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Atomic Types

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:
Ignite ignite = Ignition.start();

IgniteAtomicLong atomicLong = ignite.atomicLong("atomicName", // Atomic long name.
        0, // Initial value.
        true // Create if it does not exist.
);

// Increment atomic long on local node
System.out.println("Incremented value: " + atomicLong.incrementAndGet());
AtomicReference:
Ignite ignite = Ignition.start();

// Create an AtomicReference
IgniteAtomicReference<String> ref = ignite.atomicReference("refName", // Reference name.
        "someVal", // Initial value for atomic reference.
        true // Create if it does not exist.
);

// Compare and update the value
ref.compareAndSet("WRONG EXPECTED VALUE", "someNewVal"); // Won't change.

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:

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