groovy-core/src/main/groovy/time/TimeDuration.java

/*
 * Copyright 2003-2007 the original author or authors.
 *
 * 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 groovy.time;

import java.util.Calendar;
import java.util.Date;

/**
 * @author John Wilson tug@wilson.co.uk
 * 
 * TimeDuration represents time periods expressed in units of hours, minutes, seconds and milliseconds.
 * 
 * Whilst we can't say how long a month is without knowing the year and the name of the month,
 * we know how long a second is independant of the date.
 * 
 * This is not 100% true for minutes.
 * Minutes can be 59, 60 or 61 seconds long (due to leap seconds)
 * 
 * If you ask Duration to convert itself to milliseconds then it will work on the basis of 60 seconds in a minute.
 * If you add or subtract it from a date it will take leap seconds into account
 *
 */

public class TimeDuration extends Duration {
    public TimeDuration(final int hours, final int minutes, final int seconds, final int millis) {
        super(0, hours, minutes, seconds, millis);
     }
    
    public TimeDuration(final int days, final int hours, final int minutes, final int seconds, final int millis) {
        super(days, hours, minutes, seconds, millis);
     }
    
    public Duration plus(final Duration rhs) {
        return new TimeDuration(this.getDays() + rhs.getDays(), this.getHours() + rhs.getHours(),
                                this.getMinutes() + rhs.getMinutes(), this.getSeconds() + rhs.getSeconds(),
                                this.getMillis() + rhs.getMillis());
    }
    
    public DatumDependentDuration plus(final DatumDependentDuration rhs) {
        return new TimeDatumDependentDuration(rhs.getYears(), rhs.getMonths(),
                                              this.getDays() + rhs.getDays(), this.getHours() + rhs.getHours(),
                                              this.getMinutes() + rhs.getMinutes(), this.getSeconds() + rhs.getSeconds(),
                                              this.getMillis() + rhs.getMillis());
    }
    
    public Duration minus(final Duration rhs) {
        return new TimeDuration(this.getDays() - rhs.getDays(), this.getHours() - rhs.getHours(),
                                this.getMinutes() - rhs.getMinutes(), this.getSeconds() - rhs.getSeconds(),
                                this.getMillis() - rhs.getMillis());
    }
    
    public DatumDependentDuration minus(final DatumDependentDuration rhs) {
        return new TimeDatumDependentDuration(-rhs.getYears(), -rhs.getMonths(),
                                              this.getDays() - rhs.getDays(), this.getHours() - rhs.getHours(),
                                              this.getMinutes() - rhs.getMinutes(), this.getSeconds() - rhs.getSeconds(),
                                              this.getMillis() - rhs.getMillis());
    }
    
    public From getFrom() {
        return new From() {
            public Date getNow() {
            final Calendar cal = Calendar.getInstance();

                cal.add(Calendar.DAY_OF_YEAR, TimeDuration.this.getDays());
                cal.add(Calendar.HOUR_OF_DAY, TimeDuration.this.getHours());
                cal.add(Calendar.MINUTE, TimeDuration.this.getMinutes());
                cal.add(Calendar.SECOND, TimeDuration.this.getSeconds());
                cal.add(Calendar.MILLISECOND, TimeDuration.this.getMillis());
                
                return cal.getTime();
            }
        };
    }
}