CacheUsage (EclipseLink 2.6.1, API Reference)

java.lang.Object
- 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. 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 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`	`Invalidate` Configures a modify-all query to invalidate the cache.
`static java.lang.String`	`NoCache` Configures a modify-all query to not invalidate the cache.
`static java.lang.String`	`UseEntityDefault` By default the descriptor default is used, which is to not check the cache first.

Constructor Summary

Constructors
Constructor and Description

CacheUsage()

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 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
  - NoCache
```
public static final java.lang.String NoCache
```
    Configures a modify-all query to not invalidate the cache.
    
    See Also:
    Constant Field Values
  - Invalidate
```
public static final java.lang.String Invalidate
```
    Configures a modify-all query to invalidate the cache.
    
    See Also:
    Constant Field Values
  - DEFAULT
```
public static final java.lang.String DEFAULT
```
    See Also:
    Constant Field Values
- Constructor Detail
  - CacheUsage
```
public CacheUsage()
```

Class CacheUsage

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

UseEntityDefault

DoNotCheckCache

CheckCacheByExactPrimaryKey

CheckCacheByPrimaryKey

CheckCacheThenDatabase

CheckCacheOnly

ConformResultsInUnitOfWork

NoCache

Invalidate

DEFAULT

Constructor Detail

CacheUsage