CallResult

A CallResult<L, R> represents a value of two possible types, a Failure or a Success. This simply means that you have either a left or a right member, but never both at the same time. This class is present in JCoinbase since version 0.0.1.

Please note that CallResult, is a simplified version of the vavr Either and provide you a powerful API based on lambdas. Thus, you are not dependent on vavr if you do not wish to use it. x

CallResult usage example

For example, if a method returns a CallResult<Seq<CoinbaseError>, User>, then you will either have a Seq of CoinbaseError or a User. Then you can access the left or the right member using the CallResult API.

CallResult<Seq<CoinbaseError>, User> currentUser = client.user().getCurrentUser();

//Get the user. Throws exception if this is a failure
currentUser.get();

//Get the user or return null if this is a failure
currentUser.getOrNull();

//Get the user or return the given user if this is a failure
currentUser.getOrElse(User.builder()[...].build());

//Get the user or execute myInstruction() if this is a failure
currentUser.getOrElse(() -> myInstruction());

//Get the user or throws a new exception if this is a failure
currentUser.getOrElseThrow(() -> new RuntimeException())
        
//Get the underlying user or the result of Try.of(theSupplier).get()
currentUser.getOrElseTry(OneClass::methodToInvoke);

//Get the underlying left member. Throws exception if this is a Success.
currentUser.getFailure();

In this example, if this is a failure, client.user().getCurrentUser() will return a CallResult.Failure, otherwise it will return a CallResult.Success.

Now, imagine that we want to map the underlying user to another thing

//This method maps the value of this CallResult if it is a Success and performs no operation if this is a Failure.
currentUser.map(User::getId);

Note that the map is also available for the Failure side of a CallResult using mapFailure()``

//Transform the CoinbaseErrors to a list of messages if this is a failure. Do nothing otherwise.
currentUser.mapFailure(coinbaseErrors -> coinbaseErrors.map(CoinbaseError::getMessage));

CallResult also gives you access to useful methods like:

//Return true if this is a success, false otherwise
currentUser.isSuccess();

//Return true if this is a failure, false otherwise
currentUser.isFailure();

//Return true if this a success with an underlying value, false otherwise
currentUser.isEmpty();

Many other methods are available in the CallResult api, like peek(), peekFailure(), bimap(), flatMap(), orElse(), fold(), toOption(), toJavaOptional() ...

For more information on the CallResult class you can also check the javadoc