Package org.codehaus.groovy.runtime.memoize

Class CommonCache<K,V>

java.lang.Object

org.codehaus.groovy.runtime.memoize.CommonCache<K,V>

Type Parameters:

K - type of the keys

V - type of the values

All Implemented Interfaces:

Serializable, Map<K,V>, EvictableCache<K,V>, FlexibleCache<K,V>, MemoizeCache<K,V>, ValueConvertable<V,Object>

public class CommonCache<K,V>
extends Object
implements FlexibleCache<K,V>, ValueConvertable<V,Object>, Serializable

Represents a simple key-value cache, which is NOT thread safe and backed by a Map instance

Since:

2.5.0

See Also:

• Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from interface org.codehaus.groovy.runtime.memoize.EvictableCache

EvictableCache.Action<K,V,R>, EvictableCache.EvictionStrategy

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

Map.Entry<K extends Object,V extends Object>

Nested classes/interfaces inherited from interface org.codehaus.groovy.runtime.memoize.MemoizeCache

MemoizeCache.ValueProvider<K,V>

Field Summary

Fields

Modifier and Type	Field	Description
static final int	DEFAULT_INITIAL_CAPACITY	The default initial capacity
static final float	DEFAULT_LOAD_FACTOR	The default load factor

Constructor Summary

Constructors

Constructor	Description
CommonCache()	Constructs a cache with unlimited size
CommonCache(int maxSize)	Constructs an LRU cache with the default initial capacity
CommonCache(int initialCapacity, int maxSize)	Constructs an LRU cache with the specified initial capacity and max size.
CommonCache(int initialCapacity, int maxSize, EvictableCache.EvictionStrategy evictionStrategy)	Constructs a cache with limited size
CommonCache(Map<K,V> map)	Constructs a cache backed by the specified Map instance

Method Summary

Modifier and Type	Method	Description
void	cleanUpNullReferences()	Invoked when some of the held SoftReferences have been evicted by the garbage collector and so should be removed from the cache.
Map<K,V>	clearAll()	Clear the cache
boolean	containsKey(Object key)	Determines if the cache contains an entry for the specified key.
boolean	containsValue(Object value)	Determines whether the cache contains the specified stored value.
Object	convertValue(V value)	Returns the stored value unchanged.
Set<Map.Entry<K,V>>	entrySet()	Returns a live view of the cache entries.
V	get(Object key)	Gets a value from the cache
V	getAndPut(K key, MemoizeCache.ValueProvider<? super K,? extends V> valueProvider)	Try to get the value from cache.
V	getAndPut(K key, MemoizeCache.ValueProvider<? super K,? extends V> valueProvider, boolean shouldCache)	Returns the value associated with key, creating it with the supplied provider when necessary and optionally caching the result.
boolean	isEmpty()	Returns whether the cache currently holds no entries.
Set<K>	keys()	Get all keys associated to cached values
Set<K>	keySet()	Returns a live view of the keys in this cache.
V	put(K key, V value)	Associates the specified value with the specified key in the cache.
void	putAll(Map<? extends K,? extends V> m)	Copies all mappings from the supplied map into this cache.
V	remove(Object key)	Remove the cached value by the key
int	size()	Get the size of the cache
String	toString()	Returns a string representation of the current cache contents.
Collection<V>	values()	Get all cached values

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.codehaus.groovy.runtime.memoize.EvictableCache

clear

Methods inherited from interface java.util.Map

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

Field Details

DEFAULT_LOAD_FACTOR

public static final float DEFAULT_LOAD_FACTOR

The default load factor

See Also:

• Constant Field Values

DEFAULT_INITIAL_CAPACITY

public static final int DEFAULT_INITIAL_CAPACITY

The default initial capacity

See Also:

• Constant Field Values

Constructor Details

CommonCache

public CommonCache()

Constructs a cache with unlimited size

CommonCache

public CommonCache(int initialCapacity,
 int maxSize,
 EvictableCache.EvictionStrategy evictionStrategy)

Constructs a cache with limited size

Parameters:

initialCapacity - initial capacity of the cache

maxSize - max size of the cache

evictionStrategy - LRU or FIFO, see EvictableCache.EvictionStrategy

CommonCache

public CommonCache(int initialCapacity,
 int maxSize)

Constructs an LRU cache with the specified initial capacity and max size. The LRU cache is slower than LRUCache

Parameters:

initialCapacity - initial capacity of the LRU cache

maxSize - max size of the LRU cache

CommonCache

public CommonCache(int maxSize)

Constructs an LRU cache with the default initial capacity

Parameters:

maxSize - max size of the LRU cache

See Also:

• CommonCache(int, int)

CommonCache

public CommonCache(Map<K,V> map)

Constructs a cache backed by the specified Map instance

Parameters:

map - the Map instance

Method Details

get

public V get(Object key)

Gets a value from the cache

Specified by:

get in interface Map<K,V>

Specified by:

get in interface MemoizeCache<K,V>

Parameters:

key - the key whose associated value is to be returned

Returns:

the value, or null, if it does not exist.

put

public V put(K key,
 V value)

Associates the specified value with the specified key in the cache.

Specified by:

put in interface Map<K,V>

Specified by:

put in interface MemoizeCache<K,V>

Parameters:

key - key with which the specified value is to be associated

value - value to be associated with the specified key

Returns:

null, or the old value if the key associated with the specified key.

getAndPut

public V getAndPut(K key,
 MemoizeCache.ValueProvider<? super K,? extends V> valueProvider)

Try to get the value from cache. If not found, create the value by MemoizeCache.ValueProvider and put it into the cache, at last return the value.

Specified by:

getAndPut in interface MemoizeCache<K,V>

Parameters:

key - the key to look up

valueProvider - provide the value if the associated value not found

Returns:

the cached value

getAndPut

public V getAndPut(K key,
 MemoizeCache.ValueProvider<? super K,? extends V> valueProvider,
 boolean shouldCache)

Returns the value associated with key, creating it with the supplied provider when necessary and optionally caching the result.

Specified by:

getAndPut in interface FlexibleCache<K,V>

Parameters:

key - the key to look up

valueProvider - supplies a value when the key is not cached

shouldCache - whether a newly created value should be stored

Returns:

the cached or newly created value

values

public Collection<V> values()

Get all cached values

Specified by:

values in interface EvictableCache<K,V>

Specified by:

values in interface Map<K,V>

Returns:

all cached values

entrySet

public Set<Map.Entry<K,V>> entrySet()

Returns a live view of the cache entries.

Specified by:

entrySet in interface Map<K,V>

Returns:

the cache entries

keys

public Set<K> keys()

Get all keys associated to cached values

Specified by:

keys in interface EvictableCache<K,V>

Returns:

all keys

containsValue

public boolean containsValue(Object value)

Determines whether the cache contains the specified stored value.

Specified by:

containsValue in interface Map<K,V>

Parameters:

value - the value whose presence should be tested

Returns:

true if the cache contains the value

containsKey

public boolean containsKey(Object key)

Determines if the cache contains an entry for the specified key.

Specified by:

containsKey in interface EvictableCache<K,V>

Specified by:

containsKey in interface Map<K,V>

Parameters:

key - key whose presence in this cache is to be tested.

Returns:

true if the cache contains a mapping for the specified key

size

public int size()

Get the size of the cache

Specified by:

size in interface EvictableCache<K,V>

Specified by:

size in interface Map<K,V>

Returns:

the size of the cache

isEmpty

public boolean isEmpty()

Returns whether the cache currently holds no entries.

Specified by:

isEmpty in interface Map<K,V>

Returns:

true if the cache is empty

remove

public V remove(Object key)

Remove the cached value by the key

Specified by:

remove in interface EvictableCache<K,V>

Specified by:

remove in interface Map<K,V>

Parameters:

key - of the cached value

Returns:

returns the removed value

putAll

public void putAll(Map<? extends K,? extends V> m)

Copies all mappings from the supplied map into this cache.

Specified by:

putAll in interface Map<K,V>

Parameters:

m - the mappings to copy

keySet

public Set<K> keySet()

Returns a live view of the keys in this cache.

Specified by:

keySet in interface Map<K,V>

Returns:

the cache keys

clearAll

public Map<K,V> clearAll()

Clear the cache

Specified by:

clearAll in interface EvictableCache<K,V>

Returns:

returns the content of the cleared map

cleanUpNullReferences

public void cleanUpNullReferences()

Invoked when some of the held SoftReferences have been evicted by the garbage collector and so should be removed from the cache. The implementation must ensure that concurrent invocations of all methods on the cache may occur from other threads and thus should protect any shared resources.

Specified by:

cleanUpNullReferences in interface MemoizeCache<K,V>

toString

public String toString()

Returns a string representation of the current cache contents.

Overrides:

toString in class Object

Returns:

a string form of the backing map

convertValue

public Object convertValue(V value)

Returns the stored value unchanged.

Specified by:

convertValue in interface ValueConvertable<K,V>

Parameters:

value - the stored value

Returns:

value