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Dima
Dima

Reputation: 1828

Validate successful String to enum conversion in Java

I have a list of accounts types defined as enums in the web services implementation. However, when consumer call web service it passes a String that needs to be converted to enum.

What is a good way to validate that given String will be successfully converted to enum?

I was using the following approach, but this is probably an abuse of exceptions (according to Effective Java, item 57).

AccountType accountType = null;
try{
    accountType = AccountType.valueOf(accountTypeString);
}catch(IllegalArgumentException e){
    // report error
}

if (accountType != null){
    // do stuff
}else{
    // exit
}

Upvotes: 4

Views: 4482

Answers (4)

рüффп
рüффп

Reputation: 5448

I personally used the EnumUtils from the Apache Commons library.

That library contains many useful util classes (e.g for Strings as well) and is a must have in any Java project and quite light (300ko).

Here is a sample code I use:

TypeEnum strTypeEnum = null;

// test if String str is compatible with the enum 
if( EnumUtils.isValidEnum(TypeEnum.class, str) ){
    strTypeEnum = TypeEnum.valueOf(str);
}

Upvotes: 2

missingfaktor
missingfaktor

Reputation: 92066

Use Optional data type from Guava.

Have your method AccountType.valueOf return value of type Optional<AccountType>. Then the use-site code would become:

Optional<AccountType> accountType = AccountType.valueOf(accountTypeString));
if (accountType.isPresent()) {
  AccountType a = accountType.get();
  // do stuff
} else {
  // exit
}

Upvotes: 0

Juan Alberto L&#243;pez Cavallotti
Juan Alberto L&#243;pez Cavallotti

Reputation: 4704

You could go over the enum values and check if the name of each literal is equal to your string something like

for (Test test : Test.values()) {
    if (str.equals(test.name())) {
        return true;
    }
}
return false;

The enum is:

public enum Test {
    A,
    B,
}

Also you could return the enum constant or null, since enums are usually small it won't be a performance issue.

Upvotes: 2

Rocky Pulley
Rocky Pulley

Reputation: 23311

You can catch IllegalArgumentException, that will be thrown when a bad value is given.

Upvotes: 1

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