/* __ *\
** ________ ___ / / ___ Scala API **
** / __/ __// _ | / / / _ | (c) 2002-2008, LAMP/EPFL **
** __\ \/ /__/ __ |/ /__/ __ | http://scala-lang.org/ **
** /____/\___/_/ |_/____/_/ | | **
** |/ **
\* */
// $Id$
package scala
import scala.collection.mutable.{Map, HashMap}
/** <p>
* Defines a finite set of values specific to the enumeration. Typically
* these values enumerate all possible forms something can take and provide a
* lightweight alternative to case classes.
* </p>
* <p>
* Each call to a <code>Value</code> method adds a new unique value to the
* enumeration. To be accessible, these values are usually defined as
* <code>val</code> members of the evaluation.
* </p>
* <p>
* All values in an enumeration share a common, unique type defined as the
* <code>Value</code> type member of the enumeration (<code>Value</code>
* selected on the stable identifier path of the enumeration instance).
* </p>
* <p>
* <b>Example use</b>
* </p><pre>
* <b>object</b> Main <b>extends</b> Application {
*
* <b>object</b> WeekDay <b>extends</b> Enumeration {
* <b>type</b> WeekDay</b> = Value
* <b>val</b> Mon, Tue, Wed, Thu, Fri, Sat, Sun = Value
* }
* <b>import</b> WeekDay._
*
* <b>def</b> isWorkingDay(d: WeekDay) = ! (d == Sat || d == Sun)
*
* WeekDay filter isWorkingDay foreach println
* }</pre>
*
* @param initial The initial value from which to count the integers that
* identifies values at run-time.
* @param names The sequence of names to give to this enumeration's values.
*
* @author Matthias Zenger
* @version 1.0, 10/02/2004
*/
@serializable
@SerialVersionUID(8476000850333817230L)
abstract class Enumeration(initial: Int, names: String*) {
def this() = this(0, null)
def this(names: String*) = this(0, names: _*)
/** The name of this enumeration. */
def name = {
val cname = this.getClass().getName()
if (cname endsWith "$")
cname.substring(0, cname.length() - 1)
else if (cname endsWith "$class")
cname.substring(0, cname.length() - 6)
else
cname
}
/** The mapping from the integer used to identifying values to the actual
* values. */
private val values: Map[Int, Value] = new HashMap
/** The cache listing all values of this enumeration. */
@transient private var vcache: List[Value] = null
private def updateCache: List[Value] =
if (vcache eq null) {
vcache = values.values.toList.sort(_.id < _.id);
vcache
} else
vcache;
/** The integer to use to identify the next created value. */
protected var nextId = initial
/** The string to use to name the next created value. */
protected var nextName = names.elements
/** The highest integer amongst those used to identify values in this
* enumeration. */
private var topId = initial
/** The highest integer amongst those used to identify values in this
* enumeration. */
final def maxId = topId
/** The value in this enumeration identified by integer <code>x</code>. */
final def apply(x: Int): Value = values(x)
/** A new iterator over all values of this enumeration. */
final def elements: Iterator[Value] = updateCache.elements
/** Apply a function f to all values of this enumeration. */
def foreach(f: Value => Unit): Unit = elements foreach f
/** Apply a predicate p to all values of this enumeration and return
* true, iff the predicate yields true for all values. */
def forall(p: Value => Boolean): Boolean = elements forall p
/** Apply a predicate p to all values of this enumeration and return
* true, iff there is at least one value for which p yields true. */
def exists(p: Value => Boolean): Boolean = elements exists p
/** Returns an iterator resulting from applying the given function f to each
* value of this enumeration. */
def map[B](f: Value => B): Iterator[B] = elements map f
/** Applies the given function f to each value of this enumeration, then
* concatenates the results. */
def flatMap[B](f: Value => Iterator[B]): Iterator[B] = elements flatMap f
/** Returns all values of this enumeration that satisfy the predicate p.
* The order of values is preserved. */
def filter(p: Value => Boolean): Iterator[Value] = elements filter p
override def toString(): String = updateCache.mkString("{", ", ", "}")
/** Creates a fresh value, part of this enumeration. */
protected final def Value: Value =
new Val(nextId, if (nextName.hasNext) nextName.next else null)
/** Creates a fresh value, part of this enumeration, identified by the integer
* <code>i</code>.
*
* @param i An integer that identifies this value at run-time. It must be
* unique amongst all values of the enumeration.
* @return ..
*/
protected final def Value(i: Int): Value =
new Val(i, if (nextName.hasNext) nextName.next else null)
/** Creates a fresh value, part of this enumeration, called <code>name</code>.
*
* @param name A human-readable name for that value.
*/
protected final def Value(name: String): Value = new Val(nextId, name)
/** Creates a fresh value, part of this enumeration, called <code>name</code>
* and identified by the integer <code>i</code>.
*
* @param i An integer that identifies this value at run-time. It must be
* unique amongst all values of the enumeration.
* @param name A human-readable name for that value.
* @return ..
*/
protected final def Value(i: Int, name: String): Value = new Val(i, name)
/** The type of the enumerated values. */
@serializable
@SerialVersionUID(7091335633555234129L)
abstract class Value extends Ordered[Value] {
/** the id and bit location of this enumeration value */
def id: Int
override def compare(that: Value): Int = this.id - that.id
override def equals(other: Any): Boolean =
other match {
case that: Value => compare(that) == 0
case _ => false
}
override def hashCode: Int = id.hashCode
/** this enumeration value as an <code>Int</code> bit mask.
* @throws IllegalArgumentException if <code>id</code> is greater than 31
*/
def mask32: Int = {
if (id >= 32) throw new IllegalArgumentException
1 << id
}
/** this enumeration value as an <code>Long</code> bit mask.
* @throws IllegalArgumentException if <code>id</code> is greater than 63
*/
def mask64: Long = {
if (id >= 64) throw new IllegalArgumentException
1L << id
}
}
/** A class implementing the <a href="Enumeration.Value.html"
* target="contentFrame"><code>Value</code></a> type. This class can be
* overriden to change the enumeration's naming and integer identification
* behaviour.
*/
@serializable
@SerialVersionUID(0 - 3501153230598116017L)
protected class Val(i: Int, name: String) extends Value {
def this(i: Int) =
this(i, if (nextName.hasNext) nextName.next else i.toString())
def this(name: String) = this(nextId, name)
def this() =
this(nextId, if (nextName.hasNext) nextName.next else nextId.toString())
assert(!values.isDefinedAt(i))
values(i) = this
nextId = i + 1
if (nextId > topId) topId = nextId
def id = i
override def toString() =
if (name eq null) Enumeration.this.name + "(" + i + ")"
else name
private def readResolve(): AnyRef =
if (values ne null) values(i)
else this
}
/** A set that efficiently stores enumeration values as bits.
*
* @author Sean McDirmid
*
* @ex
*
* <pre>
* <b>object</b> flags <b>extends</b> Enumeration {
* <b>val</b> Public = Value(5, "public");
* <b>val</b> Private = Value(4, "private");
* <b>val</b> Protected = Value(6, "protected");
* <b>val</b> Final = Value(7, "final");
* }
*
* <b>class</b> Entity {
* <b>var</b> flags0 : Int = ...;
* <b>def</b> flags = flags.Set32(flags0);
* }
*
* <b>val</b> e : Entity = ...;
*
* <b>if</b> (e.flags.contains(flags.Private))
* e.flags0 = (e.flags | flags.Final).underlying;
* </pre>
*/
abstract class SetXX extends collection.immutable.Set[Value] {
/** either Int or Long */
type Underlying <: AnyVal
type TSet <: SetXX
/** The integer that bit-encodes a set of enumeration values.
*/
val underlying: Underlying
/** returns the underlying integer representation of this set as a long. */
protected def underlyingAsLong: Long
/** Equivalent to <code>++</code> for bit sets. Returns a set
* that has all values in <code>this</code> and <code>set</code>.
*/
def |(set: TSet): TSet
/** Equivalent to <code>+</code> for bit sets. Returns a set
* that has all values in <code>this</code> with the addition of <code>value</code>.
*/
def |(value: Value): TSet
/** Equivalent to <code>**</code> for bit sets.
* Returns a bit set that has all values that are both in <code>this</code> and <code>set</code>.
*/
def &(set: TSet): TSet
/** Equivalent to <code>-</code> for bit sets.
* Returns a bit set that has all values in <code>this</code> except for <code>value</code>.
*/
def &~(value: Value): TSet
def -(value: Value): TSet = this &~ value
def +(value: Value): TSet = this | value
def ++(set: TSet): TSet = this | set
def **(set: TSet): TSet = this & set
def size = {
var x = underlyingAsLong
var sz = 0
while (x != 0) {
if ((x & 1) != 0) sz += 1
x = x >> 1
}
sz
}
override def stringPrefix = Enumeration.this.name;
def elements = new Iterator[Value] {
var bit = 0
var underlying = underlyingAsLong
def hasNext = underlying != 0
private def shift = {
underlying = underlying >> 1
bit += 1
}
def next = {
if (underlying == 0) throw new NoSuchElementException
while ((underlying & 1) == 0) shift
val ret = values(bit)
shift
ret
}
}
def empty[B]: scala.collection.immutable.Set[B] = new scala.collection.immutable.HashSet[B];
}
/** An enumeration bit set that can handle enumeration values with ids up
* to 31 in an <code>Int</code>.
*/
class Set32(val underlying: Int) extends SetXX {
def this() = this(0)
type Underlying = Int
type TSet = Set32
def underlyingAsLong = {
if (underlying >= 0) underlying.toLong
else {
val underlying0 = (~(1 << 31)) & underlying
assert(underlying0 >= 0)
underlying0.toLong | (1L << 31)
}
}
def contains(value: Value) = (underlying & value.mask32) != 0
def |(set: Set32) = new Set32(underlying | set.underlying)
def |(value: Value) = new Set32(underlying | value.mask32)
def &~(value: Value) = new Set32(underlying & (~value.mask32))
def &(set: Set32) = new Set32(underlying & set.underlying)
}
/** create an empty 32 bit enumeration set */
def Set32 = new Set32
/** create a bit enumeration set according ot underlying */
def Set32(underlying: Int) = new Set32(underlying)
/** An enumeration bit set that can handle enumeration values with ids up
* to 63 in a <code>Long</code>.
*/
class Set64(val underlying: Long) extends SetXX {
def this() = this(0)
type Underlying = Long
type TSet = Set64
def underlyingAsLong = underlying
def contains(value: Value) = (underlying & value.mask64) != 0
def |(set: Set64) = new Set64(underlying | set.underlying)
def |(value: Value) = new Set64(underlying | value.mask64)
def &~(value: Value) = new Set64(underlying & (~value.mask64))
def &(set: Set64) = new Set64(underlying & set.underlying)
}
/** create an empty 64 bit enumeration set */
def Set64 = new Set64
/** create a bit enumeration set according ot underlying */
def Set64(underlying: Long) = new Set64(underlying)
/** used to reverse engineer bit locations from pre-defined bit masks */
def maskToBit(n: Long) = {
assert(n != 0)
var bit = 0
var m = n
while ((m & 1) != 1) {
m = m >> 1
bit += 1
}
assert(m == 1)
bit
}
}
