/*
* SonarQube Java
* Copyright (C) 2012-2016 SonarSource SA
* mailto:contact AT sonarsource DOT com
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 3 of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program; if not, write to the Free Software Foundation,
* Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/
package org.sonar.java.collections;
import java.util.function.Consumer;
/**
* Persistent (functional) Set.
*
* @author Evgeny Mandrikov
* @param <E> the type of elements maintained by this set
*/
public interface PSet<E> {
/**
* @return new set with added element, or this if element already in the set
*/
PSet<E> add(E e);
/**
* @return new set with removed element, or this if set does not contain given element
*/
PSet<E> remove(E e);
/**
* @return true if this set contains the specified element
*/
boolean contains(E e);
/**
* Performs the given action for each entry in this set until all elements have been processed or the action throws an exception.
*/
void forEach(Consumer<E> action);
/**
* @return true if this set contains no elements
*/
boolean isEmpty();
/**
* The string representation consists of a list of elements in the ascending order of hash codes.
* If two elements have same hash code, then their relative order is arbitrary, but stable.
*
* @return a string representation of this set
*/
@Override
String toString();
}