package com.thealgorithms.datastructures.crdt;
import java.util.HashSet;
import java.util.Set;
/**
* GSet (Grow-only Set) is a state-based CRDT (Conflict-free Replicated Data Type)
* that allows only the addition of elements and ensures that once an element is added,
* it cannot be removed. The merge operation of two G-Sets is their union.
* This implementation supports adding elements, looking up elements, comparing with other G-Sets,
* and merging with another G-Set to create a new G-Set containing all unique elements from both sets.
* (https://en.wikipedia.org/wiki/Conflict-free_replicated_data_type)
*
* @author itakurah (Niklas Hoefflin) (https://github.com/itakurah)
*/
public class GSet<T> {
private final Set<T> elements;
/**
* Constructs an empty G-Set.
*/
public GSet() {
this.elements = new HashSet<>();
}
/**
* Adds an element to the G-Set.
*
* @param e the element to be added
*/
public void addElement(T e) {
elements.add(e);
}
/**
* Checks if the given element is present in the G-Set.
*
* @param e the element to be checked
* @return true if the element is present, false otherwise
*/
public boolean lookup(T e) {
return elements.contains(e);
}
/**
* Compares the G-Set with another G-Set to check if it is a subset.
*
* @param other the other G-Set to compare with
* @return true if the current G-Set is a subset of the other, false otherwise
*/
public boolean compare(GSet<T> other) {
return other.elements.containsAll(elements);
}
/**
* Merges the current G-Set with another G-Set, creating a new G-Set
* containing all unique elements from both sets.
*
* @param other the G-Set to merge with
*/
public void merge(GSet<T> other) {
elements.addAll(other.elements);
}
}