Package com.identityworksllc.iiq.common.cache

Class CacheEntry<T>

java.lang.Object

com.identityworksllc.iiq.common.cache.CacheEntry<T>

Type Parameters:

T - The type of the object to store

All Implemented Interfaces:

Serializable, Supplier<Optional<T>>

Direct Known Subclasses:

VersionedCacheEntry

public class CacheEntry<T>
extends Object
implements Serializable, Supplier<Optional<T>>

Cache entry for use with the CacheMap class or other purposes.

This class allows you to store a dated object of any type. The entry will be considered expired when the current date is after the expiration date.

Instances of this class are Externalizable if the contained type T is serializable.

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor	Description
CacheEntry(CacheEntry<? extends T> other)	Copy constructor
CacheEntry(T entryValue, long entryExpirationTimestampMillis)	Construct a new cache entry that expires at a specific Unix timestamp (in milliseconds)
CacheEntry(T entryValue, long futureTimeAmount, TimeUnit timeUnit)	Construct a new cache entry that expires a specific amount of time in the future
CacheEntry(T entryValue, Date entryExpiration)	Construct a new cache entry that expires on a specific date

Method Summary

Modifier and Type	Method	Description
AtomicStampedReference<T>	asStampedReference()	Returns an AtomicStampedReference object with the ‘stamp’ set to the seconds (NOT milliseconds) timestamp of expiration.
static <T> CacheEntry<T>	computeIfExpired(CacheEntry<T> entry, Supplier<CacheEntry<T>> valueSupplier)	Returns either the entry (if it is not null and not expired), or invokes the Supplier to generate a new entry if it is expired.
boolean	equals(Object o)
Optional<T>	get()	If the entry is expired, returns Optional.empty().
long	getExpiration()	Returns the expiration instant, in Unix timestamp millis
T	getValue()	Gets the value associated with this cache entry
int	hashCode()
boolean	isExpired()	The entry is expired if the current time is after the expiration date
String	toString()

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

CacheEntry

public CacheEntry(CacheEntry<? extends T> other)

Copy constructor

Parameters:

other - The other cache entry

CacheEntry

public CacheEntry(T entryValue,
                  long futureTimeAmount,
                  TimeUnit timeUnit)

Construct a new cache entry that expires a specific amount of time in the future

Parameters:

entryValue - The entry value

futureTimeAmount - The amount of time in the future (from right now) to expire it

timeUnit - The units in which the amount of time is specified

CacheEntry

public CacheEntry(T entryValue,
                  Date entryExpiration)

Construct a new cache entry that expires on a specific date

Parameters:

entryValue - The value of this cache entry

entryExpiration - The expiration date of this cache entry

CacheEntry

public CacheEntry(T entryValue,
                  long entryExpirationTimestampMillis)

Construct a new cache entry that expires at a specific Unix timestamp (in milliseconds)

Parameters:

entryValue - The value of this cache entry

entryExpirationTimestampMillis - The expiration date of this cache entry

Method Detail

computeIfExpired

public static <T> CacheEntry<T> computeIfExpired(CacheEntry<T> entry,
                                                 Supplier<CacheEntry<T>> valueSupplier)

Returns either the entry (if it is not null and not expired), or invokes the Supplier to generate a new entry if it is expired.

Type Parameters:

T - The type of thing that is cached

Parameters:

entry - The existing entry (which can be null)

valueSupplier - A function to calculate a new value

Returns:

The value supplier

asStampedReference

public AtomicStampedReference<T> asStampedReference()

Returns an AtomicStampedReference object with the ‘stamp’ set to the seconds (NOT milliseconds) timestamp of expiration.

Returns:

An AtomicStampedReference

equals

public boolean equals(Object o)

Overrides:

equals in class Object

See Also:

Object.equals(Object)

get

public Optional<T> get()

If the entry is expired, returns Optional.empty().

If the entry is not expired, returns Optional.ofNullable(Object).

Specified by:

get in interface Supplier<T>

Returns:

An optional containing a non-expired entry value

getExpiration

public long getExpiration()

Returns the expiration instant, in Unix timestamp millis

Returns:

The expiration timestamp

getValue

public T getValue()

Gets the value associated with this cache entry

Returns:

The cached value

hashCode

public int hashCode()

Overrides:

hashCode in class Object

See Also:

Object.hashCode()

isExpired

public boolean isExpired()

The entry is expired if the current time is after the expiration date

Returns:

True if expired

toString

public String toString()

Overrides:

toString in class Object