Package org.apache.spark.util

Class TransientBestEffortLazyVal<T>

Object

org.apache.spark.util.TransientBestEffortLazyVal<T>

All Implemented Interfaces:

Serializable

public class TransientBestEffortLazyVal<T>
extends Object
implements Serializable

A lock-free implementation of a lazily-initialized variable. If there are concurrent initializations then the `compute()` function may be invoked multiple times. However, only a single `compute()` result will be stored and all readers will receive the same result object instance. This may be helpful for avoiding deadlocks in certain scenarios where exactly-once value computation is not a hard requirement. The main difference between this and [[BestEffortLazyVal]] is that: [[BestEffortLazyVal]] serializes the cached value after computation, while [[TransientBestEffortLazyVal]] always serializes the compute function.

See Also:

• Serialized Form

Note:

This helper class has additional requirements on the compute function: 1) The compute function MUST not return null; 2) The computation failure is not cached., Scala 3 uses a different implementation of lazy vals which doesn't have this problem. Please refer to Lazy Vals Initialization for more details.

Constructor Summary

Constructors

Constructor	Description
TransientBestEffortLazyVal(scala.Function0<T> compute)

Method Summary

Modifier and Type	Method	Description
T	apply()

Methods inherited from class java.lang.Object

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

Constructor Details

TransientBestEffortLazyVal

public TransientBestEffortLazyVal(scala.Function0<T> compute)

Method Details

apply

public T apply()