Getting a value class to have some behaviors of a handle class

Question

Olhado 2014-4-7

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/124852-getting-a-value-class-to-have-some-behaviors-of-a-handle-class

评论： NANDHINI 2024-2-13

I am new to OOP in general but most of my experience is with MATLAB and I wonder if it possible to make value classes behave like handle classes.

For Example

classdef Example
    properties
        Prop1
    end
    methods
        function obj = Example()
            obj.Prop1=1;
        end
        function ()= multiply(obj,value)
            obj.Prop=obj.Prop*value;
        end
    end
end

I know the following code will set the Prop1 value of ExpClass to 3

    ExpClass=Example
    ExpClass=ExpClass.multiply(3)

And I know if change the classdef line to classdef Example < handle then the following code will do the same this

      ExpClass=Example
      ExpClass.multiply(3)

Is there a way the get the behavior of the second example in a value class?

Thanks for the info

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per isakson 2014-4-7

编辑：per isakson 2014-4-7

I assume that Prop and Prop1 are the "same"
It is confusing to call an instance of a class ExpClass. I would prefer ExpObj.

The code you present doesn't run.

NANDHINI 2024-2-13

There are different attributes and values you can use to control how users interact with your objects. Setting the SetAccess attribute to private means that property values can be changed only by a method. Setting it to immutable means that they can only be set when the object is created. They cannot be changed later, even by a method.

Although there's no noticeable difference to the user between private and immutable properties, making a property immutable prevents you, the developer, from accidentally changing the value from inside a method.

You will often want different levels of access for different properties. You can have as many properties blocks as you need, each with their own attribute settings.

properties

Prop1

end

properties (SetAccess = immutable)

Prop2

end

properties (SetAccess = private)

Prop3

Prop4

end

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Answer 1

per isakson 2014-4-7

0
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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/124852-getting-a-value-class-to-have-some-behaviors-of-a-handle-class#answer_132625

编辑：per isakson 2014-4-7

在 MATLAB Online 中打开

Value and handle classes are different and there are reasons why Matlab has both. See

With an object of a value class you must assign the result to a new variable or overwrite the old one.

.

Try

    >> ve = ValueExample;
    >> ve2 = ve.multiply( 7 );
    >> ve.Prop
    ans =
         1
    >> ve2.Prop
        ans =
             7

where

    classdef ValueExample
        properties
            Prop
        end
        methods
            function obj = ValueExample()
                obj.Prop = 1;
            end
            function  obj = multiply( obj, value )
                obj.Prop = obj.Prop*value;
            end
        end
    end

and

    >> he = HandleExample;
    >> he.multiply(7);
    >> he.Prop
    ans =
         7

where

    classdef    HandleExample < handle
        properties
            Prop
        end
        methods
            function obj = HandleExample()
                obj.Prop = 1;
            end
            function  multiply( obj, value )
                obj.Prop = obj.Prop*value;
            end
        end
    end