Caffeine: Invalidate (or) delete an entry from cache

‘invalidate’ method is used discard any cached value for the given key.

 

Example

cache.invalidate(2);

 

Find the below working application.

 

Employee.java

package com.sample.app.model;

public class Employee {

	private int id;
	private String firstName;
	private String lastName;

	public Employee(int id, String firstName, String lastName) {
		super();
		this.id = id;
		this.firstName = firstName;
		this.lastName = lastName;
	}

	public int getId() {
		return id;
	}

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

	public String getFirstName() {
		return firstName;
	}

	public void setFirstName(String firstName) {
		this.firstName = firstName;
	}

	public String getLastName() {
		return lastName;
	}

	public void setLastName(String lastName) {
		this.lastName = lastName;
	}

	@Override
	public String toString() {
		return "Employee [id=" + id + ", firstName=" + firstName + ", lastName=" + lastName + "]";
	}

}

 

App.java

package com.sample.app;

import java.util.Map;
import java.util.concurrent.TimeUnit;

import com.github.benmanes.caffeine.cache.Cache;
import com.github.benmanes.caffeine.cache.Caffeine;
import com.sample.app.model.Employee;

public class App {

	private static void printCache(Cache cache) {
		System.out.println("\nElements of cache are");
		Map map = cache.asMap();

		for (Object key : map.keySet()) {
			System.out.println(map.get(key));
		}
	}

	public static void main(String args[]) throws InterruptedException {
		Cache<Integer, Employee> cache = Caffeine.newBuilder().expireAfterWrite(5, TimeUnit.MINUTES).recordStats().build();

		Employee emp1 = new Employee(1, "Krishna", "Gurram");
		Employee emp2 = new Employee(2, "Gopi", "Battu");
		Employee emp3 = new Employee(3, "Saurav", "Sarkar");

		cache.put(emp1.getId(), emp1);
		cache.put(emp2.getId(), emp2);
		cache.put(emp3.getId(), emp3);

		System.out.println("Inserted 3 entries into the cache");
		printCache(cache);
		
		System.out.println("\nDeleting an entry with id 2");
		cache.invalidate(emp2.getId());
		printCache(cache);
		
	}

}

 

Output

Inserted 3 entries into the cache

Elements of cache are
Employee [id=1, firstName=Krishna, lastName=Gurram]
Employee [id=2, firstName=Gopi, lastName=Battu]
Employee [id=3, firstName=Saurav, lastName=Sarkar]

Deleting an entry with id 2

Elements of cache are
Employee [id=1, firstName=Krishna, lastName=Gurram]
Employee [id=3, firstName=Saurav, lastName=Sarkar]

 

 

 

 

 

  

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