New topic: Sharing common code between disparate subclasses
<http://forums.realsoftware.com/viewtopic.php?t=46432> Page 1 of 1 [ 5 posts ] Previous topic | Next topic Author Message bachya Post subject: Sharing common code between disparate subclassesPosted: Fri Jan 04, 2013 12:57 am Joined: Wed Dec 20, 2006 1:23 pm Posts: 5 I have two separate classes (A = a subclass of BevelButtom, B = a subclass of PushButton). Both A and B implement a number of identical methods in exactly the same way. Since both subclass' superclasses are different and since RB doesn't support multiple inheritance, all I can do to tie these methods together is define a class interface, have both subclasses implement the interface, then copy/paste the method bodies in each subclass. That offends my sensibilities. Is there a way in RB to extract this common logic elsewhere? Thanks! Top timhare Post subject: Re: Sharing common code between disparate subclassesPosted: Fri Jan 04, 2013 1:36 am Joined: Fri Jan 06, 2006 3:21 pm Posts: 11944 Location: Portland, OR USA The fact that the methods are exactly the same suggests that they shouldn't be part of the controls at all. Perhaps they should be utility methods in a Module. The Class interface would then define a method that the utility method calls to perform some class-specific action. The utility method would accept a parameter of the class interface type, do its thing and then call the class method to handle the result. Top Thom McGrath Post subject: Re: Sharing common code between disparate subclassesPosted: Fri Jan 04, 2013 1:48 am Site Admin Joined: Tue May 06, 2008 1:07 pm Posts: 1318 Location: Greater Hartford Area, CT Create the interface, but don't add any methods. On a module, you can define methods which include the Extends parameter keyword on the interface name. So let's say your interface is called ButtonParent. You can create a global method in a module such as Sub Foo (Extends Button As ButtonParent) And now you can simply call PushButton.Foo. Be aware though that in your implementation code, you cannot call any methods or properties of button because it is now generic, so you have to use TypeCasting. This makes your code look something like: Sub Foo (Extends Button As ButtonParent) If Button IsA PushButton Then Dim ButtonPush As PushButton = PushButton(Button) MsgBox(ButtonPush.Caption) ElseIf Button IsA BevelButton Then Dim ButtonBevel As BevelButton = BevelButton(Button) MsgBox(ButtonBevel.Caption) End If End Sub So as you can see, you'll still need to separate your code in some way. Only you will know if this technique will actually help you. _________________ Thom McGrath - @tekcor Web Framework Architect, Real Software, Inc. Top bachya Post subject: Re: Sharing common code between disparate subclassesPosted: Fri Jan 04, 2013 8:41 am Joined: Wed Dec 20, 2006 1:23 pm Posts: 5 Thank you both. I will give this a shot and report back whether it satisfies my needs. Top bachya Post subject: Re: Sharing common code between disparate subclassesPosted: Fri Jan 04, 2013 1:50 pm Joined: Wed Dec 20, 2006 1:23 pm Posts: 5 Hi again, I was able to get Paul's eyes on this, as well (via StackOverflow: http://stackoverflow.com/questions/1415 ... s/14152440) and he provided some additional insight. Thanks to all who offered assistance. I should be able to craft a more elegant solution w/ everyone's input. Top Display posts from previous: All posts1 day7 days2 weeks1 month3 months6 months1 year Sort by AuthorPost timeSubject AscendingDescending Page 1 of 1 [ 5 posts ] -- Over 1500 classes with 29000 functions in one REALbasic plug-in collection. The Monkeybread Software Realbasic Plugin v9.3. http://www.monkeybreadsoftware.de/realbasic/plugins.shtml [email protected]
