Package org.forgerock.util

Class LazySupplier<T,E extends Exception>

java.lang.Object

org.forgerock.util.LazySupplier<T,E>

Type Parameters:

T - the type of value returned by the supplier.

E - the type of exceptions thrown by the supplier.

All Implemented Interfaces:

AutoCloseable, Supplier<T,E>

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

A Supplier that lazily computes a value the first time it is accessed and then caches the result to return on subsequent requests. This class is thread safe.

Method Summary

Modifier and Type	Method	Description
void	close()	If the lazily-cached value has been initialized and is AutoCloseable then it is closed.
T	get()	Supplies a value and caches it, ensuring the same value is returned on subsequent calls.
static <T,E extends Exception> LazySupplier<T,E>	lazy(Supplier<T,E> supplier)	Constructs a supplier that will lazily compute and cache a value from the given supplier.

Methods inherited from class java.lang.Object

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

Method Detail

get

public T get()
      throws E extends Exception

Supplies a value and caches it, ensuring the same value is returned on subsequent calls. If an exception is thrown by the underlying supplier then this is thrown from this method and not cached.

Specified by:

get in interface Supplier<T,E extends Exception>

Returns:

the lazily-computed value.

Throws:

E - if an exception occurs when computing the value.

E extends Exception

close

public void close()
           throws Exception

If the lazily-cached value has been initialized and is AutoCloseable then it is closed. If the value has not been initialized, or is not closeable, then this method does nothing.

Specified by:

close in interface AutoCloseable

Throws:

Exception - if the AutoCloseable.close() method on the cached value throws an exception.

lazy

public static <T,E extends Exception> LazySupplier<T,E> lazy(Supplier<T,E> supplier)

Constructs a supplier that will lazily compute and cache a value from the given supplier.

Type Parameters:

T - the type of values returned.

E - the type of exceptions thrown by the supplier.

Parameters:

supplier - the supplier to use to compute the value.

Returns:

a lazy version of the supplier.