Cache (Jakarta EE Platform API)

```
public interface Cache
```
Interface used to interact with the second-level cache. If a cache is not in use, the methods of this interface have no effect, except for contains, which returns false.

Since:

2.0

Method Summary

All Methods Instance Methods Abstract Methods
Modifier and Type	Method	Description
`boolean`	`contains(Class cls, Object primaryKey)`	Whether the cache contains data for the given entity.
`void`	`evict(Class cls)`	Remove the data for entities of the specified class (and its subclasses) from the cache.
`void`	`evict(Class cls, Object primaryKey)`	Remove the data for the given entity from the cache.
`void`	`evictAll()`	Clear the cache.
`<T> T`	`unwrap(Class<T> cls)`	Return an object of the specified type to allow access to the provider-specific API.

- Method Detail
  - contains
```
boolean contains(Class cls,
                 Object primaryKey)
```
    Whether the cache contains data for the given entity.
    
    Parameters:
    
    cls - entity class
    
    primaryKey - primary key
    
    Returns:
    
    boolean indicating whether the entity is in the cache
  - evict
```
void evict(Class cls,
           Object primaryKey)
```
    Remove the data for the given entity from the cache.
    
    Parameters:
    
    cls - entity class
    
    primaryKey - primary key
  - evict
```
void evict(Class cls)
```
    Remove the data for entities of the specified class (and its subclasses) from the cache.
    
    Parameters:
    
    cls - entity class
  - evictAll
```
void evictAll()
```
    Clear the cache.
  - unwrap
```
<T> T unwrap(Class<T> cls)
```
    Return an object of the specified type to allow access to the provider-specific API. If the provider's Cache implementation does not support the specified class, the PersistenceException is thrown.
    
    Parameters:
    
    cls - the class of the object to be returned. This is normally either the underlying Cache implementation class or an interface that it implements.
    
    Returns:
    
    an instance of the specified class
    
    Throws:
    
    PersistenceException - if the provider does not support the call
    
    Since:
    
    2.1