Cache (Apache Jena Base)

All Known Implementing Classes:

Cache0, Cache1, CacheGuava, CacheSimple, CacheWrapper
```
public interface Cache<Key,Value>
```
A cache

Method Summary

All Methods Instance Methods Abstract Methods
Modifier and Type	Method	Description
`void`	`clear()`
`boolean`	`containsKey(Key key)`	Does the cache contain the key?
`Value`	`getIfPresent(Key key)`	Get from cache - or return null.
`Value`	`getOrFill(Key key, java.util.concurrent.Callable<Value> callable)`	Get from cache, of not present, call the `Callable` to try to fill the cache.
`boolean`	`isEmpty()`
`java.util.Iterator<Key>`	`keys()`	Iterate over all keys.
`void`	`put(Key key, Value thing)`	Insert into the cache
`void`	`remove(Key key)`	Remove from cache - return true if key referenced an entry
`void`	`setDropHandler(java.util.function.BiConsumer<Key,Value> dropHandler)`	Register a callback - called when an object is dropped from the cache (optional operation)
`long`	`size()`	Current size of cache

- Method Detail
  - containsKey
```
boolean containsKey(Key key)
```
    Does the cache contain the key?
  - getIfPresent
```
Value getIfPresent(Key key)
```
    Get from cache - or return null.
  - getOrFill
```
Value getOrFill(Key key,
                java.util.concurrent.Callable<Value> callable)
```
    Get from cache, of not present, call the Callable to try to fill the cache. This operation should be atomic.
  - put
```
void put(Key key,
         Value thing)
```
    Insert into the cache
  - remove
```
void remove(Key key)
```
    Remove from cache - return true if key referenced an entry
  - keys
```
java.util.Iterator<Key> keys()
```
    Iterate over all keys. Iterating over the keys requires the caller be thread-safe.
  - isEmpty
```
boolean isEmpty()
```
  - clear
```
void clear()
```
  - size
```
long size()
```
    Current size of cache
  - setDropHandler
```
void setDropHandler(java.util.function.BiConsumer<Key,Value> dropHandler)
```
    Register a callback - called when an object is dropped from the cache (optional operation)