EclipseLink1.0 - 20080707 API Reference

org.eclipse.persistence.config
Class CacheUsage

java.lang.Object
  extended by org.eclipse.persistence.config.CacheUsage

public class CacheUsage
extends java.lang.Object

Cache usage hint values. Cache usage allows the cache to be used on queries to avoid accessing the database. By default for JPA queries the cache is not checked before accessing the database, but is used after accessing the database to avoid re-building the objects and avoid accessing the database for relationships. The class contains all the valid values for QueryHints.CACHE_USAGE query hint.

JPA Query Hint Usage:

query.setHint(QueryHints.CACHE_USAGE, CacheUsage.CheckCacheOnly);

or

@QueryHint(name=QueryHints.CACHE_USAGE, value=CacheUsage.CheckCacheOnly)

Hint values are case-insensitive. "" could be used instead of default value CacheUsage.DEFAULT.

See Also:
QueryHints

Field Summary
static java.lang.String CheckCacheByExactPrimaryKey
          Configure the cache to be checked first if the query is by primary key (only).
static java.lang.String CheckCacheByPrimaryKey
          Configure the cache to be checked first if the query contains the primary key.
static java.lang.String CheckCacheOnly
          Configure the cache to be searched for any matching objects.
static java.lang.String CheckCacheThenDatabase
          Configure the cache to be searched for any matching object before accesing the database.
static java.lang.String ConformResultsInUnitOfWork
          Configure the query results to be conformed with the current persistence context.
static java.lang.String DEFAULT
           
static java.lang.String DoNotCheckCache
          Do not check the cache first, this is the default for JPA Queries.
static java.lang.String UseEntityDefault
          By default the descriptor default is used, which is to not check the cache first.
 
Constructor Summary
CacheUsage()
           
 
Method Summary
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

UseEntityDefault

public static final java.lang.String UseEntityDefault
By default the descriptor default is used, which is to not check the cache first.

See Also:
Constant Field Values

DoNotCheckCache

public static final java.lang.String DoNotCheckCache
Do not check the cache first, this is the default for JPA Queries.

See Also:
Constant Field Values

CheckCacheByExactPrimaryKey

public static final java.lang.String CheckCacheByExactPrimaryKey
Configure the cache to be checked first if the query is by primary key (only). This can only be used on queries that return a single entity.

See Also:
Constant Field Values

CheckCacheByPrimaryKey

public static final java.lang.String CheckCacheByPrimaryKey
Configure the cache to be checked first if the query contains the primary key. This can only be used on queries that return a single entity.

See Also:
Constant Field Values

CheckCacheThenDatabase

public static final java.lang.String CheckCacheThenDatabase
Configure the cache to be searched for any matching object before accesing the database. This can only be used on queries that return a single entity.

See Also:
Constant Field Values

CheckCacheOnly

public static final java.lang.String CheckCacheOnly
Configure the cache to be searched for any matching objects. Any objects not currently in the cache will not be returned. This can only be used on queries that return a single set of entities.

See Also:
Constant Field Values

ConformResultsInUnitOfWork

public static final java.lang.String ConformResultsInUnitOfWork
Configure the query results to be conformed with the current persistence context. This allows non-flushed changes to be included in the query. This can only be used on queries that return a single set of entities.

See Also:
Constant Field Values

DEFAULT

public static final java.lang.String DEFAULT
See Also:
Constant Field Values
Constructor Detail

CacheUsage

public CacheUsage()

EclipseLink1.0 - 20080707 API Reference