org.starchartlabs.alloy.core

Class Suppliers

java.lang.Object

org.starchartlabs.alloy.core.Suppliers

public final class Suppliers
extends java.lang.Object

Utilities intended to enhance and streamline use of Supplier instances

Since:

0.1.0

Method Summary

Modifier and Type	Method and Description
static <S,T> java.util.function.Supplier<T>	map(java.util.function.Supplier<S> supplier, java.util.function.Function<S,T> function) Returns a new supplier which calls the provided supplier and then applies the provided function to map the result to a new representation.
static <T> java.util.function.Supplier<T>	memoize(java.util.function.Supplier<T> delegate) Returns a supplier which caches the instance retrieved during the first call to get() and returns that value on subsequent calls to get()
static <T> java.util.function.Supplier<T>	memoizeWithExpiration(java.util.function.Supplier<T> delegate, long duration, java.util.concurrent.TimeUnit unit) Returns a supplier that caches the instance supplied by the delegate and removes the cached value after the specified time has passed.
static <T> java.util.function.Supplier<T>	synchronizedSupplier(java.util.function.Supplier<T> delegate)

Methods inherited from class java.lang.Object

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

Method Detail

map

public static <S,T> java.util.function.Supplier<T> map(java.util.function.Supplier<S> supplier,
                                                       java.util.function.Function<S,T> function)

Returns a new supplier which calls the provided supplier and then applies the provided function to map the result to a new representation. Note that the resulting supplier will not call supplier or invoke function until it is called

Type Parameters:

S - Original representation provided via supplier

T - Representation to convert the original to when requested via Supplier.get()

Parameters:

supplier - Supplier which provides an initial value

function - Mapping function which converts the supplied value to a different form

Returns:

A supplier which converts a supplied value into a different representation via the provided function

Since:

0.1.0

memoize

public static <T> java.util.function.Supplier<T> memoize(java.util.function.Supplier<T> delegate)

Returns a supplier which caches the instance retrieved during the first call to get() and returns that value on subsequent calls to get()

The returned supplier is thread-safe. The delegate's get() method will be invoked at most once unless the underlying get() throws an exception

Type Parameters:

T - Representation supplied by the provided and memoized supplier

Parameters:

delegate - Supplier which will provide values when a valid cached value has not been stored

Returns:

A supplier which caches the instance retrieved during the first call to get() and returns that value on subsequent calls

Since:

0.1.0

memoizeWithExpiration

public static <T> java.util.function.Supplier<T> memoizeWithExpiration(java.util.function.Supplier<T> delegate,
                                                                       long duration,
                                                                       java.util.concurrent.TimeUnit unit)

Returns a supplier that caches the instance supplied by the delegate and removes the cached value after the specified time has passed. Subsequent calls to get() return the cached value if the expiration time has not passed. After the expiration time, a new value is retrieved, cached, and returned

The returned supplier is thread-safe

Type Parameters:

T - Representation supplied by the provided and memoized supplier

Parameters:

delegate - Supplier which will provide values when a valid cached value has not been stored or has expired

duration - the length of time after a value is created that it should stop being returned by subsequent get() calls

unit - the unit that duration is expressed in

Returns:

A supplier that caches the instance supplied by the delegate and removes the cached value after the specified time has passed

Throws:

java.lang.IllegalArgumentException - if duration is not positive

Since:

0.1.0

synchronizedSupplier

public static <T> java.util.function.Supplier<T> synchronizedSupplier(java.util.function.Supplier<T> delegate)

Type Parameters:

T - Representation supplied by the provided and synchronized supplier

Parameters:

delegate - Supplier to create a thread-safe wrapper around

Returns:

A supplier which synchronizes on the delegate before calling its get method, making it thread-safe

Since:

0.1.0