Base value, used mainly when there is no contention, but also as a fallback during table initialization races. Updated via CAS.

Spinlock (locked via CAS) used when resizing and/or creating Cells.

Table of cells. When non-null, size is a power of 2.

Number of CPUS, to place bound on table size

Generator of new random hash codes

ThreadLocal holding a single-slot int array holding hash code. Unlike the JDK8 version of this class, we use a suboptimal int[] representation to avoid introducing a new type that can impede class-unloading when ThreadLocals are not removed.

CASes the base field.

CASes the busy field from 0 to 1 to acquire lock.

Computes the function of current and new value. Subclasses should open-code this update function for most uses, but the virtualized form is needed within retryUpdate.

Parameters

currentValue:long

the current value (of either base or a cell)

newValue:long

the argument from a user update call

Returns:long

result of the update function

Sets base and all cells to the given value.

Handles cases of updates involving initialization, resizing, creating new Cells, and/or contention. See above for explanation. This method suffers the usual non-modularity problems of optimistic retry code, relying on rechecked sets of reads.

Parameters

x:long

the value

hc:int[]

the hash code holder

wasUncontended:boolean

false if CAS failed before call