| 1 | /* |
| 2 | * Copyright 2001-2006 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 org.joda.time.base.BaseSingleFieldPeriod; |
| 19 | import org.joda.time.field.FieldUtils; |
| 20 | import org.joda.time.format.ISOPeriodFormat; |
| 21 | import org.joda.time.format.PeriodFormatter; |
| 22 | |
| 23 | /** |
| 24 | * An immutable time period representing a number of years. |
| 25 | * <p> |
| 26 | * <code>Years</code> is an immutable period that can only store years. |
| 27 | * It does not store years, days or hours for example. As such it is a |
| 28 | * type-safe way of representing a number of years in an application. |
| 29 | * <p> |
| 30 | * The number of years is set in the constructor, and may be queried using |
| 31 | * <code>getYears()</code>. Basic mathematical operations are provided - |
| 32 | * <code>plus()</code>, <code>minus()</code>, <code>multipliedBy()</code> and |
| 33 | * <code>dividedBy()</code>. |
| 34 | * <p> |
| 35 | * <code>Years</code> is thread-safe and immutable. |
| 36 | * |
| 37 | * @author Stephen Colebourne |
| 38 | * @since 1.4 |
| 39 | */ |
| 40 | public final class Years extends BaseSingleFieldPeriod { |
| 41 | |
| 42 | /** Constant representing zero years. */ |
| 43 | public static final Years ZERO = new Years(0); |
| 44 | /** Constant representing one year. */ |
| 45 | public static final Years ONE = new Years(1); |
| 46 | /** Constant representing two years. */ |
| 47 | public static final Years TWO = new Years(2); |
| 48 | /** Constant representing three years. */ |
| 49 | public static final Years THREE = new Years(3); |
| 50 | /** Constant representing the maximum number of years that can be stored in this object. */ |
| 51 | public static final Years MAX_VALUE = new Years(Integer.MAX_VALUE); |
| 52 | /** Constant representing the minimum number of years that can be stored in this object. */ |
| 53 | public static final Years MIN_VALUE = new Years(Integer.MIN_VALUE); |
| 54 | |
| 55 | /** The paser to use for this class. */ |
| 56 | private static final PeriodFormatter PARSER = ISOPeriodFormat.standard().withParseType(PeriodType.years()); |
| 57 | /** Serialization version. */ |
| 58 | private static final long serialVersionUID = 87525275727380868L; |
| 59 | |
| 60 | //----------------------------------------------------------------------- |
| 61 | /** |
| 62 | * Obtains an instance of <code>Years</code> that may be cached. |
| 63 | * <code>Years</code> is immutable, so instances can be cached and shared. |
| 64 | * This factory method provides access to shared instances. |
| 65 | * |
| 66 | * @param years the number of years to obtain an instance for |
| 67 | * @return the instance of Years |
| 68 | */ |
| 69 | public static Years years(int years) { |
| 70 | switch (years) { |
| 71 | case 0: |
| 72 | return ZERO; |
| 73 | case 1: |
| 74 | return ONE; |
| 75 | case 2: |
| 76 | return TWO; |
| 77 | case 3: |
| 78 | return THREE; |
| 79 | case Integer.MAX_VALUE: |
| 80 | return MAX_VALUE; |
| 81 | case Integer.MIN_VALUE: |
| 82 | return MIN_VALUE; |
| 83 | default: |
| 84 | return new Years(years); |
| 85 | } |
| 86 | } |
| 87 | |
| 88 | //----------------------------------------------------------------------- |
| 89 | /** |
| 90 | * Creates a <code>Years</code> representing the number of whole years |
| 91 | * between the two specified datetimes. This method corectly handles |
| 92 | * any daylight savings time changes that may occur during the interval. |
| 93 | * |
| 94 | * @param start the start instant, must not be null |
| 95 | * @param end the end instant, must not be null |
| 96 | * @return the period in years |
| 97 | * @throws IllegalArgumentException if the instants are null or invalid |
| 98 | */ |
| 99 | public static Years yearsBetween(ReadableInstant start, ReadableInstant end) { |
| 100 | int amount = BaseSingleFieldPeriod.between(start, end, DurationFieldType.years()); |
| 101 | return Years.years(amount); |
| 102 | } |
| 103 | |
| 104 | /** |
| 105 | * Creates a <code>Years</code> representing the number of whole years |
| 106 | * between the two specified partial datetimes. |
| 107 | * <p> |
| 108 | * The two partials must contain the same fields, for example you can specify |
| 109 | * two <code>LocalDate</code> objects. |
| 110 | * |
| 111 | * @param start the start partial date, must not be null |
| 112 | * @param end the end partial date, must not be null |
| 113 | * @return the period in years |
| 114 | * @throws IllegalArgumentException if the partials are null or invalid |
| 115 | */ |
| 116 | public static Years yearsBetween(ReadablePartial start, ReadablePartial end) { |
| 117 | if (start instanceof LocalDate && end instanceof LocalDate) { |
| 118 | Chronology chrono = DateTimeUtils.getChronology(start.getChronology()); |
| 119 | int years = chrono.years().getDifference( |
| 120 | ((LocalDate) end).getLocalMillis(), ((LocalDate) start).getLocalMillis()); |
| 121 | return Years.years(years); |
| 122 | } |
| 123 | int amount = BaseSingleFieldPeriod.between(start, end, ZERO); |
| 124 | return Years.years(amount); |
| 125 | } |
| 126 | |
| 127 | /** |
| 128 | * Creates a <code>Years</code> representing the number of whole years |
| 129 | * in the specified interval. This method corectly handles any daylight |
| 130 | * savings time changes that may occur during the interval. |
| 131 | * |
| 132 | * @param interval the interval to extract years from, null returns zero |
| 133 | * @return the period in years |
| 134 | * @throws IllegalArgumentException if the partials are null or invalid |
| 135 | */ |
| 136 | public static Years yearsIn(ReadableInterval interval) { |
| 137 | if (interval == null) { |
| 138 | return Years.ZERO; |
| 139 | } |
| 140 | int amount = BaseSingleFieldPeriod.between(interval.getStart(), interval.getEnd(), DurationFieldType.years()); |
| 141 | return Years.years(amount); |
| 142 | } |
| 143 | |
| 144 | /** |
| 145 | * Creates a new <code>Years</code> by parsing a string in the ISO8601 format 'PnY'. |
| 146 | * <p> |
| 147 | * The parse will accept the full ISO syntax of PnYnMnWnDTnHnMnS however only the |
| 148 | * years component may be non-zero. If any other component is non-zero, an exception |
| 149 | * will be thrown. |
| 150 | * |
| 151 | * @param periodStr the period string, null returns zero |
| 152 | * @return the period in years |
| 153 | * @throws IllegalArgumentException if the string format is invalid |
| 154 | */ |
| 155 | public static Years parseYears(String periodStr) { |
| 156 | if (periodStr == null) { |
| 157 | return Years.ZERO; |
| 158 | } |
| 159 | Period p = PARSER.parsePeriod(periodStr); |
| 160 | return Years.years(p.getYears()); |
| 161 | } |
| 162 | |
| 163 | //----------------------------------------------------------------------- |
| 164 | /** |
| 165 | * Creates a new instance representing a number of years. |
| 166 | * You should consider using the factory method {@link #years(int)} |
| 167 | * instead of the constructor. |
| 168 | * |
| 169 | * @param years the number of years to represent |
| 170 | */ |
| 171 | private Years(int years) { |
| 172 | super(years); |
| 173 | } |
| 174 | |
| 175 | /** |
| 176 | * Resolves singletons. |
| 177 | * |
| 178 | * @return the singleton instance |
| 179 | */ |
| 180 | private Object readResolve() { |
| 181 | return Years.years(getValue()); |
| 182 | } |
| 183 | |
| 184 | //----------------------------------------------------------------------- |
| 185 | /** |
| 186 | * Gets the duration field type, which is <code>years</code>. |
| 187 | * |
| 188 | * @return the period type |
| 189 | */ |
| 190 | public DurationFieldType getFieldType() { |
| 191 | return DurationFieldType.years(); |
| 192 | } |
| 193 | |
| 194 | /** |
| 195 | * Gets the period type, which is <code>years</code>. |
| 196 | * |
| 197 | * @return the period type |
| 198 | */ |
| 199 | public PeriodType getPeriodType() { |
| 200 | return PeriodType.years(); |
| 201 | } |
| 202 | |
| 203 | //----------------------------------------------------------------------- |
| 204 | /** |
| 205 | * Gets the number of years that this period represents. |
| 206 | * |
| 207 | * @return the number of years in the period |
| 208 | */ |
| 209 | public int getYears() { |
| 210 | return getValue(); |
| 211 | } |
| 212 | |
| 213 | //----------------------------------------------------------------------- |
| 214 | /** |
| 215 | * Returns a new instance with the specified number of years added. |
| 216 | * <p> |
| 217 | * This instance is immutable and unaffected by this method call. |
| 218 | * |
| 219 | * @param years the amount of years to add, may be negative |
| 220 | * @return the new period plus the specified number of years |
| 221 | * @throws ArithmeticException if the result overflows an int |
| 222 | */ |
| 223 | public Years plus(int years) { |
| 224 | if (years == 0) { |
| 225 | return this; |
| 226 | } |
| 227 | return Years.years(FieldUtils.safeAdd(getValue(), years)); |
| 228 | } |
| 229 | |
| 230 | /** |
| 231 | * Returns a new instance with the specified number of years added. |
| 232 | * <p> |
| 233 | * This instance is immutable and unaffected by this method call. |
| 234 | * |
| 235 | * @param years the amount of years to add, may be negative, null means zero |
| 236 | * @return the new period plus the specified number of years |
| 237 | * @throws ArithmeticException if the result overflows an int |
| 238 | */ |
| 239 | public Years plus(Years years) { |
| 240 | if (years == null) { |
| 241 | return this; |
| 242 | } |
| 243 | return plus(years.getValue()); |
| 244 | } |
| 245 | |
| 246 | //----------------------------------------------------------------------- |
| 247 | /** |
| 248 | * Returns a new instance with the specified number of years taken away. |
| 249 | * <p> |
| 250 | * This instance is immutable and unaffected by this method call. |
| 251 | * |
| 252 | * @param years the amount of years to take away, may be negative |
| 253 | * @return the new period minus the specified number of years |
| 254 | * @throws ArithmeticException if the result overflows an int |
| 255 | */ |
| 256 | public Years minus(int years) { |
| 257 | return plus(FieldUtils.safeNegate(years)); |
| 258 | } |
| 259 | |
| 260 | /** |
| 261 | * Returns a new instance with the specified number of years taken away. |
| 262 | * <p> |
| 263 | * This instance is immutable and unaffected by this method call. |
| 264 | * |
| 265 | * @param years the amount of years to take away, may be negative, null means zero |
| 266 | * @return the new period minus the specified number of years |
| 267 | * @throws ArithmeticException if the result overflows an int |
| 268 | */ |
| 269 | public Years minus(Years years) { |
| 270 | if (years == null) { |
| 271 | return this; |
| 272 | } |
| 273 | return minus(years.getValue()); |
| 274 | } |
| 275 | |
| 276 | //----------------------------------------------------------------------- |
| 277 | /** |
| 278 | * Returns a new instance with the years multiplied by the specified scalar. |
| 279 | * <p> |
| 280 | * This instance is immutable and unaffected by this method call. |
| 281 | * |
| 282 | * @param scalar the amount to multiply by, may be negative |
| 283 | * @return the new period multiplied by the specified scalar |
| 284 | * @throws ArithmeticException if the result overflows an int |
| 285 | */ |
| 286 | public Years multipliedBy(int scalar) { |
| 287 | return Years.years(FieldUtils.safeMultiply(getValue(), scalar)); |
| 288 | } |
| 289 | |
| 290 | /** |
| 291 | * Returns a new instance with the years divided by the specified divisor. |
| 292 | * The calculation uses integer division, thus 3 divided by 2 is 1. |
| 293 | * <p> |
| 294 | * This instance is immutable and unaffected by this method call. |
| 295 | * |
| 296 | * @param divisor the amount to divide by, may be negative |
| 297 | * @return the new period divided by the specified divisor |
| 298 | * @throws ArithmeticException if the divisor is zero |
| 299 | */ |
| 300 | public Years dividedBy(int divisor) { |
| 301 | if (divisor == 1) { |
| 302 | return this; |
| 303 | } |
| 304 | return Years.years(getValue() / divisor); |
| 305 | } |
| 306 | |
| 307 | //----------------------------------------------------------------------- |
| 308 | /** |
| 309 | * Returns a new instance with the years value negated. |
| 310 | * |
| 311 | * @return the new period with a negated value |
| 312 | * @throws ArithmeticException if the result overflows an int |
| 313 | */ |
| 314 | public Years negated() { |
| 315 | return Years.years(FieldUtils.safeNegate(getValue())); |
| 316 | } |
| 317 | |
| 318 | //----------------------------------------------------------------------- |
| 319 | /** |
| 320 | * Is this years instance greater than the specified number of years. |
| 321 | * |
| 322 | * @param other the other period, null means zero |
| 323 | * @return true if this years instance is greater than the specified one |
| 324 | */ |
| 325 | public boolean isGreaterThan(Years other) { |
| 326 | if (other == null) { |
| 327 | return getValue() > 0; |
| 328 | } |
| 329 | return getValue() > other.getValue(); |
| 330 | } |
| 331 | |
| 332 | /** |
| 333 | * Is this years instance less than the specified number of years. |
| 334 | * |
| 335 | * @param other the other period, null means zero |
| 336 | * @return true if this years instance is less than the specified one |
| 337 | */ |
| 338 | public boolean isLessThan(Years other) { |
| 339 | if (other == null) { |
| 340 | return getValue() < 0; |
| 341 | } |
| 342 | return getValue() < other.getValue(); |
| 343 | } |
| 344 | |
| 345 | //----------------------------------------------------------------------- |
| 346 | /** |
| 347 | * Gets this instance as a String in the ISO8601 duration format. |
| 348 | * <p> |
| 349 | * For example, "P4Y" represents 4 years. |
| 350 | * |
| 351 | * @return the value as an ISO8601 string |
| 352 | */ |
| 353 | public String toString() { |
| 354 | return "P" + String.valueOf(getValue()) + "Y"; |
| 355 | } |
| 356 | |
| 357 | } |