simple queue

[aaron.kempf]

i need a status box on my etl tool-- where i can 'trap' the 20 most
recent status messages.

i don't want to do a whole bunch of parsing of text; and string concat.

Dim s As New Stack()

s.Push("This")
s.Push("Is")
s.Push("How")
s.Push("Stacks")
s.Push("Work")
Console.WriteLine(s.Peek())

i saw this example; this is awfully similiar to what i want to do--
would it be crazy to make 20 different stacks

stack20->stack19->stack18->

i just dont get it; and i would LOVE a little bit of guidance.

i want to be able to push

Aaron
Matt
Ray

and then add a new member 'Jose'

which would give me

Jose
Aaron
Matt

thanks team!!

[Chris]

aa*********@gmail.com wrote:

i need a status box on my etl tool-- where i can 'trap' the 20 most
recent status messages.

i don't want to do a whole bunch of parsing of text; and string concat.

Dim s As New Stack()

s.Push("This")
s.Push("Is")
s.Push("How")
s.Push("Stacks")
s.Push("Work")
Console.WriteLine(s.Peek())

i saw this example; this is awfully similiar to what i want to do--
would it be crazy to make 20 different stacks

stack20->stack19->stack18->

i just dont get it; and i would LOVE a little bit of guidance.

i want to be able to push

Aaron
Matt
Ray

and then add a new member 'Jose'

which would give me

Jose
Aaron
Matt

thanks team!!

There is a Queue collection type that may do what you want.

Chris

[Stephany Young]

It all depends on how you want to interrogate the 'queue'.

A Stack object is LIFO (Last In - First Out) and controlling the number of
entries in the stack is not a trivial exercise. Also when you 'pop' a value
from the stack, the value is removed from the stack.

Example:

Dim _s As New Stack()

_s.Push("Status Message 1")
_s.Push("Status Message 2")
...
_s.Push("Status Message 10")

Console.WriteLine(_s.Pop())
Console.WriteLine(_s.Pop())
...
Console.WriteLine(_s.Pop())

Gives:

Status Message 10
...
Status Message 2
Status Message 1

and the stack is now empty.

A Queue object is FIFO (First In - First Out) and controlling the number of
entries in the queue is musch easier. Also when you 'dequeue' a value from
the queue, the value is removed from the stack.

Dim _q As New Queue()

_q.Enqueue("Status Message 1")
_q.Enqueue("Status Message 2")
...
_q.Enqueue("Status Message 10")

Console.WriteLine(_q.Dequeue())
Console.WriteLine(_q.Dequeue())
...
Console.WriteLine(_q.Dequeue())

Gives:

Status Message 1
Status Message 2
...
Status Message 10

and the queue is now empty.

To control the number of entries:

If _q.Count = 20 then
'Dequeue the oldest entry and dump it
_q.Dequeue()
End If

_q.Enqueue("Next Status Message")

If you want to repeatedly the most recent 20 (or up to the most recent 20
rentries), I would be inclined to simply use an ArrayList object and control
the count.

Dim _a As New Queue()

_a.Add("Status Message 1")
_a.Add("Status Message 2")
...
_a.Add("Status Message 10")

For _i = 0 to _a.Count - 1
Console.WriteLine(_a(_i))
Next

Gives:

Status Message 1
Status Message 2
...
Status Message 10

and the entries are still in the arraylist.

To control the number of entries:

If _a.Count = 20 then
'Remove the oldest entry
_a.RemoveAt(0)
End If

_a.Add("Next Status Message")

If you want to read the arraylist from most recent to oldset, simply reverse
the order of the loop:

For _i = _a.Count - 1 to 0 Step -1
Console.WriteLine(_a(_i))
Next
<aa*********@gmail.com> wrote in message
news:11*********************@j33g2000cwa.googlegro ups.com...

i need a status box on my etl tool-- where i can 'trap' the 20 most
recent status messages.

i don't want to do a whole bunch of parsing of text; and string concat.

Dim s As New Stack()

s.Push("This")
s.Push("Is")
s.Push("How")
s.Push("Stacks")
s.Push("Work")
Console.WriteLine(s.Peek())

i saw this example; this is awfully similiar to what i want to do--
would it be crazy to make 20 different stacks

stack20->stack19->stack18->

i just dont get it; and i would LOVE a little bit of guidance.

i want to be able to push

Aaron
Matt
Ray

and then add a new member 'Jose'

which would give me

Jose
Aaron
Matt

thanks team!!

[Cor Ligthert [MVP]]

Aaron,

You mean something as an Listbox or whatever in what you deleteAt index 1
forever the first row as the total amount of rows is greather than 19 and
remove at (0) and add the latest everytime at the end

http://msdn.microsoft.com/library/de...oveattopic.asp

There are more controls with which you can do this.

If it has to be a kind of array, than I would use the ArrayList. In my
opinion is the (by me very much liked) queue class not the right one for
this because it is more to take and put objects automaticly in the queue and
not to show the items of that queue.

I hope this helps,

Cor

<aa*********@gmail.com> schreef in bericht
news:11*********************@j33g2000cwa.googlegro ups.com...

i need a status box on my etl tool-- where i can 'trap' the 20 most
recent status messages.

i don't want to do a whole bunch of parsing of text; and string concat.

Dim s As New Stack()

s.Push("This")
s.Push("Is")
s.Push("How")
s.Push("Stacks")
s.Push("Work")
Console.WriteLine(s.Peek())

i saw this example; this is awfully similiar to what i want to do--
would it be crazy to make 20 different stacks

stack20->stack19->stack18->

i just dont get it; and i would LOVE a little bit of guidance.

i want to be able to push

Aaron
Matt
Ray

and then add a new member 'Jose'

which would give me

Jose
Aaron
Matt

thanks team!!

[aaron.kempf]

hey

thanks so much guys; i'm kinda new to the whole .NET world; i just CANT
BELIEVE HOW FAST THIS STUFF RUNS!!!
(i'm an olap dba who also dabbles in all this newfangled programming
stuff)

that listbox method might be EXACTLY what i was looking for; i'm going
to toy around with that.
it just seems a LOT easier (and i assume faster) that all this EnQ and
DeQ and iterating through stuff.

Thanks a lot; i am really going to dive into this tonight on the bus

my current, functional version.
It works pretty well; i can just tell it's running a little bit slower
than i want.
Should i just change the AppendText method to a stringbuilder??

Or is a listbox.objectcollection.removeAt going to be faster and
simpler??

Dim Q As New Queue(Of String)
Public Sub WriteStatus(ByVal strStatus As String)
Dim strWaste As String
Dim I As Int16

Q.Enqueue(strStatus)
If Q.Count > 15 Then
strWaste = Q.Dequeue()
End If

Me.txtStatus.Clear()
I = 0

For Each strMessage As String In Q
Select Case I
Case 0
txtStatus.AppendText(strMessage)
Case Else
txtStatus.AppendText(vbCrLf & strMessage)
End Select
I = +1
Next
End Sub