Lift Framework example source code file (SimpleList.scala)

This example Lift Framework source code file (SimpleList.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

boolean, does, does, exception, exception, int, int, javacollection, javalist, object, simplelist, simplevector, t, t, util

The Lift Framework SimpleList.scala source code

/*
 * Copyright 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 common

import java.util.{List => JavaList, Iterator => JavaIterator, ArrayList,
                ListIterator, Collection => JavaCollection}

/**
 * An immutable singly linked list that uses the Scala List class
 * as backing store, but is Java-friendly.
 */
final case class SimpleList[T](underlying: List[T]) extends JavaList[T] {

  /**
   * Construct an empty List
   */
  def this() = this(Nil)

  def this(jl: JavaList[T]) = this(jl.toArray().toList.asInstanceOf[List[T]])

  /**
   * Append an item to this list.  An O(n) operation where n is the
   * number of items in the underlying List.
   */
  def append(item: T): SimpleList[T] = SimpleList(underlying :+ item)

  /**
   * Prepends an item to this list.  O(1)
   */
  def prepend(item: T): SimpleList[T] = SimpleList(item :: underlying)

  def take(n: Int): SimpleList[T] = SimpleList(underlying.take(n))
  def drop(n: Int): SimpleList[T] = SimpleList(underlying.drop(n))
  def takeRight(n: Int): SimpleList[T] = SimpleList(underlying.takeRight(n))
  def dropRight(n: Int): SimpleList[T] = SimpleList(underlying.dropRight(n))
  def reverse(): SimpleList[T] = SimpleList(underlying.reverse)

  def headOption(): Option[T] = underlying.headOption

  def head(): T = underlying.head

  def tail(): SimpleList[T] = SimpleList(underlying.tail)

  /**
   * The size of the List
   */
  def size(): Int = underlying.length

  /**
   * Is the List Empty
   */
  def isEmpty(): Boolean = underlying.isEmpty

  /**
   * Does the List contain the element
   */
  def contains(x: Object): Boolean = underlying.contains(x)

  def iterator(): JavaIterator[T] = {
    val it = underlying.iterator
    new JavaIterator[T] {
      def hasNext() = it.hasNext
      def next(): T = it.next()
      def remove() = throw new Exception("Does not support")
    }
  }

  def subList(from: Int, to: Int): JavaList[T] = 
    SimpleList(underlying.drop(from).take(to - from))

  def listIterator(): ListIterator[T] =
    (new ArrayList(this)).listIterator()

  def listIterator(pos: Int): ListIterator[T] =
    (new ArrayList(this)).listIterator(pos)

  def indexOf(obj: Object): Int = 
    underlying.indexOf(obj)

  def lastIndexOf(obj: Object): Int = 
    underlying.lastIndexOf(obj)

  def add(x: T): Boolean = throw new Exception("Does not support")

  def add(after: Int, x: T): Unit = throw new Exception("Does not support")

  def set(after: Int, x: T): T = throw new Exception("Does not support")

  def clear(): Unit = throw new Exception("Does not support")

  def remove(pos: Int): T = throw new Exception("Does not support")

  def remove(obj: Object): Boolean = throw new Exception("Does not support")

  def get(pos: Int): T = underlying(pos)

  def toArray(): Array[Object] = {
    val len = underlying.length
    val ret = java.lang.reflect.Array.newInstance(classOf[Object], len).asInstanceOf[Array[Object]]

    var pos = 0
    var hd = underlying
    while (pos < len) {
      ret(pos) = hd.head.asInstanceOf[Object]
      hd = hd.tail
      pos += 1
    }

    ret
    }


  def toArray[X](in: Array[X with Object]): Array[X with Object] = {
    val clz = in.getClass.getComponentType() 
    val len = underlying.length
    val ret = java.lang.reflect.Array.newInstance(clz, len).asInstanceOf[Array[X with Object]]

    var pos = 0
    var hd = underlying
    while (pos < len) {
      ret(pos) = clz.cast(hd.head).asInstanceOf[X with Object]
      hd = hd.tail
      pos += 1
    }


    ret
  }

  def retainAll(jc: JavaCollection[_]): Boolean = throw new Exception("Does not support")

  def removeAll(jc: JavaCollection[_]): Boolean = throw new Exception("Does not support")

  def addAll(jc: JavaCollection[_ <: T]): Boolean = throw new Exception("Does not support")

  def addAll(index: Int, jc: JavaCollection[_ <: T]): Boolean = throw new Exception("Does not support")

  def containsAll(jc: JavaCollection[_]): Boolean = {
    val it = jc.iterator()

    import scala.annotation._

    @tailrec def check(): Boolean = it.hasNext() match {
      case false => true
      case _ => contains(it.next().asInstanceOf[Object]) match {
        case false => false
        case _ => check()
      }
    }

    check()
  }

  
}

/**
 * An immutable singly linked list that uses the Scala List class
 * as backing store, but is Java-friendly.
 */
final case class SimpleVector[T](underlying: Vector[T]) extends JavaList[T] {

  /**
   * Construct an empty List
   */
  def this() = this(Vector())

  def this(jl: JavaList[T]) = this(Vector(jl.toArray().toList.asInstanceOf[List[T]] :_*))

  /**
   * Append an item to this list.  An O(n) operation where n is the
   * number of items in the underlying List.
   */
  def append(item: T): SimpleVector[T] = SimpleVector(underlying :+ item)

  /**
   * Prepends an item to this list.  O(1)
   */
  def prepend(item: T): SimpleVector[T] = SimpleVector(item +: underlying)

  def take(n: Int): SimpleVector[T] = SimpleVector(underlying.take(n))
  def drop(n: Int): SimpleVector[T] = SimpleVector(underlying.drop(n))
  def takeRight(n: Int): SimpleVector[T] = SimpleVector(underlying.takeRight(n))
  def dropRight(n: Int): SimpleVector[T] = SimpleVector(underlying.dropRight(n))
  def reverse(): SimpleVector[T] = SimpleVector(underlying.reverse)

  def headOption(): Option[T] = underlying.headOption

  def head(): T = underlying.head

  def tail(): SimpleVector[T] = SimpleVector(underlying.tail)

  /**
   * The size of the List
   */
  def size(): Int = underlying.length

  /**
   * Is the List Empty
   */
  def isEmpty(): Boolean = underlying.isEmpty

  /**
   * Does the List contain the element
   */
  def contains(x: Object): Boolean = underlying.contains(x)

  def iterator(): JavaIterator[T] = {
    val it = underlying.iterator
    new JavaIterator[T] {
      def hasNext() = it.hasNext
      def next(): T = it.next()
      def remove() = throw new Exception("Does not support")
    }
  }

  def subList(from: Int, to: Int): JavaList[T] = 
    SimpleVector(underlying.drop(from).take(to - from))

  def listIterator(): ListIterator[T] =
    (new ArrayList(this)).listIterator()

  def listIterator(pos: Int): ListIterator[T] =
    (new ArrayList(this)).listIterator(pos)

  def indexOf(obj: Object): Int = 
    underlying.indexOf(obj)

  def lastIndexOf(obj: Object): Int = 
    underlying.lastIndexOf(obj)

  def add(x: T): Boolean = throw new Exception("Does not support")

  def add(after: Int, x: T): Unit = throw new Exception("Does not support")

  def set(after: Int, x: T): T = throw new Exception("Does not support")

  def clear(): Unit = throw new Exception("Does not support")

  def remove(pos: Int): T = throw new Exception("Does not support")

  def remove(obj: Object): Boolean = throw new Exception("Does not support")

  def get(pos: Int): T = underlying(pos)

  def toArray(): Array[Object] = {
    val len = underlying.length
    val ret = java.lang.reflect.Array.newInstance(classOf[Object], len).asInstanceOf[Array[Object]]

    var pos = 0
    underlying.foreach {
      e => 
      ret(pos) = e.asInstanceOf[Object]
      pos += 1
    }

    ret
    }


  def toArray[X](in: Array[X with Object]): Array[X with Object] = {
    val clz = in.getClass.getComponentType() 
    val len = underlying.length
    val ret = java.lang.reflect.Array.newInstance(clz, len).asInstanceOf[Array[X with Object]]

    var pos = 0
    underlying.foreach{
      e => ret(pos) = clz.cast(e).asInstanceOf[X with Object]
      pos += 1
    }

    ret
  }

  def retainAll(jc: JavaCollection[_]): Boolean = throw new Exception("Does not support")

  def removeAll(jc: JavaCollection[_]): Boolean = throw new Exception("Does not support")

  def addAll(jc: JavaCollection[_ <: T]): Boolean = throw new Exception("Does not support")

  def addAll(index: Int, jc: JavaCollection[_ <: T]): Boolean = throw new Exception("Does not support")

  def containsAll(jc: JavaCollection[_]): Boolean = {
    val it = jc.iterator()

    import scala.annotation._

    @tailrec def check(): Boolean = it.hasNext() match {
      case false => true
      case _ => contains(it.next().asInstanceOf[Object]) match {
        case false => false
        case _ => check()
      }
    }

    check()
  }

  
}

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