Trying to create an ArrayList of Strings from an enum class

Question

I have been able to successfully load my ArrayList from the values of the enum class. I am not very familiar with using enums, and I was wondering if there was a way to handle this without typing add for each enum as I have shown.

public enum PartsOfSpeech {
    Adjective("Placeholder [adjective] : To be updated..."),
    Adverb("Placeholder [adverb] : To be updated..."),
    Conjunction("Placeholder [conjection] : To be updated..."),
    Interjection("Placeholder [interjection] : To be updated..."),
    Noun("Placeholder [noun] : To be updated..."),
    Preposition("Placeholder [preposition] : To be updated..."),
    Pronoun("Placeholder [pronoun] : To be updated..."),
    Verb("Placeholder [verb] : To be updated...");


    private String speechValue;

    private PartsOfSpeech(String speechValue) {
        this.speechValue= speechValue;
    }

    public String getSpeechValue() {
        return speechValue;
    }

}
public class Dictionary {
    public static void main(String args[]) {
        System.out.println("! Loading data...");
        Map<String, List<String>> dictionaryMap = new HashMap<String, List<String>>();

        List<String> POSList = new ArrayList<>();

        POSList.add(PartsOfSpeech.Adjective.getSpeechValue());
        POSList.add(PartsOfSpeech.Adverb.getSpeechValue());
        POSList.add(PartsOfSpeech.Conjunction.getSpeechValue());
        POSList.add(PartsOfSpeech.Interjection.getSpeechValue());
        POSList.add(PartsOfSpeech.Noun.getSpeechValue());
        POSList.add(PartsOfSpeech.Preposition.getSpeechValue());
        POSList.add(PartsOfSpeech.Pronoun.getSpeechValue());
        POSList.add(PartsOfSpeech.Verb.getSpeechValue());

        dictionaryMap.put("distinct",POSList);

Side issue: this Adjective("Placeholder [adjective] : To be updated..."), just doesn't look right as it looks like you're hard coding implementation details within a model, the enum. Likely better is the more simple ADJECTIVE("adjective"), ... or something similar. You would then create your "Placeholder [%s]: To be updated..." at some later place where you would display information to the user. Otherwise your code becomes rigid and hard to enhance, update and change later. — Hovercraft Full Of Eels
– Hovercraft Full Of Eels, Commented Feb 18, 2019 at 2:38

Kartik · Accepted Answer · 2019-02-18 02:27:50Z

1

values() method return an array of values of enum. You can iterate over these values, get the speech value, and add them to the list.

Here is how you can do the above using the Stream API:

List<String> POSList = Arrays.stream(PartsOfSpeech.values())
        .map(PartsOfSpeech::getSpeechValue)
        .collect(Collectors.toList());

And following the Java naming convention, it should be posList and not POSList.

edited Feb 18, 2019 at 2:27

answered Feb 18, 2019 at 2:20

Kartik

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4 Comments

Hovercraft Full Of Eels Over a year ago

Also regarding naming convention, the enum constants should be all upper-case.

Hovercraft Full Of Eels Over a year ago

The OP could get rid of speechValue and getSpeechValue(), using your code a la:

List<String> posList = Arrays.stream(PartsOfSpeech.values()).map(pos -> String.format(format, pos.toString().toLowerCase())).collect(Collectors.toList());

Hovercraft Full Of Eels Over a year ago

oops, forgot the format String: String format = "\"Placeholder [%s] : To be updated...\"";

Kartik Over a year ago

@HovercraftFullOfEels yup, it will make the enum cleaner. But I think the OP will be changing the placeholder to be updated part, so each of them have their unique value. If they don't do that, then it's not really a property of this enum and so the speechValue should be completely removed from it. It can be dynamically created (like you suggested using format) while inserting values in list/map.

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