io.vertx.core.shareddata.Counter Maven / Gradle / Ivy
/*
* Copyright (c) 2011-2019 Contributors to the Eclipse Foundation
*
* This program and the accompanying materials are made available under the
* terms of the Eclipse Public License 2.0 which is available at
* http://www.eclipse.org/legal/epl-2.0, or the Apache License, Version 2.0
* which is available at https://www.apache.org/licenses/LICENSE-2.0.
*
* SPDX-License-Identifier: EPL-2.0 OR Apache-2.0
*/
package io.vertx.core.shareddata;
import io.vertx.codegen.annotations.VertxGen;
import io.vertx.core.AsyncResult;
import io.vertx.core.Future;
import io.vertx.core.Handler;
import java.util.Objects;
/**
* An asynchronous counter that can be used to across the cluster to maintain a consistent count.
*
*
*
* @author Tim Fox
*/
@VertxGen
public interface Counter {
/**
* Get the current value of the counter
*
* @return a future notified with the value
*/
Future get();
/**
* Increment the counter atomically and return the new count
*
* @return a future notified with the value
*/
Future incrementAndGet();
/**
* Increment the counter atomically and return the value before the increment.
*
* @return a future notified with the value
*/
Future getAndIncrement();
/**
* Decrement the counter atomically and return the new count
*
* @return a future notified with the value
*/
Future decrementAndGet();
/**
* Add the value to the counter atomically and return the new count
*
* @param value the value to add
* @return a future notified with the value
*/
Future addAndGet(long value);
/**
* Add the value to the counter atomically and return the value before the add
*
* @param value the value to add
* @return a future notified with the value
*/
Future getAndAdd(long value);
/**
* Set the counter to the specified value only if the current value is the expectec value. This happens
* atomically.
*
* @param expected the expected value
* @param value the new value
* @return a future notified with {@code true} on success
*/
Future compareAndSet(long expected, long value);
}