Integrating Spring and EHCache

Using Spring Modules and EHCache, one can transparently cache method results. Spring Modules uses a proxy which intercepts call to the method of bean; consults the cache to check if method was called with same parameters before, if so will return cached result.

EHCache is the actual provider of caching solution and Spring Module handles method interception and result storing in cache.

Since I am using Maven2, so added following dependancies -

        <dependency>
            <groupId>net.sf.ehcache</groupId>
            <artifactId>ehcache</artifactId>
            <version>1.6.1</version>
        </dependency>
        <dependency>
            <groupId>org.springmodules</groupId>
            <artifactId>spring-modules-cache</artifactId>
            <version>0.9</version>
        </dependency>

My complete pom.xml -

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <groupId>Spring</groupId>
    <artifactId>Spring</artifactId>
    <version>1.0</version>
    <dependencies>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-core</artifactId>
            <version>3.0.0.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.7</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-test</artifactId>
            <version>3.0.0.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-beans</artifactId>
            <version>3.0.0.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
            <version>3.0.0.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>cglib</groupId>
            <artifactId>cglib</artifactId>
            <version>2.2</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-aop</artifactId>
            <version>3.0.0.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>org.aspectj</groupId>
            <artifactId>aspectjweaver</artifactId>
            <version>1.6.6</version>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.10</version>
        </dependency>
        <dependency>
            <groupId>commons-dbcp</groupId>
            <artifactId>commons-dbcp</artifactId>
            <version>1.2.2</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-jdbc</artifactId>
            <version>3.0.0.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>net.sf.ehcache</groupId>
            <artifactId>ehcache</artifactId>
            <version>1.6.1</version>
        </dependency>
        <dependency>
            <groupId>org.springmodules</groupId>
            <artifactId>spring-modules-cache</artifactId>
            <version>0.9</version>
        </dependency>
    </dependencies>
</project>

Contact Table sql -

 CREATE TABLE `contact` (
  `ID` int(15) NOT NULL AUTO_INCREMENT,
  `FIRSTNAME` varchar(50) DEFAULT NULL,
  `LASTNAME` varchar(50) DEFAULT NULL,
  `EMAIL` varchar(150) DEFAULT NULL,
  PRIMARY KEY (`ID`),
  UNIQUE KEY `EMAIL` (`EMAIL`)
) ENGINE=MyISAM AUTO_INCREMENT=4 DEFAULT CHARSET=latin1

Adding ehcache namespace to Spring config file -

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:aop="http://www.springframework.org/schema/aop"
       xmlns:ehcache="http://www.springmodules.org/schema/ehcache"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
       http://www.springmodules.org/schema/ehcache http://www.springmodules.org/schema/cache/springmodules-ehcache.xsd
       http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop.xsd">
...
</beans>

Created ehcache.xml file in classpath.

<ehcache>
    <defaultCache
            maxElementsInMemory="500" eternal="true" overflowToDisk="false" memoryStoreEvictionPolicy="LFU"/>
    <cache name="contactCache" maxElementsInMemory="500" eternal="true" overflowToDisk="false"
           memoryStoreEvictionPolicy="LFU"/>
</ehcache>

Adding caching to application-context.xml –

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:aop="http://www.springframework.org/schema/aop"
       xmlns:ehcache="http://www.springmodules.org/schema/ehcache"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
       http://www.springmodules.org/schema/ehcache http://www.springmodules.org/schema/cache/springmodules-ehcache.xsd
       http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop.xsd">

    <ehcache:config configLocation="classpath:ehcache.xml" />

    <ehcache:proxy id="contactDAO" refId="contactDAOTarget">
        <ehcache:caching cacheName="contactCache" methodName="findAll"/>
        <ehcache:flushing cacheNames="contactCache" methodName="createContact" when="after"/>
    </ehcache:proxy>

    <bean id="contactDAOTarget" class="byteco.de.spring.ContactDAOImpl">
        <property name="namedParameterJdbcTemplate" ref="jdbcTemplate"></property>
    </bean>

    <bean id="datasource" class="org.apache.commons.dbcp.BasicDataSource">
        <property name="driverClassName" value="com.mysql.jdbc.Driver"/>
        <property name="username" value="root"/>
        <property name="password" value="password"/>
        <property name="initialSize" value="5"/>
        <property name="url" value="jdbc:mysql://localhost:3306/springjpa"/>
    </bean>

    <bean id="jdbcTemplate" class="org.springframework.jdbc.core.namedparam.NamedParameterJdbcTemplate">
        <constructor-arg type="javax.sql.DataSource" ref="datasource"/>
    </bean>
</beans>

Here is my test class -

package byteco.de.spring;

import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.dao.DuplicateKeyException;
import org.springframework.test.annotation.ExpectedException;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;

import java.util.List;

import static org.junit.Assert.assertTrue;

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(value = "/application-context.xml")
public class ContactDAOTest {

    @Autowired
    ContactDAO contactDAO;

    @Test
    public void shouldCreateNewContact(){
         assertTrue(contactDAO.createContact("gabbar","singh","gabbar@singh.com"));
         assertTrue(contactDAO.createContact("kalia","singh","kalia@singh.com"));
    }

    @Test
    public void shouldReturnListOfContact(){
        assertTrue(contactDAO.findAll().size()>0);
        assertTrue(contactDAO.findAll().size()>0);
        assertTrue(contactDAO.findAll().size()>0);
        // This will cause the cache to be cleared. refer to logs.
        assertTrue(contactDAO.createContact("samba","singh","samba@singh.com"));
        assertTrue(contactDAO.findAll().size()>0);
        assertTrue(contactDAO.findAll().size()>0);
        assertTrue(contactDAO.findAll().size()>0);
    }
}

Executed test shouldCreateNewContact first then shouldReturnListOfContact. Below is the console output -

DEBUG [org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor] - Autowiring by type from bean name 'byteco.de.spring.ContactDAOTest' to bean named 'contactDAO'
DEBUG [org.springframework.beans.factory.support.DefaultListableBeanFactory] - Returning cached instance of singleton bean 'org.springframework.aop.aspectj.AspectJPointcutAdvisor#0'
DEBUG [org.springframework.beans.factory.support.DefaultListableBeanFactory] - Returning cached instance of singleton bean 'org.springframework.aop.aspectj.AspectJPointcutAdvisor#0'
DEBUG [org.springmodules.cache.provider.ehcache.EhCacheFacade] - Attempt to retrieve a cache entry using key <2056181503|2056171012> and cache model <org.springmodules.cache.provider.ehcache.EhCacheCachingModel@1531164[cacheName='contactCache', blocking=false, cacheEntryFactory=null]>
DEBUG [org.springmodules.cache.provider.ehcache.EhCacheFacade] - Retrieved cache element <null>
DEBUG [org.springframework.jdbc.core.JdbcTemplate] - Executing prepared SQL query
DEBUG [org.springframework.jdbc.core.JdbcTemplate] - Executing prepared SQL statement [select * from contact]
DEBUG [org.springframework.jdbc.datasource.DataSourceUtils] - Fetching JDBC Connection from DataSource
DEBUG [org.springframework.jdbc.datasource.DataSourceUtils] - Returning JDBC Connection to DataSource
DEBUG [org.springmodules.cache.provider.ehcache.EhCacheFacade] - Attempt to store the object <[0. 1 gabbar singh , 1. 2 kalia singh ]> in the cache using key <2056181503|2056171012> and model <org.springmodules.cache.provider.ehcache.EhCacheCachingModel@1531164[cacheName='contactCache', blocking=false, cacheEntryFactory=null]>
DEBUG [org.springmodules.cache.provider.ehcache.EhCacheFacade] - Object was successfully stored in the cache
DEBUG [org.springmodules.cache.provider.ehcache.EhCacheFacade] - Attempt to retrieve a cache entry using key <2056181503|2056171012> and cache model <org.springmodules.cache.provider.ehcache.EhCacheCachingModel@1531164[cacheName='contactCache', blocking=false, cacheEntryFactory=null]>
DEBUG [org.springmodules.cache.provider.ehcache.EhCacheFacade] - Retrieved cache element <[0. 1 gabbar singh , 1. 2 kalia singh ]>
DEBUG [org.springmodules.cache.provider.ehcache.EhCacheFacade] - Attempt to retrieve a cache entry using key <2056181503|2056171012> and cache model <org.springmodules.cache.provider.ehcache.EhCacheCachingModel@1531164[cacheName='contactCache', blocking=false, cacheEntryFactory=null]>
DEBUG [org.springmodules.cache.provider.ehcache.EhCacheFacade] - Retrieved cache element <[0. 1 gabbar singh , 1. 2 kalia singh ]>
DEBUG [org.springframework.jdbc.core.JdbcTemplate] - Executing prepared SQL update
DEBUG [org.springframework.jdbc.core.JdbcTemplate] - Executing prepared SQL statement [insert into contact (firstname,lastname,email) values (?,?,?)]
DEBUG [org.springframework.jdbc.datasource.DataSourceUtils] - Fetching JDBC Connection from DataSource
DEBUG [org.springframework.jdbc.core.JdbcTemplate] - SQL update affected 1 rows
DEBUG [org.springframework.jdbc.datasource.DataSourceUtils] - Returning JDBC Connection to DataSource
DEBUG [org.springmodules.cache.provider.ehcache.EhCacheFacade] - Attempt to flush the cache using model <org.springmodules.cache.provider.ehcache.EhCacheFlushingModel@2dd59d3c[cacheNames={'contactCache'}, flushBeforeMethodExecution=false]>
DEBUG [org.springmodules.cache.provider.ehcache.EhCacheFacade] - Cache has been flushed.
DEBUG [org.springmodules.cache.provider.ehcache.EhCacheFacade] - Attempt to retrieve a cache entry using key <2056181503|2056171012> and cache model <org.springmodules.cache.provider.ehcache.EhCacheCachingModel@1531164[cacheName='contactCache', blocking=false, cacheEntryFactory=null]>
DEBUG [org.springmodules.cache.provider.ehcache.EhCacheFacade] - Retrieved cache element <null>
DEBUG [org.springframework.jdbc.core.JdbcTemplate] - Executing prepared SQL query
DEBUG [org.springframework.jdbc.core.JdbcTemplate] - Executing prepared SQL statement [select * from contact]
DEBUG [org.springframework.jdbc.datasource.DataSourceUtils] - Fetching JDBC Connection from DataSource
DEBUG [org.springframework.jdbc.datasource.DataSourceUtils] - Returning JDBC Connection to DataSource
DEBUG [org.springmodules.cache.provider.ehcache.EhCacheFacade] - Attempt to store the object <[0. 1 gabbar singh , 1. 2 kalia singh , 2. 3 samba singh ]> in the cache using key <2056181503|2056171012> and model <org.springmodules.cache.provider.ehcache.EhCacheCachingModel@1531164[cacheName='contactCache', blocking=false, cacheEntryFactory=null]>
DEBUG [org.springmodules.cache.provider.ehcache.EhCacheFacade] - Object was successfully stored in the cache
DEBUG [org.springmodules.cache.provider.ehcache.EhCacheFacade] - Attempt to retrieve a cache entry using key <2056181503|2056171012> and cache model <org.springmodules.cache.provider.ehcache.EhCacheCachingModel@1531164[cacheName='contactCache', blocking=false, cacheEntryFactory=null]>
DEBUG [org.springmodules.cache.provider.ehcache.EhCacheFacade] - Retrieved cache element <[0. 1 gabbar singh , 1. 2 kalia singh , 2. 3 samba singh ]>
DEBUG [org.springmodules.cache.provider.ehcache.EhCacheFacade] - Attempt to retrieve a cache entry using key <2056181503|2056171012> and cache model <org.springmodules.cache.provider.ehcache.EhCacheCachingModel@1531164[cacheName='contactCache', blocking=false, cacheEntryFactory=null]>
DEBUG [org.springmodules.cache.provider.ehcache.EhCacheFacade] - Retrieved cache element <[0. 1 gabbar singh , 1. 2 kalia singh , 2. 3 samba singh ]>

Here are my DAO classes –

package byteco.de.spring;
import java.util.List;
public interface ContactDAO {
    boolean createContact(String firstName, String lastName, String email);
    List findAll();
}

package byteco.de.spring;

import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.jdbc.core.RowMapper;
import org.springframework.jdbc.core.namedparam.NamedParameterJdbcTemplate;

import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

public class ContactDAOImpl implements ContactDAO {

    private NamedParameterJdbcTemplate namedParameterJdbcTemplate;

    public void setNamedParameterJdbcTemplate(NamedParameterJdbcTemplate namedParameterJdbcTemplate) {
        this.namedParameterJdbcTemplate = namedParameterJdbcTemplate;
    }

    public boolean createContact(String firstName, String lastName, String email) {
        Map<String,String> map = new HashMap<String, String>();
        map.put("firstname",firstName);
        map.put("lastname",lastName);
        map.put("email",email);
        int i = namedParameterJdbcTemplate.update("insert into contact (firstname,lastname,email) values (:firstname,:lastname,:email)", map);
        return i>0;
    }

    public List findAll() {
        return namedParameterJdbcTemplate.query("select * from contact", (Map<String, ?>) null, new RowMapper() {
            public Object mapRow(ResultSet resultSet, int i) throws SQLException {
                return i + ". " + resultSet.getString(1) + " " + resultSet.getString(2) + " " + resultSet.getString(3) + " ";
            }
        });
    }
}

We are caching the result of findAll and clearing cache when createContact is executed.

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