Application: gvSIG desktop

package org.gvsig.expressionevaluator.impl.function.date;

import java.time.Duration;

import java.time.LocalDateTime;

import java.time.Period;

import org.apache.commons.lang3.Range;

import static org.gvsig.expressionevaluator.ExpressionBuilder.FUNCTION_DATEDIFF;

import org.gvsig.expressionevaluator.Interpreter;

import org.gvsig.expressionevaluator.spi.AbstractFunction;

public class DateDiffFunction extends AbstractFunction {

    public DateDiffFunction() {

        super("Date", FUNCTION_DATEDIFF,Range.is(3),

            "Returns the difference between two dates",

            FUNCTION_DATEDIFF+"({{interval}}, date1, date2)",

            new String[]{

                "interval - a string with the value year,month,day,hour,minute,second or millisecond.",

                "date1 - a Date",

                "date2 - a Date",

            },

            "Long"

        );

    }

    @Override

    public boolean allowConstantFolding() {

        return true;

    }

    @Override

    public Object call(Interpreter interpreter, Object[] args) {

        String interval = this.getStr(args, 0);

        LocalDateTime date1 = this.getLocalDateTime(args,1);

        LocalDateTime date2 = this.getLocalDateTime(args,2);

        Period p;

        Duration d;

        switch(interval.toLowerCase()) {

            case "millisecond":

            case "ms":

                d = Duration.between(date1, date2);

                return d.toMillis();

            case "second":

            case "ss":

            case "s":

                d = Duration.between(date1, date2);

                return d.getSeconds();

            case "minute":

            case "mi":

            case "n":

                d = Duration.between(date1, date2);

                return d.toMinutes();

            case "hour":

            case "hh":

                d = Duration.between(date1, date2);

                return d.toHours();

            case "day":

            case "dy":

            case "y":

                d = Duration.between(date1, date2);

                return d.toDays();

            case "month":

            case "mm":

            case "m":

                p = Period.between(date1.toLocalDate(), date2.toLocalDate());

                return (long) p.getMonths();

            case "year":

            case "yyyy":

            case "yy":

                p = Period.between(date1.toLocalDate(), date2.toLocalDate());

                return (long) p.getYears();

            default:

                throw new IllegalArgumentException("Unsupported interval '"+interval+"'.");

        } 

    }

}