Java 8 Functional Interfaces - BinaryOperator.apply() Examples

package com.logicbig.example.binaryoperator;

import java.util.function.BinaryOperator;

public class ApplyExample {

    public static void main(String... args) {
        BinaryOperator<Integer> sumOfSquare = (a, b) -> a * a + b * b;
        Integer i = sumOfSquare.apply(3, 4);
        System.out.println(i);
    }
} 

package com.logicbig.example.binaryoperator;

import java.util.function.BinaryOperator;

public class ApplyExample2 {

    public static void main(String... args) {
        BinaryOperator<Integer> sumOfSquare = ApplyExample2::getSquareSum;
        Integer i = sumOfSquare.apply(3, 4);
        System.out.println(i);
    }

    private static Integer getSquareSum(Integer a, Integer b) {
        return a * a + b * b;
    }
} 

package com.logicbig.example.binaryoperator;

import java.math.BigDecimal;
import java.util.List;
import java.util.function.BinaryOperator;
import java.util.stream.Collectors;

public class ApplyExample3 {

    public static void main(String... args) {
        List<Double> doubles = List.of(1d, 3d, 5d, 7d);
        //static method reference
        List<Double> list = transformList(doubles, Math::pow, 3d);
        System.out.println(list);

        //instance method reference
        List<BigDecimal> bigDecimals = List.of(BigDecimal.valueOf(1), BigDecimal.valueOf(3),
                BigDecimal.valueOf(5), BigDecimal.valueOf(7));
        List<BigDecimal> list2 = transformList(bigDecimals, BigDecimal::add, BigDecimal.TEN);
        System.out.println(list2);
        list2 = transformList(bigDecimals, BigDecimal::multiply, BigDecimal.TEN);
        System.out.println(list2);

        //instance method reference of a particular instance
        List<String> cars = List.of("cadillac", "chrysler", "ferrari");
        String s = "I drive a ferrari car";
        List<String> stringList = transformList(cars, s::replaceAll, "ford");
        System.out.println(stringList);
    }

    public static <T> List<T> transformList(List<T> list,BinaryOperator<T> binaryOperator,  T userObject) {
        return list.stream()
                   .map(e -> binaryOperator.apply(e, userObject))
                   .collect(Collectors.toList());
    }
}