core/org.gnit.lucenekmp.util/SetOnce

SetOnce

class SetOnce<T : Any> : Cloneable<SetOnce<T>>

A convenient class which offers a semi-immutable object wrapper implementation which allows one to set the value of an object exactly once, and retrieve it many times. If .set is called more than once, AlreadySetException is thrown and the operation will fail.

Constructors

constructor()

A default constructor which does not set the internal object, and allows setting it by calling .set.

constructor(obj: T)

Creates a new instance with the internal object set to the given object. Note that any calls to .set afterwards will result in AlreadySetException

Types

AlreadySetException

class AlreadySetException : IllegalStateException

Thrown when SetOnce.set is called more than once.

Functions

open override fun clone(): SetOnce<T>

fun get(): T?

Returns the object set by .set, or null if not set.

fun set(obj: T)

Sets the given object. If the object has already been set, an exception is thrown.

fun trySet(obj: T): Boolean

Sets the given object if none was set before.