001 /*
002 * Copyright 2001-2005 Stephen Colebourne
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 * http://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 */
016 package org.joda.time.field;
017
018 import org.joda.time.DateTimeFieldType;
019 import org.joda.time.DurationField;
020
021 /**
022 * Precise datetime field, composed of two precise duration fields.
023 * <p>
024 * This DateTimeField is useful for defining DateTimeFields that are composed
025 * of precise durations, like time of day fields. If either duration field is
026 * imprecise, then an {@link ImpreciseDateTimeField} may be used instead.
027 * <p>
028 * PreciseDateTimeField is thread-safe and immutable.
029 *
030 * @author Brian S O'Neill
031 * @author Stephen Colebourne
032 * @since 1.0
033 * @see ImpreciseDateTimeField
034 */
035 public class PreciseDateTimeField extends PreciseDurationDateTimeField {
036
037 private static final long serialVersionUID = -5586801265774496376L;
038
039 /** The maximum range in the correct units */
040 private final int iRange;
041
042 private final DurationField iRangeField;
043
044 /**
045 * Constructor.
046 *
047 * @param type the field type this field uses
048 * @param unit precise unit duration, like "seconds()".
049 * @param range precise range duration, preferably a multiple of the unit,
050 * like "minutes()".
051 * @throws IllegalArgumentException if either duration field is imprecise
052 * @throws IllegalArgumentException if unit milliseconds is less than one
053 * or effective value range is less than two.
054 */
055 public PreciseDateTimeField(DateTimeFieldType type,
056 DurationField unit, DurationField range) {
057 super(type, unit);
058
059 if (!range.isPrecise()) {
060 throw new IllegalArgumentException("Range duration field must be precise");
061 }
062
063 long rangeMillis = range.getUnitMillis();
064 iRange = (int)(rangeMillis / getUnitMillis());
065 if (iRange < 2) {
066 throw new IllegalArgumentException("The effective range must be at least 2");
067 }
068
069 iRangeField = range;
070 }
071
072 /**
073 * Get the amount of fractional units from the specified time instant.
074 *
075 * @param instant the milliseconds from 1970-01-01T00:00:00Z to query
076 * @return the amount of fractional units extracted from the input.
077 */
078 public int get(long instant) {
079 if (instant >= 0) {
080 return (int) ((instant / getUnitMillis()) % iRange);
081 } else {
082 return iRange - 1 + (int) (((instant + 1) / getUnitMillis()) % iRange);
083 }
084 }
085
086 /**
087 * Add to the component of the specified time instant, wrapping around
088 * within that component if necessary.
089 *
090 * @param instant the milliseconds from 1970-01-01T00:00:00Z to add to
091 * @param amount the amount of units to add (can be negative).
092 * @return the updated time instant.
093 */
094 public long addWrapField(long instant, int amount) {
095 int thisValue = get(instant);
096 int wrappedValue = FieldUtils.getWrappedValue
097 (thisValue, amount, getMinimumValue(), getMaximumValue());
098 // copy code from set() to avoid repeat call to get()
099 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 }