66 lines
1.6 KiB
Dart
66 lines
1.6 KiB
Dart
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/**
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桥接（Bridge）
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意图：将抽象部分与实现部分分离，使它们都可以独立的变化。
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主要解决：在有多种可能会变化的情况下，用继承会造成类爆炸问题，扩展起来不灵活。
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何时使用：实现系统可能有多个角度分类，每一种角度都可能变化。
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如何解决：把这种多角度分类分离出来，让它们独立变化，减少它们之间耦合。
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*/
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main(List<String> args) {
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Shape redCircle = new Circle(100, 100, 10, new RedCircle());
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Shape greenCircle = new Circle(100, 100, 10, new GreenCircle());
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redCircle.draw();
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greenCircle.draw();
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}
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//////////////////////////////////////////////////////////////////
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///
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/// 创建桥接实现接口
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///
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abstract class DrawAPI {
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void drawCircle(int radius, int x, int y);
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}
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///
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/// 创建实现了 DrawAPI 接口的实体桥接实现类
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///
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class RedCircle implements DrawAPI {
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@override
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void drawCircle(int radius, int x, int y) {
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print("Drawing Circle[ color: red, radius: $radius"
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", x: $x, y:$y]");
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}
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}
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class GreenCircle implements DrawAPI {
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@override
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void drawCircle(int radius, int x, int y) {
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print("Drawing Circle[ color: green, radius: $radius"
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", x: $x, y:$y]");
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}
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}
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///
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/// 使用 DrawAPI 接口创建抽象类 Shape
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///
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abstract class Shape {
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DrawAPI _drawAPI;
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Shape(this._drawAPI);
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void draw();
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}
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///
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/// 创建实现了 Shape 接口的实体类
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///
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class Circle extends Shape {
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int _x, _y, _radius;
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Circle(this._x, this._y, this._radius, DrawAPI drawAPI) : super(drawAPI);
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void draw() {
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_drawAPI.drawCircle(_radius, _x, _y);
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}
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}
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