Guava: Cache: Get Cache statistics

CacheStats class is used to track  Statistics about the performance of a Cache. CacheStats instances are immutable.

 

To get statistics of a Cache instance, we need to enable the accumulation of statistics while creating Cache instance. you can do this using recordStats() method of CacheBuilder class.

 

Cache<Integer, Employee> empCache = CacheBuilder.newBuilder().maximumSize(500)

.expireAfterWrite(10, TimeUnit.SECONDS).recordStats().build();

 

How to get CacheStats instance?

You can get it by calling stats() method of Cache object.

CacheStats cacheStats = empCache.stats();

 

Find the below working application.

 

Employee.java

package com.sample.app.cache.model;

public class Employee {
	private Integer id;
	private String firstName;
	private String lastName;

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

	public Integer getId() {
		return id;
	}

	public void setId(Integer 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 + "]";
	}

}

 

HelloWorld.java

package com.sample.app.cache;

import java.util.Arrays;
import java.util.List;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.TimeUnit;

import com.google.common.cache.Cache;
import com.google.common.cache.CacheBuilder;
import com.google.common.cache.CacheStats;
import com.sample.app.cache.model.Employee;

public class HelloWorld {
	private static void printEmployee(Employee emp, Integer id) {
		if (emp == null) {
			System.out.println("Employee not exist for the id " + id);
			return;
		}
		System.out.println(emp);
	}

	private static void getAndPrintObjects(Cache<Integer, Employee> empCache, List<Integer> empIds)
			throws ExecutionException {

		for (Integer id : empIds) {
			Employee emp = empCache.getIfPresent(id);
			printEmployee(emp, id);
		}
	}

	public static void main(String args[]) throws InterruptedException, ExecutionException {

		Cache<Integer, Employee> empCache = CacheBuilder.newBuilder().maximumSize(500)
				.expireAfterWrite(10, TimeUnit.SECONDS).recordStats().build();

		empCache.put(1, new Employee(1, "Krishna", "Gurram"));
		empCache.put(3, new Employee(3, "Chamu", "M"));

		System.out.println("Getting employee with ids 1, 2 and 3 from empCache");
		getAndPrintObjects(empCache, Arrays.asList(1, 2, 3));

		CacheStats cacheStats = empCache.stats();

		System.out.println("\n" + cacheStats);

	}

}

Output

Getting employee with ids 1, 2 and 3 from empCache
Employee [id=1, firstName=Krishna, lastName=Gurram]
Employee not exist for the id 2
Employee [id=3, firstName=Chamu, lastName=M]

CacheStats{hitCount=2, missCount=1, loadSuccessCount=0, loadExceptionCount=0, totalLoadTime=0, evictionCount=0}

 

 

 

 

 

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