Class PersistableCardinalityCacheImpl<K>

java.lang.Object

se.liu.ida.hefquin.engine.federation.access.impl.cache.PersistableCardinalityCacheImpl<K>

Type Parameters:

K - The key type for caching cardinality responses.

All Implemented Interfaces:

Cache<K,CompletableFuture<CardinalityResponse>>, PersistableCache<K,CompletableFuture<CardinalityResponse>>

public class PersistableCardinalityCacheImpl<K>
extends Object
implements PersistableCache<K,CompletableFuture<CardinalityResponse>>

A thread-safe cache implementation for storing cardinality responses. This cache uses a ConcurrentHashMap to store values and supports serialization for persistence.

Field Summary

Fields

Modifier and Type	Field	Description
protected static final String	defaultFilename
protected final String	filename
protected final Map<K,CompletableFuture<CardinalityResponse>>	map

Constructor Summary

Constructors

Constructor	Description
PersistableCardinalityCacheImpl()	Constructs a new PersistableCardinalityCacheImpl with the default cache file.
PersistableCardinalityCacheImpl(String filename)	Constructs a new PersistableCardinalityCacheImpl with a custom file path.

Method Summary

Modifier and Type	Method	Description
void	clear()	Clears all entries from the cache.
boolean	evict(K key)	Removes the entry associated with the given key from the cache.
boolean	evict(K key, CompletableFuture<CardinalityResponse> value)	Removes the specified entry from the cache only if the current value matches.
CompletableFuture<CardinalityResponse>	get(K key)	Retrieves the cardinality response associated with the given key.
boolean	isEmpty()	Checks whether the cache is currently empty.
void	load()	Loads the cache state from a file.
void	put(K key, CompletableFuture<CardinalityResponse> value)	Adds a new cardinality response to the cache, associated with the given key.
void	save()	Saves the current cache state to a file.

Methods inherited from class java.lang.Object

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

Field Details

map

protected final Map<K,CompletableFuture<CardinalityResponse>> map

filename

protected final String filename

defaultFilename

protected static final String defaultFilename

See Also:

• Constant Field Values

Constructor Details

PersistableCardinalityCacheImpl

public PersistableCardinalityCacheImpl()

Constructs a new PersistableCardinalityCacheImpl with the default cache file.

PersistableCardinalityCacheImpl

public PersistableCardinalityCacheImpl(String filename)

Constructs a new PersistableCardinalityCacheImpl with a custom file path.

Parameters:

filename - Path to the cache file.

Method Details

save

public void save()

Saves the current cache state to a file. Only completed CardinalityResponse objects are persisted.

Specified by:

save in interface PersistableCache<K,CompletableFuture<CardinalityResponse>>

load

public void load()

Loads the cache state from a file. The data is deserialized and stored in memory.

Specified by:

load in interface PersistableCache<K,CompletableFuture<CardinalityResponse>>

put

public void put(K key,
 CompletableFuture<CardinalityResponse> value)

Adds a new cardinality response to the cache, associated with the given key. If an entry already exists for this key, it is replaced.

Specified by:

put in interface Cache<K,CompletableFuture<CardinalityResponse>>

Parameters:

key - The key identifying the response.

value - The cardinality response to store.

get

public CompletableFuture<CardinalityResponse> get(K key)

Retrieves the cardinality response associated with the given key.

Specified by:

get in interface Cache<K,CompletableFuture<CardinalityResponse>>

Parameters:

key - The key to look up.

Returns:

The cached response, or

invalid @link

{@link null

} if not found.

evict

public boolean evict(K key)

Removes the entry associated with the given key from the cache.

Specified by:

evict in interface Cache<K,CompletableFuture<CardinalityResponse>>

Parameters:

key - The key to remove.

Returns:

invalid @link

{@link true

} if an entry was removed,

invalid @link

{@link false

} otherwise.

evict

public boolean evict(K key,
 CompletableFuture<CardinalityResponse> value)

Removes the specified entry from the cache only if the current value matches.

Specified by:

evict in interface Cache<K,CompletableFuture<CardinalityResponse>>

Parameters:

key - The key to remove.

value - The expected value to match before removal.

Returns:

invalid @link

{@link true

} if the entry was removed,

invalid @link

{@link false

} otherwise.

isEmpty

public boolean isEmpty()

Checks whether the cache is currently empty.

Specified by:

isEmpty in interface Cache<K,CompletableFuture<CardinalityResponse>>

Returns:

invalid @link

{@link true

} if the cache is empty,

invalid @link

{@link false

} otherwise.

clear

public void clear()

Clears all entries from the cache.

Specified by:

clear in interface Cache<K,CompletableFuture<CardinalityResponse>>