桥接是用于把抽象化与实现化解耦，使得二者可以独立变化。这种模式涉及到一个作为桥接的接口，使得实体类的功能独立于接口实现类。这两种类型的类可被结构化改变而互不影响。
例子：通过定义桥接接口DrawApi，把Shape的draw功能独立出来。
1.创建Shape抽象类
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| package com.notejava.bridge;
public abstract class Shape {
protected DrawApi drawApi;
public Shape(DrawApi drawApi) {
this.drawApi = drawApi;
}
public abstract void draw();
}
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2.创建Circle类，集成Shape
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| package com.notejava.bridge;
public class Circle extends Shape {
private int x, y, radius;
public Circle(int x, int y, int radius, DrawApi drawApi) {
super(drawApi);
this.x = x;
this.y = y;
this.radius = radius;
}
@Override
public void draw() {
drawApi.drawCircle(radius, x, y);
}
}
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3.创建桥接接口DrawApi
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| package com.notejava.bridge;
public interface DrawApi {
void drawCircle(int radius, int x, int y);
}
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4.创建实现类RedCircle
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| package com.notejava.bridge;
public class RedCircle implements DrawApi {
@Override
public void drawCircle(int radius, int x, int y) {
System.out.println("Drawing Circle\[ color: red, radius: " + radius + ", x: " + x + ", " + y + "\]");
}
}
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5.创建实现类GreenCircle
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| package com.notejava.bridge;
public class GreenCircle implements DrawApi {
@Override
public void drawCircle(int radius, int x, int y) {
System.out.println("Drawing Circle\[ color: green, radius: " + radius + ", x: " + x + ", "+ y + "\]");
}
}
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6.创建Demo类
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| package com.notejava.bridge;
public class Demo {
public static void main(String\[\] args) {
Shape redCircle = new Circle(100,100, 10, new RedCircle());
Shape greenCircle = new Circle(100,100, 10, new GreenCircle());
redCircle.draw();
greenCircle.draw();
}
}
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