Java Reference
In-Depth Information
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EntityManager em = ...;
Cache cache = em.getEntityManagerFactory().getCache();
String personPK = ...;
if (cache.contains(Person.class, personPK)) {
// the data is cached
} else {
// the data is NOT cached
}
Removing an Entity from the Cache
Call one of the Cache.evict methods to remove a particular entity or all entities of a
given type from the second-level cache. To remove a particular entity from the cache, call
the evict method and pass in the entity class and the primary key of the entity:
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EntityManager em = ...;
Cache cache = em.getEntityManagerFactory().getCache();
String personPK = ...;
cache.evict(Person.class, personPK);
To remove all instances of a particular entity class, including subclasses, call the evict
method and specify the entity class:
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EntityManager em = ...;
Cache cache = em.getEntityManagerFactory().getCache();
cache.evict(Person.class);
All instances of the Person entity class will be removed from the cache. If the Person
entity has a subclass, Student , calls to the above method will remove all instances of
Student from the cache as well.
Removing All Data from the Cache
Call the Cache.evictAll method to completely clear the second-level cache:
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EntityManager em = ...;
Cache cache = em.getEntityManagerFactory().getCache();
cache.evictAll();
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