mybatis-ehcache-spring

Why we need this project

The official mybatis-ehcache is very simple. It create ehcache like follow:

protected static CacheManager CACHE_MANAGER = CacheManager.create();

User can not set custom ehcache.xml, can not set custom CacheManager. https://github.com/mybatis/ehcache-cache

This project provide these feature:

• Load Ehcache config from custom ehcache.xml file or use a existed ehcache manager.
• Mybatis cache metrics.
• Spring integration.

##Example mybatis UserMapper xml:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="io.github.xdiamond.persistence.UserMapper">
  <resultMap id="BaseResultMap" type="io.github.xdiamond.domain.User">
  
  <cache type="io.github.hengyunabc.mybatis.FacadeCache">
  </cache>
</mapper>

spring application.xml

    <!-- this bean is important -->
	<bean  class="io.github.hengyunabc.mybatis.SharedSpringContextSetter">
	</bean>
	
	<bean id="ehCacheManager"
		class="org.springframework.cache.ehcache.EhCacheManagerFactoryBean">
		<property name="configLocation" value="classpath:my-ehcache.xml" />
	</bean>
	<!-- this bean name must be mybatisCacheDefaultFactory -->
	<bean id="mybatisCacheDefaultFactory" class="io.github.hengyunabc.mybatis.MybatisEhcacheFactory">
		<property name="cacheManager" ref="ehCacheManager"></property>
	</bean>
	
	<!-- define the SqlSessionFactory -->
	<bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean" >
		<property name="dataSource" ref="dataSource" />
		<property name="typeAliasesPackage" value="io.github.xdiamond.domain" />
	</bean>

	<!-- scan for mappers and let them be autowired -->
	<bean class="org.mybatis.spring.mapper.MapperScannerConfigurer" >
		<property name="basePackage" value="io.github.xdiamond.persistence" />
	</bean>

###How it works?

1. SharedSpringContextSetter set the concurrent spring context into SharedSpringContext.
2. When mybatis need a cache, it will new a cache object, In UserMapper.xml, cache class is FacadeCache.
3. When the FacadeCache construct, it will find SpringContext from SharedSpringContext, and get the io.github.hengyunabc.mybatis.CacheFactory bean. The CacheFactory default name is 'mybatisCacheDefaultFactory'.
4. MybatisEhcacheFactory will provide the read cache, which wrapped by FacadeCache.

public class MybatisEhcacheFactory implements CacheFactory {
  protected CacheManager cacheManager;
  CacheConfiguration cacheConfiguration;

  @Override
  public Cache getCache(String id) {
    if (!cacheManager.cacheExists(id)) {
      CacheConfiguration temp = null;
      if (cacheConfiguration != null) {
        temp = cacheConfiguration.clone();
      } else {
        // based on defaultCache
        temp = cacheManager.getConfiguration().getDefaultCacheConfiguration().clone();
      }
      temp.setName(id);
      net.sf.ehcache.Cache cache = new net.sf.ehcache.Cache(temp);
      cacheManager.addCache(cache);
    }
    return new EhcacheCache(id, cacheManager.getEhcache(id));

User can provide custom ehcache CacheManager and CacheConfiguration.

Mybatis Cache Metrics

• Config your metricRegistry.

https://github.com/ryantenney/metrics-spring

<metrics:metric-registry id="metricRegistry" />

• Use MybatisMetricsEhcacheFactory.

	<bean id="mybatisCacheDefaultFactory" class="io.github.hengyunabc.mybatis.MybatisMetricsEhcacheFactory">
		<property name="cacheManager" ref="ehCacheManager"></property>
		<property name="registry" ref="metricRegistry"></property>
	</bean>

The metrics result will like these:

net.sf.ehcache.Cache.io.github.xdiamond.persistence.UserMapper.eviction-count
             value = 0
net.sf.ehcache.Cache.io.github.xdiamond.persistence.UserMapper.hits
             value = 3
net.sf.ehcache.Cache.io.github.xdiamond.persistence.UserMapper.in-memory-hits
             value = 3
net.sf.ehcache.Cache.io.github.xdiamond.persistence.UserMapper.in-memory-misses
             value = 1
net.sf.ehcache.Cache.io.github.xdiamond.persistence.UserMapper.gets
             count = 4
         mean rate = 0.07 calls/second
     1-minute rate = 0.04 calls/second
     5-minute rate = 0.01 calls/second
    15-minute rate = 0.00 calls/second
               min = 0.06 milliseconds
               max = 0.18 milliseconds
              mean = 0.13 milliseconds
            stddev = 0.05 milliseconds
            median = 0.18 milliseconds
              75% <= 0.18 milliseconds
              95% <= 0.18 milliseconds
              98% <= 0.18 milliseconds
              99% <= 0.18 milliseconds
            99.9% <= 0.18 milliseconds
net.sf.ehcache.Cache.io.github.xdiamond.persistence.UserMapper.puts
             count = 1
         mean rate = 0.02 calls/second
     1-minute rate = 0.01 calls/second
     5-minute rate = 0.00 calls/second
    15-minute rate = 0.00 calls/second

maven repository

	<repositories>
		<repository>
			<id>hengyunabc-maven-repo</id>
			<url>https://raw.githubusercontent.com/hengyunabc/maven-repo/master/repository</url>
		</repository>
	</repositories>

More

Mybatis use mapper namespace for cache id, so you can config different cache for different table in your ehcache.xml

Licence

Apache License V2