com.hazelcast.cp.IAtomicReference Maven / Gradle / Ivy
/*
* Copyright (c) 2008-2020, Hazelcast, Inc. All Rights Reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.hazelcast.cp;
import com.hazelcast.config.cp.CPSubsystemConfig;
import com.hazelcast.core.DistributedObject;
import com.hazelcast.core.IFunction;
import java.util.concurrent.CompletionStage;
/**
* IAtomicReference is a redundant and highly available distributed alternative
* to the {@link java.util.concurrent.atomic.AtomicReference}.
*
* Asynchronous variants have been introduced in version 3.7.
* Async methods immediately return a {@link CompletionStage} 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:
*
* CompletionStage<E> future = atomicRef.getAsync();
* future.whenCompleteAsync((v, throwable) -> {
* if (throwable == null) {
* // do something with the old value returned by put operation
* } else {
* // handle failure
* }
* });
*
*
* Actions supplied for dependent completions of default non-async methods and async methods
* without an explicit {@link java.util.concurrent.Executor} argument are performed
* by the {@link java.util.concurrent.ForkJoinPool#commonPool()} (unless it does not
* support a parallelism level of at least 2, in which case a new {@code Thread} is
* created per task).
*
* IAtomicReference is accessed via {@link CPSubsystem#getAtomicReference(String)}.
* 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.
*
* 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
* {@link CPSubsystemConfig#setFailOnIndeterminateOperationState(boolean)}
*
* @param the type of object referred to by this reference
* @see IAtomicLong
* @since 3.2
*/
public interface IAtomicReference extends DistributedObject {
/**
* Atomically sets the value to the given updated value
* only if the current value {@code ==} the expected value.
*
* @param expect the expected value
* @param update the new value
* @return {@code true} if successful; or {@code false} if the actual value
* was not equal to the expected value
*/
boolean compareAndSet(E expect, E update);
/**
* Gets the current value.
*
* @return the current value
*/
E get();
/**
* Atomically sets the given value.
*
* @param newValue the new value
*/
void set(E newValue);
/**
* Gets the old value and sets the new value.
*
* @param newValue the new value
* @return the old value
*/
E getAndSet(E newValue);
/**
* Checks if the stored reference is {@code null}.
*
* @return {@code true} if {@code null}, {@code false} otherwise
*/
boolean isNull();
/**
* Clears the current stored reference.
*/
void clear();
/**
* Checks if the reference contains the value.
*
* @param value the value to check (is allowed to be {@code null})
* @return {@code true} if the value is found, {@code false} otherwise
*/
boolean contains(E value);
/**
* Alters the currently stored reference by applying a function on it.
*
* @param function the function that alters the currently stored reference
* @throws IllegalArgumentException if function is {@code null}
*/
void alter(IFunction function);
/**
* Alters the currently stored reference by applying a function on it and
* gets the result.
*
* @param function the function that alters the currently stored reference
* @return the new value, the result of the applied function
* @throws IllegalArgumentException if function is {@code null}
*/
E alterAndGet(IFunction function);
/**
* Alters the currently stored reference by applying a function on it on
* and gets the old value.
*
* @param function the function that alters the currently stored reference
* @return the old value, the value before the function is applied
* @throws IllegalArgumentException if function is {@code null}
*/
E getAndAlter(IFunction function);
/**
* Applies a function on the value, the actual stored value will not
* change.
*
* @param function the function applied on the value, the stored value does not change
* @param the result type of the function
* @return the result of the function application
* @throws IllegalArgumentException if function is {@code null}
*/
R apply(IFunction function);
/**
* Atomically sets the value to the given updated value only if the
* current value {@code ==} the expected value.
*
* @param expect the expected value
* @param update the new value
* @return {@code true} if successful; or {@code false} if the actual value
* was not equal to the expected value
*/
CompletionStage compareAndSetAsync(E expect, E update);
/**
* Gets the current value.
*
* @return the current value
*/
CompletionStage getAsync();
/**
* Atomically sets the given value.
*
* @param newValue the new value
*/
CompletionStage setAsync(E newValue);
/**
* Gets the value and sets the new value.
*
* @param newValue the new value
* @return the old value
*/
CompletionStage getAndSetAsync(E newValue);
/**
* Checks if the stored reference is {@code null}.
*
* @return {@code true} if {@code null}, {@code false} otherwise
*/
CompletionStage isNullAsync();
/**
* Clears the current stored reference.
*/
CompletionStage clearAsync();
/**
* Checks if the reference contains the value.
*
* @param expected the value to check (is allowed to be null)
* @return {@code true} if the value is found, {@code false} otherwise
*/
CompletionStage containsAsync(E expected);
/**
* Alters the currently stored reference by applying a function on it.
*
* @param function the function
* @throws IllegalArgumentException if function is {@code null}
*/
CompletionStage alterAsync(IFunction function);
/**
* Alters the currently stored reference by applying a function on it and
* gets the result.
*
* @param function the function
* @return the new value
* @throws IllegalArgumentException if function is {@code null}
*/
CompletionStage alterAndGetAsync(IFunction function);
/**
* Alters the currently stored reference by applying a function on it on
* and gets the old value.
*
* @param function the function
* @return the old value
* @throws IllegalArgumentException if function is {@code null}
*/
CompletionStage getAndAlterAsync(IFunction function);
/**
* Applies a function on the value, the actual stored value will not
* change.
*
* @param function the function
* @param the result type of the function
* @return the result of the function application
* @throws IllegalArgumentException if function is {@code null}
*/
CompletionStage applyAsync(IFunction function);
}