org.jgrapht.util.ArrayUnenforcedSet Maven / Gradle / Ivy
/*
* (C) Copyright 2006-2023, by John V Sichi and Contributors.
*
* JGraphT : a free Java graph-theory library
*
* See the CONTRIBUTORS.md file distributed with this work for additional
* information regarding copyright ownership.
*
* 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
* GNU Lesser General Public License v2.1 or later
* which is available at
* http://www.gnu.org/licenses/old-licenses/lgpl-2.1-standalone.html.
*
* SPDX-License-Identifier: EPL-2.0 OR LGPL-2.1-or-later
*/
package org.jgrapht.util;
import java.util.*;
/**
* Helper for efficiently representing small sets whose elements are known to be unique by
* construction, implying we don't need to enforce the uniqueness property in the data structure
* itself. Use with caution.
*
*
* Note that for equals/hashCode, the class implements the Set behavior (unordered), not the list
* behavior (ordered); the fact that it subclasses ArrayList should be considered an implementation
* detail.
*
* @param the element type
*
* @author John V. Sichi
*/
public class ArrayUnenforcedSet
extends ArrayList
implements Set
{
private static final long serialVersionUID = -7413250161201811238L;
/**
* Constructs a new empty set
*/
public ArrayUnenforcedSet()
{
super();
}
/**
* Constructs a set containing the elements of the specified collection.
*
* @param c the collection whose elements are to be placed into this set
* @throws NullPointerException if the specified collection is null
*/
public ArrayUnenforcedSet(Collection c)
{
super(c);
}
/**
* Constructs an empty set with the specified initial capacity.
*
* @param n the initial capacity of the set
* @throws IllegalArgumentException if the specified initial capacity is negative
*/
public ArrayUnenforcedSet(int n)
{
super(n);
}
@Override
public boolean equals(Object o)
{
return new SetForEquality().equals(o);
}
@Override
public int hashCode()
{
return new SetForEquality().hashCode();
}
/**
* Multiple inheritance helper.
*/
private class SetForEquality
extends AbstractSet
{
@Override
public Iterator iterator()
{
return ArrayUnenforcedSet.this.iterator();
}
@Override
public int size()
{
return ArrayUnenforcedSet.this.size();
}
}
}