How do I convert java.util.Map[String, Object] to scala.collection.immutable.Map[String, Any], so that all values in the original map (integers, booleans etc.) are converted to the right value to work well in Scala.
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I don't know scala, but can't you do if(objecdt instanceof Integer)... and so on? It's not the best approach but it should work... Maybe you can wrap the objects and use the visitor pattern...pakore– pakore2010-06-27 12:12:54 +00:00Commented Jun 27, 2010 at 12:12
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3 Answers
As VonC says, scala.collections.JavaConversion supports mutable collections only, but you don't have to use a separate library. Mutable collections are derived from TraversableOnce which defines a toMap method that returns an immutable Map:
import scala.collection.JavaConversions._
val m = new java.util.HashMap[String, Object]()
m.put("Foo", java.lang.Boolean.TRUE)
m.put("Bar", java.lang.Integer.valueOf(1))
val m2: Map[String, Any] = m.toMap
println(m2)
This will output
Map(Foo -> true, Bar -> 1)
1 Comment
IttayD
That answers my question. In my more specific case, I needed to map over the values of the map, so m.map{...}(breakOut) also did the trick
The JavaConversions package of Scala2.8 deals only with mutable collections.
The scalaj-collection library might help here.
java.util.Map[A, B] #asScala: scala.collection.Map[A, B]
#asScalaMutable: scala.collection.mutable.Map[A, B]
#foreach(((A, B)) => Unit): Unit
1 Comment
IttayD
JavaConversions is only mapping of the Map object itself, not its values
In order to convert convert java.util.Map[String, Object] to scala.collection.immutable.Map[String,Object] , you need to simple import below statement in Scala Project and clean build.
import collection.JavaConversions._
Refer to below code:
var empMap= Map[String.Object]()
var emp= new Employee(empMap) // Employee is java POJO in which,passing scala map to overloaded constructor for setting default values.
