Samples of design patterns in Kotlin.
Defination : Gneral and reusable solution to common problems in software design (Not algorithm)
They are design patterns that deal with object creation mechanisms, trying to create objects in a manner suitable to the situation
Builder is a creational design pattern that lets you construct complex objects step by step. The pattern allows you to produce different types and representations of an object using the same construction code.
=> Uml :
- builder interface
interface UserBuilder {
fun setName(_name:String):UserBuilder
fun setAddress (_Address:String):UserBuilder
fun setAge (_age:Int):UserBuilder
fun setPhone (_phone:String):UserBuilder
fun build():User
}- User Class
data class User (val name : String? ,val age :Int? , val address:String?,val phone :String?) {}- User builder
class UserBuilderImpl :UserBuilder {
private var name : String? =null
private var age :Int? = null
private var address:String? = null
private var phone :String? = null
override fun setName(_name: String): UserBuilder {
this.name =_name
return this
}
override fun setAddress(_Address: String): UserBuilder {
this.address =_Address
return this
}
override fun setAge(_age: Int): UserBuilder {
this.age =_age
return this
}
override fun setPhone(_phone: String): UserBuilder {
this.phone=_phone
return this
}
override fun build(): User {
return User(this.name, this.age, this.address, this.phone)
}
}- Using code in main
fun main(){
val user =UserBuilderImpl().setName("ahmed")
.setAge(15).build()
print(user.toString())
}Prototype is a creational design pattern that lets you copy existing objects without making your code dependent on their classes (Clonning)
=> Uml :
class FirstSuit :Cloneable {
var name = "XR8"
fun properties(){
println("flying")
}
public override fun clone(): FirstSuit {
return super.clone()as FirstSuit
}
}- Second Prototype
class SecondSuit:Cloneable {
fun properties(){
print("can dive")
}
public override fun clone(): SecondSuit {
return super.clone() as SecondSuit
}
}- Using code in main
fun main(){
val firstSuit = FirstSuit()
firstSuit.name = "LL1"
val firstSuitClone = firstSuit.clone()
println(firstSuitClone.name)
val secondSuit = SecondSuit()
val secondSuitCloneable = secondSuit.clone()
secondSuitCloneable.properties()
}
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