Duration.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;

/**
 * <p>Duration represents time periods which have values independent of the context.
 * So, 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 day is independent of the date.</p>
 * 
 * <p>This is not 100% true for days.
 * Days can actually be 23, 24 or 25 hours long (due to daylight saving adjustments.)</p>
 * 
 * <p>If you ask Duration to convert itself to milliseconds then it will work on the basis of 24 hours
 * in a day. If you add or subtract it from a date it will take daylight saving into account.</p>
 *
 * @author John Wilson tug@wilson.co.uk
 */
public class Duration extends BaseDuration {
    public Duration(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 Duration(this.getDays() + rhs.getDays(), this.getHours() + rhs.getHours(),
                            this.getMinutes() + rhs.getMinutes(), this.getSeconds() + rhs.getSeconds(),
                            this.getMillis() + rhs.getMillis());
    }

    public Duration plus(final TimeDuration rhs) {
        return rhs.plus(this);
    }
    
    public DatumDependentDuration plus(final DatumDependentDuration rhs) {
        return rhs.plus(this);
    }
    
    public Duration minus(final Duration rhs) {
        return new Duration(this.getDays() - rhs.getDays(), this.getHours() - rhs.getHours(),
                            this.getMinutes() - rhs.getMinutes(), this.getSeconds() - rhs.getSeconds(),
                            this.getMillis() - rhs.getMillis());
    }
    
    public TimeDuration minus(final TimeDuration 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 DatumDependentDuration(-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 TimeDatumDependentDuration minus(final TimeDatumDependentDuration 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 long toMilliseconds() {
        return ((((((long)(this.getDays() * 24 ) + this.getHours()) * 60 + this.getMinutes()) * 60) + this.getSeconds()) * 1000) + this.getMillis();
    }
    
    public Date getAgo() {
    final Calendar cal = Calendar.getInstance();

        cal.add(Calendar.DAY_OF_YEAR, -this.getDays());
        cal.add(Calendar.HOUR_OF_DAY, -this.getHours());
        cal.add(Calendar.MINUTE, -this.getMinutes());
        cal.add(Calendar.SECOND, -this.getSeconds());
        cal.add(Calendar.MILLISECOND, -this.getMillis());
        
        
        //
        // SqlDate should not really care about these values but it seems to "remember" them
        // so we clear them.
        // We do the adds first incase we get carry into the day field
        //
        cal.set(Calendar.HOUR_OF_DAY, 0);
        cal.set(Calendar.MINUTE, 0);
        cal.set(Calendar.SECOND, 0);
        cal.set(Calendar.MILLISECOND, 0);
        
        return new java.sql.Date(cal.getTimeInMillis());
    }
     
    public From getFrom() {
        return new From() {
            public Date getNow() {
            final Calendar cal = Calendar.getInstance();

                cal.add(Calendar.DAY_OF_YEAR, Duration.this.getDays());
                
                //
                // SqlDate should not really care about these values but it seems to "remember" them
                // so we clear them.
                // We do the adds first incase we get carry into the day field
                //
                cal.set(Calendar.HOUR_OF_DAY, 0);
                cal.set(Calendar.MINUTE, 0);
                cal.set(Calendar.SECOND, 0);
                cal.set(Calendar.MILLISECOND, 0);
                
                return new java.sql.Date(cal.getTimeInMillis());
            }
        };
    }
}