Package com.identityworksllc.iiq.common.cache

Class GuardedCacheValue<ValueType,GuardType>

java.lang.Object

com.identityworksllc.iiq.common.cache.GuardedCacheValue<ValueType,GuardType>

Type Parameters:

ValueType - The type of the thing being stored here

GuardType - The type of the guard value

All Implemented Interfaces:

Function<GuardType,Optional<ValueType>>

public class GuardedCacheValue<ValueType,GuardType>
extends Object
implements Function<GuardType,Optional<ValueType>>

A cache value wrapper that allows access based on matching an arbitrary guard value.

If the guard value is not matched, the getValue(Object) method returns an empty Optional.

This can be used, for example, to detect changes to permissions or logged in users and clear the cache accordingly.

This is similar to AtomicStampedReference, but can use any value or behavior as the ‘stamp’. With a guard type of Integer, and the default matcher of Object::equals, this class would be identical to that.

Constructor Summary

Constructors

Constructor	Description
GuardedCacheValue(ValueType value, GuardType token)	Constructs a new cache value with the given token and value.
GuardedCacheValue(ValueType value, GuardType token, BiPredicate<GuardType,GuardType> matcher)	Constructs a new cache value with the given token, value, and token matcher.

Method Summary

Modifier and Type	Method	Description
Optional<ValueType>	apply(GuardType guardTest)	Functional version of getValue(Object).
Optional<ValueType>	getValue(GuardType guardTest)

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.util.function.Function

andThen, compose

Constructor Detail

GuardedCacheValue

public GuardedCacheValue(ValueType value,
                         GuardType token)

Constructs a new cache value with the given token and value.

The token will be matched using Object.equals.

Parameters:

value - The value wrapped by this cache token

token - The token that must be matched to retrieve the value

GuardedCacheValue

public GuardedCacheValue(ValueType value,
                         GuardType token,
                         BiPredicate<GuardType,GuardType> matcher)

Constructs a new cache value with the given token, value, and token matcher.

At getValue time, the matcher will be used to decide whether the input actually matches the token.

Parameters:

value - The value wrapped by this cache token

token - The token that must be matched to retrieve the value

matcher - The predicate that decides whether the input token matches

Method Detail

apply

public Optional<ValueType> apply(GuardType guardTest)

Functional version of getValue(Object).

Specified by:

apply in interface Function<ValueType,GuardType>

Parameters:

guardTest - the function argument

Returns:

An optional containing the stored value, if the guard value input matches, or else an empty optional object

getValue

public Optional<ValueType> getValue(GuardType guardTest)

Parameters:

guardTest - The guard test value

Returns:

An optional containing the stored value, if the guard value input matches, or else an empty optional object