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 org.joda.time.DateTimeFieldType;
19 import org.joda.time.DurationField;
20
21 /**
22 * Precise datetime field, composed of two precise duration fields.
23 * <p>
24 * This DateTimeField is useful for defining DateTimeFields that are composed
25 * of precise durations, like time of day fields. If either duration field is
26 * imprecise, then an {@link ImpreciseDateTimeField} may be used instead.
27 * <p>
28 * PreciseDateTimeField is thread-safe and immutable.
29 *
30 * @author Brian S O'Neill
31 * @author Stephen Colebourne
32 * @since 1.0
33 * @see ImpreciseDateTimeField
34 */
35 public class PreciseDateTimeField extends PreciseDurationDateTimeField {
36
37 private static final long serialVersionUID = -5586801265774496376L;
38
39 /** The maximum range in the correct units */
40 private final int iRange;
41
42 private final DurationField iRangeField;
43
44 /**
45 * Constructor.
46 *
47 * @param type the field type this field uses
48 * @param unit precise unit duration, like "seconds()".
49 * @param range precise range duration, preferably a multiple of the unit,
50 * like "minutes()".
51 * @throws IllegalArgumentException if either duration field is imprecise
52 * @throws IllegalArgumentException if unit milliseconds is less than one
53 * or effective value range is less than two.
54 */
55 public PreciseDateTimeField(DateTimeFieldType type,
56 DurationField unit, DurationField range) {
57 super(type, unit);
58
59 if (!range.isPrecise()) {
60 throw new IllegalArgumentException("Range duration field must be precise");
61 }
62
63 long rangeMillis = range.getUnitMillis();
64 iRange = (int)(rangeMillis / getUnitMillis());
65 if (iRange < 2) {
66 throw new IllegalArgumentException("The effective range must be at least 2");
67 }
68
69 iRangeField = range;
70 }
71
72 /**
73 * Get the amount of fractional units from the specified time instant.
74 *
75 * @param instant the milliseconds from 1970-01-01T00:00:00Z to query
76 * @return the amount of fractional units extracted from the input.
77 */
78 public int get(long instant) {
79 if (instant >= 0) {
80 return (int) ((instant / getUnitMillis()) % iRange);
81 } else {
82 return iRange - 1 + (int) (((instant + 1) / getUnitMillis()) % iRange);
83 }
84 }
85
86 /**
87 * Add to the component of the specified time instant, wrapping around
88 * within that component if necessary.
89 *
90 * @param instant the milliseconds from 1970-01-01T00:00:00Z to add to
91 * @param amount the amount of units to add (can be negative).
92 * @return the updated time instant.
93 */
94 public long addWrapField(long instant, int amount) {
95 int thisValue = get(instant);
96 int wrappedValue = FieldUtils.getWrappedValue
97 (thisValue, amount, getMinimumValue(), getMaximumValue());
98 // copy code from set() to avoid repeat call to get()
99 return instant + (wrappedValue - thisValue) * getUnitMillis();
100 }
101
102 /**
103 * Set the specified amount of units to the specified time instant.
104 *
105 * @param instant the milliseconds from 1970-01-01T00:00:00Z to set in
106 * @param value value of units to set.
107 * @return the updated time instant.
108 * @throws IllegalArgumentException if value is too large or too small.
109 */
110 public long set(long instant, int value) {
111 FieldUtils.verifyValueBounds(this, value, getMinimumValue(), getMaximumValue());
112 return instant + (value - get(instant)) * iUnitMillis;
113 }
114
115 /**
116 * Returns the range duration of this field. For example, if this field
117 * represents "minute of hour", then the range duration field is an hours.
118 *
119 * @return the range duration of this field, or null if field has no range
120 */
121 public DurationField getRangeDurationField() {
122 return iRangeField;
123 }
124
125 /**
126 * Get the maximum value for the field.
127 *
128 * @return the maximum value
129 */
130 public int getMaximumValue() {
131 return iRange - 1;
132 }
133
134 /**
135 * Returns the range of the field in the field's units.
136 * <p>
137 * For example, 60 for seconds per minute. The field is allowed values
138 * from 0 to range - 1.
139 *
140 * @return unit range
141 */
142 public int getRange() {
143 return iRange;
144 }
145
146 }