Basic Kotlin Syntax into Java Converter

About

The program translates the basic Kotlin Syntax into a Java code. Kotlin.g4 is a grammar written using antl4 that accepts a code written in Kotlin, while Kotlin2Java.java converts the code using rules specified. However, it does not handle String templates.

How to run?

run the following command in your terminal

java Kotlin2Java [file].kt #creates a default input.java file where the code is stored

java Kotlin2Java [file].kt [file].java # creates a file with a specified name

Example

Kotlin code

fun main() {
val rectangle = Rectangle(5.0, 2.0)
val triangle = Triangle(3.0, 4.0, 5.0)
println("Area of rectangle is ${rectangle.calculateArea()}, its perimeter is ${rectangle.perimeter}")
println("Area of triangle is ${triangle.calculateArea()}, its perimeter is ${triangle.perimeter}")
}

abstract class Shape(val sides: List<Double>) {
val perimeter: Double get() = sides.sum()
abstract fun calculateArea(): Double
}

interface RectangleProperties {
val isSquare: Boolean
}

class Rectangle(
var height: Double,
var length: Double
) : Shape(listOf(height, length, height, length)), RectangleProperties {
override val isSquare: Boolean get() = length == height
override fun calculateArea(): Double = height * length
}

class Triangle(
var sideA: Double,
var sideB: Double,
var sideC: Double
) : Shape(listOf(sideA, sideB, sideC)) {
override fun calculateArea(): Double {
val s = perimeter / 2
return Math.sqrt(s * (s - sideA) * (s - sideB) * (s - sideC))
}
}

Translation

import java.util.*;
public class output27{
public static void main ( String[] args ) {
final Rectangle rectangle = new Rectangle( 5.0 , 2.0 ) ;
final Triangle triangle = new Triangle( 3.0 , 4.0 , 5.0 ) ;
System.out.println( rectangle.calculateArea( ) ) ;
System.out.println( rectangle.getperimeter() ) ;
System.out.println( triangle.calculateArea( ) ) ;
System.out.println( triangle.getperimeter() ) ;
}
static abstract class Shape {
final List<Double> sides;
public Shape( final List<Double> temp0 ){
sides=temp0;
}
private Double perimeter;
public double getperimeter (){
perimeter= sides.stream().mapToDouble(Double::doubleValue).sum() ;
return perimeter; }
abstract public double calculateArea ( ) ;
}
interface RectangleProperties { final Boolean isSquare =null ;
}
static class Rectangle extends Shape implements RectangleProperties {
double height;
double length;
public Rectangle( double temp0 , double temp2 ){
super( List.of( temp0 , temp2 , temp0 , temp2 ) );
length=temp2;
height=temp0;
}
private Boolean isSquare;
public Boolean getisSquare (){
isSquare= length == height ;
return isSquare; }
@Override
public double calculateArea ( ) {
return height * length ; }
}
static class Triangle extends Shape {
double sideA;
double sideB;
double sideC;
public Triangle( double temp0 , double temp2 , double temp4 ){
super( List.of( temp0 , temp2 , temp4 ) );
sideC=temp4;
sideB=temp2;
sideA=temp0;
}
@Override
public double calculateArea ( ) {
final double s = getperimeter() / 2 ;
return Math.sqrt( s * ( s - sideA ) * ( s - sideB ) * ( s - sideC ) ) ;
}
}
}

Result