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Lift Framework example source code file (KeyedCache.scala)

This example Lift Framework source code file (KeyedCache.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

box, box, empty, full, int, int, k, k, keyedcache, lru, t, t

The Lift Framework KeyedCache.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 util 

import common._


/**
 * A simple Read-through cache.
 *
 * An example of using it with a ProtoUser subclass:
 *
 * object UserCache extends KeyedCache[Long, User](100, Full(0.75f),
 *   (id: Long) => User.find(By(User.id, id)))
 *
 * @param size the size of the cache
 * @param loadFactor the optional Load Factor
 * @param cons A function that will take a value of type K and return a Box[T]
 *   populated into the cache if the return value is Full.
 *
 * @author Steve Jenson (stevej@pobox.com)
 */
class KeyedCache[K, T](size: Int, loadFactor: Box[Float], cons: K => Box[T]) {
  val cache = new LRU[K, T](size, loadFactor)

  /**
   * Evict a value from the cache.
   */
  def remove(key: K) = cache.remove(key)

  /**
   * Update the cache yourself with KeyedCache(1) = "hello"
   */
  def update(key: K, value: T) = cache.update(key, value)

  /**
   * If the cache contains a value mapped to {@code key} then return it,
   * otherwise run cons and add that value to the cache and return it.
   */
  def apply(key: K): Box[T] = if (cache.contains(key)) {
    Full(cache(key))
  } else {
    cons(key) match {
      case f@Full(v) => cache.update(key, v); f
      case _ => Empty
    }
  }
}

Other Lift Framework examples (source code examples)

Here is a short list of links related to this Lift Framework KeyedCache.scala source code file:

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