Java to Kotlin converter: refactoring

j2k/src/org/jetbrains/jet/j2k/Converter.kt

@@ -23,6 +23,7 @@ import java.util.*
 import com.intellij.psi.CommonClassNames.*
 import org.jetbrains.jet.lang.types.expressions.OperatorConventions.*
 import com.intellij.openapi.project.Project
+import com.intellij.psi.util.PsiMethodUtil
 
 public trait ConversionScope {
     public fun contains(element: PsiElement): Boolean
@@ -100,6 +101,16 @@ public class Converter private(val project: Project, val settings: ConverterSett
         return File(convertedChildren, createMainFunction(javaFile)).assignPrototype(javaFile)
     }
 
+    private fun createMainFunction(file: PsiJavaFile): String? {
+        for (`class` in file.getClasses()) {
+            val mainMethod = PsiMethodUtil.findMainMethod(`class`)
+            if (mainMethod != null) {
+                return "fun main(args: Array<String>) = ${`class`.getName()}.${mainMethod.getName()}(args)"
+            }
+        }
+        return null
+    }
+
     fun convertAnonymousClassBody(anonymousClass: PsiAnonymousClass): AnonymousClassBody {
         return AnonymousClassBody(convertBody(anonymousClass, null), anonymousClass.getBaseClassType().resolve()?.isInterface() ?: false).assignPrototype(anonymousClass)
     }

j2k/src/org/jetbrains/jet/j2k/MainMethodUtils.kt

@@ -1,39 +0,0 @@
-/*
- * Copyright 2010-2013 JetBrains s.r.o.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package org.jetbrains.jet.j2k
-
-import com.intellij.psi.PsiMethod
-import com.intellij.psi.PsiClass
-import com.intellij.psi.PsiJavaFile
-import java.util.ArrayList
-import com.intellij.psi.PsiAnonymousClass
-import com.intellij.psi.PsiModifier
-import com.intellij.psi.PsiType
-import com.intellij.psi.PsiArrayType
-import com.intellij.psi.util.PsiMethodUtil
-
-fun createMainFunction(file: PsiJavaFile): String {
-    for (`class` in file.getClasses()) {
-        val mainMethod = PsiMethodUtil.findMainMethod(`class`)
-        if (mainMethod != null) {
-            return "fun main(args: Array<String>) = ${`class`.getName()}.${mainMethod.getName()}(args)"
-        }
-    }
-    return ""
-}
-
-fun PsiMethod.isMainMethod(): Boolean = PsiMethodUtil.isMainMethod(this)

j2k/src/org/jetbrains/jet/j2k/Utils.kt

@@ -22,6 +22,7 @@ import com.intellij.psi.util.PsiUtil
 import com.intellij.psi.search.LocalSearchScope
 import com.intellij.psi.search.searches.ReferencesSearch
 import org.jetbrains.jet.j2k.ast.*
+import com.intellij.psi.util.PsiMethodUtil
 
 fun quoteKeywords(packageName: String): String = packageName.split("\\.").map { Identifier.toKotlin(it) }.joinToString(".")
 
@@ -133,3 +134,5 @@ fun PsiModifierListOwner.accessModifier(): String = when {
     hasModifierProperty(PsiModifier.PROTECTED) -> PsiModifier.PROTECTED
     else -> PsiModifier.PACKAGE_LOCAL
 }
+
+fun PsiMethod.isMainMethod(): Boolean = PsiMethodUtil.isMainMethod(this)

j2k/src/org/jetbrains/jet/j2k/ast/File.kt

@@ -25,12 +25,11 @@ class PackageStatement(val packageName: String) : Element() {
     }
 }
 
-class File(
-        val elements: List<Element>,
-        val mainFunction: String
-) : Element() {
-
+class File(val elements: List<Element>, val mainFunction: String?) : Element() {
     override fun generateCode(builder: CodeBuilder) {
-        builder.append(elements, "\n").append(mainFunction)
+        builder.append(elements, "\n")
+        if (mainFunction != null) {
+            builder.append(mainFunction)
+        }
     }
 }