io.cloudstate.javasupport.crdt.PNCounter Maven / Gradle / Ivy
package io.cloudstate.javasupport.crdt;
/**
* A Positive-Negative Counter.
*
* A Positive-Negative Counter is a counter that allows both incrementing, and decrementing. It
* is based on two {@link GCounter}'s, a positive one that is incremented for every increment, and a
* negative one that is incremented for every decrement. The current value of the counter is
* calculated by subtracting the negative counter from the positive counter.
*/
public interface PNCounter extends Crdt {
/**
* Get the current value of the counter.
*
* @return The current value of the counter.
*/
long getValue();
/**
* Increment the counter.
*
*
If by is negative, then the counter will be decremented by that much instead.
*
* @param by The amount to increment the counter by.
* @return The new value of the counter.
*/
long increment(long by);
/**
* Decrement the counter.
*
*
If by is negative, then the counter will be incremented by that much instead.
*
* @param by The amount to decrement the counter by.
* @return The new value of the counter.
*/
long decrement(long by);
}