SoftCache (Hive Standalone Metastore Common Code 4.0.0 API)

java.lang.Object
- org.apache.hadoop.hive.metastore.properties.SoftCache<K,V>

Type Parameters:

K - the cache key entry type

V - the cache key value type
```
public class SoftCache<K,V>
extends Object
```
A soft referenced cache.
The actual cache is held through a soft reference, allowing it to be GCed under memory pressure.

This class is not thread-safe.

Constructor Summary

Constructors
Constructor and Description
`SoftCache()` Creates a new instance of a soft cache.
`SoftCache(int theCapacity)` Creates a new instance of a soft cache.
`SoftCache(int theCapacity, float theLoadFactor, boolean synchronizd)` Creates a new instance of a soft cache.

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`int`	`capacity()` Returns the cache capacity.
`void`	`clear()` Clears the cache.
`V`	`compute(K key, BiFunction<? super K,? super V,? extends V> remappingFunction)` Calls compute on underlying map, useful when cache is meant to behave as a pull-thru.
`V`	`computeIfAbsent(K key, Function<? super K,? extends V> mappingFunction)` Calls computeIfAbsent on underlying map, useful when cache is meant to behave as a pull-thru.
`boolean`	`containsKey(K key)`
`protected Map<K,V>`	`createCache(int capacity, float loadFactor, boolean synchro)` Creates the underlying cache map.
`Set<Map.Entry<K,V>>`	`entrySet()` Produces the cache entry set.
`V`	`get(K key)` Gets a value from cache.
`V`	`put(K key, V value)` Puts a value in cache.
`V`	`putIfAbsent(K key, V value)` Calls putIfAbsent on underlying map, useful when cache is meant to behave as a pull-thru.
`V`	`remove(K key)` Removes a value from cache.
`int`	`size()` Returns the cache size.
`Collection<V>`	`values()` Produces the cache values collection.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Constructor Detail
  - SoftCache
```
public SoftCache()
```
    Creates a new instance of a soft cache.
  - SoftCache
```
public SoftCache(int theCapacity)
```
    Creates a new instance of a soft cache.
    
    Parameters:
    
    theCapacity - the cache size
  - SoftCache
```
public SoftCache(int theCapacity,
                 float theLoadFactor,
                 boolean synchronizd)
```
    Creates a new instance of a soft cache.
    
    Parameters:
    
    theCapacity - the cache capacity
    
    theLoadFactor - the cache load actor
    
    synchronizd - whether it is synchronized or not
- Method Detail
  - capacity
```
public int capacity()
```
    Returns the cache capacity.
    
    Returns:
    
    the cache capacity
  - size
```
public int size()
```
    Returns the cache size.
    
    Returns:
    
    the cache size
  - clear
```
public void clear()
```
    Clears the cache.
  - entrySet
```
public Set<Map.Entry<K,V>> entrySet()
```
    Produces the cache entry set.
    
    Returns:
    
    the cache entry set
  - values
```
public Collection<V> values()
```
    Produces the cache values collection.
    
    Returns:
    
    the cache values collection
  - containsKey
```
public boolean containsKey(K key)
```
  - get
```
public V get(K key)
```
    Gets a value from cache.
    
    Parameters:
    
    key - the cache entry key
    
    Returns:
    
    the cache entry value
  - put
```
public V put(K key,
             V value)
```
    Puts a value in cache.
    
    Parameters:
    
    key - the cache entry key
    
    value - the cache entry value
    
    Returns:
    
    the previous value if any
  - putIfAbsent
```
public V putIfAbsent(K key,
                     V value)
```
    Calls putIfAbsent on underlying map, useful when cache is meant to behave as a pull-thru.
    
    Parameters:
    
    key - tke key
    
    value - the value
    
    Returns:
    
    the value associated to the key
  - computeIfAbsent
```
public V computeIfAbsent(K key,
                         Function<? super K,? extends V> mappingFunction)
```
    Calls computeIfAbsent on underlying map, useful when cache is meant to behave as a pull-thru.
    
    Parameters:
    
    key - tke key
    
    mappingFunction - the function called if key does not associate to a value
    
    Returns:
    
    the value associated to the key
  - compute
```
public V compute(K key,
                 BiFunction<? super K,? super V,? extends V> remappingFunction)
```
    Calls compute on underlying map, useful when cache is meant to behave as a pull-thru.
    
    Parameters:
    
    key - tke key
    
    remappingFunction - the function called if key does not associate to a value
    
    Returns:
    
    the value associated to the key
  - remove
```
public V remove(K key)
```
    Removes a value from cache.
    
    Parameters:
    
    key - the cache entry key
    
    Returns:
    
    the cache entry value
  - createCache
```
protected Map<K,V> createCache(int capacity,
                               float loadFactor,
                               boolean synchro)
```
    Creates the underlying cache map.
    
    Parameters:
    
    capacity - the cache size, must be > 0
    
    loadFactor - the cache load factor
    
    synchro - whether the cache is synchronized or not
    
    Returns:
    
    a Map usable as a cache bounded to the given size

Class SoftCache<K,V>

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

SoftCache

SoftCache

SoftCache

Method Detail

capacity

size

clear

entrySet

values

containsKey

get

put

putIfAbsent

computeIfAbsent

compute

remove

createCache