New J2K: Add collection operations conversion

j2k/newSrc/org/jetbrains/kotlin/j2k/ConversionsRunner.kt

@@ -54,6 +54,7 @@ object ConversionsRunner {
             +InstanceOfConversion()
             +ForConversion(context)
             +ForInConversion()
+            +CollectionOperationsConversion(context)
             +ArrayOperationsConversion(context)
             +TypeMappingConversion(context)
 

j2k/newSrc/org/jetbrains/kotlin/j2k/conversions/CollectionOperationsConversion.kt

@@ -0,0 +1,32 @@
+/*
+ * Copyright 2010-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
+ * that can be found in the license/LICENSE.txt file.
+ */
+
+package org.jetbrains.kotlin.j2k.conversions
+
+import org.jetbrains.kotlin.j2k.ConversionContext
+import org.jetbrains.kotlin.j2k.tree.*
+import org.jetbrains.kotlin.j2k.tree.impl.JKFieldAccessExpressionImpl
+
+
+class CollectionOperationsConversion(private val context: ConversionContext) : RecursiveApplicableConversionBase() {
+    override fun applyToElement(element: JKTreeElement): JKTreeElement {
+        if (element !is JKQualifiedExpression) return recurse(element)
+        val receiverType = element.receiver.type(context) ?: return recurse(element)
+        if (!receiverType.isCollectionType(context.symbolProvider)) return recurse(element)
+
+        convertSizeCall(element.selector)?.also {
+            element.selector = it
+        }
+
+        return recurse(element)
+    }
+
+    private fun convertSizeCall(selector: JKExpression): JKFieldAccessExpressionImpl? {
+        if (selector !is JKMethodCallExpression) return null
+        return if (selector.identifier.name =="size")  {
+            JKFieldAccessExpressionImpl(context.symbolProvider.provideByFqName("kotlin.collections.Collection.size"))
+        } else null
+    }
+}

j2k/newSrc/org/jetbrains/kotlin/j2k/tree/types.kt

@@ -156,4 +156,10 @@ fun JKType.updateNullability(newNullability: Nullability): JKType =
     }
 
 fun JKJavaMethod.returnTypeNullability(context: ConversionContext): Nullability =
-    context.typeFlavorCalculator.methodNullability(psi()!!)
+    context.typeFlavorCalculator.methodNullability(psi()!!)
+
+fun JKType.isCollectionType(symbolProvider: JKSymbolProvider): Boolean {
+    if (this !is JKClassType) return false
+    val collectionType = JKClassTypeImpl(symbolProvider.provideByFqName("java.util.Collection"), emptyList())
+    return this.isSubtypeOf(collectionType, symbolProvider)
+}