Java Enum parameter in method

Question

I have a method lets say   private static String drawCellValue      int maxCellLength  String cellValue  String align        and as you can notice  I have a parameter called align  Inside this method I m going to have some if condition on whether the value is a  left  or  right    setting the parameter as String  obviously I can pass any string value   I would like to know if it s possible to have an Enum value as a method parameter  and if so  how   Just in case someone thinks about this  I thought about using a Boolean value but I don t really fancy it  First  how to associate true false with left right    Ok  I can use comments but I still find it dirty  and secondly  I might decide to add a new value  like  justify   so if I have more than 2 possible values  Boolean type is definitely not possible to use   Any ideas

User · Accepted Answer

This should do it   private enum Alignment   LEFT  RIGHT        String drawCellValue  int maxCellLength  String cellValue  Alignment align     if  align    Alignment LEFT            Process it

User · Answer

I like this a lot better   reduces the if switch  just do    private enum Alignment   LEFT  RIGHT   void process       Process it              String drawCellValue  int maxCellLength  String cellValue  Alignment align     align process        of course   it can be    String process          Process it

User · Answer

You can use an enum in said parameters like this   public enum Alignment   LEFT  RIGHT   private static String drawCellValue  int maxCellLength  String cellValue  Alignment align       then you can use either a switch or if statement to actually do something with said parameter   switch align    case LEFT    something case RIGHT    something default    something    if align    Alignment RIGHT      code

User · Answer

I am not too sure I would go and use an enum as a full fledged class - this is an object oriented language  and one of the most basic tenets of object orientation is that a class should do one thing and do it well   An enum is doing a pretty good job at being an enum  and a class is doing a good job as a class   Mixing the two I have a feeling will get you into trouble - for example  you can t pass an instance of an enum as a parameter to a method  primarily because you can t create an instance of an enum   So  even though you might be able to enum process   does not mean that you should

User · Answer

I like this a lot better   reduces the if switch  just do    private enum Alignment   LEFT  RIGHT   void process       Process it              String drawCellValue  int maxCellLength  String cellValue  Alignment align     align process        of course   it can be    String process          Process it

User · Answer

You could also reuse SwingConstants  LEFT RIGHT   They are not enums  but they do already exist and are used in many places

User · Answer

Even cooler with enums you can use switch   switch  align       case LEFT              do stuff       break          case RIGHT             do stuff       break          default      added TOP RIGHT but forgot about it        throw new IllegalArgumentException  Can t yet handle     align             Enums are cool because the output of the exception will be the name of the enum value  rather than some arbitrary int value

User · Answer

Sure  you could use an enum   Would something like the following work   enum Alignment       LEFT      RIGHT     private static String drawCellValue int maxCellLength  String cellValue  Alignment alignment       If you wanted to use a boolean  you could rename the align parameter to something like alignLeft  I agree that this implementation is not as clean  but if you don t anticipate a lot of changes and this is not a public interface  it might be a good choice

[java] Java: Enum parameter in method

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