Refactoring legend

plot-builder/src/commonMain/kotlin/org/jetbrains/letsPlot/core/plot/builder/assemble/LegendAssembler.kt

@@ -78,27 +78,14 @@ class LegendAssembler(
  }
  }
 
- val legendBreaks = ArrayList<LegendBreak>()
- for (legendBreak in legendBreaksByLabel.values) {
- if (legendBreak.isEmpty) {
- continue
- }
- legendBreaks.add(legendBreak)
- }
-
-
+ val legendBreaks = legendBreaksByLabel.values.filterNot { it.isEmpty }
  if (legendBreaks.isEmpty()) {
  return LegendBoxInfo.EMPTY
  }
 
- // legend options
- val legendOptionsList = ArrayList<LegendOptions>()
- for (legendLayer in legendLayers) {
- val aesList = legendLayer.aesList
- for (aes in aesList) {
- if (guideOptionsMap[aes] is LegendOptions) {
- legendOptionsList.add(guideOptionsMap[aes] as LegendOptions)
- }
+ val legendOptionsList = legendLayers.flatMap { legendLayer ->
+ legendLayer.aesList.mapNotNull { aes ->
+ guideOptionsMap[aes] as? LegendOptions
  }
  }
 
@@ -157,7 +144,7 @@ class LegendAssembler(
 
  overrideAesValues.forEach { (aesToOverride, v) ->
  val newAesValue = if (v is List<*>) {
- v.getOrElse(index) { v.last() }
+ v.getOrElse(index) { v.lastOrNull() }
  } else {
  v
  }

plot-builder/src/commonMain/kotlin/org/jetbrains/letsPlot/core/plot/builder/assemble/PlotAssemblerUtil.kt

@@ -117,19 +117,18 @@ internal object PlotAssemblerUtil {
  val legendKeyFactory = layerInfo.legendKeyElementFactory
  val aestheticsDefaults = layerInfo.aestheticsDefaults
 
- val overrideAesValues = mutableMapOf<Aes<*>, Any>()
- aesListForScaleName.forEach { aes ->
- val overrideOptionsForAes = (guideOptionsMap[aes] as? LegendOptions)?.overrideAesValues
- if (!overrideOptionsForAes.isNullOrEmpty()) {
- // ToDo Need to check for conflicting settings?
- overrideAesValues += overrideOptionsForAes
- }
- }
+ val allOverrideAesValues =
+ guideOptionsMap
+ .filter { (aes, _) -> aes in aesListForScaleName }
+ .values
+ .filterIsInstance<LegendOptions>()
+ .map{it.overrideAesValues.orEmpty()}
+ .fold(mapOf<Aes<*>, Any>(), { acc, overrideAesValues -> acc + overrideAesValues })
 
  legendAssembler.addLayer(
  legendKeyFactory,
  aesListForScaleName,
- overrideAesValues,
+ allOverrideAesValues,
  layerConstantByAes,
  aestheticsDefaults,
  layerInfo.colorByAes,