From aeb29ddfbb4ed2000c6e8ed2bc80619e2c157aff Mon Sep 17 00:00:00 2001
From: Philipp Haller <hallerp@gmail.com>
Date: Fri, 18 Jul 2008 16:11:46 +0000
Subject: Made mailbox in Actor protected (this is necess...

Made mailbox in Actor protected (this is necessary for JoinActor). Added
get and remove methods to MessageQueue.
---
 src/actors/scala/actors/Actor.scala        |  2 +-
 src/actors/scala/actors/MessageQueue.scala | 83 +++++++++++++++++++++++++++++-
 2 files changed, 83 insertions(+), 2 deletions(-)

(limited to 'src/actors')

diff --git a/src/actors/scala/actors/Actor.scala b/src/actors/scala/actors/Actor.scala
index a5eb0a7422..de64880847 100644
--- a/src/actors/scala/actors/Actor.scala
+++ b/src/actors/scala/actors/Actor.scala
@@ -362,7 +362,7 @@ trait Actor extends OutputChannel[Any] {
   private var waitingFor: Any => Boolean = waitingForNone
   private var isSuspended = false
 
-  private val mailbox = new MessageQueue
+  protected val mailbox = new MessageQueue
   private var sessions: List[OutputChannel[Any]] = Nil
 
   /**
diff --git a/src/actors/scala/actors/MessageQueue.scala b/src/actors/scala/actors/MessageQueue.scala
index 8f2f6c72cc..66555b3a7f 100644
--- a/src/actors/scala/actors/MessageQueue.scala
+++ b/src/actors/scala/actors/MessageQueue.scala
@@ -30,7 +30,7 @@ class MessageQueueElement {
  * library. Classes in this package are supposed to be the only
  * clients of this class.
  *
- * @version 0.9.8
+ * @version 0.9.9
  * @author Philipp Haller
  */
 @serializable
@@ -67,6 +67,87 @@ class MessageQueue {
     }
   }
 
+  def foldLeft[B](z: B)(f: (B, Any) => B): B = {
+    var acc = z
+    var curr = first
+    while (curr != null) {
+      acc = f(acc, curr.msg)
+      curr = curr.next
+    }
+    acc
+  }
+
+  /** Returns the n-th msg that satisfies the predicate
+   *  without removing it.
+   */
+  def get(n: Int)(p: Any => Boolean): Option[Any] = {
+    var pos = 0
+    val msg = if (null eq last) None
+    else {
+      // test first element
+      if (n == 0 && p(first.msg))
+        Some(first.msg)
+      else {
+        var curr = first
+        while(curr.next != null) {
+          curr = curr.next
+          if (p(curr.msg)) {
+            pos += 1
+            if (pos == n)
+              return Some(curr.msg)
+          }
+        }
+        None
+      }
+    }
+    msg
+  }
+
+  /** Removes the n-th msg that satisfies the predicate.
+   */
+  def remove(n: Int)(p: Any => Boolean): Option[(Any, OutputChannel[Any])] = {
+    var pos = 0
+    val msg = if (null eq last) None
+    else {
+      // test first element
+      if (n == 0 && p(first.msg)) {
+        val tmp = first
+        // remove first element
+        first = first.next
+
+        // might have to update last
+        if (tmp eq last) {
+          last = null
+        }
+
+        Some((tmp.msg, tmp.session))
+      } else {
+        var curr = first
+        var prev = curr
+        while(curr.next != null) {
+          prev = curr
+          curr = curr.next
+          if (p(curr.msg)) {
+            pos += 1
+            if (pos == n) {
+              // remove curr
+              prev.next = curr.next
+
+              // might have to update last
+              if (curr eq last) {
+                last = prev
+              }
+
+              return Some((curr.msg, curr.session))
+            }
+          }
+        }
+        None
+      }
+    }
+    msg
+  }
+
   def extractFirst(p: Any => Boolean): MessageQueueElement = {
     changeSize(-1) // assume size decreases by 1
 
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