? 组合(结构型模式)
将对象组合成树形结构以表示‘部分-整体’的层次结构。组合模式使得用户对单个对象和组合对象的使用具有一致性。
示例:
组件(Component)
protocol Shape {
func draw(fillColor: String)
}
叶子节点(Leafs)
final class Square: Shape {
func draw(fillColor: String) {
print("Drawing a Square with color \(fillColor)")
}
}
final class Circle: Shape {
func draw(fillColor: String) {
print("Drawing a circle with color \(fillColor)")
}
}
组合
final class Whiteboard: Shape {
private lazy var shapes = [Shape]()
init(_ shapes: Shape...) {
self.shapes = shapes
}
func draw(fillColor: String) {
for shape in self.shapes {
shape.draw(fillColor: fillColor)
}
}
}
用法
var whiteboard = Whiteboard(Circle(), Square())
whiteboard.draw(fillColor: "Red")