Scala 槽点 - require
require
def this(name: String, age: Int) = {
this()
require(name != null && !name.isEmpty, "name")
require(age > 0, "illegal age")
Preconditions.checkArgument(name != null && !name.isEmpty, "name required") // 使用 guava 工具类,这行编译不过... 改写为下两种调用方式可通过
// Preconditions.checkArgument(name != null && !name.isEmpty, "name required".asInstanceOf[Any])
// Preconditions.checkArgument(name != null && !name.isEmpty, "name required", null)
setAge(age)
setName(name)
}
什么鬼
-
require
- 函数签名:
final def require(requirement: Boolean, message: => Any)
,注意第二个参数类型是一个函数 - 以上栗子中调用了两次
require
函数,生成两个匿名对象...
- 函数签名:
-
ambiguous reference to overloaded definition
- 编译错误信息:
Error:(44, 21) ambiguous reference to overloaded definition, both method checkArgument in object Preconditions of type (x$1: Boolean, x$2: String, x$3: Object*)Unit and method checkArgument in object Preconditions of type (x$1: Boolean, x$2: Any)Unit match argument types (Boolean,String) Preconditions.checkArgument(name != null && !name.isEmpty, "name required")
- 编译错误信息: