it.unimi.dsi.fastutil.objects.AbstractReferenceSet Maven / Gradle / Ivy

Show more of this group Show more artifacts with this name
Show all versions of fastutil Show documentation

fastutil extends the Java Collections Framework by providing type-specific maps, sets, lists, and queues with a small memory footprint and fast access and insertion; it provides also big (64-bit) arrays, sets and lists, sorting algorithms, fast, practical I/O classes for binary and text files, and facilities for memory mapping large files. Note that if you have both this jar and fastutil-core.jar in your dependencies, fastutil-core.jar should be excluded.

There is a newer version: 8.5.13

Show newest version

/*
	* Copyright (C) 2002-2023 Sebastiano Vigna
	*
	* Licensed under the Apache License, Version 2.0 (the "License");
	* you may not use this file except in compliance with the License.
	* You may obtain a copy of the License at
	*
	*     http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/
package it.unimi.dsi.fastutil.objects;

import java.util.Set;

/**
 * An abstract class providing basic methods for sets implementing a type-specific interface.
 *
 * 
 * Note that the type-specific {@link Set} interface adds a type-specific {@code remove()} method,
 * as it is no longer harmful for subclasses. Thus, concrete subclasses of this class must implement
 * {@code remove()} (the {@code rem()} implementation of this class just delegates to
 * {@code remove()}).
 */
public abstract class AbstractReferenceSet extends AbstractReferenceCollection implements Cloneable, ReferenceSet {
	protected AbstractReferenceSet() {
	}

	@Override
	public abstract ObjectIterator iterator();

	@Override
	public boolean equals(final Object o) {
		if (o == this) return true;
		if (!(o instanceof Set)) return false;
		Set s = (Set)o;
		if (s.size() != size()) return false;
		return containsAll(s);
	}

	/**
	 * Returns a hash code for this set.
	 *
	 * The hash code of a set is computed by summing the hash codes of its elements.
	 *
	 * @return a hash code for this set.
	 */
	@Override
	public int hashCode() {
		int h = 0, n = size();
		ObjectIterator i = iterator();
		K k;
		while (n-- != 0) {
			k = i.next(); // We need k because KEY2JAVAHASH() is a macro with repeated evaluation.
			h += (System.identityHashCode(k));
		}
		return h;
	}
}