KT-871 Add main function to generated code

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

@@ -14,6 +14,7 @@ import org.jetbrains.jet.j2k.visitors.*;
 
 import java.util.*;
 
+import static org.jetbrains.jet.j2k.ConverterUtil.createMainFunction;
 import static org.jetbrains.jet.j2k.visitors.TypeVisitor.*;
 
 /**
@@ -58,17 +59,21 @@ public class Converter {
 
   @NotNull
   public static File fileToFile(@NotNull PsiJavaFile javaFile) {
-    final PsiImportList importList = javaFile.getImportList();
-    List<Import> imports = importList == null ? Collections.<Import>emptyList() : importsToImportList(importList.getAllImportStatements());
-    return new File(quoteKeywords(javaFile.getPackageName()), imports, classesToClassList(javaFile.getClasses()));
+    return fileToFile(javaFile, Collections.<String>emptyList());
   }
 
   @NotNull
   public static File fileToFileWithCompatibilityImport(@NotNull PsiJavaFile javaFile) {
+    return fileToFile(javaFile, Collections.singletonList("std.compatibility.*"));
+  }
+
+  @NotNull
+  private static File fileToFile(PsiJavaFile javaFile, List<String> additionalImports) {
     final PsiImportList importList = javaFile.getImportList();
     List<Import> imports = importList == null ? Collections.<Import>emptyList() : importsToImportList(importList.getAllImportStatements());
-    imports.add(new Import("std.compatibility.*"));
-    return new File(quoteKeywords(javaFile.getPackageName()), imports, classesToClassList(javaFile.getClasses()));
+    for (String i : additionalImports)
+      imports.add(new Import(i));
+    return new File(quoteKeywords(javaFile.getPackageName()), imports, classesToClassList(javaFile.getClasses()), createMainFunction(javaFile));
   }
 
   @NotNull

src/org/jetbrains/jet/j2k/ConverterUtil.java

@@ -0,0 +1,71 @@
+package org.jetbrains.jet.j2k;
+
+import com.intellij.openapi.util.Pair;
+import com.intellij.psi.*;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import java.text.MessageFormat;
+import java.util.LinkedList;
+import java.util.List;
+
+/**
+ * @author ignatov
+ */
+public class ConverterUtil {
+  private ConverterUtil() {
+  }
+
+  @NotNull
+  public static String createMainFunction(@NotNull PsiFile file) {
+    List<Pair<String, PsiMethod>> classNamesWithMains = new LinkedList<Pair<String, PsiMethod>>();
+
+    for (PsiClass c : ((PsiJavaFile) file).getClasses()) {
+      PsiMethod main = findMainMethod(c);
+      if (main != null) {
+        classNamesWithMains.add(new Pair<String, PsiMethod>(c.getName(), main));
+      }
+    }
+    if (classNamesWithMains.size() > 0) {
+      String className = classNamesWithMains.get(0).getFirst();
+      return MessageFormat.format("fun main(args : Array<String?>?) = {0}.main(args)", className);
+    }
+    return "";
+  }
+
+  @Nullable
+  private static PsiMethod findMainMethod(@NotNull PsiClass aClass) {
+    if (isMainClass(aClass)) {
+      final PsiMethod[] mainMethods = aClass.findMethodsByName("main", false);
+      return findMainMethod(mainMethods);
+    }
+    return null;
+  }
+
+  @Nullable
+  private static PsiMethod findMainMethod(@NotNull PsiMethod[] mainMethods) {
+    for (PsiMethod mainMethod : mainMethods) {
+      if (isMainMethod(mainMethod)) return mainMethod;
+    }
+    return null;
+  }
+
+  private static boolean isMainClass(@NotNull PsiClass psiClass) {
+    if (psiClass instanceof PsiAnonymousClass) return false;
+    if (psiClass.isInterface()) return false;
+    return psiClass.getContainingClass() == null || psiClass.hasModifierProperty(PsiModifier.STATIC);
+  }
+
+  public static boolean isMainMethod(@Nullable PsiMethod method) {
+    if (method == null || method.getContainingClass() == null) return false;
+    if (PsiType.VOID != method.getReturnType()) return false;
+    if (!method.hasModifierProperty(PsiModifier.STATIC)) return false;
+    if (!method.hasModifierProperty(PsiModifier.PUBLIC)) return false;
+    final PsiParameter[] parameters = method.getParameterList().getParameters();
+    if (parameters.length != 1) return false;
+    final PsiType type = parameters[0].getType();
+    if (!(type instanceof PsiArrayType)) return false;
+    final PsiType componentType = ((PsiArrayType) type).getComponentType();
+    return componentType.equalsToText("java.lang.String");
+  }
+}

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

@@ -12,17 +12,19 @@ public class File extends Node {
   private final String myPackageName;
   private final List<Import> myImports;
   private final List<Class> myClasses;
+  private final String myMainFunction;
 
-  public File(String packageName, List<Import> imports, List<Class> classes) {
+  public File(String packageName, List<Import> imports, List<Class> classes, String mainFunction) {
     myPackageName = packageName;
     myImports = imports;
     myClasses = classes;
+    myMainFunction = mainFunction;
   }
 
   @NotNull
   @Override
   public String toKotlin() {
-    final String common = AstUtil.joinNodes(myImports, N) + N2 + AstUtil.joinNodes(myClasses, N) + N;
+    final String common = AstUtil.joinNodes(myImports, N) + N2 + AstUtil.joinNodes(myClasses, N) + N + myMainFunction;
     if (myPackageName.isEmpty())
       return common;
     return "package" + SPACE + myPackageName + N +

testData/ast/issues/file/kt-871.jav

@@ -0,0 +1,7 @@
+package demo;
+
+class Program {
+  public static void main(String[] args) {
+    System.out.println("Halo!");
+  }
+}

testData/ast/issues/file/kt-871.kt

@@ -0,0 +1,9 @@
+package demo
+open class Program() {
+class object {
+open public fun main(args : Array<String?>?) : Unit {
+System.out?.println("Halo!")
+}
+}
+}
+fun main(args : Array<String?>?) = Program.main(args)

testData/ast/switch/file/comlicatedFallDown.kt

@@ -84,4 +84,5 @@ open public fun main(args : Array<String?>?) : Unit {
 for (i in 1..12) test(i)
 }
 }
-}
+}
+fun main(args : Array<String?>?) = SwitchDemo.main(args)

testData/ast/switch/file/fallDown.kt

@@ -15,4 +15,5 @@ monthString = "Invalid month"
 System.out?.println(monthString)
 }
 }
-}
+}
+fun main(args : Array<String?>?) = SwitchDemo.main(args)

testData/ast/switch/file/kt-539.kt

@@ -48,4 +48,5 @@ monthString = "Invalid month"
 System.out?.println(monthString)
 }
 }
-}
+}
+fun main(args : Array<String?>?) = SwitchDemo.main(args)