All Questions
Tagged with lazy-initialization scala
23 questions
2
votes
1
answer
51
views
Scala initialization order object vs. val
In the following program an object is reported as null, even though it is clearly initialized.
class MyClass()
class MyOtherClass(c: MyClass)
object Foo {
val myClass = new MyClass()
object ...
- 1,505
0
votes
1
answer
44
views
Instantiate lazy val which depends on runtime parameter in concurrent env
I need to instantiate MyHttpClient as Singleton. MyHttpClient is used by multiple threads.
Solution below works, but it's ugly and should have issue with endpoint, I just didn't hit it yet.
endpoint ...
- 3,758
1
vote
1
answer
304
views
Scala proper way to initialize ones changed in runtime fields: placeholder/null, None or zero element?
I got class with fields which value at initialization is unknown. But after, in runtime that values is will gained and setted to fields just ones.
I want to decide what first initialization is best ...
- 337
2
votes
0
answers
223
views
lazy initialization for Scala?
I have a Scalatest with the following structure which is emasculated within a class
var dataHolder: Holder // some lazy initialization here?
def runTest(filePath: String): Unit = {
//Test 1
...
- 5,112
3
votes
1
answer
346
views
Wordspec "should" "when" "in"
I'm initializing a companion object for one of my scala test suites. One of the fields in this companion object is lazy evaluated and uses some of the fields in the test suite for initialization. ...
- 412
3
votes
1
answer
361
views
How can I do pattern matching on tuple with lazy initialization?
I have an scenario where I need to call up to three services to do something. Each service has some kind of priority and my algorithm depends on the combination of the result of each service (all of ...
- 1,428
2
votes
3
answers
2k
views
Is it possible to declare a val before assignment/initialization in Scala?
In general, can you declare a val in scala before assigning it a value? If not, why not? An example where this might be useful (in my case at least) is that I want to declare a val which will be ...
0
votes
2
answers
258
views
How to Initialize an Immutable val outside scope of class
I was wondering if there is a way in scala to define an immutable value without initializing it to any parameters until it is explicitly called with a value to initialize it outside the scope of that ...
- 89
2
votes
2
answers
122
views
Strange behavior of Scala compiler when initializing a class with a lazy argument
How possible that the first is correct Scala code but the second won't even compile?
The one that does compile
object First {
class ABC(body: => Unit) {
val a = 1
val b = 2
println(...
- 2,858
0
votes
1
answer
560
views
scala using a class argument a placeholder (or input variable)
Lets say i have a data structure that holds a parameterised type of data:
case class Terminal[A](value: A, name: String ="")
I can easily create a Terminal[Double] if i pass it a materialised ...
- 916
30
votes
2
answers
20k
views
Difference when serializing a lazy val with or without @transient
Working on spark, sometimes I need to send a non-serializable object in each task.
A common pattern is @transient lazy val, e.g
class A(val a: Int)
def compute(rdd: RDD[Int]) = {
// lazy val ...
- 986
2
votes
1
answer
1k
views
Can Try be lazy or eager in Scala?
AFAIK, Iterator.map is lazy while Vector.map is eager, basically because they are different types of monads.
I would like to know if there is any chance of having a EagerTry and LazyTry that behave ...
- 1,498
2
votes
2
answers
148
views
How to find unreferenced objects in scala
I'm trying to create a map of all objects extending a specific class. I want to have access to this list before the objects are used in any other way. I tried this code:
import scala.collection....
- 1,012
0
votes
1
answer
231
views
How to avoid lazy vals when using cross dependent traits in cake pattern without additional traits
Suppose we have
scala> trait A { val y: Int; val x = 1; val y2 = y + 1 }
scala> trait B { val y: Int = 1; val x: Int; val x2 = x + 1 }
scala> class C extends A with B
Then both y2 and x2 ...
- 31.6k
1
vote
0
answers
312
views
usage of `def` vs `lazy val` vs `val` for configuration properties in Scala
I have an application which is capable of reloading the properties whenever they are changed while the application is running i.e., on the fly!
I created a Singleton to hold all the configuration ...
- 2,144