Return object from list while looping java 8

Question

Is there some straight forward way to return object from list which map to condition we passed.

Ex :

public enum CarType {
    TOYOTA,
    NISSAN,
    UNKNOWN;

    public static CarType getByName(String name) {
        for (CarType carType : values()) {
            if (carType.name().equals(name)) {
                return carType;
            }
        }
        return UNKNOWN;
    }
}

Is there some another way support by java 8 below method and for loop I have used.

public static CarType getByName(String name) {
    for (CarType carType : values()) {
        if (carType.name().equals(name)) {
            return carType;
        }
    }
    return UNKNOWN;
}

Why did you post getByName(String) twice ? I find it confusing. — c0der
– c0der, Commented Nov 14, 2017 at 4:15
Are you looking for the valueOf method that every Enum has? It's not Java 8. — Dawood ibn Kareem
– Dawood ibn Kareem, Commented Nov 14, 2017 at 4:15
I would have thought that OP knew what equals and equalsIgnoreCase are. — Naman
– Naman, Commented Nov 14, 2017 at 5:22
try { return valueOf(name); } catch(IllegalArgumentException ex) { return UNKNOWN; } — Holger
– Holger, Commented Nov 15, 2017 at 11:09

Naman · Accepted Answer · 2017-11-14 04:38:24Z

5

Something like this with findFirst and orElse as :

return Arrays.stream(values())
               .filter(carType -> carType.name().equals(name))
               .findFirst().orElse(CarType.UNKNOWN);

edited Nov 14, 2017 at 4:38

answered Nov 14, 2017 at 4:16

Naman

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Comments

user140547 · Accepted Answer · 2017-11-14 04:17:55Z

4

You can use a stream this way:

public static CarType getByName(String name) {
    return Arrays.stream(values())
            .filter(carType -> carType.name().equals(name))
            .findFirst()
            .orElse(UNKNOWN);
}

BTW, when using IntellliJ (I am not affiliated to them ;)), it offers you an option to do this conversion automatically.

answered Nov 14, 2017 at 4:17

user140547

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ΦXocę 웃 Пepeúpa ツ · Accepted Answer · 2017-11-14 05:01:14Z

3

another option

enum CarType {
    TOYOTA, NISSAN, UNKNOWN;

    public static CarType getByName(String name) {
        return Stream.of(CarType.values())
          .filter(x -> x.name().equals(name))
          .findFirst()
          .orElse(UNKNOWN);
    }
}

edited Nov 14, 2017 at 5:01

answered Nov 14, 2017 at 4:45

ΦXocę 웃 Пepeúpa ツ

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