Sometimes is necessary to convert a String value to an Enum, perhaps because we have the value as a String in the database, but we want to manipulate it as an Enumerator in the Java code.
The follow code shows hot to obtain the Enum value from a String. Basically, a static method is added to the Enum to return the specif Enum value. This is accomplished by iterating all the Enum values and making a comparison with the String value passed as a parameter. If the String does not match with any of the values, then an illegal argument exception is thrown.
public enum Volcano {
IRAZU("Irazu"), POAS("Poas"), ARENAL("Arenal"), RINCON_DE_LA_VIEJA("Rincon de la vieja");
private String name;
private Volcano(String name) {
this.name = name;
}
public static Volcano fromString(String name) {
if (name == null) {
throw new IllegalArgumentException();
}
for (Volcano volcano : values()) {
if (name.equalsIgnoreCase(volcano.getName())) {
return volcano;
}
}
// Passed string value does not correspond to a valid enum value.
throw new IllegalArgumentException();
}
public String getName() {
return this.name;
}
public static void main(String[] args) {
Volcano volcano1 = Volcano.fromString("Poas");
System.out.println(volcano1);
Volcano volcano2 = Volcano.fromString("rincon de la vieja");
System.out.println(volcano2);
Volcano volcano3 = Volcano.fromString("Fuji");
}
}
Output:
POAS RINCON_DE_LA_VIEJA java.lang.IllegalArgumentException at com.bodybuilding.common.enums.Volcano.fromString(Volcano.java:22) at com.bodybuilding.common.enums.Volcano.main(Volcano.java:36)
