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 static org.gvsig.expressionevaluator.ExpressionBuilder.FUNCTION_TIMESTAMP;

import org.gvsig.expressionevaluator.Interpreter;

import org.gvsig.expressionevaluator.spi.AbstractFunction;

public class TimestampFunction extends AbstractFunction {

    public TimestampFunction() {

        super("Date", FUNCTION_TIMESTAMP,Range.between(1,2),

            "Returns a time stamp from the arguments",

            FUNCTION_TIMESTAMP+"({{timestamp}}, format)",

            new String[]{

                "timestamp - a string with a date/time",

                "format - Optional. Format to use to parse the timestamp"

            },

            "Timestamp"

        );

    }

    @Override

    public boolean allowConstantFolding() {

        return true;

    }

    @Override

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

        String date = getStr(args, 0);

        String format = null;

        if( args.length==2 ) {

            format = getStr(args, 1);

        }

        SimpleDateFormat df = new SimpleDateFormat();

        if( format != null ) {

            df.applyPattern(format);

        }

        try {

            Date x = df.parse(date);

            return x;

        } catch (ParseException ex) {

            throw new RuntimeException("Can't parse date value '"+date+"' with format '"+format==null?"":format+"'", ex);

        }

    }

}