Application: gvSIG desktop

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

import java.text.ParseException;

import java.text.SimpleDateFormat;

import java.util.Date;

import org.apache.commons.lang3.Range;

import org.gvsig.expressionevaluator.Interpreter;

import org.gvsig.expressionevaluator.spi.AbstractFunction;

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

public class DateFunction extends AbstractFunction {

    public DateFunction() {

        super("Date", FUNCTION_DATE,Range.is(1),

            "Returns a date from the arguments",

            FUNCTION_DATE+"({{date}})",

            new String[]{

                "date - a string with a date"

            },

            "Date"

        );

    }

    @Override

    public boolean allowConstantFolding() {

        return true;

    }

    @Override

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

        Object date_obj = getObject(args, 0);

        if( date_obj instanceof Date ) {

            Date x = new Date(((Date) date_obj).getTime());

            x.setHours(0);

            x.setMinutes(0);

            x.setSeconds(0);

            return x;

        }

        String date = getStr(args, 0);

        SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd");

        try {

            Date x = df.parse(date);

            x.setHours(0);

            x.setMinutes(0);

            x.setSeconds(0);

            return x;

        } catch (ParseException ex) {

            throw new RuntimeException("Can't parse date value '"+date+"', expected format 'yyyy-MM-dd'.", ex);

        }

    }

}