001 /* Enumeration.java -- Interface for enumerating lists of objects 002 Copyright (C) 1998, 1999, 2001, 2004, 2005 003 Free Software Foundation, Inc. 004 005 This file is part of GNU Classpath. 006 007 GNU Classpath is free software; you can redistribute it and/or modify 008 it under the terms of the GNU General Public License as published by 009 the Free Software Foundation; either version 2, or (at your option) 010 any later version. 011 012 GNU Classpath is distributed in the hope that it will be useful, but 013 WITHOUT ANY WARRANTY; without even the implied warranty of 014 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 015 General Public License for more details. 016 017 You should have received a copy of the GNU General Public License 018 along with GNU Classpath; see the file COPYING. If not, write to the 019 Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 020 02110-1301 USA. 021 022 Linking this library statically or dynamically with other modules is 023 making a combined work based on this library. Thus, the terms and 024 conditions of the GNU General Public License cover the whole 025 combination. 026 027 As a special exception, the copyright holders of this library give you 028 permission to link this library with independent modules to produce an 029 executable, regardless of the license terms of these independent 030 modules, and to copy and distribute the resulting executable under 031 terms of your choice, provided that you also meet, for each linked 032 independent module, the terms and conditions of the license of that 033 module. An independent module is a module which is not derived from 034 or based on this library. If you modify this library, you may extend 035 this exception to your version of the library, but you are not 036 obligated to do so. If you do not wish to do so, delete this 037 exception statement from your version. */ 038 039 package java.util; 040 041 /* Written using "Java Class Libraries", 2nd edition, ISBN 0-201-31002-3 042 * "The Java Language Specification", ISBN 0-201-63451-1. 043 * Status: Believed complete and correct 044 */ 045 046 /** 047 * Interface for lists of objects that can be returned in sequence. Successive 048 * objects are obtained by the nextElement method. 049 * <p> 050 * As of Java 1.2, the Iterator interface provides the same functionality, but 051 * with shorter method names and a new optional method to remove items from the 052 * list. If writing for 1.2, consider using Iterator instead. Enumerations over 053 * the new collections classes, for use with legacy APIs that require them, can 054 * be obtained by the enumeration method in class Collections. 055 * 056 * @author Warren Levy (warrenl@cygnus.com) 057 * @author Eric Blake (ebb9@email.byu.edu) 058 * @see Iterator 059 * @see Hashtable 060 * @see Vector 061 * @since 1.0 062 * @status updated to 1.4 063 */ 064 public interface Enumeration<E> 065 { 066 /** 067 * Tests whether there are elements remaining in the enumeration. 068 * 069 * @return true if there is at least one more element in the enumeration, 070 * that is, if the next call to nextElement will not throw a 071 * NoSuchElementException. 072 */ 073 boolean hasMoreElements(); 074 075 /** 076 * Obtain the next element in the enumeration. 077 * 078 * @return the next element in the enumeration 079 * @throws NoSuchElementException if there are no more elements 080 */ 081 E nextElement(); 082 }