| 1 | /* |
| 2 | * Copyright 2001-2005 Stephen Colebourne |
| 3 | * |
| 4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | * you may not use this file except in compliance with the License. |
| 6 | * You may obtain a copy of the License at |
| 7 | * |
| 8 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | * |
| 10 | * Unless required by applicable law or agreed to in writing, software |
| 11 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | * See the License for the specific language governing permissions and |
| 14 | * limitations under the License. |
| 15 | */ |
| 16 | package org.joda.time; |
| 17 | |
| 18 | import java.io.Serializable; |
| 19 | |
| 20 | /** |
| 21 | * Identifies a duration field, such as years or minutes, in a chronology-neutral way. |
| 22 | * <p> |
| 23 | * A duration field type defines the type of the field, such as hours. |
| 24 | * If does not directly enable any calculations, however it does provide a |
| 25 | * {@link #getField(Chronology)} method that returns the actual calculation engine |
| 26 | * for a particular chronology. |
| 27 | * <p> |
| 28 | * Instances of <code>DurationFieldType</code> are singletons. |
| 29 | * They can be compared using <code>==</code>. |
| 30 | * <p> |
| 31 | * If required, you can create your own field, for example a quarters. |
| 32 | * You must create a subclass of <code>DurationFieldType</code> that defines the field type. |
| 33 | * This class returns the actual calculation engine from {@link #getField(Chronology)}. |
| 34 | * |
| 35 | * @author Stephen Colebourne |
| 36 | * @author Brian S O'Neill |
| 37 | * @since 1.0 |
| 38 | */ |
| 39 | public abstract class DurationFieldType implements Serializable { |
| 40 | |
| 41 | /** Serialization version */ |
| 42 | private static final long serialVersionUID = 8765135187319L; |
| 43 | |
| 44 | // Ordinals for standard field types. |
| 45 | static final byte |
| 46 | ERAS = 1, |
| 47 | CENTURIES = 2, |
| 48 | WEEKYEARS = 3, |
| 49 | YEARS = 4, |
| 50 | MONTHS = 5, |
| 51 | WEEKS = 6, |
| 52 | DAYS = 7, |
| 53 | HALFDAYS = 8, |
| 54 | HOURS = 9, |
| 55 | MINUTES = 10, |
| 56 | SECONDS = 11, |
| 57 | MILLIS = 12; |
| 58 | |
| 59 | /** The eras field type. */ |
| 60 | static final DurationFieldType ERAS_TYPE = new StandardDurationFieldType("eras", ERAS); |
| 61 | /** The centuries field type. */ |
| 62 | static final DurationFieldType CENTURIES_TYPE = new StandardDurationFieldType("centuries", CENTURIES); |
| 63 | /** The weekyears field type. */ |
| 64 | static final DurationFieldType WEEKYEARS_TYPE = new StandardDurationFieldType("weekyears", WEEKYEARS); |
| 65 | /** The years field type. */ |
| 66 | static final DurationFieldType YEARS_TYPE = new StandardDurationFieldType("years", YEARS); |
| 67 | /** The months field type. */ |
| 68 | static final DurationFieldType MONTHS_TYPE = new StandardDurationFieldType("months", MONTHS); |
| 69 | /** The weeks field type. */ |
| 70 | static final DurationFieldType WEEKS_TYPE = new StandardDurationFieldType("weeks", WEEKS); |
| 71 | /** The days field type. */ |
| 72 | static final DurationFieldType DAYS_TYPE = new StandardDurationFieldType("days", DAYS); |
| 73 | /** The halfdays field type. */ |
| 74 | static final DurationFieldType HALFDAYS_TYPE = new StandardDurationFieldType("halfdays", HALFDAYS); |
| 75 | /** The hours field type. */ |
| 76 | static final DurationFieldType HOURS_TYPE = new StandardDurationFieldType("hours", HOURS); |
| 77 | /** The minutes field type. */ |
| 78 | static final DurationFieldType MINUTES_TYPE = new StandardDurationFieldType("minutes", MINUTES); |
| 79 | /** The seconds field type. */ |
| 80 | static final DurationFieldType SECONDS_TYPE = new StandardDurationFieldType("seconds", SECONDS); |
| 81 | /** The millis field type. */ |
| 82 | static final DurationFieldType MILLIS_TYPE = new StandardDurationFieldType("millis", MILLIS); |
| 83 | |
| 84 | /** The name of the field type. */ |
| 85 | private final String iName; |
| 86 | |
| 87 | //----------------------------------------------------------------------- |
| 88 | /** |
| 89 | * Constructor. |
| 90 | * |
| 91 | * @param name the name to use, which by convention, are plural. |
| 92 | */ |
| 93 | protected DurationFieldType(String name) { |
| 94 | super(); |
| 95 | iName = name; |
| 96 | } |
| 97 | |
| 98 | //----------------------------------------------------------------------- |
| 99 | /** |
| 100 | * Get the millis field type. |
| 101 | * |
| 102 | * @return the DateTimeFieldType constant |
| 103 | */ |
| 104 | public static DurationFieldType millis() { |
| 105 | return MILLIS_TYPE; |
| 106 | } |
| 107 | |
| 108 | /** |
| 109 | * Get the seconds field type. |
| 110 | * |
| 111 | * @return the DateTimeFieldType constant |
| 112 | */ |
| 113 | public static DurationFieldType seconds() { |
| 114 | return SECONDS_TYPE; |
| 115 | } |
| 116 | |
| 117 | /** |
| 118 | * Get the minutes field type. |
| 119 | * |
| 120 | * @return the DateTimeFieldType constant |
| 121 | */ |
| 122 | public static DurationFieldType minutes() { |
| 123 | return MINUTES_TYPE; |
| 124 | } |
| 125 | |
| 126 | /** |
| 127 | * Get the hours field type. |
| 128 | * |
| 129 | * @return the DateTimeFieldType constant |
| 130 | */ |
| 131 | public static DurationFieldType hours() { |
| 132 | return HOURS_TYPE; |
| 133 | } |
| 134 | |
| 135 | /** |
| 136 | * Get the halfdays field type. |
| 137 | * |
| 138 | * @return the DateTimeFieldType constant |
| 139 | */ |
| 140 | public static DurationFieldType halfdays() { |
| 141 | return HALFDAYS_TYPE; |
| 142 | } |
| 143 | |
| 144 | //----------------------------------------------------------------------- |
| 145 | /** |
| 146 | * Get the days field type. |
| 147 | * |
| 148 | * @return the DateTimeFieldType constant |
| 149 | */ |
| 150 | public static DurationFieldType days() { |
| 151 | return DAYS_TYPE; |
| 152 | } |
| 153 | |
| 154 | /** |
| 155 | * Get the weeks field type. |
| 156 | * |
| 157 | * @return the DateTimeFieldType constant |
| 158 | */ |
| 159 | public static DurationFieldType weeks() { |
| 160 | return WEEKS_TYPE; |
| 161 | } |
| 162 | |
| 163 | /** |
| 164 | * Get the weekyears field type. |
| 165 | * |
| 166 | * @return the DateTimeFieldType constant |
| 167 | */ |
| 168 | public static DurationFieldType weekyears() { |
| 169 | return WEEKYEARS_TYPE; |
| 170 | } |
| 171 | |
| 172 | /** |
| 173 | * Get the months field type. |
| 174 | * |
| 175 | * @return the DateTimeFieldType constant |
| 176 | */ |
| 177 | public static DurationFieldType months() { |
| 178 | return MONTHS_TYPE; |
| 179 | } |
| 180 | |
| 181 | /** |
| 182 | * Get the years field type. |
| 183 | * |
| 184 | * @return the DateTimeFieldType constant |
| 185 | */ |
| 186 | public static DurationFieldType years() { |
| 187 | return YEARS_TYPE; |
| 188 | } |
| 189 | |
| 190 | /** |
| 191 | * Get the centuries field type. |
| 192 | * |
| 193 | * @return the DateTimeFieldType constant |
| 194 | */ |
| 195 | public static DurationFieldType centuries() { |
| 196 | return CENTURIES_TYPE; |
| 197 | } |
| 198 | |
| 199 | /** |
| 200 | * Get the eras field type. |
| 201 | * |
| 202 | * @return the DateTimeFieldType constant |
| 203 | */ |
| 204 | public static DurationFieldType eras() { |
| 205 | return ERAS_TYPE; |
| 206 | } |
| 207 | |
| 208 | //----------------------------------------------------------------------- |
| 209 | /** |
| 210 | * Get the name of the field. |
| 211 | * By convention, names are plural. |
| 212 | * |
| 213 | * @return field name |
| 214 | */ |
| 215 | public String getName() { |
| 216 | return iName; |
| 217 | } |
| 218 | |
| 219 | /** |
| 220 | * Gets a suitable field for this type from the given Chronology. |
| 221 | * |
| 222 | * @param chronology the chronology to use, null means ISOChronology in default zone |
| 223 | * @return a suitable field |
| 224 | */ |
| 225 | public abstract DurationField getField(Chronology chronology); |
| 226 | |
| 227 | /** |
| 228 | * Checks whether this field supported in the given Chronology. |
| 229 | * |
| 230 | * @param chronology the chronology to use, null means ISOChronology in default zone |
| 231 | * @return true if supported |
| 232 | */ |
| 233 | public boolean isSupported(Chronology chronology) { |
| 234 | return getField(chronology).isSupported(); |
| 235 | } |
| 236 | |
| 237 | /** |
| 238 | * Get a suitable debug string. |
| 239 | * |
| 240 | * @return debug string |
| 241 | */ |
| 242 | public String toString() { |
| 243 | return getName(); |
| 244 | } |
| 245 | |
| 246 | private static class StandardDurationFieldType extends DurationFieldType { |
| 247 | /** Serialization version */ |
| 248 | private static final long serialVersionUID = 31156755687123L; |
| 249 | |
| 250 | /** The ordinal of the standard field type, for switch statements */ |
| 251 | private final byte iOrdinal; |
| 252 | |
| 253 | /** |
| 254 | * Constructor. |
| 255 | * |
| 256 | * @param name the name to use |
| 257 | */ |
| 258 | StandardDurationFieldType(String name, byte ordinal) { |
| 259 | super(name); |
| 260 | iOrdinal = ordinal; |
| 261 | } |
| 262 | |
| 263 | public DurationField getField(Chronology chronology) { |
| 264 | chronology = DateTimeUtils.getChronology(chronology); |
| 265 | |
| 266 | switch (iOrdinal) { |
| 267 | case ERAS: |
| 268 | return chronology.eras(); |
| 269 | case CENTURIES: |
| 270 | return chronology.centuries(); |
| 271 | case WEEKYEARS: |
| 272 | return chronology.weekyears(); |
| 273 | case YEARS: |
| 274 | return chronology.years(); |
| 275 | case MONTHS: |
| 276 | return chronology.months(); |
| 277 | case WEEKS: |
| 278 | return chronology.weeks(); |
| 279 | case DAYS: |
| 280 | return chronology.days(); |
| 281 | case HALFDAYS: |
| 282 | return chronology.halfdays(); |
| 283 | case HOURS: |
| 284 | return chronology.hours(); |
| 285 | case MINUTES: |
| 286 | return chronology.minutes(); |
| 287 | case SECONDS: |
| 288 | return chronology.seconds(); |
| 289 | case MILLIS: |
| 290 | return chronology.millis(); |
| 291 | default: |
| 292 | // Shouldn't happen. |
| 293 | throw new InternalError(); |
| 294 | } |
| 295 | } |
| 296 | |
| 297 | /** |
| 298 | * Ensure a singleton is returned. |
| 299 | * |
| 300 | * @return the singleton type |
| 301 | */ |
| 302 | private Object readResolve() { |
| 303 | switch (iOrdinal) { |
| 304 | case ERAS: |
| 305 | return ERAS_TYPE; |
| 306 | case CENTURIES: |
| 307 | return CENTURIES_TYPE; |
| 308 | case WEEKYEARS: |
| 309 | return WEEKYEARS_TYPE; |
| 310 | case YEARS: |
| 311 | return YEARS_TYPE; |
| 312 | case MONTHS: |
| 313 | return MONTHS_TYPE; |
| 314 | case WEEKS: |
| 315 | return WEEKS_TYPE; |
| 316 | case DAYS: |
| 317 | return DAYS_TYPE; |
| 318 | case HALFDAYS: |
| 319 | return HALFDAYS_TYPE; |
| 320 | case HOURS: |
| 321 | return HOURS_TYPE; |
| 322 | case MINUTES: |
| 323 | return MINUTES_TYPE; |
| 324 | case SECONDS: |
| 325 | return SECONDS_TYPE; |
| 326 | case MILLIS: |
| 327 | return MILLIS_TYPE; |
| 328 | default: |
| 329 | // Shouldn't happen. |
| 330 | return this; |
| 331 | } |
| 332 | } |
| 333 | |
| 334 | } |
| 335 | } |