Package com.yahoo.yolean.concurrent

Class Memoized<T,E extends Exception>

java.lang.Object

com.yahoo.yolean.concurrent.Memoized<T,E>

All Implemented Interfaces:

AutoCloseable, Supplier<T>

public class Memoized<T,E extends Exception>
extends Object
implements Supplier<T>, AutoCloseable

Wraps a lazily initialised resource which needs to be shut down. The wrapped supplier may not return null, and should be retryable on failure. If it throws, it will be retried if get() is retried. A supplier that fails to clean up partial state on failure may cause a resource leak.

Author:

jonmv

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static interface	Memoized.Closer<T,E extends Exception>	Provides a tighter bound on the thrown exception type.

Constructor Summary

Constructors

Constructor	Description
Memoized(Supplier<T> factory)	Returns a new Memoized which has no close method.
Memoized(Supplier<T> factory, Memoized.Closer<T,E> closer)	Returns a new Memoized with the given factory and closer.

Method Summary

Modifier and Type	Method	Description
void	close()
static <T, U, E extends Exception> Memoized<U,E>	combine(Memoized<T,? extends E> inner, Function<T,U> outer, Memoized.Closer<U,? extends E> closer)	Composes the given memoized with a function taking its output as an argument to produce a new Memoized, with the given closer.
T	get()
static <T extends AutoCloseable> Memoized<T,?>	of(Supplier<T> factory)	Returns a generic AutoCloseable Memoized with the given AutoCloseable-supplier.

Methods inherited from class java.lang.Object

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

Constructor Details

Memoized

public Memoized(Supplier<T> factory)

Returns a new Memoized which has no close method.

Memoized

public Memoized(Supplier<T> factory,
 Memoized.Closer<T,E> closer)

Returns a new Memoized with the given factory and closer.

Method Details

of

public static <T extends AutoCloseable>
Memoized<T,?> of(Supplier<T> factory)

Returns a generic AutoCloseable Memoized with the given AutoCloseable-supplier.

combine

public static <T,
U,
E extends Exception>
Memoized<U,E> combine(Memoized<T,? extends E> inner,
 Function<T,U> outer,
 Memoized.Closer<U,? extends E> closer)

Composes the given memoized with a function taking its output as an argument to produce a new Memoized, with the given closer.

get

public T get()

Specified by:

get in interface Supplier<T>

close

public void close()
           throws E

Specified by:

close in interface AutoCloseable

Throws:

E extends Exception