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linking properties in object oriented code

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nathan blanc
nathan blanc on 14 May 2021
Answered: TADA on 29 Aug 2021
I have an object oriented code where I want to be able to link several properties in several manners. e.g. "these properties are always equal", "these properties maintain a ratio of 5" etc. these are not properites of the same object, and sometimes not of objects from the same class.
I was thinking of using linkprop but it is not recommended for objects other than graphic objects. also to the best of my knowledge it can only link properties as equal.
I was thinking of adding postset listeners to the properties where the callback function changes the other properties accordingly, but I am not sure how to prevent recursive calling. i.e one function changes the other property changing the first one etc.
would be thankfull for any assistance
Nathan

Accepted Answer

TADA
TADA on 29 Aug 2021
it is possible using Post set events.
I am working on an MVVM toolbox which relies on post set events (TaDuAs/Flow: Framework for matlab (github.com))
heres an example which uses a similar notion
The attachment has 3 classes:
ObjectA - a generic handle class with set-observable properties
PropertyBinding - represents a single bound object, its property and an update function
PropertyBinder - manages the bindings for a list of objects.
How to use:
% a simple binding example which copies the values of specified proeprties
% between the objects in the list.
list = {ObjectA(), ObjectA(), ObjectA()};
props = {'X', 'X', 'Y'};
pb = PropertyBinder(list, props);
list{1}.X = 100;
list{1}
ans =
ObjectA with properties: X: 100 Y: [] Z: []
list{2}
ans =
ObjectA with properties: X: 100 Y: [] Z: []
list{3}
ans =
ObjectA with properties: X: [] Y: 100 Z: []
% a more complex relationship, where some of the bindings copy the value
% as-is and some alter the copied value
list2 = {ObjectA(), ObjectA(), ObjectA()};
props2 = {'X', 'X', 'Y'};
pb2(1) = PropertyBinder(list([1,3]), props([1,3]), {@(x) x/5, @(x) x*5});
pb(2) = PropertyBinder(list([2,3]), props([2,3]), {@(x) x/5, @(x) x*5})
pb =
1×2 PropertyBinder array with properties: Bindings Listeners
pb(3) = PropertyBinder(list(1:2), props(1:2));
list{1}.X = 100;
list{1}
ans =
ObjectA with properties: X: 100 Y: [] Z: []
list{2}
ans =
ObjectA with properties: X: 100 Y: [] Z: []
list{3}
ans =
ObjectA with properties: X: [] Y: 500 Z: []

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