Safeguarding Collections and Object References with Scala's Option

We often use Option to handle collections safely:

val collection = Map.empty[Int, Int]

// unsafe way that will throw an exception if key is not present
val value = collection(1)

// safe way
val valueOpt = collection.get(1) match {
    case Some(value) => // key is present
    case None => // key is not present
}

In Scala, object references can have a value of null. That makes them unsafe. Bugs, that are related to unsafe calls, are very hard to detect. Luckily, the Option class can help to handle them for free:

var mutableRef: Car = null
Option(mutableRef) match {
    case Some(value) => // non-null
    case None => // null
}

This also lets us use Option composition to make safe calls:

class Car() {
    val width: Int = 100
}

var mutableRef: Car = null

// unsafe way that will throw an exception if mutableRef is null
val carWidth = mutableRef.width

// safe way
val carWidthOpt = Option(mutableRef).map(_.width)

Scala's Option class provides a powerful way to handle null values and safeguard collections and object references, minimizing the risk of bugs related to unsafe calls. By utilizing Option composition, developers can create more robust and maintainable code, ensuring a safer and more efficient development experience.

Safeguarding Collections and Object References with Scala's Option

Comments

More from this blog

Data Races Are a Compile Error Now: GALA in July (0.63 -> 0.72)

GALA in June: do-notation, applicative validation, and concurrent binds (0.56 -> 0.62)

From Zero to a Go Module on Bazel in One Sitting: Onboarding to GALA 0.53

Productionizing the GALA Build Stack: rules_gala, a Real Toolchain, and Gazelle

The State of GALA: May 2026

Command Palette

Comments

More from this blog