Spring Boot + Hibernate Ehcache

Example Spring Boot + Hibernate + Ehcache project for demonstration purposes of cache mechanism. Detailed explanations here

Getting started

To run application:

mvn package && java -jar target\company-structure-hibernate-cache-1.0-SNAPSHOT.jar

Prerequisites:

• Java 8
• Maven
• H2/PostgreSQL

It is possible to run application in one of two profiles:

• h2
• postgres

depending on database engine chose for testing.

To enable cache statistics dev profile needs to be turned on.

Testing database schema

Configuration

Cache regions are configured via ehcache.xml file. Following regions are defined:

• companies by id

<cache name="company.byId"
           maxElementsInMemory="10000" eternal="false" timeToIdleSeconds="600"
           timeToLiveSeconds="3600" overflowToDisk="true"/>

• companies by name

<cache name="company.byName"
           maxElementsInMemory="10000" eternal="false" timeToIdleSeconds="600"
           timeToLiveSeconds="3600" overflowToDisk="true"/>

To enable cache mechanism @EnableCaching annotation is added to configuration class. Cache beans are created via annotation:

@Configuration
@EnableCaching(mode = AdviceMode.ASPECTJ)
public class CacheConfiguration {

    @Bean
    public EhCacheManagerFactoryBean ehCacheManagerFactory() {
        EhCacheManagerFactoryBean cacheManagerFactoryBean = new EhCacheManagerFactoryBean();
        cacheManagerFactoryBean.setConfigLocation(new ClassPathResource("ehcache.xml"));
        cacheManagerFactoryBean.setShared(true);

        return cacheManagerFactoryBean;
    }

    @Bean
    public EhCacheCacheManager ehCacheCacheManager() {
        EhCacheCacheManager cacheManager = new EhCacheCacheManager();
        cacheManager.setCacheManager(ehCacheManagerFactory().getObject());
        cacheManager.setTransactionAware(true);

        return cacheManager;
    }
}

Implementation

Caching rules are defined in CompanyRepository implementation:

• cache creation

@Cacheable(value = "company.byId", key = "#id", unless = "#result != null and #result.name.toUpperCase().startsWith('TEST')")
public Company find(Long id) {
    CriteriaBuilder builder = entityManager.getCriteriaBuilder();
    CriteriaQuery<Company> query = builder.createQuery(Company.class);

    Root<Company> root = query.from(Company.class);
    root.fetch(Company_.cars, JoinType.LEFT);
    Fetch<Company, Department> departmentFetch = root.fetch(Company_.departments, JoinType.LEFT);
    Fetch<Department, Employee> employeeFetch = departmentFetch.fetch(Department_.employees, JoinType.LEFT);
    employeeFetch.fetch(Employee_.address, JoinType.LEFT);
    departmentFetch.fetch(Department_.offices, JoinType.LEFT);

    query.select(root).distinct(true);
    Predicate idPredicate = builder.equal(root.get(Company_.id), id);
    query.where(builder.and(idPredicate));

    return DataAccessUtils.singleResult(entityManager.createQuery(query).getResultList());
}

@Cacheable(value = "company.byName", key = "#name", unless = "#name != null and #name.toUpperCase().startsWith('TEST')")
public Company find(String name) {
    CriteriaBuilder builder = entityManager.getCriteriaBuilder();
    CriteriaQuery<Company> query = builder.createQuery(Company.class);

    Root<Company> root = query.from(Company.class);
    root.fetch(Company_.cars, JoinType.LEFT);
    Fetch<Company, Department> departmentFetch = root.fetch(Company_.departments, JoinType.LEFT);
    Fetch<Department, Employee> employeeFetch = departmentFetch.fetch(Department_.employees, JoinType.LEFT);
    employeeFetch.fetch(Employee_.address, JoinType.LEFT);
    departmentFetch.fetch(Department_.offices, JoinType.LEFT);

    query.select(root).distinct(true);
    Predicate idPredicate = builder.equal(root.get(Company_.name), name);
    query.where(builder.and(idPredicate));

    return DataAccessUtils.singleResult(entityManager.createQuery(query).getResultList());
}

• cache invalidation

@Caching(evict = {@CacheEvict(value = "company.byId", key = "#company.id"), @CacheEvict(value = "company.byName", key = "#company.name")})
public void delete(Company company) {
    entityManager.remove(company);
}

• cache update

@Caching(evict = {@CacheEvict(value = "company.byName", allEntries = true), @CacheEvict(value = "company.byId", key = "#result.id", condition = "#result != null and #result.name.toUpperCase().startsWith('TEST')")},
            put = {@CachePut(value = "company.byId", key = "#result.id", unless = "#result != null and #result.name.toUpperCase().startsWith('TEST')")})
public Company update(Company company) {
    return entityManager.merge(company);
}

Cache statistics

Optionally it's possible to expose MBean to gather cache statistics:

@Bean
public MBeanServer mBeanServer() {
    MBeanServer mBeanServer = ManagementFactory.getPlatformMBeanServer();

    return mBeanServer;
}

@Bean
public ManagementService managementService() {
    ManagementService managementService = new ManagementService(ehCacheCacheManager.getCacheManager(), mBeanServer(), true, true, true, true);
    managementService.init();

    return managementService;
}