Functional Programming in Java

Chapter 7. Handling errors and exceptions

This chapter covers

• Holding information about errors with the Either type
• Easier error handling with the biased Result type
• Accessing the data inside a Result
• Applying effects to Result data
• Lifting functions to operate on Result

In chapter 6, you learned how to deal with optional data without having to manipulate null references by using the Option data type. As you saw, this data type is perfect for dealing with the absence of data when this isn’t the result of an error. But it’s not an efficient way to handle errors, because, although it allows you to cleanly report the absence of data, it swallows the cause of this absence. All missing data is thus treated the same way, and it’s up to the ...