Re-added updated auction example.

1 files changed, 129 insertions, 0 deletions

diff --git a/docs/examples/actors/auction.scala b/docs/examples/actors/auction.scala
new file mode 100644
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+++ b/docs/examples/actors/auction.scala
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+package examples.actors
+
+import java.util.Date
+import scala.actors._
+
+/** A simple demonstrator program implementing an online auction service
+ *  The example uses the actor abstraction defined in the API of
+ *  package scala.actors.
+ */
+
+trait AuctionMessage
+case class Offer(bid: int, client: Actor) extends AuctionMessage // make a bid
+case class Inquire(client: Actor) extends AuctionMessage         // inquire status
+
+trait AuctionReply
+case class Status(asked: int, expiration: Date)           // asked sum, expiration date
+  extends AuctionReply
+case object BestOffer extends AuctionReply                // yours is the best offer
+case class BeatenOffer(maxBid: int) extends AuctionReply  // offer beaten by maxBid
+case class AuctionConcluded(seller: Actor, client: Actor) // auction concluded
+  extends AuctionReply
+case object AuctionFailed extends AuctionReply            // failed with no bids
+case object AuctionOver extends AuctionReply              // bidding is closed
+
+class Auction(seller: Actor, minBid: int, closing: Date) extends Actor {
+  val timeToShutdown = 3000 // msec
+  val bidIncrement = 10
+
+  def act() {
+    var maxBid = minBid - bidIncrement
+    var maxBidder: Actor = null
+
+    loop {
+      reactWithin (closing.getTime() - new Date().getTime()) {
+
+        case Offer(bid, client) =>
+          if (bid >= maxBid + bidIncrement) {
+            if (maxBid >= minBid)
+              maxBidder ! BeatenOffer(bid)
+            maxBid = bid
+            maxBidder = client
+            client ! BestOffer
+          }
+          else
+            client ! BeatenOffer(maxBid)
+
+        case Inquire(client) =>
+          client ! Status(maxBid, closing)
+
+        case TIMEOUT =>
+          if (maxBid >= minBid) {
+            val reply = AuctionConcluded(seller, maxBidder)
+            maxBidder ! reply
+            seller ! reply
+          } else {
+            seller ! AuctionFailed
+          }
+          reactWithin(timeToShutdown) {
+            case Offer(_, client) => client ! AuctionOver
+            case TIMEOUT => exit()
+          }
+
+      }
+    }
+  }
+}
+
+object auction {
+
+  val random = new java.util.Random()
+
+  val minBid = 100
+  val closing = new Date(new Date().getTime() + 4000)
+
+  val seller = Actor.actor { }
+  val auction = new Auction(seller, minBid, closing)
+
+  def client(i: int, increment: int, top: int) = new Actor {
+    val name = "Client " + i
+    def log(msg: String) = Console.println(name + ": " + msg)
+    var max: int = _
+    var current: int = 0
+    def act() {
+      log("started")
+      auction ! Inquire(this)
+      receive {
+        case Status(maxBid, _) =>
+          log("status(" + maxBid + ")")
+          max = maxBid
+      }
+      loop {
+        if (max >= top) {
+          log("too high for me")
+        }
+        else if (current < max) {
+          current = max + increment
+          Thread.sleep(1 + random.nextInt(1000))
+          auction ! Offer(current, this)
+        }
+
+        reactWithin(3000) {
+          case BestOffer =>
+            log("bestOffer(" + current + ")")
+
+          case BeatenOffer(maxBid) =>
+            log("beatenOffer(" + maxBid + ")")
+            max = maxBid
+
+          case AuctionConcluded(seller, maxBidder) =>
+            log("auctionConcluded"); exit()
+
+          case AuctionOver =>
+            log("auctionOver"); exit()
+
+          case TIMEOUT =>
+            exit()
+        }
+      }
+    }
+  }
+
+  def main(args: Array[String]) = {
+    seller.start()
+    auction.start()
+    client(1, 20, 200).start()
+    client(2, 10, 300).start()
+  }
+
+}