001 /*
002 * Copyright 2001-2009 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;
017
018 /**
019 * Defines an exact duration of time in milliseconds.
020 * <p>
021 * The implementation of this interface may be mutable or immutable. This
022 * interface only gives access to retrieve data, never to change it.
023 * <p>
024 * Methods that are passed a duration as a parameter will treat <code>null</code>
025 * as a zero length duration.
026 * <p>
027 * The {@code compareTo} method is no longer defined in this class in version 2.0.
028 * Instead, the definition is simply inherited from the {@code Comparable} interface.
029 * This approach is necessary to preserve binary compatibility.
030 * The definition of the comparison is ascending order by millisecond duration.
031 * Implementors are recommended to extend {@code AbstractInstant} instead of this interface.
032 *
033 * @see ReadableInterval
034 * @see ReadablePeriod
035 * @author Brian S O'Neill
036 * @author Stephen Colebourne
037 * @since 1.0
038 */
039 public interface ReadableDuration extends Comparable<ReadableDuration> {
040
041 /**
042 * Gets the total length of this duration in milliseconds.
043 *
044 * @return the total length of the time duration in milliseconds.
045 */
046 long getMillis();
047
048 //-----------------------------------------------------------------------
049 /**
050 * Get this duration as an immutable <code>Duration</code> object.
051 * <p>
052 * This will either typecast this instance, or create a new <code>Duration</code>.
053 *
054 * @return a Duration created using the millisecond duration from this instance
055 */
056 Duration toDuration();
057
058 //-----------------------------------------------------------------------
059 /**
060 * Converts this duration to a Period instance using the standard period type
061 * and the ISO chronology.
062 * <p>
063 * Only precise fields in the period type will be used. Thus, only the hour,
064 * minute, second and millisecond fields on the period will be used.
065 * The year, month, week and day fields will not be populated.
066 * <p>
067 * If the duration is small, less than one day, then this method will perform
068 * as you might expect and split the fields evenly.
069 * If the duration is larger than one day then all the remaining duration will
070 * be stored in the largest available field, hours in this case.
071 * <p>
072 * For example, a duration effectively equal to (365 + 60 + 5) days will be
073 * converted to ((365 + 60 + 5) * 24) hours by this constructor.
074 * <p>
075 * For more control over the conversion process, you must pair the duration with
076 * an instant, see {@link Period#Period(ReadableInstant,ReadableDuration)}.
077 *
078 * @return a Period created using the millisecond duration from this instance
079 */
080 Period toPeriod();
081
082 //-----------------------------------------------------------------------
083 // Method is no longer defined here as that would break generic backwards compatibility
084 // /**
085 // * Compares this duration with the specified duration based on length.
086 // *
087 // * @param obj a duration to check against
088 // * @return negative value if this is less, 0 if equal, or positive value if greater
089 // * @throws NullPointerException if the object is null
090 // * @throws ClassCastException if the given object is not supported
091 // */
092 // int compareTo(ReadableDuration obj);
093
094 /**
095 * Is the length of this duration equal to the duration passed in.
096 *
097 * @param duration another duration to compare to, null means zero milliseconds
098 * @return true if this duration is equal to than the duration passed in
099 */
100 boolean isEqual(ReadableDuration duration);
101
102 /**
103 * Is the length of this duration longer than the duration passed in.
104 *
105 * @param duration another duration to compare to, null means zero milliseconds
106 * @return true if this duration is equal to than the duration passed in
107 */
108 boolean isLongerThan(ReadableDuration duration);
109
110 /**
111 * Is the length of this duration shorter than the duration passed in.
112 *
113 * @param duration another duration to compare to, null means zero milliseconds
114 * @return true if this duration is equal to than the duration passed in
115 */
116 boolean isShorterThan(ReadableDuration duration);
117
118 //-----------------------------------------------------------------------
119 /**
120 * Compares this object with the specified object for equality based
121 * on the millisecond length. All ReadableDuration instances are accepted.
122 *
123 * @param readableDuration a readable duration to check against
124 * @return true if the length of the duration is equal
125 */
126 boolean equals(Object readableDuration);
127
128 /**
129 * Gets a hash code for the duration that is compatable with the
130 * equals method.
131 * The following formula must be used:
132 * <pre>
133 * long len = getMillis();
134 * return (int) (len ^ (len >>> 32));
135 * </pre>
136 *
137 * @return a hash code
138 */
139 int hashCode();
140
141 //-----------------------------------------------------------------------
142 /**
143 * Gets the value as a String in the ISO8601 duration format using hours,
144 * minutes and seconds (including fractional milliseconds).
145 * <p>
146 * For example, "PT6H3M7S" represents 6 hours, 3 minutes, 7 seconds.
147 *
148 * @return the value as an ISO8601 string
149 */
150 String toString();
151
152 }