Class NullCache<T extends Cacheable>

java.lang.Object

org.deltava.util.cache.Cache<T>

org.deltava.util.cache.NullCache<T>

Type Parameters:

T - the Cacheable object type

All Implemented Interfaces:

GeoCache<T>

public class NullCache<T extends Cacheable>
extends Cache<T>
implements GeoCache<T>

A cache implementation that does no caching. This is used to ensure that CacheManager never returns null.

Since:

5.0

Version:

11.3

Author:

Luke

Field Summary

Fields inherited from class Cache

_cache

Modifier and Type	Field	Description
protected final ConcurrentMap<Object, CacheEntry<T>>	_cache

Constructor Summary

Constructors

Constructor	Description
NullCache()	Creates a new null cache.

Method Summary

Modifier and Type	Method	Description
void	add(GeoLocation loc, T data)	Adds a geographically located object to the cache.
protected void	addEntry(T entry)	Adds an entry to the cache.
void	addNull(GeoLocation loc)	Adds a null entry to the cache.
protected void	addNullEntry(Object key)	Adds a null entry to the cache.
boolean	contains(GeoLocation loc)	Returns whether the cache contains an entry for a particular location.
T	get(Object key)	Retrieves an entry from the cache.
T	get(GeoLocation loc)	Retrieves an object from the cache.
Map<Object,T>	getAll(Collection<?> keys)	Returns multiple objects from the cache.
final int	getMaxSize()	Returns the maximum size of the cache.
double	getRoundingAmount()	Returns the precision of the lat/long key rounding.
void	remove(GeoLocation loc)	Removes a location entry from the cache.

Methods inherited from class Cache

add, addAll, addNull, checkOverflow, clear, contains, getErrors, getHits, getRequests, hit, isRemote, remove, request, setMaxSize, size

Modifier and Type	Method	Description
final void	add(T entry)	Adds an entry to the cache.
void	addAll(Collection<? extends T> entries)	Adds a number of entries to the cache.
final void	addNull(String key)	Adds a null entry to the cache.
protected void	checkOverflow()	Automatically resizes the cache in the case of an overflow.
void	clear()	Clears the cache.
boolean	contains(Object key)	Returns if the cache contains a particular cache key.
long	getErrors()	Returns the total number of cache errors.
final long	getHits()	Returns the total number of cache hits.
final long	getRequests()	Returns the total number of cache requests.
protected void	hit()	Log a cache hit.
boolean	isRemote()	Returns if the cache is a remote cache.
void	remove(Object key)	Invalidate a cache entry.
protected void	request()	Log a cache request.
final void	setMaxSize(int size)	Sets the maximum size of the cache.
int	size()	Returns the current size of the cache.

Methods inherited from class Object

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

Methods inherited from interface GeoCache

createGeoKey

Modifier and Type	Method	Description
default String	createGeoKey(GeoLocation loc)	Creates a lat/long key by rounding to the specific number of decimal places.

Constructor Details

NullCache

NullCache()

Creates a new null cache.

Method Details

getMaxSize

public final int getMaxSize()

Returns the maximum size of the cache.

Overrides:

getMaxSize in class Cache<T extends Cacheable>

Returns:

the maximum number of entries in the cache

addEntry

protected void addEntry(T entry)

Description copied from class: Cache

Adds an entry to the cache. Subclasses need to implement this method to handle cache additions, the public method forces an overflow check.

Specified by:

addEntry in class Cache<T extends Cacheable>

Parameters:

entry - the entry to add

addNullEntry

protected void addNullEntry(Object key)

Description copied from class: Cache

Adds a null entry to the cache. Subclasses need to implement this method to handle cache additions, the public method forces an overflow check.

Specified by:

addNullEntry in class Cache<T extends Cacheable>

Parameters:

key - the entry key

get

public T get(Object key)

Description copied from class: Cache

Retrieves an entry from the cache.

Specified by:

get in class Cache<T extends Cacheable>

Parameters:

key - the cache key

Returns:

the cache entry, or null if the key is not present or the entry is invalid

getRoundingAmount

public double getRoundingAmount()

Description copied from interface: GeoCache

Returns the precision of the lat/long key rounding.

Specified by:

getRoundingAmount in interface GeoCache<T extends Cacheable>

Returns:

the rounding amount

add

public void add(GeoLocation loc,
 T data)

Description copied from interface: GeoCache

Adds a geographically located object to the cache.

Specified by:

add in interface GeoCache<T extends Cacheable>

Parameters:

loc - the GeoLocation

data - the data to cache

addNull

public void addNull(GeoLocation loc)

Description copied from interface: GeoCache

Adds a null entry to the cache.

Specified by:

addNull in interface GeoCache<T extends Cacheable>

Parameters:

loc - the GeoLocation

contains

public boolean contains(GeoLocation loc)

Description copied from interface: GeoCache

Returns whether the cache contains an entry for a particular location.

Specified by:

contains in interface GeoCache<T extends Cacheable>

Parameters:

loc - the GeoLocation

Returns:

TRUE if the cache contains an entry, otherwise FALSE

get

public T get(GeoLocation loc)

Description copied from interface: GeoCache

Retrieves an object from the cache.

Specified by:

get in interface GeoCache<T extends Cacheable>

Parameters:

loc - the GeoLocation

Returns:

the Object, or null if not found

getAll

public Map<Object,T> getAll(Collection<?> keys)

Description copied from class: Cache

Returns multiple objects from the cache.

Overrides:

getAll in class Cache<T extends Cacheable>

Parameters:

keys - the cache keys

Returns:

a Map of results keyed by cache key

remove

public void remove(GeoLocation loc)

Description copied from interface: GeoCache

Removes a location entry from the cache.

Specified by:

remove in interface GeoCache<T extends Cacheable>

Parameters:

loc - the GeoLocation