New Feature! Preloading Configurable Dao's

Introduction

If you have some static data - or any data you would like to preload into a cache on container startup, Crank now supports this capability through the GenericDao support.

Details

Purpose:

Preloads data into second level cache on container startup (per configuration). Note that in the current implementation entities MUST be annotated with @Cache to get preloaded/cached. (configurable generic dao's now support spring-configured caching setup). Tested only with EHCache so far. EHCache 1.3.0 is required for JMX MBean integration.

Use GenericDaoFactory

Give it some cache configuration. <bean id="preloadingEmployeeDao" parent="daoFactory" lazy-init="true"> <property name="interface"> <value>org.crank.crud.test.dao.EmployeeDAO</value> </property> <property name="bo"> <value>org.crank.crud.test.model.Employee</value> </property> <property name="preloadConfiguration"> <bean class="org.crank.crud.cache.PreloadConfiguration"> <property name="preloadingRecordCount" value="10" /> </bean> </property> </bean> It will get instanced as a PreloadableCacheableGenericDao rather than a standard GenericDao.

From the above example, PreloadableCacheableGenericDao will load up the first ten records existing in the table the Employee pojo is mapped to.

You can also configure the preload with some JQL. <property name="preloadConfiguration"> <bean class="org.crank.crud.cache.PreloadConfiguration"> <property name="preloadingHQL" value="from Employee e where e." /> </bean> </property>

Finally, if you need to override the lazy-load behavior of one of your model objects, forcing a full load for the cached copies, you can use the initialize children option: <bean id="preloadingEmployeeDao" parent="daoFactory" lazy-init="true"> <property name="interface"> <value>org.crank.crud.test.dao.EmployeeDAO</value> </property> <property name="bo"> <value>org.crank.crud.test.model.Employee</value> </property> <property name="preloadConfiguration"> <bean class="org.crank.crud.cache.PreloadConfiguration"> <property name="preloadingRecordCount" value="10" /> <property name="childrenToInitialize"> <list> <value>getDepartment</value> </list> </property> </bean> </property> </bean> EHCache support

To use with ehcache, you must configure your persistence.xml to use ehcache: <property name="hibernate.cache.provider_configuration_file_resource_path" value="org/crank/crud/cache/spring/crank-test-ehcache.xml" /> <property name="hibernate.cache.provider_class" value="org.hibernate.cache.EhCacheProvider" /> <property name="hibernate.cache.use_second_level_cache" value="true" />

You will need a cache service entry in a context file, and utilize the EHCacheManagerFactoryBean. <bean id="ehCacheService" class="org.crank.crud.cache.EHCacheService"> <property name="setupMBeans" value="true" /> </bean>