维基百科
桥接模式
桥接模式是软件设计模式中最复杂的模式之一，它把事物对象和其具体行为、具体特征分离开来，使它们可以各自独立的变化。事物对象仅是一个抽象的概念。如“圆形”、“三角形”归于抽象的“形状”之下，而“画圆”、“画三角”归于实现行为的“画图”类之下，然后由“形状”调用“画图”。
Java
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/** "Implementor" */
interface DrawingAPI
{
public void drawCircle(double x, double y, double radius);
}
/** "ConcreteImplementor" 1/2 */
class DrawingAPI1 implements DrawingAPI
{
public void drawCircle(double x, double y, double radius)
{
System.out.printf("API1.circle at %f:%f radius %f\n", x, y, radius);
}
}
/** "ConcreteImplementor" 2/2 */
class DrawingAPI2 implements DrawingAPI
{
public void drawCircle(double x, double y, double radius)
{
System.out.printf("API2.circle at %f:%f radius %f\n", x, y, radius);
}
}
/** "Abstraction" */
interface Shape
{
public void draw(); // low-level
public void resizeByPercentage(double pct); // high-level
}
/** "Refined Abstraction" */
class CircleShape implements Shape
{
private double x, y, radius;
private DrawingAPI drawingAPI;
public CircleShape(double x, double y, double radius, DrawingAPI drawingAPI)
{
this.x = x; this.y = y; this.radius = radius;
this.drawingAPI = drawingAPI;
}
// low-level i.e. Implementation specific
public void draw()
{
drawingAPI.drawCircle(x, y, radius);
}
// high-level i.e. Abstraction specific
public void resizeByPercentage(double pct)
{
radius *= pct;
}
}
/** "Client" */
class BridgePattern {
public static void main(String[] args)
{
Shape[] shapes = new Shape[2];
shapes[0] = new CircleShape(1, 2, 3, new DrawingAPI1());
shapes[1] = new CircleShape(5, 7, 11, new DrawingAPI2());
for (Shape shape : shapes)
{
shape.resizeByPercentage(2.5);
shape.draw();
}
}
}
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运行结果：
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API1.circle at 1.000000:2.000000 radius 7.500000
API2.circle at 5.000000:7.000000 radius 27.500000
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