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= Atomic Types

:javaFile: {javaCodeDir}/DataStructures.java

Ignite supports distributed atomic long and atomic reference, similar to `java.util.concurrent.atomic.AtomicLong` and `java.util.concurrent.atomic.AtomicReference` respectively.

Atomics in Ignite are distributed across the cluster, essentially enabling performing atomic operations (such as increment-and-get or compare-and-set) with the same globally-visible value. For example, you could update the value of an atomic long on one node and read it from another node.

Features:

  * Retrieve current value.
  * Atomically modify current value.
  * Atomically increment or decrement current value.
  * Atomically compare-and-set the current value to new value.

Distributed atomic long and atomic reference can be obtained via `IgniteAtomicLong` and `IgniteAtomicReference` interfaces respectively, as shown below:



.AtomicLong:
[source, java]
----
include::{javaFile}[tags=atomic-long, indent=0]
----

.AtomicReference:
[source, java]
----
include::{javaFile}[tags=atomic-reference, indent=0]
----

All atomic operations provided by `IgniteAtomicLong` and `IgniteAtomicReference` are synchronous. The time an atomic operation will take depends on the number of nodes performing concurrent operations with the same instance of atomic long, the intensity of these operations, and network latency.


== Atomic Configuration

Atomics in Ignite can be configured via the `atomicConfiguration` property of `IgniteConfiguration`.

The following table lists available configuration parameters:

[cols="1,1,1",opts="header"]
|===
| Setter | Description | Default
| `setBackups(int)` | The number of backups. | 0
| `setCacheMode(CacheMode)` | Cache mode for all atomic types. | `PARTITIONED`
| `setAtomicSequenceReserveSize(int)` | Sets the number of sequence values reserved for `IgniteAtomicSequence` instances. |  1000
|===


