Lift Framework example source code file (Currency.scala)

This example Lift Framework source code file (Currency.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

any, box, currency, currency, currencymismatchexception, currencymismatchexception, empty, exception, int, int, list, long, string, string

The Lift Framework Currency.scala source code

/*
 * Copyright 2007-2011 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 Helpers._
import common._

/**
 * A simple fixed-point currency representation
 */
class Currency(val amount: Long, val symbol: String, val decimals: Int) {
  override def toString = {
    if (decimals == 0) symbol+amount
    else {
      val d = amount.toDouble
      val pow = math.pow(10, decimals)
      symbol+(d / pow)
    }
  }

  /**
   * Return a string formatted as the URL-encoded symbol followed
   * by the amount and decimals delimited by the "&" symbol.
   */
  def forDB: String = Helpers.urlEncode(symbol)+"&"+amount+"&"+decimals

  /**
   * Determines whether two currencies are equal with respect to
   * symbol, amount, and decimal value.
   */
  override def equals(other: Any) = other match {
    case c: Currency => c.amount == amount && c.symbol == symbol && c.decimals == decimals
    case _ => false
  }

  /**
   * Addition on Currency objects. This compares currency symbols to prevent
   * addition of different types of currency to one another.
   * @throws CurrencyMismatchException for mismatched currency types.
   */
  def +(other: Currency): Currency =
  if (symbol != other.symbol || decimals != other.decimals) throw new CurrencyMismatchException
  else new Currency(amount + other.amount, symbol, decimals)

  /**
   * Subtraction on Currency objects. This compares currency symbols to prevent
   * subtraction of different types of currency from one another.
   * @throws CurrencyMismatchException for mismatched currency types.
   */
  def -(other: Currency): Currency =
  if (symbol != other.symbol || decimals != other.decimals) throw new CurrencyMismatchException
  else new Currency(amount - other.amount, symbol, decimals)
}

/**
 * This exception is thrown if an operation is attempted on two currency values
 * where currency symbols do not match.
 */
class CurrencyMismatchException extends Exception

object Currency {
  /**
   * Parse a currency from the format specified by Currency.forDB
   */
  def apply(s: String): Box[Currency] = s.roboSplit("&") match {
    case List(cur, a, d) => for (av <- asLong(a); dv <- asInt(d)) yield new Currency(av, urlDecode(cur), dv)
    case _ => Empty
  }
}