概要

Bridge パターンは、機能と実装を分離することで機能拡張をしやすくする、デザインパターンの一つである。

ソースコード

Display.m

classdef Display < handle
    properties (Access = private)
        impl(1,1) % DisplayImpl
    end
    methods (Access = public)
        function obj = Display(impl)
            arguments (Input)
                impl(1,1) DisplayImpl
            end
            arguments (Output)
                obj(1,1) Display
            end
            obj.impl = impl;
        end
        function open(obj)
            arguments (Input)
                obj(1,1) Display
            end
            obj.impl.rawOpen();
        end
        function print(obj)
            arguments (Input)
                obj(1,1) Display
            end
            obj.impl.rawPrint();
        end
        function close(obj)
            arguments (Input)
                obj(1,1) Display
            end
            obj.impl.rawClose();
        end
    end
    methods (Access = public, Sealed)
        function display_(obj)
            arguments (Input)
                obj(1,1) Display
            end
            obj.open();
            obj.print();
            obj.close();
        end
    end
end

CountDisplay.m

classdef CountDisplay < Display
    methods (Access = public)
        function obj = CountDisplay(impl)
            arguments (Input)
                impl(1,1) DisplayImpl
            end
            arguments (Output)
                obj(1,1) CountDisplay
            end
            obj = obj@Display(impl);
        end
        function multiDisplay(obj, times)
            arguments (Input)
                obj(1,1) CountDisplay
                times(1,1) int32
            end
            obj.open();
            for k = 1:times
                obj.print();
            end
            obj.close();
        end
    end
end

DisplayImpl.m

classdef (Abstract) DisplayImpl
    methods (Abstract, Access = public)
        rawOpen(obj)
        rawPrint(obj)
        rawClose(obj)
    end
end

StringDisplayImpl.m

classdef StringDisplayImpl < DisplayImpl
    properties (Access = private)
        string(1,:) char {mustBeTextScalar}
        width(1,1) double {mustBeInteger}
    end
    methods (Access = public)
        function obj = StringDisplayImpl(string)
            obj.string = string;
            obj.width = length(string);
        end
        function rawOpen(obj)
            obj.printLine();
        end
        function rawPrint(obj)
            disp(['|', obj.string, '|']);
        end
        function rawClose(obj)
            obj.printLine();
        end
    end
    methods (Access = private)
        function printLine(obj)
            fprintf('+');
            for k = 1:obj.width
                fprintf('-');
            end
            disp('+');
        end
    end
end

main.m

function main()
d1 = Display(StringDisplayImpl('Hello, Japan.'));
d2 = CountDisplay(StringDisplayImpl('Hello, World.'));
d3 = CountDisplay(StringDisplayImpl('Hello, Universe.'));
d1.display_();
d2.display_();
d3.display_();
d3.multiDisplay(5);
end

実行結果

>> main
+-------------+
|Hello, Japan.|
+-------------+
+-------------+
|Hello, World.|
+-------------+
+----------------+
|Hello, Universe.|
+----------------+
+----------------+
|Hello, Universe.|
|Hello, Universe.|
|Hello, Universe.|
|Hello, Universe.|
|Hello, Universe.|
+----------------+