Package org.elasticsearch.common.util

Class LazyInitializable<T,E extends Exception>

java.lang.Object

org.elasticsearch.common.util.LazyInitializable<T,E>

public final class LazyInitializable<T,E extends Exception>
extends Object

Encapsulates a CheckedSupplier which is lazily invoked once on the first call to #getOrCompute(). The value which the supplier returns is memorized and will be served until #reset() is called. Each value returned by #getOrCompute(), newly minted or cached, will be passed to the onGet Consumer. On #reset() the value will be passed to the onReset Consumer and the next #getOrCompute() will regenerate the value.

Constructor Summary

Constructors

Constructor	Description
LazyInitializable(CheckedSupplier<T,E> supplier)	Creates the simple LazyInitializable instance.
LazyInitializable(CheckedSupplier<T,E> supplier, Consumer<T> onGet, Consumer<T> onReset)	Creates the complete LazyInitializable instance.

Method Summary

Modifier and Type	Method	Description
T	getOrCompute()	Returns a value that was created by supplier.
void	reset()	Clears the value, if it has been previously created by calling #getOrCompute().

Methods inherited from class java.lang.Object

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

Constructor Details

LazyInitializable

public LazyInitializable(CheckedSupplier<T,E> supplier)

Creates the simple LazyInitializable instance.

Parameters:

supplier - The CheckedSupplier to generate values which will be served on #getOrCompute() invocations.

LazyInitializable

public LazyInitializable(CheckedSupplier<T,E> supplier,
 Consumer<T> onGet,
 Consumer<T> onReset)

Creates the complete LazyInitializable instance.

Parameters:

supplier - The CheckedSupplier to generate values which will be served on #getOrCompute() invocations.

onGet - A Consumer which is called on each value, newly forged or stale, that is returned by #getOrCompute()

onReset - A Consumer which is invoked on the value that will be erased when calling #reset()

Method Details

getOrCompute

public T getOrCompute()
               throws E

Returns a value that was created by supplier. The value might have been previously created, if not it will be created now, thread safe of course.

Throws:

E extends Exception

reset

public void reset()

Clears the value, if it has been previously created by calling #getOrCompute(). The onReset will be called on this value. The next call to #getOrCompute() will recreate the value.