first implementation for switch conversion added

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

@@ -0,0 +1,29 @@
+package org.jetbrains.jet.j2k.ast;
+
+import org.jetbrains.annotations.NotNull;
+
+import java.util.LinkedList;
+import java.util.List;
+
+/**
+ * @author ignatov
+ */
+public class CaseContainer extends Statement {
+  private Statement myCaseStatement;
+  private Block myBlock;
+
+  public CaseContainer(final Statement caseStatement, final List<Statement> statements) {
+    myCaseStatement = caseStatement;
+    List<Statement> newStatements = new LinkedList<Statement>();
+    for (Statement s : statements)
+      if (s.getKind() != Kind.BREAK && s.getKind() != Kind.CONTINUE )
+        newStatements.add(s);
+    myBlock = new Block(newStatements);
+  }
+
+  @NotNull
+  @Override
+  public String toKotlin() {
+    return myCaseStatement.toKotlin() + SPACE + "=>" + SPACE + myBlock.toKotlin();
+  }
+}

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

@@ -0,0 +1,14 @@
+package org.jetbrains.jet.j2k.ast;
+
+import org.jetbrains.annotations.NotNull;
+
+/**
+ * @author ignatov
+ */
+public class DefaultSwitchLabelStatement extends Statement {
+  @NotNull
+  @Override
+  public String toKotlin() {
+    return "else";
+  }
+}

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

@@ -0,0 +1,27 @@
+package org.jetbrains.jet.j2k.ast;
+
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.jet.j2k.util.AstUtil;
+
+import java.util.List;
+
+/**
+ * @author ignatov
+ */
+public class SwitchContainer extends Statement {
+  private Expression myExpression;
+  private List<CaseContainer> myCaseContainers;
+
+  public SwitchContainer(final Expression expression, final List<CaseContainer> caseContainers) {
+    myExpression = expression;
+    myCaseContainers = caseContainers;
+  }
+
+  @NotNull
+  @Override
+  public String toKotlin() {
+    return "when" + SPACE + "(" + myExpression.toKotlin() + ")" + SPACE + "{" + N +
+      AstUtil.joinNodes(myCaseContainers, N) + N +
+      "}";
+  }
+}

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

@@ -0,0 +1,20 @@
+package org.jetbrains.jet.j2k.ast;
+
+import org.jetbrains.annotations.NotNull;
+
+/**
+ * @author ignatov
+ */
+public class SwitchLabelStatement extends Statement {
+  private Expression myExpression;
+
+  public SwitchLabelStatement(final Expression expression) {
+    myExpression = expression;
+  }
+
+  @NotNull
+  @Override
+  public String toKotlin() {
+    return myExpression.toKotlin();
+  }
+}

src/org/jetbrains/jet/j2k/visitors/StatementVisitor.java

@@ -5,9 +5,11 @@ import com.intellij.psi.search.searches.ReferencesSearch;
 import com.intellij.psi.tree.IElementType;
 import com.intellij.psi.util.PsiUtil;
 import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
 import org.jetbrains.jet.j2k.ast.*;
 
 import java.util.Arrays;
+import java.util.Collections;
 import java.util.LinkedList;
 import java.util.List;
 
@@ -190,11 +192,57 @@ public class StatementVisitor extends ElementVisitor {
   @Override
   public void visitSwitchLabelStatement(PsiSwitchLabelStatement statement) {
     super.visitSwitchLabelStatement(statement);
+    myResult = statement.isDefaultCase() ?
+      new DefaultSwitchLabelStatement() :
+      new SwitchLabelStatement(expressionToExpression(statement.getCaseValue()));
   }
 
   @Override
   public void visitSwitchStatement(PsiSwitchStatement statement) {
     super.visitSwitchStatement(statement);
+    List<CaseContainer> caseContainers = listToCases(splitToCases(statement.getBody()));
+    myResult = new SwitchContainer(
+      expressionToExpression(statement.getExpression()),
+      caseContainers
+    );
+  }
+
+  @NotNull
+  private static List<CaseContainer> listToCases(@NotNull final List<List<PsiStatement>> cases) {
+    List<CaseContainer> result = new LinkedList<CaseContainer>();
+    for (List<PsiStatement> ls : cases) {
+      assert ls.size() > 0;
+      PsiStatement label = ls.get(0);
+      assert label instanceof PsiSwitchLabelStatement;
+      result.add(new CaseContainer(statementToStatement(label),
+        ls.size() > 1 ?
+          statementsToStatementList(ls.subList(1, ls.size()).toArray(new PsiStatement[ls.size() - 1])) :
+          Collections.<Statement>emptyList()
+      ));
+    }
+    return result;
+  }
+
+  @NotNull
+  private static List<List<PsiStatement>> splitToCases(@Nullable final PsiCodeBlock body) {
+    List<List<PsiStatement>> cases = new LinkedList<List<PsiStatement>>();
+    List<PsiStatement> currentCaseStatements = new LinkedList<PsiStatement>();
+    boolean isFirst = true;
+    if (body != null) {
+      for (PsiStatement s : body.getStatements()) {
+        if (s instanceof PsiSwitchLabelStatement) {
+          if (isFirst)
+            isFirst = false;
+          else {
+            cases.add(currentCaseStatements);
+            currentCaseStatements = new LinkedList<PsiStatement>();
+          }
+        }
+        currentCaseStatements.add(s);
+      }
+      cases.add(currentCaseStatements);
+    }
+    return cases;
   }
 
   @Override

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

@@ -0,0 +1,25 @@
+package switch_demo;
+
+public class SwitchDemo {
+    public static void main(String[] args) {
+
+        int month = 8;
+        String monthString;
+        switch (month) {
+            case 1:  monthString = "January";       break;
+            case 2:  monthString = "February";      break;
+            case 3:  monthString = "March";         break;
+            case 4:  monthString = "April";         break;
+            case 5:  monthString = "May";           break;
+            case 6:  monthString = "June";          break;
+            case 7:  monthString = "July";          break;
+            case 8:  monthString = "August";        break;
+            case 9:  monthString = "September";     break;
+            case 10: monthString = "October";       break;
+            case 11: monthString = "November";      break;
+            case 12: monthString = "December";      break;
+            default: monthString = "Invalid month"; break;
+        }
+        System.out.println(monthString);
+    }
+}

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

@@ -0,0 +1,51 @@
+namespace switch_demo
+public open class SwitchDemo() {
+class object {
+open public fun main(args : Array<String?>?) : Unit {
+var month : Int = 8
+var monthString : String?
+when (month) {
+1 => {
+monthString = "January"
+}
+2 => {
+monthString = "February"
+}
+3 => {
+monthString = "March"
+}
+4 => {
+monthString = "April"
+}
+5 => {
+monthString = "May"
+}
+6 => {
+monthString = "June"
+}
+7 => {
+monthString = "July"
+}
+8 => {
+monthString = "August"
+}
+9 => {
+monthString = "September"
+}
+10 => {
+monthString = "October"
+}
+11 => {
+monthString = "November"
+}
+12 => {
+monthString = "December"
+}
+else => {
+monthString = "Invalid month"
+}
+}
+System.out?.println(monthString)
+}
+}
+}