Java tutorial
/* * Copyright 2001-2009 Stephen Colebourne * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package org.joda.time; /** * Defines an exact duration of time in milliseconds. * <p> * The implementation of this interface may be mutable or immutable. This * interface only gives access to retrieve data, never to change it. * <p> * Methods that are passed a duration as a parameter will treat <code>null</code> * as a zero length duration. * <p> * The {@code compareTo} method is no longer defined in this class in version 2.0. * Instead, the definition is simply inherited from the {@code Comparable} interface. * This approach is necessary to preserve binary compatibility. * The definition of the comparison is ascending order by millisecond duration. * Implementors are recommended to extend {@code AbstractInstant} instead of this interface. * * @see ReadableInterval * @see ReadablePeriod * @author Brian S O'Neill * @author Stephen Colebourne * @since 1.0 */ public interface ReadableDuration extends Comparable<ReadableDuration> { /** * Gets the total length of this duration in milliseconds. * * @return the total length of the time duration in milliseconds. */ long getMillis(); //----------------------------------------------------------------------- /** * Get this duration as an immutable <code>Duration</code> object. * <p> * This will either typecast this instance, or create a new <code>Duration</code>. * * @return a Duration created using the millisecond duration from this instance */ Duration toDuration(); //----------------------------------------------------------------------- /** * Converts this duration to a Period instance using the standard period type * and the ISO chronology. * <p> * Only precise fields in the period type will be used. Thus, only the hour, * minute, second and millisecond fields on the period will be used. * The year, month, week and day fields will not be populated. * <p> * If the duration is small, less than one day, then this method will perform * as you might expect and split the fields evenly. * If the duration is larger than one day then all the remaining duration will * be stored in the largest available field, hours in this case. * <p> * For example, a duration effectively equal to (365 + 60 + 5) days will be * converted to ((365 + 60 + 5) * 24) hours by this constructor. * <p> * For more control over the conversion process, you must pair the duration with * an instant, see {@link Period#Period(ReadableInstant,ReadableDuration)}. * * @return a Period created using the millisecond duration from this instance */ Period toPeriod(); //----------------------------------------------------------------------- // Method is no longer defined here as that would break generic backwards compatibility // /** // * Compares this duration with the specified duration based on length. // * // * @param obj a duration to check against // * @return negative value if this is less, 0 if equal, or positive value if greater // * @throws NullPointerException if the object is null // * @throws ClassCastException if the given object is not supported // */ // int compareTo(ReadableDuration obj); /** * Is the length of this duration equal to the duration passed in. * * @param duration another duration to compare to, null means zero milliseconds * @return true if this duration is equal to the duration passed in */ boolean isEqual(ReadableDuration duration); /** * Is the length of this duration longer than the duration passed in. * * @param duration another duration to compare to, null means zero milliseconds * @return true if this duration is greater than the duration passed in */ boolean isLongerThan(ReadableDuration duration); /** * Is the length of this duration shorter than the duration passed in. * * @param duration another duration to compare to, null means zero milliseconds * @return true if this duration is less than the duration passed in */ boolean isShorterThan(ReadableDuration duration); //----------------------------------------------------------------------- /** * Compares this object with the specified object for equality based * on the millisecond length. All ReadableDuration instances are accepted. * * @param readableDuration a readable duration to check against * @return true if the length of the duration is equal */ boolean equals(Object readableDuration); /** * Gets a hash code for the duration that is compatible with the * equals method. * The following formula must be used: * <pre> * long len = getMillis(); * return (int) (len ^ (len >>> 32)); * </pre> * * @return a hash code */ int hashCode(); //----------------------------------------------------------------------- /** * Gets the value as a String in the ISO8601 duration format using hours, * minutes and seconds (including fractional milliseconds). * <p> * For example, "PT6H3M7S" represents 6 hours, 3 minutes, 7 seconds. * * @return the value as an ISO8601 string */ String toString(); }