| 1 | /* This file is part of the project "Hilbert II" - http://www.qedeq.org |
| 2 | * |
| 3 | * Copyright 2000-2014, Michael Meyling <mime@qedeq.org>. |
| 4 | * |
| 5 | * "Hilbert II" is free software; you can redistribute |
| 6 | * it and/or modify it under the terms of the GNU General Public |
| 7 | * License as published by the Free Software Foundation; either |
| 8 | * version 2 of the License, or (at your option) any later version. |
| 9 | * |
| 10 | * This program is distributed in the hope that it will be useful, |
| 11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 13 | * GNU General Public License for more details. |
| 14 | */ |
| 15 | |
| 16 | package org.qedeq.base.utility; |
| 17 | |
| 18 | import java.util.Iterator; |
| 19 | |
| 20 | |
| 21 | /** |
| 22 | * Split given string into parts delimited by white space. |
| 23 | * |
| 24 | * @author Michael Meyling |
| 25 | */ |
| 26 | public final class Splitter implements Iterator { |
| 27 | |
| 28 | /** Text to split. */ |
| 29 | private final String text; |
| 30 | |
| 31 | /** Last found position. */ |
| 32 | private int found; |
| 33 | |
| 34 | /** Start searching from here. */ |
| 35 | private int start; |
| 36 | |
| 37 | /** Current found separator string. Consists of (perhaps several) delimiters. */ |
| 38 | private String separator; |
| 39 | |
| 40 | /** Current found token. */ |
| 41 | private String token; |
| 42 | |
| 43 | /** |
| 44 | * Constructor. |
| 45 | * |
| 46 | * @param text Text to split. |
| 47 | */ |
| 48 | public Splitter(final String text) { |
| 49 | this.text = text; |
| 50 | iterate(); |
| 51 | } |
| 52 | |
| 53 | /** |
| 54 | * Split String by given delimiter. |
| 55 | * "a b c" is converted to "a", " ", "b", " ", "c". |
| 56 | * "a b c " is converted to "a", " ", "b", " ", "c", " ". |
| 57 | * "a b c" is converted to "a", " ", "b", " ", "c". |
| 58 | * |
| 59 | * @return Split text. |
| 60 | */ |
| 61 | public Object next() { |
| 62 | return nextToken(); |
| 63 | } |
| 64 | |
| 65 | /** |
| 66 | * Qualified next method. |
| 67 | * |
| 68 | * @return Get next token. |
| 69 | */ |
| 70 | public String nextToken() { |
| 71 | if (token != null) { |
| 72 | final String result = token; |
| 73 | token = null; |
| 74 | return result; |
| 75 | } |
| 76 | if (separator != null) { |
| 77 | final String result = separator; |
| 78 | separator = null; |
| 79 | iterate(); |
| 80 | return result; |
| 81 | } |
| 82 | return null; |
| 83 | } |
| 84 | |
| 85 | /** |
| 86 | * Iterate token and whitespace. |
| 87 | */ |
| 88 | private void iterate() { |
| 89 | found = start; |
| 90 | while (found < text.length() && !Character.isWhitespace(text.charAt(found))) { |
| 91 | found++; |
| 92 | } |
| 93 | if (found < text.length()) { |
| 94 | token = text.substring(start, found); |
| 95 | start = found; |
| 96 | while (found < text.length() && Character.isWhitespace(text.charAt(found))) { |
| 97 | found++; |
| 98 | } |
| 99 | separator = text.substring(start, found); |
| 100 | start = found; |
| 101 | } else { |
| 102 | separator = null; |
| 103 | token = text.substring(start); |
| 104 | } |
| 105 | if (token.length() == 0) { |
| 106 | token = null; |
| 107 | } |
| 108 | } |
| 109 | |
| 110 | public boolean hasNext() { |
| 111 | return token != null || separator != null; |
| 112 | } |
| 113 | |
| 114 | |
| 115 | public void remove() { |
| 116 | throw new UnsupportedOperationException("this iterator doesn't support this method"); |
| 117 | } |
| 118 | |
| 119 | } |