Override valueof() and toString() in Java enum
Solution 1:
You can try out this code. Since you cannot override valueOf
method you have to define a custom method (getEnum
in the sample code below) which returns the value that you need and change your client to use this method instead.
public enum RandomEnum {
StartHere("Start Here"),
StopHere("Stop Here");
private String value;
RandomEnum(String value) {
this.value = value;
}
public String getValue() {
return value;
}
@Override
public String toString() {
return this.getValue();
}
public static RandomEnum getEnum(String value) {
for(RandomEnum v : values())
if(v.getValue().equalsIgnoreCase(value)) return v;
throw new IllegalArgumentException();
}
}
Solution 2:
Try this, but i don't sure that will work every where :)
public enum MyEnum {
A("Start There"),
B("Start Here");
MyEnum(String name) {
try {
Field fieldName = getClass().getSuperclass().getDeclaredField("name");
fieldName.setAccessible(true);
fieldName.set(this, name);
fieldName.setAccessible(false);
} catch (Exception e) {}
}
}
Solution 3:
You can use a static Map in your enum that maps Strings to enum constants. Use it in a 'getEnum' static method. This skips the need to iterate through the enums each time you want to get one from its String value.
public enum RandomEnum {
StartHere("Start Here"),
StopHere("Stop Here");
private final String strVal;
private RandomEnum(String strVal) {
this.strVal = strVal;
}
public static RandomEnum getEnum(String strVal) {
if(!strValMap.containsKey(strVal)) {
throw new IllegalArgumentException("Unknown String Value: " + strVal);
}
return strValMap.get(strVal);
}
private static final Map<String, RandomEnum> strValMap;
static {
final Map<String, RandomEnum> tmpMap = Maps.newHashMap();
for(final RandomEnum en : RandomEnum.values()) {
tmpMap.put(en.strVal, en);
}
strValMap = ImmutableMap.copyOf(tmpMap);
}
@Override
public String toString() {
return strVal;
}
}
Just make sure the static initialization of the map occurs below the declaration of the enum constants.
BTW - that 'ImmutableMap' type is from the Google guava API, and I definitely recommend it in cases like this.
EDIT - Per the comments:
- This solution assumes that each assigned string value is unique and non-null. Given that the creator of the enum can control this, and that the string corresponds to the unique & non-null enum value, this seems like a safe restriction.
- I added the 'toSTring()' method as asked for in the question
Solution 4:
How about a Java 8 implementation? (null can be replaced by your default Enum)
public static RandomEnum getEnum(String value) {
return Arrays.stream(RandomEnum.values()).filter(m -> m.value.equals(value)).findAny().orElse(null);
}
Or you could use:
...findAny().orElseThrow(NotFoundException::new);