de.ipcon.tools.ref

Class SoftReferenceCache<K,V>

java.lang.Object

de.ipcon.tools.ref.SoftReferenceCache<K,V>

Type Parameters:

K - the type of keys maintained by this cache

V - the type of mapped values

All Implemented Interfaces:

CacheI<K,V>, ExpungingCacheI<K,V>

public class SoftReferenceCache<K,V>
extends java.lang.Object
implements ExpungingCacheI<K,V>, CacheI<K,V>

Simple cache implementation with soft referenced values listening to ReferenceQueue removing stale key/value tuples.

Constructor Summary

Constructors

Constructor and Description
SoftReferenceCache()
SoftReferenceCache(CacheFetcherI<K,V> fetcher, DependencyCalculatorI<K,V> dependencyCalculator, java.util.Map<K,ExpungeableReferenceI<?>> cache)
SoftReferenceCache(CacheFetcherI<K,V> fetcher, DependencyCalculatorI<K,V> dependencyCalculator, java.util.Map<K,ExpungeableReferenceI<?>> cache, java.lang.Class<V> cachedClass)
SoftReferenceCache(CacheFetcherI<K,V> fetcher, java.util.Map<K,ExpungeableReferenceI<?>> cache)
SoftReferenceCache(CacheFetcherI<K,V> fetcher, java.util.Map<K,ExpungeableReferenceI<?>> cache, java.lang.Class<V> cachedClass)
SoftReferenceCache(java.lang.Class<V> cachedClass)
SoftReferenceCache(java.util.Map<K,ExpungeableReferenceI<?>> cache)
SoftReferenceCache(java.util.Map<K,ExpungeableReferenceI<?>> cache, java.lang.Class<V> cachedClass)

Method Summary

Modifier and Type	Method and Description
void	clear()
V	computeIfAbsent(K key, java.util.function.Function<? super K,? extends V> mappingFunction) Returns the value associated with the specified key, computing it if necessary.
boolean	contains(K key)
void	expunge(K key)
void	expungeAll(K[] keys)
void	expungeAllForDependencies(long[] deps)
void	expungeAllForDependencies(java.lang.Long[] deps)
void	expungeForDependency(long dep)
void	expungeForDependency(java.lang.Long dep)
V	get(K key)
java.lang.Object[]	get(K[] keys)
java.lang.Object[]	get(K[] keys, boolean dontCacheNulls)
java.lang.Object[]	get(K[] keys, boolean dontCacheNulls, boolean dontFetch)
V	get(K key, boolean dontCacheNulls)
V	get(K key, boolean dontCacheNulls, boolean dontFetch)
V	getAt(K key)
ExpungeableReferenceI<V>	getExpungeableReference(K key)
java.util.Set<K>	keySet()
void	put(K key, V value)
void	put(K key, V value, boolean dontCacheNulls)
void	put(K key, V value, boolean dontCacheNulls, long[] dependencies)
void	putAt(K key, V value)
V	putIfAbsent(K key, V value) Associates the specified key with the given value if it is not already associated with a live value.
void	remove(K key)
int	size()
java.util.Collection<java.lang.Object>	values()

Methods inherited from class java.lang.Object

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

Constructor Detail

SoftReferenceCache

public SoftReferenceCache()

SoftReferenceCache

public SoftReferenceCache(java.lang.Class<V> cachedClass)

SoftReferenceCache

public SoftReferenceCache(java.util.Map<K,ExpungeableReferenceI<?>> cache)

SoftReferenceCache

public SoftReferenceCache(java.util.Map<K,ExpungeableReferenceI<?>> cache,
                          java.lang.Class<V> cachedClass)

SoftReferenceCache

public SoftReferenceCache(CacheFetcherI<K,V> fetcher,
                          DependencyCalculatorI<K,V> dependencyCalculator,
                          java.util.Map<K,ExpungeableReferenceI<?>> cache)

SoftReferenceCache

public SoftReferenceCache(CacheFetcherI<K,V> fetcher,
                          DependencyCalculatorI<K,V> dependencyCalculator,
                          java.util.Map<K,ExpungeableReferenceI<?>> cache,
                          java.lang.Class<V> cachedClass)

SoftReferenceCache

public SoftReferenceCache(CacheFetcherI<K,V> fetcher,
                          java.util.Map<K,ExpungeableReferenceI<?>> cache)

SoftReferenceCache

public SoftReferenceCache(CacheFetcherI<K,V> fetcher,
                          java.util.Map<K,ExpungeableReferenceI<?>> cache,
                          java.lang.Class<V> cachedClass)

Method Detail

getAt

public V getAt(K key)

get

public java.lang.Object[] get(K[] keys)

Specified by:

get in interface CacheI<K,V>

get

public java.lang.Object[] get(K[] keys,
                              boolean dontCacheNulls)

get

public java.lang.Object[] get(K[] keys,
                              boolean dontCacheNulls,
                              boolean dontFetch)

get

public V get(K key)

Specified by:

get in interface CacheI<K,V>

Specified by:

get in interface ExpungingCacheI<K,V>

get

public V get(K key,
             boolean dontCacheNulls)

get

public V get(K key,
             boolean dontCacheNulls,
             boolean dontFetch)

getExpungeableReference

public ExpungeableReferenceI<V> getExpungeableReference(K key)

Specified by:

getExpungeableReference in interface ExpungingCacheI<K,V>

putAt

public void putAt(K key,
                  V value)

put

public void put(K key,
                V value)

Specified by:

put in interface CacheI<K,V>

put

public void put(K key,
                V value,
                boolean dontCacheNulls)

put

public void put(K key,
                V value,
                boolean dontCacheNulls,
                long[] dependencies)

remove

public void remove(K key)

Specified by:

remove in interface CacheI<K,V>

expunge

public void expunge(K key)

Specified by:

expunge in interface ExpungingCacheI<K,V>

expungeAll

public void expungeAll(K[] keys)

Specified by:

expungeAll in interface ExpungingCacheI<K,V>

expungeForDependency

public void expungeForDependency(long dep)

Specified by:

expungeForDependency in interface ExpungingCacheI<K,V>

expungeForDependency

public void expungeForDependency(java.lang.Long dep)

Specified by:

expungeForDependency in interface ExpungingCacheI<K,V>

expungeAllForDependencies

public void expungeAllForDependencies(long[] deps)

Specified by:

expungeAllForDependencies in interface ExpungingCacheI<K,V>

expungeAllForDependencies

public void expungeAllForDependencies(java.lang.Long[] deps)

Specified by:

expungeAllForDependencies in interface ExpungingCacheI<K,V>

values

public java.util.Collection<java.lang.Object> values()

keySet

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

contains

public boolean contains(K key)

Specified by:

contains in interface CacheI<K,V>

clear

public void clear()

Specified by:

clear in interface CacheI<K,V>

size

public int size()

putIfAbsent

public V putIfAbsent(K key,
                     V value)

Associates the specified key with the given value if it is not already associated with a live value.

Treats "ghost entries" (keys with GC-cleared SoftReferences) as absent, replacing them with the new value atomically.

Parameters:

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

value - value to be associated with the specified key

Returns:

the previous live value associated with the key, or the new value

Throws:

java.lang.IllegalStateException - if the map is not concurrent or dependency tracking is enabled

computeIfAbsent

public V computeIfAbsent(K key,
                         java.util.function.Function<? super K,? extends V> mappingFunction)

Returns the value associated with the specified key, computing it if necessary.

Handles the "Ghost Entry" problem by checking if an existing SoftReference has been cleared. If cleared, it re-computes the value.

Specified by:

computeIfAbsent in interface CacheI<K,V>

Parameters:

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

mappingFunction - the function to compute a value if missing

Returns:

the current live value associated with the key

Throws:

java.lang.IllegalStateException - if the underlying map is not concurrent