E
- the type of object referred to by this referencepublic interface IAtomicReference<E> extends DistributedObject
AtomicReference
.
Asynchronous variants have been introduced in version 3.7.
Async methods immediately return an ICompletableFuture
from which
the operation's result can be obtained either in a blocking manner or by
registering a callback to be executed upon completion. For example:
ICompletableFuture future = atomicRef.getAsync();
future.andThen(new ExecutionCallback() {
void onResponse(Long response) {
// do something with the result
}
void onFailure(Throwable t) {
// handle failure
}
});
As of version 3.12, Hazelcast offers 2 different IAtomicReference
impls. Behaviour of IAtomicReference
under failure scenarios,
including network partitions, depends on the impl. The first impl is
the good old IAtomicReference
that is accessed via
HazelcastInstance.getAtomicReference(String)
. It works on top of
Hazelcast's async replication algorithm and does not guarantee
linearizability during failures. It is possible for an
IAtomicReference
instance to exist in each of the partitioned
clusters or to not exist at all. Under these circumstances, the values held
in the IAtomicReference
instance may diverge. Once the network
partition heals, Hazelcast will use the configured split-brain merge policy
to resolve conflicting values.
This IAtomicReference
impl also supports Quorum QuorumConfig
in cluster versions 3.10 and higher. However, Hazelcast quorums do not
guarantee strong consistency under failure scenarios.
The second impl is a new one introduced with the CPSubsystem
in
version 3.12. It is accessed via
CPSubsystem.getAtomicReference(String)
. It has a major difference to
the old implementation, that is, it works on top of the Raft consensus
algorithm. It offers linearizability during crash failures and network
partitions. It is CP with respect to the CAP principle. If a network
partition occurs, it remains available on at most one side of the partition.
The CP IAtomicReference impl does not offer exactly-once / effectively-once
execution semantics. It goes with at-least-once execution semantics
by default and can cause an API call to be committed multiple times
in case of CP member failures. It can be tuned to offer at-most-once
execution semantics. Please see
CPSubsystemConfig.setFailOnIndeterminateOperationState(boolean)
IAtomicLong
Modifier and Type | Method and Description |
---|---|
void |
alter(IFunction<E,E> function)
Alters the currently stored reference by applying a function on it.
|
E |
alterAndGet(IFunction<E,E> function)
Alters the currently stored reference by applying a function on it and
gets the result.
|
ICompletableFuture<E> |
alterAndGetAsync(IFunction<E,E> function)
Alters the currently stored reference by applying a function on it and
gets the result.
|
ICompletableFuture<Void> |
alterAsync(IFunction<E,E> function)
Alters the currently stored reference by applying a function on it.
|
<R> R |
apply(IFunction<E,R> function)
Applies a function on the value, the actual stored value will not
change.
|
<R> ICompletableFuture<R> |
applyAsync(IFunction<E,R> function)
Applies a function on the value, the actual stored value will not
change.
|
void |
clear()
Clears the current stored reference.
|
ICompletableFuture<Void> |
clearAsync()
Clears the current stored reference.
|
boolean |
compareAndSet(E expect,
E update)
Atomically sets the value to the given updated value
only if the current value
== the expected value. |
ICompletableFuture<Boolean> |
compareAndSetAsync(E expect,
E update)
Atomically sets the value to the given updated value only if the
current value
== the expected value. |
boolean |
contains(E value)
Checks if the reference contains the value.
|
ICompletableFuture<Boolean> |
containsAsync(E expected)
Checks if the reference contains the value.
|
E |
get()
Gets the current value.
|
E |
getAndAlter(IFunction<E,E> function)
Alters the currently stored reference by applying a function on it on
and gets the old value.
|
ICompletableFuture<E> |
getAndAlterAsync(IFunction<E,E> function)
Alters the currently stored reference by applying a function on it on
and gets the old value.
|
E |
getAndSet(E newValue)
Gets the old value and sets the new value.
|
ICompletableFuture<E> |
getAndSetAsync(E newValue)
Gets the value and sets the new value.
|
ICompletableFuture<E> |
getAsync()
Gets the current value.
|
boolean |
isNull()
Checks if the stored reference is
null . |
ICompletableFuture<Boolean> |
isNullAsync()
Checks if the stored reference is
null . |
void |
set(E newValue)
Atomically sets the given value.
|
E |
setAndGet(E update)
Deprecated.
will be removed from Hazelcast 3.4 since it doesn't really serve a purpose
|
ICompletableFuture<Void> |
setAsync(E newValue)
Atomically sets the given value.
|
destroy, getName, getPartitionKey, getServiceName
boolean compareAndSet(E expect, E update)
==
the expected value.expect
- the expected valueupdate
- the new valuetrue
if successful; or false
if the actual value
was not equal to the expected valueE get()
void set(E newValue)
newValue
- the new valueE getAndSet(E newValue)
newValue
- the new valueE setAndGet(E update)
update
- the new valueboolean isNull()
null
.true
if null
, false
otherwisevoid clear()
boolean contains(E value)
value
- the value to check (is allowed to be null
)true
if the value is found, false
otherwisevoid alter(IFunction<E,E> function)
function
- the function that alters the currently stored referenceIllegalArgumentException
- if function is null
E alterAndGet(IFunction<E,E> function)
function
- the function that alters the currently stored referenceIllegalArgumentException
- if function is null
E getAndAlter(IFunction<E,E> function)
function
- the function that alters the currently stored referenceIllegalArgumentException
- if function is null
<R> R apply(IFunction<E,R> function)
function
- the function applied on the value, the stored value does not changeIllegalArgumentException
- if function is null
ICompletableFuture<Boolean> compareAndSetAsync(E expect, E update)
==
the expected value.expect
- the expected valueupdate
- the new valuetrue
if successful; or false
if the actual value
was not equal to the expected valueICompletableFuture<E> getAsync()
ICompletableFuture<Void> setAsync(E newValue)
newValue
- the new valueICompletableFuture<E> getAndSetAsync(E newValue)
newValue
- the new valueICompletableFuture<Boolean> isNullAsync()
null
.true
if null
, false
otherwiseICompletableFuture<Void> clearAsync()
ICompletableFuture<Boolean> containsAsync(E expected)
expected
- the value to check (is allowed to be null)true
if the value is found, false
otherwiseICompletableFuture<Void> alterAsync(IFunction<E,E> function)
function
- the functionIllegalArgumentException
- if function is null
ICompletableFuture<E> alterAndGetAsync(IFunction<E,E> function)
function
- the functionIllegalArgumentException
- if function is null
ICompletableFuture<E> getAndAlterAsync(IFunction<E,E> function)
function
- the functionIllegalArgumentException
- if function is null
<R> ICompletableFuture<R> applyAsync(IFunction<E,R> function)
function
- the functionIllegalArgumentException
- if function is null
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