Get the taste of Lambdas

Lambdas_02.java

package com.ucguy4u.functional.java;

import java.math.BigInteger;
import java.util.function.Consumer;
import java.util.function.Function;
import java.util.function.IntFunction;
import java.util.function.UnaryOperator;

/**
 *
 * @author chauhanuday
 */
public class Lambdas_02 {

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        
        IntFunction<String> intToString = num -> Integer.toString(num);
        System.out.println("expected value 3, actual value: " + 
                intToString.apply(123).length());
     
        //static method reference using ::
        IntFunction<String> intToString2 = Integer::toString;
        System.out.println("\nexpected value 4, actual value:  " + 
                intToString2.apply(4567).length());
        
        //lambdas made using a constructor
        Function<String,BigInteger> newBigInt = BigInteger::new;
        System.out.println("\nexpected value: 123456789, actual value: "+ 
                newBigInt.apply("123456789"));
        
        //example of a lambda made from an instance method
        Consumer<String> print = System.out::println;
        print.accept("\nComing to you directly from a lambda...");
        
        //these two are the same using the static method concat
        UnaryOperator<String> greeting = x -> "Hello, ".concat(x);
        System.out.println("\n"+greeting.apply("World"));
        
        UnaryOperator<String> makeGreeting = "Hello, "::concat;
        System.out.println("\n"+makeGreeting.apply("Peggy"));
        
        
    }
    
}