| /******************************************************************************* |
| * Copyright (c) 2005, 2007 Oracle. All rights reserved. |
| * This program and the accompanying materials are made available under the |
| * terms of the Eclipse Public License v1.0, which accompanies this distribution |
| * and is available at http://www.eclipse.org/legal/epl-v10.html. |
| * |
| * Contributors: |
| * Oracle - initial API and implementation |
| ******************************************************************************/ |
| package org.eclipse.jpt.utility.internal; |
| |
| /** |
| * A collection that allows duplicate elements. |
| * <p> |
| * The <code>Bag</code> interface places additional stipulations, |
| * beyond those inherited from the <code>java.util.Collection</code> interface, |
| * on the contracts of the <code>equals</code> and <code>hashCode</code> methods. |
| * |
| * @version 1.00 Jan-2002 |
| * @see java.util.Collection |
| * @see HashBag |
| */ |
| |
| public interface Bag<E> extends java.util.Collection<E> { |
| |
| /** |
| * Compares the specified object with this bag for equality. Returns |
| * <code>true</code> if the specified object is also a bag, the two bags |
| * have the same size, and every member of the specified bag is |
| * contained in this bag with the same number of occurrences (or equivalently, |
| * every member of this bag is contained in the specified bag with the same |
| * number of occurrences). This definition ensures that the |
| * equals method works properly across different implementations of the |
| * bag interface. |
| */ |
| boolean equals(Object o); |
| |
| /** |
| * Returns the hash code value for this bag. The hash code of a bag is |
| * defined to be the sum of the hash codes of the elements in the bag, |
| * where the hashcode of a <code>null</code> element is defined to be zero. |
| * This ensures that <code>b1.equals(b2)</code> implies that |
| * <code>b1.hashCode() == b2.hashCode()</code> for any two bags |
| * <code>b1</code> and <code>b2</code>, as required by the general |
| * contract of the <code>Object.hashCode</code> method. |
| */ |
| int hashCode(); |
| |
| } |
