com.codetaco.math.function.FuncDateFmt Maven / Gradle / Ivy

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package com.codetaco.math.function;

import com.codetaco.date.CalendarFactory;
import com.codetaco.math.Function;
import com.codetaco.math.ValueStack;
import com.codetaco.math.token.TokVariable;

import java.text.ParseException;
import java.time.LocalDate;
import java.time.LocalDateTime;
import java.time.LocalTime;
import java.time.format.DateTimeFormatter;

/**
 * 
 * FuncDateTimeFmt class.
 * 
 *
 * @author Chris DeGreef [email protected]
 */
public class FuncDateFmt extends Function {

    /**
     * 
     * Constructor for FuncDate.
     * 
     */
    public FuncDateFmt() {
        super();
    }

    /**
     * 
     * Constructor for FuncDateTimeFmt.
     * 
     *
     * @param var a {@link com.codetaco.math.token.TokVariable} object.
     */
    public FuncDateFmt(final TokVariable var) {
        super(var);
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public void resolve(final ValueStack values) throws Exception {
        if (values.size() < 2) {
            throw new Exception("missing operands for " + toString());
        }

        try {
            String adjustments = "";

            if (getParameterCount() == 3) {
                adjustments = values.popString();
            }

            final DateTimeFormatter dtf = DateTimeFormatter.ofPattern(values.popString());

            final String dateInputObject = values.popString();
            final LocalDate convertedInputDate = LocalDate.parse(dateInputObject, dtf);

            final LocalDateTime adjLdt = CalendarFactory.modify(convertedInputDate, adjustments);
            if (adjLdt.toLocalTime() != LocalTime.MIN) {
                throw new ParseException("Adjustments to time are not allowed", 0);
            }
            values.push(adjLdt);

        } catch (final ParseException e) {
            e.fillInStackTrace();
            throw new Exception(toString() + "; " + e.getMessage(), e);
        }
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public String toString() {
        return "function(dateFmt)";
    }
}