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Lift Framework example source code file (BasicTypesHelpers.scala)

This example Lift Framework source code file (BasicTypesHelpers.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

a, array, b, b, boolean, boolean, box, empty, full, full, int, io, number, string, string

The Lift Framework BasicTypesHelpers.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 java.io.{InputStream, ByteArrayOutputStream, ByteArrayInputStream, Reader, File, FileInputStream, BufferedReader}
import scala.xml._
import common._

/**
 * This object adds functionality to Scala standard types.
 */
object BasicTypesHelpers extends BasicTypesHelpers with StringHelpers with ControlHelpers

/**
 * This trait adds functionality to Scala standard types
 */
trait BasicTypesHelpers { self: StringHelpers with ControlHelpers =>

  /**
   * Allows an implicit transform from a Boolean to a Boolean2, allowing expressions such as:
   * <code>(1 == 2) ? "a" | "b" (This expression will return "b")
   * @param b the predicate to be tested by the ternary operator.
   */
  implicit def boolean2(b: => Boolean) = new Boolean2(b)

  /**
   * This decorator class adds a ternary operator to a Boolean value
   * @param b the predicate to be tested by the ternary operator.
   */
  class Boolean2(b: => Boolean) {
    /**
     * Ternary operator.
     * @returns a BooleanSome containing the specified value
     * if the decorated boolean is true, or a BooleanNone otherwise.
     */
    def ? [A](first: => A): BooleanOption[A] = {
      if (b) BooleanSome(() => first)
      else BooleanNone
    }

    /**
     * Class for return values from the Boolean2 ternary operator.
     * This class provides the "|" operator that can be used to
     * specify a default value (i.e. the RHS of the "or")
     */
    sealed abstract class BooleanOption[+A] {
      def |[B >: A](default: => B): B
    }

    /**
     * The value returned by the ternary operator if the predicate is true.
     */
    case class BooleanSome[+A](x: () => A) extends BooleanOption[A] {
      def |[B >: A](default: => B): B = x()
    }

    /**
     * The value returned by the ternary operator if the predicate is false.
     */
    case object BooleanNone extends BooleanOption[Nothing] {
      def |[B](default: => B): B  = default
    }
  }

  /**
   * Compare two NodeSeq and return true if they are equal, even if
   * attribute order of Elems is different
   */
  def compareXml(left: NodeSeq, right: NodeSeq): Boolean = {
    val ls: Seq[Node] = left.toSeq
    val rs: Seq[Node] = right.toSeq
    if (ls.length == rs.length) {
     ls.zip(rs).foldLeft(true){case (b, (l, r)) => b && compareNode(l, r)}
    } else {
      false
    }
  }

  /**
   * Compare two Elems
   */
  def compareElem(left: Elem, right: Elem): Boolean =
    compareXml(left.child, right.child) &&
  left.label == right.label &&
  (((null eq left.prefix) && (null eq right.prefix)) || left.prefix == right.prefix) &&
    left.scope == right.scope &&
    compareMetaData(left.attributes.toList, right.attributes.toList)

  private def findFilter(m: MetaData, lst: List[MetaData]): Box[List[MetaData]] = {
    var found = false
    val ret = lst.filter {
      case PrefixedAttribute(pre, label, value, _) if !found =>
        m match {
          case PrefixedAttribute(p2, l2, v2, _) if p2 == pre && l2 == label && v2.text == value.text =>
            found = true
            false
          case _ => true
        }
      case UnprefixedAttribute(label, value, _) if !found =>
        m match {
          case UnprefixedAttribute(l2, v2, _) if l2 == label && v2.text == value.text =>
            found = true
            false
          case _ => true
        }
      case _ => true
    }
    if (found) Full(ret) else Empty
  }

  /**
   * Compare the metadata of two attributes
   */
    def compareMetaData(left: List[MetaData], right: List[MetaData]): Boolean =
    (left, right) match {
      case (Nil, Nil) => true
      case (_, Nil) => false
      case (Nil, _) => false
      case (attr :: rl, right) => findFilter(attr, right) match {
        case Full(rr) => compareMetaData(rl, rr)
        case _ => false
      }
      case _ => false
    }

  /**
   * Comparse two XML nodes
   */
  def compareNode(left: Node, right: Node): Boolean = {
    (left, right) match {
      case (Group(gl), Group(gr)) => compareXml(gl, gr)
      case (el: Elem, er: Elem) => compareElem(el, er)
      case (Unparsed(tl), Unparsed(tr)) => tl == tr
      case (Text(tl), Text(tr)) => tl == tr

      case (el: EntityRef, er: EntityRef) => el === er
      case (Comment(cl), Comment(cr)) => cl == cr
      case (PCData(dl), PCData(dr)) => dl == dr
      case (pl: ProcInstr, pr: ProcInstr) => pl === pr
      case (a, b) => a.toString == b.toString
    }

  }

  /**
   * Implicit transformation from a Boolean expression to an OptionalCons object so
   * that an element can be added to a list if the expression is true
   */
  implicit def toOptiCons(expr: => Boolean): OptionalCons = new OptionalCons(expr)

  /**
   * promote a partial function such that we can invoke the guard method
   * to wrap the guarded partial function with a guard
   */
  implicit def pfToGuardable[A](in: PartialFunction[A, _]):
                         PartialFunctionWrapper[A] =
                           new PartialFunctionWrapper[A](in)

  /**
   * Convert any object to an "equivalent" Boolean depending on its value
   */
  def toBoolean(in: Any): Boolean = {
    in match {
      case null => false
      case b : Boolean => b
      case i: Int => i != 0
      case lo: Long => lo != 0
      case n : Number => n.intValue != 0
      case s : String => {
        val sl = s.toLowerCase
        if (sl.length == 0) false
        else {
          if (sl.charAt(0) == 't') true
          else if (sl == "yes") true
          else toInt(s) != 0
        }
      }
      case None => false
      case Empty | Failure(_, _, _) => false
      case Full(n) => toBoolean(n)
      case Some(n) => toBoolean(n)
      case x :: xs => toBoolean(x)
      case o => toBoolean(o.toString)
    }
  }

  /**
   * A helper that will convert the String to a Boolean if it's
   * t, true, yes, 1, f, false, no, or 0
   */
  def asBoolean(in: String): Box[Boolean] = AsBoolean.unapply(in)

/**
* A helpful Boolean extractor
*/
object AsBoolean {
  def unapply(in: String): Option[Boolean] =
  if (null eq in) None else
  in.toLowerCase match {
    case "t" | "true" | "yes" | "1" => Full(true)
    case "f" | "false" | "no" | "0" => Full(false)
    case _ => None
  }
}

  /**
   * Safely convert the specified String to an Int.
   */
  def asInt(in: String): Box[Int] = tryo{in.trim.toInt}

/**
* A helpful Int extractor
*/
object AsInt {
  def unapply(in: String): Option[Int] = asInt(in)
}

  /**
   * Safely convert the specified String to an Int.
   */
  def asDouble(in: String): Box[Double] = tryo{in.trim.toDouble}

/**
* A helpful Int extractor
*/
object AsDouble {
  def unapply(in: String): Option[Double] = asDouble(in)
}

  /**
   * Safely convert the specified String to a Long.
   */
  def asLong(in: String): Box[Long] = tryo(in.toLong)


/**
* A helpful Long extractor
*/
object AsLong {
  def unapply(in: String): Option[Long] = asLong(in)
}


/**
   * Convert any object to an "equivalent" Long depending on its value
   */
  def asLong(in: Any): Box[Long] = {
    in match {
      case null => Empty
      case i: Int => Full(i.toLong)
      case n: Long => Full(n)
      case d: java.util.Date => Full(d.getTime)
      case n : Number => Full(n.longValue)
      case (n: Number) :: _ => Full(n.longValue)
      case Some(n) => asLong(n)
      case Full(n) => asLong(n)
      case None | Empty | Failure(_, _, _) => Empty
      case s: String => asLong(s)
      case x :: xs => asLong(x)
      case o => asLong(o.toString)
    }
  }

  /**
   * Convert any object to an "equivalent" Int depending on its value
   */
  def toInt(in: Any): Int = {
    in match {
      case null => 0
      case n: Int => n
      case lo: Long => lo.toInt
      case n : Number => n.intValue
      case (n: Number) :: _ => n.intValue
      case Some(n) => toInt(n)
      case Full(n) => toInt(n)
      case None | Empty | Failure(_, _, _) => 0
      case s: String => parseNumber(s).toInt
      case d: java.util.Date => (d.getTime / 1000L).toInt
      case x :: xs => toInt(x)
      case o => toInt(o.toString)
    }
  }

  /**
   * Convert any object to an "equivalent" Long depending on its value
   */
  def toLong(in: Any): Long = {
    in match {
      case null => 0L
      case i: Int => i
      case n: Long => n
      case d: java.util.Date => d.getTime
      case n : Number => n.longValue
      case (n: Number) :: _ => n.longValue
      case Some(n) => toLong(n)
      case Full(n) => toLong(n)
      case None | Empty | Failure(_, _, _) => 0L
      case s: String => parseNumber(s)
      case x :: xs => toLong(x)
      case o => toLong(o.toString)
    }
  }

  /**
   * Convert any InputStream to a ByteArrayInputStream
   */
  def toByteArrayInputStream(in: InputStream) = {
    val ba = new Array[Byte](4096)
    val bos = new ByteArrayOutputStream
    var len = 0
    while (len >= 0) {
      len = in.read(ba)
      if (len > 0) {
        bos.write(ba, 0, len)
      }
    }
    new ByteArrayInputStream(bos.toByteArray)
  }

  /**
   * Compare two arrays of Byte for byte equality.
   * @return true if two Byte arrays don't contain the same bytes
   */
  def notEq(a: Array[Byte], b: Array[Byte]) = !isEq(a,b)

  /**
   * Compare two arrays of Byte for byte equality.
   * @return true if two Byte arrays contain the same bytes
   */
  def isEq(a: Array[Byte], b: Array[Byte]) = {
    def eq(a: Array[Byte], b: Array[Byte], pos: Int, len: Int): Boolean = {
      if (pos == len) true
      else if (a(pos) != b(pos)) false
      else eq(a , b, pos + 1, len)
    }
    a.length == b.length && eq(a, b, 0, a.length)
  }
}

/**
 * Optional cons that implements the expression: <code>expr ?> value ::: List
 * @param expr the predicate to evaluate
 */
final class OptionalCons(expr: => Boolean) {
  /**
   * Return the specified value in a single-element list if the predicate
   * evaluates to true.
   */
  def ?>[T](f: => T): List[T] = if (expr) List(f) else Nil
}

/**
 * The helper class that facilitates wrapping of one PartialFunction
 * around another
 */
final class PartialFunctionWrapper[A](around: PartialFunction[A, _]) {
  /**
   * Allows you to put a guard around a partial function
   * such that the around's isDefinedMethod must return true
   * before the other's isDefinedAt method is tested
   */
  def guard[B](other: PartialFunction[A, B]): PartialFunction[A,B] =
    new PartialFunction[A, B] {
      def isDefinedAt(a: A) = around.isDefinedAt(a) && other.isDefinedAt(a)
      def apply(a: A): B = other.apply(a)
    }

}

Other Lift Framework examples (source code examples)

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