| 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.field; |
| 17 | |
| 18 | import java.io.Serializable; |
| 19 | import org.joda.time.DurationField; |
| 20 | import org.joda.time.DurationFieldType; |
| 21 | |
| 22 | /** |
| 23 | * BaseDurationField provides the common behaviour for DurationField |
| 24 | * implementations. |
| 25 | * <p> |
| 26 | * This class should generally not be used directly by API users. The |
| 27 | * DurationField class should be used when different kinds of DurationField |
| 28 | * objects are to be referenced. |
| 29 | * <p> |
| 30 | * BaseDurationField is thread-safe and immutable, and its subclasses must |
| 31 | * be as well. |
| 32 | * |
| 33 | * @author Brian S O'Neill |
| 34 | * @see DecoratedDurationField |
| 35 | * @since 1.0 |
| 36 | */ |
| 37 | public abstract class BaseDurationField extends DurationField implements Serializable { |
| 38 | |
| 39 | /** Serialization lock. */ |
| 40 | private static final long serialVersionUID = -2554245107589433218L; |
| 41 | |
| 42 | /** A desriptive name for the field. */ |
| 43 | private final DurationFieldType iType; |
| 44 | |
| 45 | protected BaseDurationField(DurationFieldType type) { |
| 46 | super(); |
| 47 | if (type == null) { |
| 48 | throw new IllegalArgumentException("The type must not be null"); |
| 49 | } |
| 50 | iType = type; |
| 51 | } |
| 52 | |
| 53 | public final DurationFieldType getType() { |
| 54 | return iType; |
| 55 | } |
| 56 | |
| 57 | public final String getName() { |
| 58 | return iType.getName(); |
| 59 | } |
| 60 | |
| 61 | /** |
| 62 | * @return true always |
| 63 | */ |
| 64 | public final boolean isSupported() { |
| 65 | return true; |
| 66 | } |
| 67 | |
| 68 | //------------------------------------------------------------------------ |
| 69 | /** |
| 70 | * Get the value of this field from the milliseconds, which is approximate |
| 71 | * if this field is imprecise. |
| 72 | * |
| 73 | * @param duration the milliseconds to query, which may be negative |
| 74 | * @return the value of the field, in the units of the field, which may be |
| 75 | * negative |
| 76 | */ |
| 77 | public int getValue(long duration) { |
| 78 | return FieldUtils.safeToInt(getValueAsLong(duration)); |
| 79 | } |
| 80 | |
| 81 | /** |
| 82 | * Get the value of this field from the milliseconds, which is approximate |
| 83 | * if this field is imprecise. |
| 84 | * |
| 85 | * @param duration the milliseconds to query, which may be negative |
| 86 | * @return the value of the field, in the units of the field, which may be |
| 87 | * negative |
| 88 | */ |
| 89 | public long getValueAsLong(long duration) { |
| 90 | return duration / getUnitMillis(); |
| 91 | } |
| 92 | |
| 93 | /** |
| 94 | * Get the value of this field from the milliseconds relative to an |
| 95 | * instant. |
| 96 | * |
| 97 | * <p>If the milliseconds is positive, then the instant is treated as a |
| 98 | * "start instant". If negative, the instant is treated as an "end |
| 99 | * instant". |
| 100 | * |
| 101 | * <p>The default implementation returns |
| 102 | * <code>Utils.safeToInt(getAsLong(millisDuration, instant))</code>. |
| 103 | * |
| 104 | * @param duration the milliseconds to query, which may be negative |
| 105 | * @param instant the start instant to calculate relative to |
| 106 | * @return the value of the field, in the units of the field, which may be |
| 107 | * negative |
| 108 | */ |
| 109 | public int getValue(long duration, long instant) { |
| 110 | return FieldUtils.safeToInt(getValueAsLong(duration, instant)); |
| 111 | } |
| 112 | |
| 113 | /** |
| 114 | * Get the millisecond duration of this field from its value, which is |
| 115 | * approximate if this field is imprecise. |
| 116 | * |
| 117 | * @param value the value of the field, which may be negative |
| 118 | * @return the milliseconds that the field represents, which may be |
| 119 | * negative |
| 120 | */ |
| 121 | public long getMillis(int value) { |
| 122 | return value * getUnitMillis(); // safe |
| 123 | } |
| 124 | |
| 125 | /** |
| 126 | * Get the millisecond duration of this field from its value, which is |
| 127 | * approximate if this field is imprecise. |
| 128 | * |
| 129 | * @param value the value of the field, which may be negative |
| 130 | * @return the milliseconds that the field represents, which may be |
| 131 | * negative |
| 132 | */ |
| 133 | public long getMillis(long value) { |
| 134 | return FieldUtils.safeMultiply(value, getUnitMillis()); |
| 135 | } |
| 136 | |
| 137 | // Calculation API |
| 138 | //------------------------------------------------------------------------ |
| 139 | public int getDifference(long minuendInstant, long subtrahendInstant) { |
| 140 | return FieldUtils.safeToInt(getDifferenceAsLong(minuendInstant, subtrahendInstant)); |
| 141 | } |
| 142 | |
| 143 | //------------------------------------------------------------------------ |
| 144 | public int compareTo(Object durationField) { |
| 145 | DurationField otherField = (DurationField) durationField; |
| 146 | long otherMillis = otherField.getUnitMillis(); |
| 147 | long thisMillis = getUnitMillis(); |
| 148 | // cannot do (thisMillis - otherMillis) as can overflow |
| 149 | if (thisMillis == otherMillis) { |
| 150 | return 0; |
| 151 | } |
| 152 | if (thisMillis < otherMillis) { |
| 153 | return -1; |
| 154 | } else { |
| 155 | return 1; |
| 156 | } |
| 157 | } |
| 158 | |
| 159 | /** |
| 160 | * Get a suitable debug string. |
| 161 | * |
| 162 | * @return debug string |
| 163 | */ |
| 164 | public String toString() { |
| 165 | return "DurationField[" + getName() + ']'; |
| 166 | } |
| 167 | |
| 168 | } |