JAVA EE: How to use method reference in Java 8 Stream | Java 8 streams tutorial

Thursday 13 July 2017

How to use method reference in Java 8 Stream | Java 8 streams tutorial | Streams in Java 8

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Product.java

class Product
{
    private int id;
    private String name;
    private int price;

    public Product(int id, String name, int price)
    {
        super();
        this.id = id;
        this.name = name;
        this.price = price;
    }

    public int getId()
    {
        return id;
    }

    public void setId(int id)
    {
        this.id = id;
    }

    public String getName()
    {
        return name;
    }

    public void setName(String name)
    {
        this.name = name;
    }

    public int getPrice()
    {
        return price;
    }

    public void setPrice(int price)
    {
        this.price = price;
    }

    @Override
    public String toString()
    {
        return "Product [id=" + id + ", name=" + name + ", price="
                + price + "]";
    }

}

StreamDemo.java

import java.util.ArrayList;
import java.util.List;
import java.util.stream.Collectors;

/**
 * 
 * Method Reference in stream.
 * 
 */
public class StreamDemo
{
    public static void main(String[] args)
    {
        List<Product> productList = new ArrayList<Product>();

        // Adding Products
        productList.add(new Product(1, "Sony mobile", 25000));
        productList.add(new Product(2, "Lenovo mobile", 15000));
        productList.add(new Product(3, "Nokia mobile", 10000));
        productList.add(new Product(4, "Samsung mobile", 40000));
        productList.add(new Product(5, "Micromax mobile", 10000));

        List<String> productNameList = productList.stream()
                .filter(p -> p.getPrice() > 20000) // filtering data
                .map(Product::getName) // fetching Name by referring getName method
                .collect(Collectors.toList()); // collecting as list
        
        System.out.println(productNameList);

    }
}