--- a/SharedQueue.st	Wed Feb 22 15:32:46 2017 +0100
+++ b/SharedQueue.st	Wed Feb 22 15:33:50 2017 +0100
@@ -123,6 +123,22 @@
 
 !SharedQueue methodsFor:'accessing'!
 
+remove:anElement ifAbsent:exceptionalValue
+    |retVal noSuchElement|
+
+    noSuchElement := false.
+    retVal := accessLock critical:[
+        super remove:anElement ifAbsent:[noSuchElement := true]
+    ].
+    noSuchElement ifTrue:[
+        ^ exceptionalValue value.
+    ].
+    spaceAvailable signal.
+    ^ retVal.
+
+    "Created: / 22-02-2017 / 14:53:13 / stefan"
+!
+
 removeAll
     "remove all elements in the queue; do not wait, but
      synchronize access to the queue.
@@ -146,14 +162,16 @@
     |retVal noSuchElement|
 
     noSuchElement := false.
-    accessLock critical:[
-        retVal := super removeIdentical:anElement ifAbsent:[noSuchElement := true]
+    retVal := accessLock critical:[
+        super removeIdentical:anElement ifAbsent:[noSuchElement := true]
     ].
     noSuchElement ifTrue:[
         ^ exceptionalValue value.
     ].
     spaceAvailable signal.
     ^ retVal.
+
+    "Modified: / 22-02-2017 / 14:39:40 / stefan"
 !
 
 removeLast
@@ -165,12 +183,12 @@
     |retVal|
 
     dataAvailable wait.
-    accessLock critical:[
-        retVal := super removeLast.
-    ].
+    retVal := accessLock critical:[super removeLast].
     spaceAvailable signal.
 
     ^ retVal.
+
+    "Modified: / 22-02-2017 / 14:40:02 / stefan"
 ! !
 
 !SharedQueue methodsFor:'accessing-internals'!
@@ -234,32 +252,34 @@
     |retVal|
 
     dataAvailable wait.
-    accessLock critical:[
-        retVal := super nextOrNil.
-    ].
+    retVal := accessLock critical:[super nextOrNil].
     spaceAvailable signal.
 
     ^ retVal.
+
+    "Modified: / 22-02-2017 / 14:40:32 / stefan"
 !
 
-nextIfEmpty:exceptionValue
+nextIfEmpty:exceptionBlock
     "return the next value in the queue; if it its empty do not wait, but return
-     the value of exceptionValue.
+     the value of exceptionBlock.
      When a datum has been removed, signal space-availability to writers"
 
-    |retVal anyRemoved|
+    |retVal isEmpty|
 
-    accessLock critical:[
-        self isEmpty ifTrue:[
-            retVal := exceptionValue value
-        ] ifFalse:[
-            retVal := super nextOrNil.
-            anyRemoved := true.
+    retVal := accessLock critical:[
+        isEmpty := self isEmpty.
+        isEmpty ifFalse:[
+            super nextOrNil
         ].
     ].
-    anyRemoved == true ifTrue:[spaceAvailable signal].
+    isEmpty ifTrue:[
+        ^ exceptionBlock value
+    ].
+    spaceAvailable signal.
+    ^ retVal.
 
-    ^ retVal.
+    "Modified (comment): / 22-02-2017 / 15:29:30 / stefan"
 !
 
 nextOrNil
@@ -280,12 +300,12 @@
     (dataAvailable waitWithTimeout:seconds) isNil ifTrue:[
         ^ nil
     ].
-    accessLock critical:[
-        retVal := super nextOrNil.
-    ].
+    retVal := accessLock critical:[super nextOrNil].
     spaceAvailable signal.
 
     ^ retVal.
+
+    "Modified: / 22-02-2017 / 14:35:09 / stefan"
 !
 
 peek
@@ -299,21 +319,23 @@
 
 nextPut:anObject
     "enter anObject to the end of the queue; 
-     do NOT wait for available space, if the queue is full; instead resize as required. 
+     Wait for available space, if the queue is full. 
      After the put, signal availablity of a datum to readers."
 
     self commonWriteWith:[self superNextPut:anObject].
-    ^ self.
+
+    "Modified (comment): / 22-02-2017 / 15:18:36 / stefan"
 !
 
 nextPutFirst:anObject
     "insert anObject at the beginning of the queue; 
-     do NOT wait for available space, if the queue is full, instead resize as required. 
+     Wait for available space, if the queue is full. 
      After the put, signal availablity of a datum to readers.
      Insertion at the beginning may be useful to add hi-prio elements (for example, in a job-scheduler)"
 
     self commonWriteWith:[self superNextPutFirst:anObject].
-    ^ self
+
+    "Modified (comment): / 22-02-2017 / 15:18:42 / stefan"
 ! !
 
 !SharedQueue methodsFor:'enumerating'!
@@ -321,12 +343,17 @@
 do:anObject
     "evaluate the argument, aBlock for each element in the queue"
 
-    |retVal|
+    ^ accessLock critical:[super do:anObject].
+
+    "Modified: / 22-02-2017 / 14:54:45 / stefan"
+!
 
-    accessLock critical:[
-        retVal := super do:anObject.
-    ].
-    ^ retVal.
+reverseDo:anObject
+    "evaluate the argument, aBlock for each element in the queue"
+
+    ^ accessLock critical:[super reverseDo:anObject].
+
+    "Created: / 22-02-2017 / 14:54:22 / stefan"
 ! !
 
 !SharedQueue methodsFor:'initialization'!
@@ -348,7 +375,7 @@
 
 commonWriteWith:aBlock
     "common code for nextPut / nextPutFirst; 
-     do NOT wait for available space, if the queue is full; instead resize as required. 
+     wait for available space, if the queue is full. 
      After the put, signal availablity of a datum to readers."
 
     spaceAvailable wait.
@@ -356,6 +383,8 @@
         aBlock value.
         dataAvailable signal.
     ].
+
+    "Modified (comment): / 22-02-2017 / 15:18:03 / stefan"
 ! !
 
 !SharedQueue class methodsFor:'documentation'!