Questions tagged [scala]
Scala is a general purpose programming language principally targeting the Java Virtual Machine. Designed to express common programming patterns in a concise, elegant, and type-safe way, it fuses both imperative and functional programming styles.
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How to connect to SFTP using Apache Spark 3.5 with Scala 2.12 for parallel file transfers?
I am working on a project where I need to transfer thousands of files (each sized between 50-60 MB) every hour from an SFTP server to local storage or AWS S3. I am using Apache Spark 3.5 with Scala 2....
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Scala Option vs. conditional branches
If I'm writing Scala functions and have to check for nulls in situations where I can't avoid it (say, working with Spark UDFs and some legacy Java types), is it better to turn things into Option or to ...
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Sharing akka actors on multiple backend instances
I have a web applications (angular) which is connected to backend using websockets. The role of web app is to display data from multiple sources (which are updated constantly by some Scala Spark apps) ...
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Postgres: Storing a task instruction to be run on a schedule, with multiple workers
As a prerequisite I will say that we are wedded to postgres to provide this solution.
This is a very broad problem, and I think it must be solved many times over, but unfortunately as it's so general ...
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Good design for a class with multiple methods to test but one public method
I've been trying to refactor some existing code which is in essence a giant nested procedural call inside what should otherwise be an object oriented architecture. The entry point to the relevant code ...
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Trying to understand how this class representation truly represents Natural numbers in Scala
Following Martin Odersky's course on coursera - Functional Programming with Scala and I'm on Week 4 where we're learning about Types and Pattern Matching. In the video lecture, this is the ...
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Export huge excel file
I develop a web application in Angular (frontend) and Scala (backend) for a big data team. Because they use large files for export/import, I build a module which is a copy of Microsoft Excel.
So, what ...
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What is the benefit of Java collection streams over C# or Scala collections?
Java collection streams were introduced in Java 8, which came out in March of 2014.
By that time, we already had well-established mechanisms for manipulating collections in several other languages, ...
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How to avoid code duplication from handling "structually similar types" in Scala?
Often, when programming, you'll have different degrees of information to you in different contexts.
For example, a web server may have two routes, which recieve information about a Person, one of ...
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Operate on data that doesn't fit into JVM
We have a service where we have billions of key-value data stored in some storage. Before actually querying the data, we query the bloom filter to determine if the key may exist or definitely does not ...
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Is my server design safe regarding multiple threads and concurrent database reads/writes?
I'm making a chat server using sockets and a MySQL database, and after it's working I want to expand it to become a more complex game server.
I want to know whether my design is missing anything.
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Preferable design for overriding sealed trait method in Scala case classes/objects
Say I have a sealed trait Person that requires the definition of a method work :: Unit -> Unit. I then have three case objects Accountant, Doctor, and Lawyer. I can think of two ways to implement ...
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Why is this "more efficient" version of a Scala Collatz solution slower than tail recursion?
I implememted two versions of the collatz problem and felt an icy terror in the pit of my stomach as an optimized solution was slower than tail. The tail recursion is simple:
// calculate the next ...
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Does variance make sense in a fully immutable language?
In many OOP programming languages, types can be made co-, contra- or in- variant. Most (if not all of these languages) are able to let variables be mutated in place, i.e. they are not fully immutable ...
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Scala Option apply method when passed a None
Not sure if this is an appropriate question for here, please let me know!
In Scala, the ever so useful Option class has an apply method in its companion object that allows us to quickly wrap any ...
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