Package org.eclipse.persistence.config

Class FlushClearCache

  • public class FlushClearCache
extends java.lang.Object
    FlushClearCache persistence property defines modes of cache handling after em.flush call followed by em.clear call. This property could be specified while creating either EntityManagerFactory (createEntityManagerFactory or persistence.xml) or EntityManager (createEntityManager); the latter overrides the former.

    JPA persistence property Usage:

    properties.add(PersistenceUnitProperties.FLUSH_CLEAR_CACHE, FlushClearCache.Drop);

    Values are case-insensitive. "" could be used instead of default value FlushClearCache.DEFAULT.

    • Field Summary

      Fields 
      Modifier and Type Field Description
      static java.lang.String DEFAULT  
      static java.lang.String Drop
      Call to clear method causes to drop the whole EntityManager cache.
      static java.lang.String DropInvalidate
      Call to clear method causes to drops the whole EntityManager cache, on commit the classes that have at least one object updated or deleted are invalidated in the shared cache.
      static java.lang.String Merge
      Call to clear method causes to drop from EntityManager cache only the objects that haven't been flushed.

    • Constructor Summary

      Constructors 
      Constructor Description
      FlushClearCache()  

    • Method Summary

      • Methods inherited from class java.lang.Object

        clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

    • Field Detail

      • Merge

        public static final java.lang.String Merge
        Call to clear method causes to drop from EntityManager cache only the objects that haven't been flushed. This is the most accurate mode: shared cache is perfect after commit; but the least memory effective: smbd repeatedly using flush followed by clear may eventually run out of memory in a huge transaction.
        See Also:
        Constant Field Values

      • Drop

        public static final java.lang.String Drop
        Call to clear method causes to drop the whole EntityManager cache. This is the fasteset and using the least memory mode - but after commit the shared cache potentially contains stale data.
        See Also:
        Constant Field Values

      • DropInvalidate

        public static final java.lang.String DropInvalidate
        Call to clear method causes to drops the whole EntityManager cache, on commit the classes that have at least one object updated or deleted are invalidated in the shared cache. This is a compromise mode: potentially a bit slower than drop, but has virtually the same memory efficiency. After commit all potentially stale data is invalidated in the shared cache.
        See Also:
        Constant Field Values

    • Constructor Detail

      • FlushClearCache

        public FlushClearCache()