1 /* 2 * Copyright (c) 1998, 2011, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. Oracle designates this 8 * particular file as subject to the "Classpath" exception as provided 9 * by Oracle in the LICENSE file that accompanied this code. 10 * 11 * This code is distributed in the hope that it will be useful, but WITHOUT 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 * version 2 for more details (a copy is included in the LICENSE file that 15 * accompanied this code). 16 * 17 * You should have received a copy of the GNU General Public License version 18 * 2 along with this work; if not, write to the Free Software Foundation, 19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 20 * 21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have any 23 * questions. 24 */ 25 26 package sun.misc; 27 28 import java.util.Enumeration; 29 import java.util.NoSuchElementException; 30 31 /* 32 * A useful utility class that will enumerate over an array of 33 * enumerations. 34 */ 35 public class CompoundEnumeration<E> implements Enumeration<E> { 36 private Enumeration<E>[] enums; 37 private int index = 0; 38 CompoundEnumeration(Enumeration<E>[] enums)39 public CompoundEnumeration(Enumeration<E>[] enums) { 40 this.enums = enums; 41 } 42 next()43 private boolean next() { 44 while (index < enums.length) { 45 if (enums[index] != null && enums[index].hasMoreElements()) { 46 return true; 47 } 48 index++; 49 } 50 return false; 51 } 52 hasMoreElements()53 public boolean hasMoreElements() { 54 return next(); 55 } 56 nextElement()57 public E nextElement() { 58 if (!next()) { 59 throw new NoSuchElementException(); 60 } 61 return enums[index].nextElement(); 62 } 63 } 64