J. Duke | 319a3b9 | 2007-12-01 00:00:00 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 1996-2000 Sun Microsystems, Inc. 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. Sun designates this |
| 8 | * particular file as subject to the "Classpath" exception as provided |
| 9 | * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
| 22 | * CA 95054 USA or visit www.sun.com if you need additional information or |
| 23 | * have any questions. |
| 24 | */ |
| 25 | |
| 26 | /* |
| 27 | * (C) Copyright Taligent, Inc. 1996, 1997 - All Rights Reserved |
| 28 | * (C) Copyright IBM Corp. 1996 - 1998 - All Rights Reserved |
| 29 | * |
| 30 | * The original version of this source code and documentation |
| 31 | * is copyrighted and owned by Taligent, Inc., a wholly-owned |
| 32 | * subsidiary of IBM. These materials are provided under terms |
| 33 | * of a License Agreement between Taligent and Sun. This technology |
| 34 | * is protected by multiple US and International patents. |
| 35 | * |
| 36 | * This notice and attribution to Taligent may not be removed. |
| 37 | * Taligent is a registered trademark of Taligent, Inc. |
| 38 | * |
| 39 | */ |
| 40 | |
| 41 | package java.text; |
| 42 | |
| 43 | |
| 44 | /** |
| 45 | * This interface defines a protocol for bidirectional iteration over text. |
| 46 | * The iterator iterates over a bounded sequence of characters. Characters |
| 47 | * are indexed with values beginning with the value returned by getBeginIndex() and |
| 48 | * continuing through the value returned by getEndIndex()-1. |
| 49 | * <p> |
| 50 | * Iterators maintain a current character index, whose valid range is from |
| 51 | * getBeginIndex() to getEndIndex(); the value getEndIndex() is included to allow |
| 52 | * handling of zero-length text ranges and for historical reasons. |
| 53 | * The current index can be retrieved by calling getIndex() and set directly |
| 54 | * by calling setIndex(), first(), and last(). |
| 55 | * <p> |
| 56 | * The methods previous() and next() are used for iteration. They return DONE if |
| 57 | * they would move outside the range from getBeginIndex() to getEndIndex() -1, |
| 58 | * signaling that the iterator has reached the end of the sequence. DONE is |
| 59 | * also returned by other methods to indicate that the current index is |
| 60 | * outside this range. |
| 61 | * |
| 62 | * <P>Examples:<P> |
| 63 | * |
| 64 | * Traverse the text from start to finish |
| 65 | * <pre> |
| 66 | * public void traverseForward(CharacterIterator iter) { |
| 67 | * for(char c = iter.first(); c != CharacterIterator.DONE; c = iter.next()) { |
| 68 | * processChar(c); |
| 69 | * } |
| 70 | * } |
| 71 | * </pre> |
| 72 | * |
| 73 | * Traverse the text backwards, from end to start |
| 74 | * <pre> |
| 75 | * public void traverseBackward(CharacterIterator iter) { |
| 76 | * for(char c = iter.last(); c != CharacterIterator.DONE; c = iter.previous()) { |
| 77 | * processChar(c); |
| 78 | * } |
| 79 | * } |
| 80 | * </pre> |
| 81 | * |
| 82 | * Traverse both forward and backward from a given position in the text. |
| 83 | * Calls to notBoundary() in this example represents some |
| 84 | * additional stopping criteria. |
| 85 | * <pre> |
| 86 | * public void traverseOut(CharacterIterator iter, int pos) { |
| 87 | * for (char c = iter.setIndex(pos); |
| 88 | * c != CharacterIterator.DONE && notBoundary(c); |
| 89 | * c = iter.next()) { |
| 90 | * } |
| 91 | * int end = iter.getIndex(); |
| 92 | * for (char c = iter.setIndex(pos); |
| 93 | * c != CharacterIterator.DONE && notBoundary(c); |
| 94 | * c = iter.previous()) { |
| 95 | * } |
| 96 | * int start = iter.getIndex(); |
| 97 | * processSection(start, end); |
| 98 | * } |
| 99 | * </pre> |
| 100 | * |
| 101 | * @see StringCharacterIterator |
| 102 | * @see AttributedCharacterIterator |
| 103 | */ |
| 104 | |
| 105 | public interface CharacterIterator extends Cloneable |
| 106 | { |
| 107 | |
| 108 | /** |
| 109 | * Constant that is returned when the iterator has reached either the end |
| 110 | * or the beginning of the text. The value is '\\uFFFF', the "not a |
| 111 | * character" value which should not occur in any valid Unicode string. |
| 112 | */ |
| 113 | public static final char DONE = '\uFFFF'; |
| 114 | |
| 115 | /** |
| 116 | * Sets the position to getBeginIndex() and returns the character at that |
| 117 | * position. |
| 118 | * @return the first character in the text, or DONE if the text is empty |
| 119 | * @see #getBeginIndex() |
| 120 | */ |
| 121 | public char first(); |
| 122 | |
| 123 | /** |
| 124 | * Sets the position to getEndIndex()-1 (getEndIndex() if the text is empty) |
| 125 | * and returns the character at that position. |
| 126 | * @return the last character in the text, or DONE if the text is empty |
| 127 | * @see #getEndIndex() |
| 128 | */ |
| 129 | public char last(); |
| 130 | |
| 131 | /** |
| 132 | * Gets the character at the current position (as returned by getIndex()). |
| 133 | * @return the character at the current position or DONE if the current |
| 134 | * position is off the end of the text. |
| 135 | * @see #getIndex() |
| 136 | */ |
| 137 | public char current(); |
| 138 | |
| 139 | /** |
| 140 | * Increments the iterator's index by one and returns the character |
| 141 | * at the new index. If the resulting index is greater or equal |
| 142 | * to getEndIndex(), the current index is reset to getEndIndex() and |
| 143 | * a value of DONE is returned. |
| 144 | * @return the character at the new position or DONE if the new |
| 145 | * position is off the end of the text range. |
| 146 | */ |
| 147 | public char next(); |
| 148 | |
| 149 | /** |
| 150 | * Decrements the iterator's index by one and returns the character |
| 151 | * at the new index. If the current index is getBeginIndex(), the index |
| 152 | * remains at getBeginIndex() and a value of DONE is returned. |
| 153 | * @return the character at the new position or DONE if the current |
| 154 | * position is equal to getBeginIndex(). |
| 155 | */ |
| 156 | public char previous(); |
| 157 | |
| 158 | /** |
| 159 | * Sets the position to the specified position in the text and returns that |
| 160 | * character. |
| 161 | * @param position the position within the text. Valid values range from |
| 162 | * getBeginIndex() to getEndIndex(). An IllegalArgumentException is thrown |
| 163 | * if an invalid value is supplied. |
| 164 | * @return the character at the specified position or DONE if the specified position is equal to getEndIndex() |
| 165 | */ |
| 166 | public char setIndex(int position); |
| 167 | |
| 168 | /** |
| 169 | * Returns the start index of the text. |
| 170 | * @return the index at which the text begins. |
| 171 | */ |
| 172 | public int getBeginIndex(); |
| 173 | |
| 174 | /** |
| 175 | * Returns the end index of the text. This index is the index of the first |
| 176 | * character following the end of the text. |
| 177 | * @return the index after the last character in the text |
| 178 | */ |
| 179 | public int getEndIndex(); |
| 180 | |
| 181 | /** |
| 182 | * Returns the current index. |
| 183 | * @return the current index. |
| 184 | */ |
| 185 | public int getIndex(); |
| 186 | |
| 187 | /** |
| 188 | * Create a copy of this iterator |
| 189 | * @return A copy of this |
| 190 | */ |
| 191 | public Object clone(); |
| 192 | |
| 193 | } |