType] = Nil

  private val others = FatLazy[List[To]] {
    DB.use(owner.connectionIdentifier) { conn =>
      val query = "SELECT DISTINCT "+otherSingleton._dbTableNameLC+".* FROM "+otherSingleton._dbTableNameLC+","+
      through._dbTableNameLC+" WHERE "+
      otherSingleton._dbTableNameLC+"."+otherSingleton.indexedField(otherSingleton.asInstanceOf[To]).open_!._dbColumnNameLC+" = "+
      through._dbTableNameLC+"."+throughToField._dbColumnNameLC+" AND "+
      through._dbTableNameLC+"."+throughFromField._dbColumnNameLC+" = ?"
      DB.prepareStatement(query, conn) { st =>
        owner.getSingleton.indexedField(owner).map { indVal =>
          if (indVal.dbIgnoreSQLType_?)
            st.setObject(1, indVal.jdbcFriendly)
          else
            st.setObject(1, indVal.jdbcFriendly, indVal.targetSQLType)

          DB.exec(st) { rs =>
            otherSingleton.createInstances(owner.connectionIdentifier, rs, Empty, Empty)
          }
        } openOr Nil
      }
    }
  }

  def apply(): List[To] = others.get

  def get: List[To] = this()

  def reset = others.reset

  def set(what: Seq[ThroughType]): Seq[ThroughType] = {
    theSetList = what
    theSetList
  }

  override def beforeDelete {
    through.findAll(By(throughFromField, owner.primaryKeyField)).foreach {
      toDelete => toDelete.delete_!
    }
  }

  override def afterUpdate {
    val current = through.findAll(By(throughFromField,owner.primaryKeyField))

    val newKeys = new HashSet[ThroughType];

    theSetList.foreach(i => newKeys += i)
    val toDelete = current.filter(c => !newKeys.contains(throughToField.actualField(c).is))
    toDelete.foreach(_.delete_!)

    val oldKeys = new HashSet[ThroughType];
    current.foreach(i => oldKeys += throughToField.actualField(i))

    theSetList.toList.distinct.filter(i => !oldKeys.contains(i)).foreach { i =>
      val toCreate = through.createInstance
      throughFromField.actualField(toCreate).set(owner.primaryKeyField)
      throughToField.actualField(toCreate).set(i)
      toCreate.save
    }

    theSetList = Nil
    others.reset
    super.afterUpdate
  }

  override def afterCreate {
    theSetList.toList.distinct.foreach { i =>
      val toCreate = through.createInstance
      throughFromField.actualField(toCreate)(owner.primaryKeyField)
      throughToField.actualField(toCreate)(i)
      toCreate.save
    }
    theSetList = Nil
    others.reset
    super.afterCreate
  }
}