Scala Final
Scala Final
Final 是一个关键字，用于防止超类成员继承到派生类。您还可以声明 final 变量、方法和类。
Scala 最终变量示例
您不能在子类中覆盖最终变量。让我们看一个例子。
class Vehicle{
final val speed:int = 60
}
class Bike extends Vehicle{
override val speed:int = 100
def show(){
println(speed)
}
}
object MainObject{
def main(args:Array[String]){
var b = new Bike()
b.show()
}
}
输出:
Error-value speed cannot override final member
Scala Final Method
在父类中声明的Final方法不能被覆盖。如果您不想被覆盖，您可以将任何方法设置为 final。尝试覆盖 final 方法将导致编译时错误。
Scala Final Method Example
class Vehicle{
final def show(){
println("vehicle is running")
}
}
class Bike extends Vehicle{
//override val speed:int = 100
override def show(){
println("bike is running")
}
}
object MainObject{
def main(args:Array[String]){
var b = new Bike()
b.show()
}
}
输出:
method show cannot override final member
override def show(){
^
one error found
Scala Final Class 示例
您也可以制作 final 类。 final 类不能被继承。如果您将课程设置为期末考试，则不能进一步延长。
final class Vehicle{
def show(){
println("vehicle is running")
}
}
class Bike extends Vehicle{
override def show(){
println("bike is running")
}
}
object MainObject{
def main(args:Array[String]){
var b = new Bike()
b.show()
}
}
输出:
error: illegal inheritance from final class Vehicle
class Bike extends Vehicle{
^
one error found
