B4J Question Map Bug or WAI?

[cyiwin]

I ran into a little problem transferring and clearing Maps. Maybe I'm doing it wrong, here is the code:

Sub Process_Globals
    Private fx As JFX
    Private MainForm As Form
    Dim Map_A, Map_B As Map
End Sub

Sub AppStart (Form1 As Form, Args() As String)
    MainForm = Form1
    'MainForm.RootPane.LoadLayout("Layout1") 'Load the layout file.
    MainForm.Show
   
    Map_A.Initialize
    Map_B.Initialize
   
    For i = 0 To 99
        Map_A.Put(i, Rnd(0,1000))
    Next
   
    Map_B = Map_A               'Works
    Log(Map_B)
    Map_A.Clear                 'Why does this clear Map_A and Map_B ?
    Log(Map_B)
End Sub

Why would both maps clear? Is there a better way to write Map_B = Map_A?

 

[thedesolatesoul]

This is indeed a major bug...in your code.

Map_B = Map_A makes both maps point to one object.

You need top copy/clone Map_A into Map_B item by item.

 

[cyiwin]

Thanks for the info. I need to learn more about objects...

 

[Erel]

You can use this code to create a copy:

Sub CopyMap(original As Map) As Map
   Dim m As Map
   m.Initialize
   For Each k As Object In original.Keys
     m.Put(k, original.Get(k))
   Next
   Return m
End Sub