1 | /*
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2 | * @copyright (c) 2016, Philipp Thürwächter & Pattrick Hüper
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3 | * @copyright (c) 2007-present, Stephen Colebourne & Michael Nascimento Santos
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4 | * @license BSD-3-Clause (see LICENSE in the root directory of this source tree)
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5 | */
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6 |
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7 | import {abstractMethodFail} from '../assert';
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8 |
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9 | /**
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10 | * A unit of date-time, such as Days or Hours.
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11 | *
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12 | * Measurement of time is built on units, such as years, months, days, hours, minutes and seconds.
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13 | * Implementations of this interface represent those units.
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14 | *
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15 | * An instance of this interface represents the unit itself, rather than an amount of the unit.
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16 | * See {@link Period} for a class that represents an amount in terms of the common units.
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17 | *
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18 | * The most commonly used units are defined in {@link ChronoUnit}.
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19 | * Further units are supplied in {@link IsoFields}.
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20 | * Units can also be written by application code by implementing this interface.
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21 | *
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22 | * The unit works using double dispatch. Client code calls methods on a date-time like
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23 | * {@link LocalDateTime} which check if the unit is a {@link ChronoUnit}.
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24 | * If it is, then the date-time must handle it.
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25 | * Otherwise, the method call is re-dispatched to the matching method in this interface.
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26 | *
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27 | * @interface
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28 | */
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29 | export class TemporalUnit {
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30 | /**
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31 | * Gets the duration of this unit, which may be an estimate.
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32 | *
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33 | * All units return a duration measured in standard nanoseconds from this method.
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34 | * The duration will be positive and non-zero.
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35 | * For example, an hour has a duration of `60 * 60 * 1,000,000,000 ns`.
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36 | *
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37 | * Some units may return an accurate duration while others return an estimate.
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38 | * For example, days have an estimated duration due to the possibility of
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39 | * daylight saving time changes.
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40 | * To determine if the duration is an estimate, use {@link isDurationEstimated}.
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41 | *
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42 | * @return {Duration} the duration of this unit, which may be an estimate.
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43 | */
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44 | duration() {
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45 | abstractMethodFail('duration');
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46 | }
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47 |
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48 | /**
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49 | * Checks if the duration of the unit is an estimate.
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50 | *
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51 | * All units have a duration, however the duration is not always accurate.
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52 | * For example, days have an estimated duration due to the possibility of
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53 | * daylight saving time changes.
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54 | * This method returns true if the duration is an estimate and false if it is
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55 | * accurate. Note that accurate/estimated ignores leap seconds.
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56 | *
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57 | * @return {boolean} `true` if the duration is estimated, `false` if accurate.
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58 | */
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59 | isDurationEstimated() {
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60 | abstractMethodFail('isDurationEstimated');
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61 | }
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62 |
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63 | /**
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64 | * Checks if this unit is date-based.
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65 | *
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66 | * @return {boolean} `true` if date unit, `false` if a time unit.
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67 | */
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68 | isDateBased() {
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69 | abstractMethodFail('isDateBased');
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70 | }
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71 |
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72 | /**
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73 | * Checks if this unit is time-based.
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74 | *
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75 | * @return {boolean} `true` if time unit, `false` if a date unit.
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76 | */
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77 | isTimeBased() {
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78 | abstractMethodFail('isTimeBased');
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79 | }
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80 |
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81 | //-----------------------------------------------------------------------
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82 | /**
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83 | * Checks if this unit is supported by the specified temporal object.
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84 | *
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85 | * This checks that the implementing date-time can add/subtract this unit.
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86 | * This can be used to avoid throwing an exception.
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87 | *
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88 | * @param {!Temporal} temporal the temporal object to check.
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89 | * @return {boolean} `true` if the unit is supported.
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90 | */
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91 | // eslint-disable-next-line no-unused-vars
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92 | isSupportedBy(temporal) {
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93 | abstractMethodFail('isSupportedBy');
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94 | }
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95 |
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96 | /**
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97 | * Returns a copy of the specified temporal object with the specified period added.
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98 | *
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99 | * The period added is a multiple of this unit. For example, this method
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100 | * could be used to add "3 days" to a date by calling this method on the
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101 | * instance representing "days", passing the date and the period "3".
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102 | * The period to be added may be negative, which is equivalent to subtraction.
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103 | *
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104 | * There are two equivalent ways of using this method.
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105 | * The first is to invoke this method directly.
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106 | * The second is to use {@link Temporal#plus}:
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107 | * <pre>
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108 | * // these two lines are equivalent, but the second approach is recommended
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109 | * temporal = thisUnit.doPlus(temporal);
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110 | * temporal = temporal.plus(thisUnit);
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111 | * </pre>
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112 | * It is recommended to use the second approach, {@link plus},
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113 | * as it is a lot clearer to read in code.
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114 | *
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115 | * Implementations should perform any queries or calculations using the units
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116 | * available in {@link ChronoUnit} or the fields available in {@link ChronoField}.
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117 | * If the field is not supported a {@link DateTimeException} must be thrown.
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118 | *
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119 | * Implementations must not alter the specified temporal object.
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120 | * Instead, an adjusted copy of the original must be returned.
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121 | * This provides equivalent, safe behavior for immutable and mutable implementations.
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122 | *
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123 | * @param {!Temporal} dateTime the temporal object to adjust.
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124 | * @param {number} periodToAdd the period of this unit to add, positive or negative.
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125 | * @return {Temporal} the adjusted temporal object.
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126 | * @throws DateTimeException if the period cannot be added.
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127 | */
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128 | // eslint-disable-next-line no-unused-vars
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129 | addTo(dateTime, periodToAdd) {
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130 | abstractMethodFail('addTo');
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131 | }
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132 |
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133 | //-----------------------------------------------------------------------
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134 | /**
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135 | * Calculates the period in terms of this unit between two temporal objects of the same type.
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136 | *
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137 | * This calculates the period between two temporals in terms of this unit.
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138 | * The start and end points are supplied as temporal objects and must be of the same type.
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139 | * The result will be negative if the end is before the start.
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140 | * For example, the period in hours between two temporal objects can be calculated
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141 | * using {@link HOURS.between}.
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142 | *
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143 | * The calculation returns a whole number, representing the number of complete units between the two temporals.
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144 | * For example, the period in hours between the times 11:30 and 13:29 will only be
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145 | * one hour as it is one minute short of two hours.
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146 | *
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147 | * There are two equivalent ways of using this method.
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148 | * The first is to invoke this method directly.
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149 | * The second is to use {@link Temporal#until}:
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150 | * <pre>
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151 | * // these two lines are equivalent
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152 | * between = thisUnit.between(start, end);
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153 | * between = start.until(end, thisUnit);
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154 | * </pre>
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155 | * The choice should be made based on which makes the code more readable.
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156 | *
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157 | * For example, this method allows the number of days between two dates to be calculated:
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158 | * <pre>
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159 | * long daysBetween = DAYS.between(start, end);
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160 | * // or alternatively
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161 | * long daysBetween = start.until(end, DAYS);
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162 | * </pre>
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163 | * Implementations should perform any queries or calculations using the units available in
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164 | * {@link ChronoUnit} or the fields available in {@link ChronoField}.
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165 | * If the unit is not supported a {@link DateTimeException} must be thrown.
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166 | * Implementations must not alter the specified temporal objects.
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167 | *
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168 | * @param {!Temporal} temporal1 the base temporal object.
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169 | * @param {!Temporal} temporal2 the other temporal object.
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170 | * @return {number} the period between temporal1 and temporal2 in terms of this unit;
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171 | * positive if temporal2 is later than temporal1, negative if earlier.
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172 | * @throws DateTimeException if the period cannot be calculated.
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173 | * @throws ArithmeticException if numeric overflow occurs.
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174 | */
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175 | // eslint-disable-next-line no-unused-vars
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176 | between(temporal1, temporal2) {
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177 | abstractMethodFail('between');
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178 | }
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179 | }
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