Scala：Functional Objects

先上代码

 1 class FunctionalObjects(var _x: Int, var _y: Int) {
 2   require(_x > 0)
 3   require(_y > 0)
 4
 5   def this(value: Int) = this(value, value)
 6
 7   def x = _x
 8
 9   def x_=(value: Int) { _x = value }
10
11   def y = _y
12
13   def y_=(value: Int) { _y = value }
14
15   def +(value: Int): FunctionalObjects = {
16     _x += value
17     _y += value
18
19     this
20   }
21
22   def +(value: FunctionalObjects): FunctionalObjects = {
23     _x += value.x
24     _y += value.y
25
26     this
27   }
28
29
30   override def toString(): String = {
31     "("+ _x +", "+ _y +")"
32   }
33 }
34
35 object FunctionalObjects {
36   implicit def intToFunctionalObjectsTest(value: Int) = new FunctionalObjects(value)
37
38   def main(args: Array[String]) {
39     var test = new FunctionalObjects(5)
40     test.y = 6
41     println(test)
42     println(test + 4)
43     println(4 + test)
44   }
45 }

隐式类型转换、运算符方法、属性语法，这些都不必多说，大家一看就明白，scala的构造方法得简单的解释一下，类型名称后面跟随的参数列表就是“主要构造函数”的签名，类型定义中出现的可执行语句，都是其方法体。def this 定义的构造方法为“次要构造方法”。