1 /******************************************************************************* 2 * Copyright (c) 2000, 2006 IBM Corporation and others. 3 * All rights reserved. This program and the accompanying materials 4 * are made available under the terms of the Eclipse Public License v1.0 5 * which accompanies this distribution, and is available at 6 * http://www.eclipse.org/legal/epl-v10.html 7 * 8 * Contributors: 9 * IBM Corporation - initial API and implementation 10 *******************************************************************************/ 11 12 package org.eclipse.jface.viewers; 13 14 /** 15 * This interface is used to compare elements in a viewer for equality, 16 * and to provide the hash code for an element. 17 * This allows the client of the viewer to specify different equality criteria 18 * and a different hash code implementation than the 19 * <code>equals</code> and <code>hashCode</code> implementations of the 20 * elements themselves. 21 * 22 * @see StructuredViewer#setComparer 23 */ 24 public interface IElementComparer { 25 26 /** 27 * Compares two elements for equality 28 * 29 * @param a the first element 30 * @param b the second element 31 * @return whether a is equal to b 32 */ 33 boolean equals(Object a, Object b); 34 35 /** 36 * Returns the hash code for the given element. 37 * @param element the element the hash code is calculated for 38 * 39 * @return the hash code for the given element 40 */ 41 int hashCode(Object element); 42 } 43