TwoQueueCache (egothor2 4.0.5-SNAPSHOT API)

java.lang.Object
- org.egothor.cache.AbstractCache<K,V>
- - org.egothor.cache.twoQueue.TwoQueueCache<K,V>

Type Parameters:

K - type of the key

V - type of the value

All Implemented Interfaces:

Cache<K,V>
```
public class TwoQueueCache<K,V>
extends AbstractCache<K,V>
```
Implementation of Cache that uses the 2Q algorithm as an eviction policy.

Field Summary
- Fields inherited from class org.egothor.cache.AbstractCache
  DEFAULT_CAPACITY

Constructor Summary

Constructors
Constructor and Description
`TwoQueueCache()` Constructor for the TwoQueueCache object.
`TwoQueueCache(int capacity)` Constructor for the TwoQueueCache object.
`TwoQueueCache(int capacity, int kIn, int kOut)` Constructor for the TwoQueueCache object.
`TwoQueueCache(Resolver<K,V> resolver)` Constructor for the TwoQueueCache object.
`TwoQueueCache(Resolver<K,V> resolver, int capacity)` Constructor for the TwoQueueCache object.
`TwoQueueCache(Resolver<K,V> resolver, int capacity, int kIn, int kOut)` Constructor for the TwoQueueCache object.

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`void`	`clear()` Removes all key-value mappings from the cache and cleans all queues.
`boolean`	`containsKey(K key)` Checks whether the specified key is cached.
`void`	`evict()` Removes the next key from the cache according to the 2Q algorithm.
`V`	`get(K key)` Gets the value associated with the specified key from the cache if a mapping exists, or the value returned by the resolver.
`int`	`inCapacity()` Returns the capacity of the history AIn FIFO queue.
`Set<K>`	`keySet()` Gets all keys contained in the cache.
`K`	`nextEvicted()` Gets the next key that would be removed from the cache according to the 2Q algorithm.
`int`	`outCapacity()` Returns the capacity of the history AOut LRU queue.
`V`	`put(K key, V value)` Adds a new key-value mapping to the cache.
`V`	`remove(K key)` Removes the specified key and its value from the cache.
`int`	`size()` Returns the number of key-value mappings in the cache.
`String`	`toString()` Returns a text representation of the cache.
`V`	`update(K key, V value)` Updates the value associated with the specified key in the cache if a mapping exists for the key.

Methods inherited from class org.egothor.cache.AbstractCache
capacity, getResolver, hitRatio, hits, misses, requests, resetCounters, setResolver

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

- Constructor Detail
  - TwoQueueCache
```
public TwoQueueCache()
```
    Constructor for the TwoQueueCache object. Uses default cache, AIn and AOut capacity and the resolver alwasy return null.
  - TwoQueueCache
```
public TwoQueueCache(int capacity)
```
    Constructor for the TwoQueueCache object. Uses default AIn and AOut capacity abd the resolver always returns null.
    
    Parameters:
    
    capacity - capacity of the cache
  - TwoQueueCache
```
public TwoQueueCache(int capacity,
                     int kIn,
                     int kOut)
```
    Constructor for the TwoQueueCache object. Resolver always return null.
    
    Parameters:
    
    capacity - capacity of the cache
    
    kIn - capacity of AIn queue
    
    kOut - capacity of AOut queue
  - TwoQueueCache
```
public TwoQueueCache(Resolver<K,V> resolver)
```
    Constructor for the TwoQueueCache object. Uses default cache, AIn and AOut capacity.
    
    Parameters:
    
    resolver - resolver to associate with the cache
  - TwoQueueCache
```
public TwoQueueCache(Resolver<K,V> resolver,
                     int capacity)
```
    Constructor for the TwoQueueCache object. Uses default AIn and AOut capacity.
    
    Parameters:
    
    resolver - resolver to associate with the cache
    
    capacity - capacity of the cache
  - TwoQueueCache
```
public TwoQueueCache(Resolver<K,V> resolver,
                     int capacity,
                     int kIn,
                     int kOut)
```
    Constructor for the TwoQueueCache object.
    
    Parameters:
    
    resolver - resolver to associate with the cache
    
    capacity - capacity of the cache
    
    kIn - capacity of AIn queue
    
    kOut - capacity of AOut queue
- Method Detail
  - put
```
public V put(K key,
             V value)
```
    Adds a new key-value mapping to the cache. If a mapping previously existed for the specified key, it is removed at first. If the cache is full, a mapping is removed from the cache according to 2Q algorithm.
    
    Specified by:
    
    put in interface Cache<K,V>
    
    Overrides:
    
    put in class AbstractCache<K,V>
    
    Parameters:
    
    key - key to add to the cache
    
    value - value to map the key on
    
    Returns:
    
    previous value associated with the key or null if a previous mapping did not exists in the cache for the specified key
  - get
```
public V get(K key)
```
    Gets the value associated with the specified key from the cache if a mapping exists, or the value returned by the resolver.
    
    Specified by:
    
    get in interface Cache<K,V>
    
    Overrides:
    
    get in class AbstractCache<K,V>
    
    Parameters:
    
    key - key to get the value for
    
    Returns:
    
    value associated with the key from the cache, or from the resolver if a mapping does not exits in the cache
  - remove
```
public V remove(K key)
```
    Removes the specified key and its value from the cache.
    
    Specified by:
    
    remove in interface Cache<K,V>
    
    Overrides:
    
    remove in class AbstractCache<K,V>
    
    Parameters:
    
    key - key to remove from the cache.
    
    Returns:
    
    value associated with the key, or null if a mapping did not exist
  - update
```
public V update(K key,
                V value)
```
    Updates the value associated with the specified key in the cache if a mapping exists for the key.
    
    Specified by:
    
    update in interface Cache<K,V>
    
    Overrides:
    
    update in class AbstractCache<K,V>
    
    Parameters:
    
    key - key to change the value for
    
    value - new value associated with the key
    
    Returns:
    
    previous associated value or null if the key is not cached
  - containsKey
```
public boolean containsKey(K key)
```
    Checks whether the specified key is cached.
    
    Specified by:
    
    containsKey in interface Cache<K,V>
    
    Specified by:
    
    containsKey in class AbstractCache<K,V>
    
    Parameters:
    
    key - key to check
    
    Returns:
    
    true, if the key is currently cached, false otherwise
  - clear
```
public void clear()
```
    Removes all key-value mappings from the cache and cleans all queues.
  - keySet
```
public Set<K> keySet()
```
    Gets all keys contained in the cache.
    
    Returns:
    
    Set of keys contained in the cache.
  - size
```
public int size()
```
    Returns the number of key-value mappings in the cache.
    
    Specified by:
    
    size in interface Cache<K,V>
    
    Specified by:
    
    size in class AbstractCache<K,V>
    
    Returns:
    
    number of key-value mappings in the cache
  - nextEvicted
```
public K nextEvicted()
```
    Gets the next key that would be removed from the cache according to the 2Q algorithm.
    
    Specified by:
    
    nextEvicted in interface Cache<K,V>
    
    Specified by:
    
    nextEvicted in class AbstractCache<K,V>
    
    Returns:
    
    key, that would be removed next from the cache or null if the cache is empty
  - evict
```
public void evict()
```
    Removes the next key from the cache according to the 2Q algorithm.
    
    Specified by:
    
    evict in interface Cache<K,V>
    
    Specified by:
    
    evict in class AbstractCache<K,V>
  - inCapacity
```
public int inCapacity()
```
    Returns the capacity of the history AIn FIFO queue.
    
    Returns:
    
    capacity of AIn queue
  - outCapacity
```
public int outCapacity()
```
    Returns the capacity of the history AOut LRU queue.
    
    Returns:
    
    capacity of AOut queue
  - toString
```
public String toString()
```
    Returns a text representation of the cache.
    
    Specified by:
    
    toString in class AbstractCache<K,V>
    
    Returns:
    
    text representation of the cache

Class TwoQueueCache<K,V>

Field Summary

Fields inherited from class org.egothor.cache.AbstractCache

Constructor Summary

Method Summary

Methods inherited from class org.egothor.cache.AbstractCache

Methods inherited from class java.lang.Object

Constructor Detail

TwoQueueCache

TwoQueueCache

TwoQueueCache

TwoQueueCache

TwoQueueCache

TwoQueueCache

Method Detail

put

get

remove

update

containsKey

clear

keySet

size

nextEvicted

evict

inCapacity

outCapacity

toString