Get value of java object variable name

If you can modify your task list object to hold a Set of working days rather than 7 Boolean values, you don’t even need a loop. A table lookup in linear time will do.

    DateTimeFormatter dowFormatter = DateTimeFormatter.ofPattern("cccc", Locale.ENGLISH);

    EnumSet<DayOfWeek> workdays = EnumSet
            .of(DayOfWeek.MONDAY, DayOfWeek.TUESDAY, DayOfWeek.THURSDAY);
    String day = "Tuesday";

    DayOfWeek dow = dowFormatter.parse(day, DayOfWeek::from);
    boolean isWorkDay = workdays.contains(dow);

    System.out.println("Is work day? " + isWorkDay);

Output from the example:

Is work day? true

An EnumSet is implemented as an array of Boolean values.

I trust you to fit the EnumSet into your object and wrap the code in a method similar to what you are doing in the question.

The pattern letter c that I am using in the format pattern string used for defining the formatter for day of week is not often used. Frankly I am in doubt whether it is correct to use it here. According to the documentation it gives us the standalone form of the localized day of week text. Since the day of week standa alone — it is not part of a date string — I figured it might be right. If not, use the more common EEEE. At least for English, both work.

Edit: Even though your 7 boolean values come from a CSV file, I would probably still use the set approach. For initializing the set, I don’t think I’d resort to reflection, but accept 7 if statemnts (here condensed more than most of us do in real code):

    boolean sunday = false;
    boolean monday = true;
    boolean tuesday = true;
    boolean wednesday = false;
    boolean thursday = true;
    boolean friday = false;
    boolean saturday = false;

    Set<DayOfWeek> workdays = EnumSet.noneOf(DayOfWeek.class);
    if (sunday) workdays.add(DayOfWeek.SUNDAY);
    if (monday) workdays.add(DayOfWeek.MONDAY);
    if (tuesday) workdays.add(DayOfWeek.TUESDAY);
    if (wednesday) workdays.add(DayOfWeek.WEDNESDAY);
    if (thursday) workdays.add(DayOfWeek.THURSDAY);
    if (friday) workdays.add(DayOfWeek.FRIDAY);
    if (saturday) workdays.add(DayOfWeek.SATURDAY);

    System.out.println(workdays);

[MONDAY, TUESDAY, THURSDAY]

Edit 2:

Here is a simple example of converting a line of Boolean values from a CSV file to an EnumSet<DayOfWeek>.

    String lineFromCsv = "false;true;true;false;true;false;false";

    String[] workDayStrings = lineFromCsv.split(";");
    Set<DayOfWeek> workdays = EnumSet.noneOf(DayOfWeek.class);
    // Sunday
    if (Boolean.valueOf(workDayStrings[0])) {
        workdays.add(DayOfWeek.SUNDAY);
    }
    // Monday through Saturday
    for (int i = 1; i < workDayStrings.length; i++) {
        if (Boolean.valueOf(workDayStrings[i])) {
            workdays.add(DayOfWeek.of(i));
        }
    }
    System.out.println(workdays);

[MONDAY, TUESDAY, THURSDAY]

Link

• Oracle tutorial: Date Time explaining how to use java.time.

You can use the Object class .getClass().getFields() method to fetch all the variables in a class or use specific .getClass().getField("variableName") to fetch a particular variable.

The java reflection api will allow to fetch the variable as a Field (java.lang.reflect)

  private boolean isWorkDay(String day, Object pgMasterTaskList)
      throws IllegalArgumentException, IllegalAccessException, NoSuchFieldException, SecurityException {
    Object obj = null;
    if (pgMasterTaskList.getClass().getField(day).get(obj).equals(true)) {
      return true;
    } else
      return false;
  }

The line Object obj = null; in above is just a placeholder to fetch of the variable using .get().

However, this will work only when the value for day parameter exactly matches the variable name as defined in pgMasterTaskList class. If you want a fetch based on case-insensitive scenario you can use the .getFields() method. Below is an example for the same:

  private boolean isWorkDay(String day, Object pgMasterTaskList) throws IllegalArgumentException, IllegalAccessException, NoSuchFieldException, SecurityException {
    Object obj = null;
    for (Field field : pgMasterTaskList.getClass().getFields()) {
      if (day.equalsIgnoreCase(field.getName())) {
        obj = field.get(obj);
        if ((boolean) obj == true)
          return true;
      }
    }
    return false;
  }

The .get(obj) will return an object of class type of your variable (your variable was boolean, then return obj will be of type boolean).

You must use reflection for this:

private boolean isWorkDay(String day, Object pgMasterTaskList) throws NoSuchFieldException, NullPointerException, SecurityException {
    return pgMasterTaskList.getClass().getField(day);
}

NOTE: callers must handle the cases where they pass a day that's null or just wrong, or the boolean member aren't public.

Try creating an enum and then you method logic would simply look like below,

public class WeekMap {

    public static void main(String[] args) {
        System.out.println(isWorkDay("SUNDAY",WeekDays.SUNDAY));
        System.out.println(isWorkDay("sunday",WeekDays.SUNDAY));
        System.out.println(isWorkDay("sunday",WeekDays.SATURDAY));
        System.out.println(isWorkDay("ABS",WeekDays.SATURDAY));
    }

    private static boolean isWorkDay(String day, WeekDays pgMasterTaskList) {
        WeekDays day1 = WeekDays.valueOf(day.toUpperCase()); // Fetch the mapped day for the string
        try{
            day1 = WeekDays.valueOf(day.toUpperCase());
        } catch (IllegalArgumentException iex) {
            iex.printStackTrace(); // this can be suppress
        }
        return day1 == pgMasterTaskList;
    }
}

enum WeekDays{ // Create enum for week day names
    SUNDAY,MONDAY,TUESDAY,WEDNESDAY,THURSDAY,FRIDAY,SATURDAY;
}