OOP design question

jaberwacky · May 8, 2010

First I'd like to say that I am not a c++ geek.

HI!

My question is this, if my program has two objects that use the same data then what should I do?

Say object1 one uses $variable0 and object2 uses $variable0 also. Should I declare $variable0 as global? But wouldn't that defeat the purpose of OOP? Or should I pass that variable to each object? But wouldn't that violate the DRY principle?

Hopelessly confused,

Matt

Hmmm, maybe that data should be public data so that any object can use it?

I've read that you should avoid getter and setter functions though.

Edited May 8, 2010 by jaberwocky6669

Richard Robertson · May 8, 2010

Declaring globally versus copy per instance depends on the context of the data. What kind of data is it?

jaberwacky · May 8, 2010

You know what, I need to take more time to study independantly. I appreciate it though. Thank you.

jaberwacky · May 8, 2010

Well, ok, lemme see, I'm making a program that takes a number of images; shrinks them all to the height of the shortest image; appends those into a panorama; and then shrinks the width of the panorama to 715px. I realize now that I should have an image object whose properties are height and width, I think. So:

Object:

Image

Properties:

Width

Height

Directory Location

Image Name

Format

Method(s):

Shrink Width

Shrink Height

Note: I'm trying to learn how to use autoitobject btw

Here is what I have so far...

Will someone be so kind to take a look and see if I am on the right track?

Func ImageObject()
    Local $self = _AutoItObject_Create()
    _AutoItObject_AddMethod($self, "Height", "_SetHeight")
    _AutoItObject_AddMethod($self, "Width", "_SetHeight")
    _AutoItObject_AddMethod($self, "Format", "_SetFormat")
    _AutoItObject_AddMethod($self, "Name", "_SetName")
    _AutoItObject_AddMethod($self, "Directory", "_SetDirectory")
    _AutoItObject_AddProperty($self, "Height", $ELSCOPE_PRIVATE)
    _AutoItObject_AddProperty($self, "Width", $ELSCOPE_PRIVATE)
    _AutoItObject_AddProperty($self, "Format", $ELSCOPE_PRIVATE)
    _AutoItObject_AddProperty($self, "Name", $ELSCOPE_PRIVATE)
    _AutoItObject_AddProperty($self, "Directory", $ELSCOPE_PRIVATE)
EndFunc

Edited May 8, 2010 by jaberwocky6669

Kip · May 8, 2010

Func ImageObject()
    Local $self = _AutoItObject_Create()
    _AutoItObject_AddMethod($self, "Height", "_SetHeight")
    _AutoItObject_AddMethod($self, "Width", "_SetHeight")
    _AutoItObject_AddMethod($self, "Format", "_SetFormat")
    _AutoItObject_AddMethod($self, "Name", "_SetName")
    _AutoItObject_AddMethod($self, "Directory", "_SetDirectory")
    _AutoItObject_AddProperty($self, "Height", $ELSCOPE_PRIVATE)
    _AutoItObject_AddProperty($self, "Width", $ELSCOPE_PRIVATE)
    _AutoItObject_AddProperty($self, "Format", $ELSCOPE_PRIVATE)
    _AutoItObject_AddProperty($self, "Name", $ELSCOPE_PRIVATE)
    _AutoItObject_AddProperty($self, "Directory", $ELSCOPE_PRIVATE)
EndFunc

This way you'll add every member twice to the object: once as a method, and once as a property.

You'd probably want to do something like this:

_AutoItObject_AddMethod($self, "Height", "_SetHeight", $ELSCOPE_PRIVATE)
_AutoItObject_AddMethod($self, "Width", "_SetHeight", $ELSCOPE_PRIVATE)
....

Edited May 8, 2010 by Kip

jaberwacky · May 8, 2010

Im beginning to think that maybe an image object isn't the way to go either. I might stick with procedural programming for now I guess...

Yoriz · May 9, 2010

Dont give up its fun to play with, if your design isnt quite right yet but you can get the desired result does it really matter while your trying to grasp the concept of it.

I've never used oop before this udf was made so i cant claim that this is 'the' way to do it, this is how i would approach it with the knowledge ive gained of it so far, im sure some one can look over it and improve on it.

#include <AutoItObject.au3>
_AutoItObject_Startup()

Global $oError = ObjEvent("Autoit.Error", "_myErrFunc")
Func _ErrFunc()
    ConsoleWrite("! COM Error ! Number: 0x" & Hex($oError.number, 8) & " ScriptLine: " & $oError.scriptline & " - " & $oError.windescription & @CRLF)
EndFunc ;==>_ErrFunc

$oPanorama = _oPanorama("My New Panorama")
$oPanorama.AddImage("GoodPic")
$oPanorama.AddImage("BadPic")
$oPanorama.AddImage("UglyPic")
$oPanorama.Create

#region _oPanorama
Func _oPanorama($hFileName)
    local $oSelf = _AutoItObject_Create()
    ; _oPanorama Property
    _AutoItObject_AddProperty($oSelf, "FileName", $ELSCOPE_PRIVATE, $hFileName)
    _AutoItObject_AddProperty($oSelf, "ImgCount", $ELSCOPE_PRIVATE, 0)
    _AutoItObject_AddProperty($oSelf, "MinHeight", $ELSCOPE_PRIVATE, 0)
    ; _oPanorama Method
    _AutoItObject_AddMethod($oSelf, "AddImage", "_oPanorama_AddImage")
    _AutoItObject_AddMethod($oSelf, "Create", "_oPanorama_Create")
    Return $oSelf
EndFunc
;_oPanorama Methods
Func _oPanorama_AddImage($oSelf, $hFileName)
    Local $iMinHeight
    $oSelf.ImgCount = $oSelf.ImgCount + 1
    _AutoItObject_AddProperty($oSelf, "Image" & $oSelf.ImgCount, $ELSCOPE_PRIVATE, _oImage($hFileName))
    $iMinHeight = Execute("$oSelf.Image" & $oSelf.ImgCount & ".Height")
    Select
        Case $oSelf.MinHeight > $iMinHeight
            $oSelf.MinHeight = $iMinHeight
        Case $oSelf.MinHeight = 0
            $oSelf.MinHeight = $iMinHeight
        Case Else
            Return $oSelf
    EndSelect
    ConsoleWrite("new smallest height of " & $oSelf.MinHeight & " Found for Image" & $oSelf.ImgCount & " FileName = " & $hFileName & @CR)
    Return $oSelf
EndFunc

Func _oPanorama_Create($oSelf)
    Local $vJoinedImg, $hFileName
    For $i = 1 To $oSelf.ImgCount Step 1
        Execute("$oSelf.Image" & $i & ".ReSize(" & $oSelf.MinHeight & ")")
        $hFileName = Execute("$oSelf.Image" & $i & ".FileName")
        $vJoinedImg &= "|" & $hFileName
    Next
    $vJoinedImg &= "|"
    ; do some resizing
    ConsoleWrite(@CR & "Save image as " & $oSelf.FileName & " = " & $vJoinedImg & @CR)
EndFunc
#endregion _oPanorama

#region _oImage
Func _oImage($hFileName)
    local $oSelf = _AutoItObject_Create()
    ; _oImage Property
    _AutoItObject_AddProperty($oSelf, "FileName", $ELSCOPE_READONLY, $hFileName)
    _AutoItObject_AddProperty($oSelf, "Height", $ELSCOPE_READONLY, 0)
    _AutoItObject_AddProperty($oSelf, "Width", $ELSCOPE_READONLY, 0)
    ; _oImage Method
    _AutoItObject_AddMethod($oSelf, "GetSize", "_oImage_GetSize")
    _AutoItObject_AddMethod($oSelf, "ReSize", "_oImage_ReSize")
    ; _oImage Contructor
    $oSelf.GetSize
    Return $oSelf
EndFunc
; _oImage Methods
Func _oImage_GetSize($oSelf)
    ; this would contain code that uses $oSelf.FileName to obtain and set $oSelf.Height & $oSelf.Width
    $oSelf.Height = Random(25, 100, 1) ; just to guess a size for example purpose
    $oSelf.Width = Random(25, 100, 1) ; just to guess a size for example purpose
    ConsoleWrite("[Inside _oImage_GetSize] FileName = " & $oSelf.FileName & " $oSelf.Height = " & $oSelf.Height & " $oSelf.Width = " & $oSelf.Width & @CR)
EndFunc

Func _oImage_ReSize($oSelf, $iHeight)
    If $oSelf.Height = $iHeight Then
        ConsoleWrite("No need to resize " & $oSelf.FileName & ", its already at smallest size" & @CR)
        Return
    EndIf
    Local $iPercentage = $iHeight / $oSelf.Height
    $oSelf.Height = $iHeight
    $oSelf.Width = round($iPercentage*$oSelf.Width)
    ConsoleWrite("[Inside _oImage_ReSize] FileName = " & $oSelf.FileName & " New $oSelf.Height = " & $oSelf.Height & " New $oSelf.Width = " & $oSelf.Width & @CR)
EndFunc
#endregion _oImage
#cs console output
[Inside _oImage_GetSize] FileName = GoodPic $oSelf.Height = 82 $oSelf.Width = 63
new smallest height of 82 Found for Image1 FileName = GoodPic
[Inside _oImage_GetSize] FileName = BadPic $oSelf.Height = 98 $oSelf.Width = 35
[Inside _oImage_GetSize] FileName = UglyPic $oSelf.Height = 53 $oSelf.Width = 40
new smallest height of 53 Found for Image3 FileName = UglyPic
[Inside _oImage_ReSize] FileName = GoodPic New $oSelf.Height = 53 New $oSelf.Width = 41
[Inside _oImage_ReSize] FileName = BadPic New $oSelf.Height = 53 New $oSelf.Width = 19
No need to resize UglyPic, its already at smallest size

Save image as My New Panorama = |GoodPic|BadPic|UglyPic|
#ce

Richard Robertson · May 9, 2010

Eh, AutoIt isn't the best place to learn OOP. In fact it's a pretty bad one.

I don't see where you have a data field that would be the same on all objects though.

jaberwacky · May 9, 2010

Wow! That's really awesome of you to take the time to come up with that Yoriz! From what I can tell you have two objects, a panorama object and an image object. That's along the lines of what I was thinking.

How did you go from not doing oop to being able to do oop so quickly?

Yoriz · May 9, 2010

lots of reading

go here download 'Thinking in C++, 2nd edition, Volume 1'

http://math.hws.edu/eck/cs124/downloads/OOP2_from_Univ_KwaZulu-Natal.pdf

http://math-cs.gordon.edu/courses/cs211/ATMExample/

Yoriz · May 9, 2010

I think this is more kind of like your original question, which i havent figured out myself yet.

If you create a lightbulb object and a switch object, the lightbulb object can recieve a message volts in(%), the switch object can send a message volts out(%).

create a circuit object that conatains a switch and a bulb object, how when you do $oCircuit.Switch.on does circuit pass on the message from the switch to the lightbulb ?.

#include <AutoItObject.au3>
_AutoItObject_Startup()

Global $oError = ObjEvent("Autoit.Error", "_myErrFunc")
Func _ErrFunc()
    ConsoleWrite("! COM Error ! Number: 0x" & Hex($oError.number, 8) & " ScriptLine: " & $oError.scriptline & " - " & $oError.windescription & @CRLF)
EndFunc ;==>_ErrFunc


$oBulb = _oLightBulb()

$oPlainSwitch = _oPlainSwitch()
$oBulb.VoltsIn($oPlainSwitch.On)
$oBulb.VoltsIn($oPlainSwitch.Off)

$oDimmerSwitch = _oDimmerSwitch()
$oBulb.VoltsIn($oDimmerSwitch.SetDimmerPos(50))
$oBulb.VoltsIn($oDimmerSwitch.Off)
$oBulb.VoltsIn($oDimmerSwitch.SetDimmerPos(75))
$oBulb.VoltsIn($oDimmerSwitch.On)


$oCircuit = _oCircuit()
$oCircuit.Switch.On ; want this to return message from lightbulb object 'Light bulb is On at 100%'


#region _oLightBulb
Func _oLightBulb()
    local $oSelf = _AutoItObject_Create()
    ; _oLightBulb Property (variables)
    _AutoItObject_AddProperty($oSelf, "State", $ELSCOPE_PRIVATE, "Off")
    _AutoItObject_AddProperty($oSelf, "Brightness", $ELSCOPE_PRIVATE, "0")
    ; _oLightBulb Method (functions)
    _AutoItObject_AddMethod($oSelf, "VoltsIn", "_oLightBulb_VoltsIn")
    _AutoItObject_AddMethod($oSelf, "OutPut", "_oLightBulb_OutPut")
    Return $oSelf
EndFunc
; _oLightBulb Methods  (functions)

Func _oLightBulb_VoltsIn($oSelf, $iPercentage)
    $oSelf.Brightness = $iPercentage
    If $iPercentage < 1 Then $oSelf.State = "Off"
    If $iPercentage > 0 Then $oSelf.State = "On"
    $oSelf.OutPut
EndFunc

Func _oLightBulb_OutPut($oSelf)
    ConsoleWrite("Light bulb is " & $oSelf.State & " at " & $oSelf.Brightness & "%" & @CR)
EndFunc
#endregion _oLightBulb

#region _oPlainSwitch
Func _oPlainSwitch()
    local $oSelf = _AutoItObject_Create()
    ; _oPlainSwitch Property (variables)
    _AutoItObject_AddProperty($oSelf, "volts", $ELSCOPE_PRIVATE, 0)
    ; _oPlainSwitch Method (functions)
    _AutoItObject_AddMethod($oSelf, "On", "_oPlainSwitch_On")
    _AutoItObject_AddMethod($oSelf, "Off", "_oPlainSwitch_Off")
    Return $oSelf
EndFunc
; _oPlainSwitch Methods  (functions)
Func _oPlainSwitch_On($oSelf)
    $oSelf.volts = 100
    Return $oSelf.volts
EndFunc

Func _oPlainSwitch_Off($oSelf)
    $oSelf.volts = 0
    Return $oSelf.volts
EndFunc
#endregion _oPlainSwitch

#region _oDimmerSwitch
Func _oDimmerSwitch()
    local $oSelf = _AutoItObject_Create(_oPlainSwitch()) ; inherit from _oPlainSwitch
    _AutoItObject_AddProperty($oSelf, "State", $ELSCOPE_PRIVATE, False)
    ; _oPlainSwitch Method (functions)
    _AutoItObject_AddMethod($oSelf, "On", "_oDimmerSwitch_On") ; overwrites plainswitch
    _AutoItObject_AddMethod($oSelf, "Off", "_oDimmerSwitch_Off") ; overwrites plainswitch
    _AutoItObject_AddMethod($oSelf, "SetDimmerPos", "_oDimmerSwitch_SetDimmerPos")
    Return $oSelf
EndFunc
; _oDimmerSwitch Methods  (functions)
Func _oDimmerSwitch_On($oSelf)
    $oSelf.State = True
    Return $oSelf.volts
EndFunc

Func _oDimmerSwitch_Off($oSelf)
    $oSelf.State = False
    return 0
EndFunc

Func _oDimmerSwitch_SetDimmerPos($oSelf, $iPercentage)
    If $iPercentage < 0 Then $iPercentage = 0
    If $iPercentage > 100 Then $iPercentage = 100
    $oSelf.volts = $iPercentage
    If $oSelf.State Then
        Return $oSelf.volts
    Else
        Return 0
    EndIf
EndFunc
#endregion _oDimmerSwitch

#region _oCircuit
Func _oCircuit()
    local $oSelf = _AutoItObject_Create()
    ; _oCircuit Property (variables)
    _AutoItObject_AddProperty($oSelf, "Switch", $ELSCOPE_READONLY, _oPlainSwitch())
    _AutoItObject_AddProperty($oSelf, "Bulb", $ELSCOPE_READONLY, _oLightBulb())
    ; _oCircuit Methods  (functions)
    _AutoItObject_AddMethod($oSelf, "Connect", "_oCircuit_Connect")
    Return $oSelf
EndFunc
; _oCircuit Methods  (functions)
Func _oCircuit_Connect($oSelf)

    $oSelf.Bulb.VoltsIn($oSelf.Switch)
EndFunc

#endregion _oCircuit

jvanegmond · May 9, 2010

how when you do $oCircuit.Switch.on does circuit pass on the message from the switch to the lightbulb ?.

The circuit tells the switch to pass on the message on his behalf.

Yoriz · May 9, 2010

The circuit tells the switch to pass on the message on his behalf.

Would you mind giving an example using my code above, as althought i can tell that i want to make the return of switch send its message to bulb.

I dont see how inside of $oCircuit i get the return value from switch when calling $oCircuit.Switch.on to be able to pass its return value into $oSelf.Bulb.VoltsIn inside of the oCircuit object.

jaberwacky · May 9, 2010

I ive begun to read the ATM Example now. Turns out I already had the thinking in c++ but I never got around to reading it! If you like puzzles then take a look at the 23 prisoners puzzle if you haven't already. See if you can turn it into an oo program.

jvanegmond · May 9, 2010

Would you mind giving an example using my code above, as althought i can tell that i want to make the return of switch send its message to bulb.
I dont see how inside of $oCircuit i get the return value from switch when calling $oCircuit.Switch.on to be able to pass its return value into $oSelf.Bulb.VoltsIn inside of the oCircuit object.

I've looked at your example a bit closer. I think the best options is this:

You can create a relationship between the switch and the lightbulb (can be a relationship via circuit). But you must be careful not to introduce additional dependancies. You can safely assume that everything inside an electrical circuit will be an electrical device. The switch and the lightbulb can then inherit from an abstract device object, which has a current/voltage in and a current/voltage out (and thus also resistance).

Edit: Although more closer to reality, it would be better to give each electrical device a resistance, and the power supply a voltage and let the circuit figure out the rest. But this is more computational intensive.

Edited May 9, 2010 by Manadar

jaberwacky · May 9, 2010

Ok, I made my own lightbulb and switch class. So far it merely switches the light on and off. I'm assuming that OO will make it easy to add a dimmer switch into the mix. Because isn't that a part of what OO is about, ease of maintenance (wow for a sec. I forgot how to spell maintenance!), and ability to add to and change the classes without affecting the user?

#include "AutoItObject.au3"

_AutoItObject_Startup()

Global $oError = ObjEvent("Autoit.Error", "_myErrFunc")

Global $lightBulb = LightBulbObj()
Global $Switch = SwitchObj()

$Switch.Flip()

$Switch.Flip()

#region LightBulb Class
Func LightBulbObj()
    Local $self = _AutoItObject_Create()
    _AutoItObject_AddProperty($self, "BulbState", $ELSCOPE_PRIVATE, False)
    _AutoItObject_AddMethod($self, "Output", "_declareBulbState", True)
    _AutoItObject_AddMethod($self, "Flip", "_changeBulbState")
    Return $self
EndFunc ;==>LightBulbObj

Func _declareBulbState($self)
    MsgBox(0, "Light Bulb", $self.BulbState)
EndFunc ;==>_declareBulbState

Func _changeBulbState($self)
    $self.BulbState = Not $self.BulbState
    $self.Output()
EndFunc ;==>_changeBulbState
#endregion LightBulb Class

#region LightSwitch Class
Func SwitchObj()
    Local $self = _AutoItObject_Create()
    _AutoItObject_AddProperty($self, "SwitchState", $ELSCOPE_PRIVATE, False)
    _AutoItObject_AddMethod($self, "Flip", "_flipSwitch")
    _AutoItObject_AddMethod($self, "Output", "_declareSwitchState", True)
    Return $self
EndFunc ;==>SwitchObj

Func _declareSwitchState($self)
    MsgBox(0, "Light Bulb", $self.SwitchState)
EndFunc ;==>_declareSwitchState

Func _flipSwitch($self)
    $lightBulb.Flip()
    $self.SwitchState = Not $self.SwitchState
EndFunc ;==>_flipSwitch
#endregion LightSwitch Class

Func _ErrFunc()
    ConsoleWrite("! COM Error ! Number: 0x" & Hex($oError.number, 8) & " ScriptLine: " & $oError.scriptline & " - " & $oError.windescription & @CRLF)
EndFunc ;==>_ErrFunc

Edited May 9, 2010 by jaberwocky6669

monoceres · May 9, 2010

Shouldn't the switch be connected to the light bulb? Maybe the switch should take an light bulb instance in it's constructor and save it as an property?

jaberwacky · May 9, 2010

I have no idea what constructor and desctructors are about or if you're even replying to my code lulz

I did see that the lightbulb.state is independant of whatever state the switch is in though

Edited May 9, 2010 by jaberwocky6669

jaberwacky · May 9, 2010

According to this site: (http://www.linuxtopia.org/online_books/programming_books/thinking_in_c%2B%2B/Chapter01_002.html) a lightbulb should have four methods: on, off, dim, bright. The light can cut itself on and off and dim and brighten itself? Or deosn't it need another object to do that? And then expand on that based on what Manadar said, use resistance and voltage to determine the light bulb's state.

jaberwacky · May 9, 2010

ooookkkkkk, when I instantiate an object of the switch object then automagically an object of light bulb class is instantiated and then the ligthbulb is set according to the state of the switch?

OOP design question

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