Using ‘this()’ you can define a constructor.
Define default constructor
class Employee(id: Int, firstName: String, lastName: String) {
def this() = {
this(0, "no_name", "no_name")
}
}
Define constructor with arguments
class Employee(id: Int, firstName: String, lastName: String) {
def this(id: Int) = {
this(id, "no_name", "no_name")
}
def this(id: Int, firstName: String) = {
this(id, firstName, "no_name")
}
}
Final Employee class looks like below.
class Employee(id: Int, firstName: String, lastName: String) {
def this() = {
this(0, "no_name", "no_name")
}
def this(id: Int) = {
this(id, "no_name", "no_name")
}
def this(id: Int, firstName: String) = {
this(id, firstName, "no_name")
}
def getId = {
id
}
def getFirstName = {
firstName
}
def getLastName = {
lastName
}
override def toString = {
s"id = $id, firstName: $firstName, lastName: $lastName"
}
}
Examples to define object using constructors.
val emp1 = new Employee()
val emp2 = new Employee(123)
val emp3 = new Employee(123, "Krishna")
val emp4 = new Employee(123, "Krishna", "Gurram")
Find the below working application.
scala> class Employee(id: Int, firstName: String, lastName: String) {
|
| def this() = {
| this(0, "no_name", "no_name")
| }
|
| def this(id: Int) = {
| this(id, "no_name", "no_name")
| }
|
| def this(id: Int, firstName: String) = {
| this(id, firstName, "no_name")
| }
|
| def getId = {
| id
| }
|
| def getFirstName = {
| firstName
| }
|
| def getLastName = {
| lastName
| }
|
| override def toString = {
| s"id = $id, firstName: $firstName, lastName: $lastName"
| }
|
| }
class Employee
scala> val emp1 = new Employee()
val emp1: Employee = id = 0, firstName: no_name, lastName: no_name
scala> val emp2 = new Employee(123)
val emp2: Employee = id = 123, firstName: no_name, lastName: no_name
scala> val emp3 = new Employee(123, "Krishna")
val emp3: Employee = id = 123, firstName: Krishna, lastName: no_name
scala> val emp4 = new Employee(123, "Krishna", "Gurram")
val emp4: Employee = id = 123, firstName: Krishna, lastName: Gurram
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