Lambdas Expression

1 Nisan 2022 · tarafından · in Genel · Yorum bırakın

Merhabalar uzun zamandır yazamıyordum güzel bir projeye geçiş yaptım burada kullanılan teknolojileri blogumda yansıtmaya çalışacağım;

kullanımları; bir veya birden fazla parametre alabilir parametre almaya bilir

() -> { }

(p1) -> { }

(p1, p2) -> { }

örnek;

interface Drawable{  
    public void draw();  
}  
public class LambdaExpressionExample {  
    public static void main(String[] args) {  
        int width=10;   
        Drawable d=new Drawable(){  
            public void draw(){System.out.println("Drawing "+width);}  
        };  
        d.draw();  
    }  
} 
//bu kodu şimdi lamda ile yazalım

interface Drawable{  
    public void draw();  
}  
public class LambdaExpressionExample {  
    public static void main(String[] args) {  
        int width=10;   
        Drawable d=() ->{  
            System.out.println("Drawing "+width);
        };  
        d.draw();  
    }  
}

1.Comparator

klasik comparator

Comparator<Developer> byName = new Comparator<Developer>() {
		@Override
		public int compare(Developer o1, Developer o2) {
			return o1.getName().compareTo(o2.getName());
		}
	};
 Yeni biçim ⇓ Comparator<Developer> byName = (Developer o1, Developer o2)->o1.getName().compareTo(o2.getName());

2.foreach

Map<String, Integer> items = new HashMap<>();
	items.put("A", 10);
	items.put("B", 20);
	items.put("C", 30);
	items.put("D", 40);
	items.put("E", 50);
	items.put("F", 60);
	
	items.forEach((k,v)->System.out.println("Item : " + k + " Count : " + v));

3. A list of Strings to Uppercase

List<String> alpha = Arrays.asList("a", "b", "c", "d");

        //Before Java8
        List<String> alphaUpper = new ArrayList<>();
        for (String s : alpha) {
            alphaUpper.add(s.toUpperCase());
        }

        System.out.println(alpha); //[a, b, c, d]
        System.out.println(alphaUpper); //[A, B, C, D]

        // Java 8
        List<String> collect = 
            alpha.stream().map(String::toUpperCase).collect(Collectors.toList());
        System.out.println(collect); //[A, B, C, D]

        // Extra, streams apply to any data type.
        List<Integer> num = Arrays.asList(1,2,3,4,5);
        List<Integer> collect1 = num.stream().map(n -> 
                            n*2).collect(Collectors.toList());
        System.out.println(collect1); //[2, 4, 6, 8, 10]Filter Collection Dat

4. Filter Collection Data

import java.util.ArrayList;  
import java.util.List;  
import java.util.stream.Stream;   
class Product{  
    int id;  
    String name;  
    float price;  
    public Product(int id, String name, float price) {  
        super();  
        this.id = id;  
        this.name = name;  
        this.price = price;  
    }  
}  
public class Filter{  
    public static void main(String[] args) {  
        List<Product> list=new ArrayList<Product>();  
        list.add(new Product(1,"Samsung A5",17000f));  
        list.add(new Product(3,"Iphone 6S",65000f));  
        list.add(new Product(2,"Sony Xperia",25000f));  
        list.add(new Product(4,"Nokia Lumia",15000f));  
        list.add(new Product(5,"Redmi4 ",26000f));  
        list.add(new Product(6,"Lenevo Vibe",19000f));  
          
        // using lambda to filter data  
        Stream<Product> filtered_data = list.stream().filter(p -> p.price > 20000);  
          
        // using lambda to iterate through collection  
        filtered_data.forEach(  
                product -> System.out.println(product.name+": "+product.price)  
        );  
    }  
}

String new methods

Set<String> set1 = Set.of("a","b", "c");
List<String> list1 = List.of("a","b", "c");

Etiketler: ,

Yorum bırakın