cascading.util.cache

Class LRUHashMapCache<Key,Value>

java.lang.Object

cascading.util.cache.LRUHashMapCache<Key,Value>

All Implemented Interfaces:

CascadingCache<Key,Value>, java.util.Map<Key,Value>

public class LRUHashMapCache<Key,Value>
extends java.lang.Object
implements CascadingCache<Key,Value>

Implementation of the CascadingCache interface backed by a LinkedHashMap configured to evict the least recently used key.

That is, if duplicate keys are clustered near each other in the incoming tuple stream, this cache will provide the most benefit as keys that begin to occur less frequently or not at all will be evicted as the key capacity is reached.

If the keys are very random, if not uniformly distributed in the stream, consider using the DirectMappedCache to reduce the amount of hash and equality comparisons.

This implementation is used by default by Unique and AggregateBy and their subclasses.

See Also:

Unique, AggregateBy, LRUHashMapCacheFactory, DirectMappedCacheFactory, DirectMappedCache

Nested Class Summary

Nested classes/interfaces inherited from interface java.util.Map

java.util.Map.Entry<K,V>

Constructor Summary

Constructors

Constructor and Description
LRUHashMapCache()

Method Summary

Modifier and Type	Method and Description
void	clear()
boolean	containsKey(java.lang.Object key)
boolean	containsValue(java.lang.Object value)
java.util.Set<java.util.Map.Entry<Key,Value>>	entrySet()
Value	get(java.lang.Object key)
int	getCapacity() Returns the capacity of this cache.
void	initialize() Method to initialize the Cache.
boolean	isEmpty()
java.util.Set<Key>	keySet()
Value	put(Key key, Value value)
void	putAll(java.util.Map<? extends Key,? extends Value> m)
Value	remove(java.lang.Object key)
void	setCacheEvictionCallback(CacheEvictionCallback cacheEvictionCallback) Sets the CacheEvictionCallback of this Cache.
void	setCapacity(int capacity) Sets the capacity of the Cache.
int	size()
java.util.Collection<Value>	values()

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface java.util.Map

compute, computeIfAbsent, computeIfPresent, equals, forEach, getOrDefault, hashCode, merge, putIfAbsent, remove, replace, replace, replaceAll

Constructor Detail

LRUHashMapCache

public LRUHashMapCache()

Method Detail

getCapacity

public int getCapacity()

Description copied from interface: CascadingCache

Returns the capacity of this cache.

Specified by:

getCapacity in interface CascadingCache<Key,Value>

setCacheEvictionCallback

public void setCacheEvictionCallback(CacheEvictionCallback cacheEvictionCallback)

Description copied from interface: CascadingCache

Sets the CacheEvictionCallback of this Cache.

Specified by:

setCacheEvictionCallback in interface CascadingCache<Key,Value>

setCapacity

public void setCapacity(int capacity)

Description copied from interface: CascadingCache

Sets the capacity of the Cache.

Specified by:

setCapacity in interface CascadingCache<Key,Value>

initialize

public void initialize()

Description copied from interface: CascadingCache

Method to initialize the Cache. Any setup should be done in here.

Specified by:

initialize in interface CascadingCache<Key,Value>

size

public int size()

Specified by:

size in interface java.util.Map<Key,Value>

isEmpty

public boolean isEmpty()

Specified by:

isEmpty in interface java.util.Map<Key,Value>

containsKey

public boolean containsKey(java.lang.Object key)

Specified by:

containsKey in interface java.util.Map<Key,Value>

containsValue

public boolean containsValue(java.lang.Object value)

Specified by:

containsValue in interface java.util.Map<Key,Value>

get

public Value get(java.lang.Object key)

Specified by:

get in interface java.util.Map<Key,Value>

put

public Value put(Key key,
                 Value value)

Specified by:

put in interface java.util.Map<Key,Value>

remove

public Value remove(java.lang.Object key)

Specified by:

remove in interface java.util.Map<Key,Value>

putAll

public void putAll(java.util.Map<? extends Key,? extends Value> m)

Specified by:

putAll in interface java.util.Map<Key,Value>

clear

public void clear()

Specified by:

clear in interface java.util.Map<Key,Value>

keySet

public java.util.Set<Key> keySet()

Specified by:

keySet in interface java.util.Map<Key,Value>

values

public java.util.Collection<Value> values()

Specified by:

values in interface java.util.Map<Key,Value>

entrySet

public java.util.Set<java.util.Map.Entry<Key,Value>> entrySet()

Specified by:

entrySet in interface java.util.Map<Key,Value>