Switch to case class

public/biopet-framework/src/main/scala/nl/lumc/sasc/biopet/core/config/ConfigValueIndex.scala

@@ -15,15 +15,6 @@
  */
 package nl.lumc.sasc.biopet.core.config
 
-class ConfigValueIndex(val module: String, val path: List[String], val key: String, val freeVar: Boolean = true) {
+case class ConfigValueIndex(module: String, path: List[String], key: String, freeVar: Boolean = true) {
   override def toString = "Module = " + module + ",  path = " + path + ",  key = " + key + ",  freeVar = " + freeVar
-}
-
-object ConfigValueIndex {
-  private var cache: Map[(String, List[String], String), ConfigValueIndex] = Map()
-
-  def apply(module: String, path: List[String], key: String, freeVar: Boolean = true): ConfigValueIndex = {
-    if (!cache.contains(module, path, key)) cache += ((module, path, key) -> new ConfigValueIndex(module, path, key, freeVar))
-    return cache(module, path, key)
-  }
 }
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