J. Duke | 319a3b9 | 2007-12-01 00:00:00 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 1996-2002 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 - All Rights Reserved |
| 28 | * (C) Copyright IBM Corp. 1996 - All Rights Reserved |
| 29 | * |
| 30 | * The original version of this source code and documentation is copyrighted |
| 31 | * and owned by Taligent, Inc., a wholly-owned subsidiary of IBM. These |
| 32 | * materials are provided under terms of a License Agreement between Taligent |
| 33 | * and Sun. This technology is protected by multiple US and International |
| 34 | * patents. This notice and attribution to Taligent may not be removed. |
| 35 | * Taligent is a registered trademark of Taligent, Inc. |
| 36 | * |
| 37 | */ |
| 38 | |
| 39 | package java.text; |
| 40 | |
| 41 | /** |
| 42 | * <code>FieldPosition</code> is a simple class used by <code>Format</code> |
| 43 | * and its subclasses to identify fields in formatted output. Fields can |
| 44 | * be identified in two ways: |
| 45 | * <ul> |
| 46 | * <li>By an integer constant, whose names typically end with |
| 47 | * <code>_FIELD</code>. The constants are defined in the various |
| 48 | * subclasses of <code>Format</code>. |
| 49 | * <li>By a <code>Format.Field</code> constant, see <code>ERA_FIELD</code> |
| 50 | * and its friends in <code>DateFormat</code> for an example. |
| 51 | * </ul> |
| 52 | * <p> |
| 53 | * <code>FieldPosition</code> keeps track of the position of the |
| 54 | * field within the formatted output with two indices: the index |
| 55 | * of the first character of the field and the index of the last |
| 56 | * character of the field. |
| 57 | * |
| 58 | * <p> |
| 59 | * One version of the <code>format</code> method in the various |
| 60 | * <code>Format</code> classes requires a <code>FieldPosition</code> |
| 61 | * object as an argument. You use this <code>format</code> method |
| 62 | * to perform partial formatting or to get information about the |
| 63 | * formatted output (such as the position of a field). |
| 64 | * |
| 65 | * <p> |
| 66 | * If you are interested in the positions of all attributes in the |
| 67 | * formatted string use the <code>Format</code> method |
| 68 | * <code>formatToCharacterIterator</code>. |
| 69 | * |
| 70 | * @author Mark Davis |
| 71 | * @see java.text.Format |
| 72 | */ |
| 73 | public class FieldPosition { |
| 74 | |
| 75 | /** |
| 76 | * Input: Desired field to determine start and end offsets for. |
| 77 | * The meaning depends on the subclass of Format. |
| 78 | */ |
| 79 | int field = 0; |
| 80 | |
| 81 | /** |
| 82 | * Output: End offset of field in text. |
| 83 | * If the field does not occur in the text, 0 is returned. |
| 84 | */ |
| 85 | int endIndex = 0; |
| 86 | |
| 87 | /** |
| 88 | * Output: Start offset of field in text. |
| 89 | * If the field does not occur in the text, 0 is returned. |
| 90 | */ |
| 91 | int beginIndex = 0; |
| 92 | |
| 93 | /** |
| 94 | * Desired field this FieldPosition is for. |
| 95 | */ |
| 96 | private Format.Field attribute; |
| 97 | |
| 98 | /** |
| 99 | * Creates a FieldPosition object for the given field. Fields are |
| 100 | * identified by constants, whose names typically end with _FIELD, |
| 101 | * in the various subclasses of Format. |
| 102 | * |
| 103 | * @see java.text.NumberFormat#INTEGER_FIELD |
| 104 | * @see java.text.NumberFormat#FRACTION_FIELD |
| 105 | * @see java.text.DateFormat#YEAR_FIELD |
| 106 | * @see java.text.DateFormat#MONTH_FIELD |
| 107 | */ |
| 108 | public FieldPosition(int field) { |
| 109 | this.field = field; |
| 110 | } |
| 111 | |
| 112 | /** |
| 113 | * Creates a FieldPosition object for the given field constant. Fields are |
| 114 | * identified by constants defined in the various <code>Format</code> |
| 115 | * subclasses. This is equivalent to calling |
| 116 | * <code>new FieldPosition(attribute, -1)</code>. |
| 117 | * |
| 118 | * @param attribute Format.Field constant identifying a field |
| 119 | * @since 1.4 |
| 120 | */ |
| 121 | public FieldPosition(Format.Field attribute) { |
| 122 | this(attribute, -1); |
| 123 | } |
| 124 | |
| 125 | /** |
| 126 | * Creates a <code>FieldPosition</code> object for the given field. |
| 127 | * The field is identified by an attribute constant from one of the |
| 128 | * <code>Field</code> subclasses as well as an integer field ID |
| 129 | * defined by the <code>Format</code> subclasses. <code>Format</code> |
| 130 | * subclasses that are aware of <code>Field</code> should give precedence |
| 131 | * to <code>attribute</code> and ignore <code>fieldID</code> if |
| 132 | * <code>attribute</code> is not null. However, older <code>Format</code> |
| 133 | * subclasses may not be aware of <code>Field</code> and rely on |
| 134 | * <code>fieldID</code>. If the field has no corresponding integer |
| 135 | * constant, <code>fieldID</code> should be -1. |
| 136 | * |
| 137 | * @param attribute Format.Field constant identifying a field |
| 138 | * @param fieldID integer constantce identifying a field |
| 139 | * @since 1.4 |
| 140 | */ |
| 141 | public FieldPosition(Format.Field attribute, int fieldID) { |
| 142 | this.attribute = attribute; |
| 143 | this.field = fieldID; |
| 144 | } |
| 145 | |
| 146 | /** |
| 147 | * Returns the field identifier as an attribute constant |
| 148 | * from one of the <code>Field</code> subclasses. May return null if |
| 149 | * the field is specified only by an integer field ID. |
| 150 | * |
| 151 | * @return Identifier for the field |
| 152 | * @since 1.4 |
| 153 | */ |
| 154 | public Format.Field getFieldAttribute() { |
| 155 | return attribute; |
| 156 | } |
| 157 | |
| 158 | /** |
| 159 | * Retrieves the field identifier. |
| 160 | */ |
| 161 | public int getField() { |
| 162 | return field; |
| 163 | } |
| 164 | |
| 165 | /** |
| 166 | * Retrieves the index of the first character in the requested field. |
| 167 | */ |
| 168 | public int getBeginIndex() { |
| 169 | return beginIndex; |
| 170 | } |
| 171 | |
| 172 | /** |
| 173 | * Retrieves the index of the character following the last character in the |
| 174 | * requested field. |
| 175 | */ |
| 176 | public int getEndIndex() { |
| 177 | return endIndex; |
| 178 | } |
| 179 | |
| 180 | /** |
| 181 | * Sets the begin index. For use by subclasses of Format. |
| 182 | * @since 1.2 |
| 183 | */ |
| 184 | public void setBeginIndex(int bi) { |
| 185 | beginIndex = bi; |
| 186 | } |
| 187 | |
| 188 | /** |
| 189 | * Sets the end index. For use by subclasses of Format. |
| 190 | * @since 1.2 |
| 191 | */ |
| 192 | public void setEndIndex(int ei) { |
| 193 | endIndex = ei; |
| 194 | } |
| 195 | |
| 196 | /** |
| 197 | * Returns a <code>Format.FieldDelegate</code> instance that is associated |
| 198 | * with the FieldPosition. When the delegate is notified of the same |
| 199 | * field the FieldPosition is associated with, the begin/end will be |
| 200 | * adjusted. |
| 201 | */ |
| 202 | Format.FieldDelegate getFieldDelegate() { |
| 203 | return new Delegate(); |
| 204 | } |
| 205 | |
| 206 | /** |
| 207 | * Overrides equals |
| 208 | */ |
| 209 | public boolean equals(Object obj) |
| 210 | { |
| 211 | if (obj == null) return false; |
| 212 | if (!(obj instanceof FieldPosition)) |
| 213 | return false; |
| 214 | FieldPosition other = (FieldPosition) obj; |
| 215 | if (attribute == null) { |
| 216 | if (other.attribute != null) { |
| 217 | return false; |
| 218 | } |
| 219 | } |
| 220 | else if (!attribute.equals(other.attribute)) { |
| 221 | return false; |
| 222 | } |
| 223 | return (beginIndex == other.beginIndex |
| 224 | && endIndex == other.endIndex |
| 225 | && field == other.field); |
| 226 | } |
| 227 | |
| 228 | /** |
| 229 | * Returns a hash code for this FieldPosition. |
| 230 | * @return a hash code value for this object |
| 231 | */ |
| 232 | public int hashCode() { |
| 233 | return (field << 24) | (beginIndex << 16) | endIndex; |
| 234 | } |
| 235 | |
| 236 | /** |
| 237 | * Return a string representation of this FieldPosition. |
| 238 | * @return a string representation of this object |
| 239 | */ |
| 240 | public String toString() { |
| 241 | return getClass().getName() + |
| 242 | "[field=" + field + ",attribute=" + attribute + |
| 243 | ",beginIndex=" + beginIndex + |
| 244 | ",endIndex=" + endIndex + ']'; |
| 245 | } |
| 246 | |
| 247 | |
| 248 | /** |
| 249 | * Return true if the receiver wants a <code>Format.Field</code> value and |
| 250 | * <code>attribute</code> is equal to it. |
| 251 | */ |
| 252 | private boolean matchesField(Format.Field attribute) { |
| 253 | if (this.attribute != null) { |
| 254 | return this.attribute.equals(attribute); |
| 255 | } |
| 256 | return false; |
| 257 | } |
| 258 | |
| 259 | /** |
| 260 | * Return true if the receiver wants a <code>Format.Field</code> value and |
| 261 | * <code>attribute</code> is equal to it, or true if the receiver |
| 262 | * represents an inteter constant and <code>field</code> equals it. |
| 263 | */ |
| 264 | private boolean matchesField(Format.Field attribute, int field) { |
| 265 | if (this.attribute != null) { |
| 266 | return this.attribute.equals(attribute); |
| 267 | } |
| 268 | return (field == this.field); |
| 269 | } |
| 270 | |
| 271 | |
| 272 | /** |
| 273 | * An implementation of FieldDelegate that will adjust the begin/end |
| 274 | * of the FieldPosition if the arguments match the field of |
| 275 | * the FieldPosition. |
| 276 | */ |
| 277 | private class Delegate implements Format.FieldDelegate { |
| 278 | /** |
| 279 | * Indicates whether the field has been encountered before. If this |
| 280 | * is true, and <code>formatted</code> is invoked, the begin/end |
| 281 | * are not updated. |
| 282 | */ |
| 283 | private boolean encounteredField; |
| 284 | |
| 285 | public void formatted(Format.Field attr, Object value, int start, |
| 286 | int end, StringBuffer buffer) { |
| 287 | if (!encounteredField && matchesField(attr)) { |
| 288 | setBeginIndex(start); |
| 289 | setEndIndex(end); |
| 290 | encounteredField = (start != end); |
| 291 | } |
| 292 | } |
| 293 | |
| 294 | public void formatted(int fieldID, Format.Field attr, Object value, |
| 295 | int start, int end, StringBuffer buffer) { |
| 296 | if (!encounteredField && matchesField(attr, fieldID)) { |
| 297 | setBeginIndex(start); |
| 298 | setEndIndex(end); |
| 299 | encounteredField = (start != end); |
| 300 | } |
| 301 | } |
| 302 | } |
| 303 | } |