org.eclipse.persistence.config

Class CacheUsage

java.lang.Object

org.eclipse.persistence.config.CacheUsage

public class CacheUsage
extends 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. Cache usage can also be used for modify Update-All and Delete-All queries. For modify-all queries it effects how the cache is updated, either NoCache or Invalidate. By default modify-all queries invalidate the cache. 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

Fields

Modifier and Type	Field and Description
static String	CheckCacheByExactPrimaryKey Configure the cache to be checked first if the query is by primary key (only).
static String	CheckCacheByPrimaryKey Configure the cache to be checked first if the query contains the primary key.
static String	CheckCacheOnly Configure the cache to be searched for any matching objects.
static String	CheckCacheThenDatabase Configure the cache to be searched for any matching object before accesing the database.
static String	ConformResultsInUnitOfWork Configure the query results to be conformed with the current persistence context.
static String	DEFAULT
static String	DoNotCheckCache Do not check the cache first, this is the default for JPA Queries.
static String	Invalidate Configures a modify-all query to invalidate the cache.
static String	NoCache Configures a modify-all query to not invalidate the cache.
static String	UseEntityDefault By default the descriptor default is used, which is to not check the cache first.

Constructor Summary

Constructors

Constructor and Description
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 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 String DoNotCheckCache

Do not check the cache first, this is the default for JPA Queries.

See Also:

Constant Field Values

CheckCacheByExactPrimaryKey

public static final 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 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 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 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 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

NoCache

public static final String NoCache

Configures a modify-all query to not invalidate the cache.

See Also:

Constant Field Values

Invalidate

public static final String Invalidate

Configures a modify-all query to invalidate the cache.

See Also:

Constant Field Values

DEFAULT

public static final String DEFAULT

See Also:

Constant Field Values

Constructor Detail

CacheUsage

public CacheUsage()