| Classes in this File | Line Coverage | Branch Coverage | Complexity | ||||
| FilteredEnumeration |
|
| 2.0;2 |
| 1 | /* | |
| 2 | * $Source$ | |
| 3 | * $Revision$ | |
| 4 | * | |
| 5 | * Copyright (C) 2000 William Chesters | |
| 6 | * | |
| 7 | * Part of Melati (http://melati.org), a framework for the rapid | |
| 8 | * development of clean, maintainable web applications. | |
| 9 | * | |
| 10 | * Melati is free software; Permission is granted to copy, distribute | |
| 11 | * and/or modify this software under the terms either: | |
| 12 | * | |
| 13 | * a) the GNU General Public License as published by the Free Software | |
| 14 | * Foundation; either version 2 of the License, or (at your option) | |
| 15 | * any later version, | |
| 16 | * | |
| 17 | * or | |
| 18 | * | |
| 19 | * b) any version of the Melati Software License, as published | |
| 20 | * at http://melati.org | |
| 21 | * | |
| 22 | * You should have received a copy of the GNU General Public License and | |
| 23 | * the Melati Software License along with this program; | |
| 24 | * if not, write to the Free Software Foundation, Inc., | |
| 25 | * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA to obtain the | |
| 26 | * GNU General Public License and visit http://melati.org to obtain the | |
| 27 | * Melati Software License. | |
| 28 | * | |
| 29 | * Feel free to contact the Developers of Melati (http://melati.org), | |
| 30 | * if you would like to work out a different arrangement than the options | |
| 31 | * outlined here. It is our intention to allow Melati to be used by as | |
| 32 | * wide an audience as possible. | |
| 33 | * | |
| 34 | * This program is distributed in the hope that it will be useful, | |
| 35 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
| 36 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
| 37 | * GNU General Public License for more details. | |
| 38 | * | |
| 39 | * Contact details for copyright holder: | |
| 40 | * | |
| 41 | * William Chesters <williamc At paneris.org> | |
| 42 | * http://paneris.org/~williamc | |
| 43 | * Obrechtstraat 114, 2517VX Den Haag, The Netherlands | |
| 44 | */ | |
| 45 | ||
| 46 | package org.melati.poem.util; | |
| 47 | ||
| 48 | import java.util.Enumeration; | |
| 49 | import java.util.NoSuchElementException; | |
| 50 | ||
| 51 | /** | |
| 52 | * An <code>Enumeration</code> created by filtering another | |
| 53 | * according to an abstract inclusion function. | |
| 54 | * <p> | |
| 55 | * Implementations must provide {@link #isIncluded(Object)}. | |
| 56 | */ | |
| 57 | public abstract class FilteredEnumeration <T> implements SkipEnumeration<T> { | |
| 58 | private Enumeration<T> base; | |
| 59 | 2640 | private int finished = -1; |
| 60 | private T next; | |
| 61 | ||
| 62 | /** | |
| 63 | * Constructor. | |
| 64 | * @param base the Enumeration we are based upon | |
| 65 | */ | |
| 66 | 2640 | public FilteredEnumeration(Enumeration<T> base) { |
| 67 | 2640 | this.base = base; |
| 68 | 2640 | } |
| 69 | ||
| 70 | protected abstract boolean isIncluded(T o); | |
| 71 | ||
| 72 | private void probe() { | |
| 73 | 3776 | if (finished == -1) { |
| 74 | for (;;) { | |
| 75 | 20553 | if (!base.hasMoreElements()) { |
| 76 | 2638 | finished = 1; |
| 77 | 2638 | next = null; |
| 78 | 2638 | break; |
| 79 | } | |
| 80 | ||
| 81 | 17915 | next = base.nextElement(); |
| 82 | 17915 | if (isIncluded(next)) { |
| 83 | 335 | finished = 0; |
| 84 | 335 | break; |
| 85 | } | |
| 86 | } | |
| 87 | } | |
| 88 | 3776 | } |
| 89 | ||
| 90 | /** | |
| 91 | * {@inheritDoc} | |
| 92 | * @see java.util.Enumeration#hasMoreElements() | |
| 93 | */ | |
| 94 | public synchronized boolean hasMoreElements() { | |
| 95 | 3776 | probe(); |
| 96 | 3776 | return finished == 0; |
| 97 | } | |
| 98 | ||
| 99 | /** | |
| 100 | * {@inheritDoc} | |
| 101 | * @see java.util.Enumeration#nextElement() | |
| 102 | */ | |
| 103 | public synchronized T nextElement() { | |
| 104 | 337 | if (!hasMoreElements()) |
| 105 | 2 | throw new NoSuchElementException(); |
| 106 | ||
| 107 | 335 | finished = -1; |
| 108 | 335 | return next; |
| 109 | } | |
| 110 | ||
| 111 | /** | |
| 112 | * {@inheritDoc} | |
| 113 | * @see org.melati.poem.util.SkipEnumeration#skip() | |
| 114 | */ | |
| 115 | public synchronized void skip() { | |
| 116 | 4 | nextElement(); |
| 117 | 3 | } |
| 118 | } |