Let’s continue with our lessons during this corona lockdown. In the last two posts we discussed textblocks and instanceof in Java 13 and 14.

• improved instanceof
• text blocks

In this post, we’ll discuss a very cool feature introduced in Java 14, record.

Say, you have a shopping cart that is a collection of ShoppingItem with id, name, price and quantity members. Building this will involve writing so many lines of code as shown below.

class ShoppingItem {
   private int id;	
   private String name;
   private double price;
   private int quantity;
	
   public ShoppingItem(int id, String name, double price, int quantity) {
	this.id = id;
	this.name = name;
	this.price = price;
	this.quantity = quantity;
   }
	
   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 double getPrice() {
	return price;
   }
   public void setPrice(double price) {
	this.price = price;
   }
   public int getQuantity() {
	return quantity;
   }
   public void setQuantity(int quantity) {
	this.quantity = quantity;
   }
	
   public int hashCode() {
	return id;
   }
	
   public boolean equals(Object obj) {
	if(obj instanceof ShoppingItem item) {
		return item.id == this.id;
	}
	return false;
   }
   
   public String toString() {
	return name;
   }
}

public class RecordsExample {
   public static void main(String[] args) {
	ShoppingItem book = new ShoppingItem(21321, "Programming Java", 12.34, 1);
	ShoppingItem mobile = new ShoppingItem(21233, "iPhone 11 pro", 999, 1);
	List<ShoppingItem> cart = Arrays.asList(book, mobile);
	cart.forEach(System.out::println);
   }
}

Phew! That’s lot of code for just storing some data

Image source: https://blog.submain.com/evaluate-code-readability/

Enter record

ShoppingItem class can be replaced with just one line code using a record. If you define a class as record with the members, the hashCode(), equals(), toString(), getters/setters are automatically generated for you by the compiler. So the code using record is as shown below.

public class RecordsExample {
   record ShoppingItem(int id, String name, double price, int quantity) {}
   public static void main(String[] args) {
	ShoppingItem book = new ShoppingItem(21321, "Programming Java", 12.34, 1);
	ShoppingItem mobile = new ShoppingItem(21233, "iPhone 11 pro", 999, 1);
	List<ShoppingItem> cart = Arrays.asList(book, mobile);
	cart.forEach(System.out::println);
  }
}

This one line
record ShoppingItem(int id, String name, double price, int quantity) {}
does the trick

Record in Java, in short is a data class or a tuple that’s a simple data structure.

Please remember to compile using –enable-preview and –release 14 switches