Converter from Java: optimization to not instantiate visitor objects each time

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

@@ -42,6 +42,9 @@ public class Converter private(val project: Project, val settings: ConverterSett
     val typeConverter: TypeConverter get() = state.typeConverter
     val methodReturnType: PsiType? get() = state.methodReturnType
 
+    private val expressionVisitor = state.expressionVisitorFactory(this)
+    private val statementVisitor = state.statementVisitorFactory(this)
+
     class object {
         public fun create(project: Project, settings: ConverterSettings, conversionScope: ConversionScope): Converter
                 = Converter(project, settings, conversionScope, State(TypeConverter(settings, conversionScope), null, { ExpressionVisitor(it) }, { StatementVisitor(it) }))
@@ -488,7 +491,7 @@ public class Converter private(val project: Project, val settings: ConverterSett
     public fun convertStatement(statement: PsiStatement?): Statement {
         if (statement == null) return Statement.Empty
 
-        val statementVisitor = state.statementVisitorFactory(this)
+        statementVisitor.reset()
         statement.accept(statementVisitor)
         return statementVisitor.result
     }
@@ -499,7 +502,7 @@ public class Converter private(val project: Project, val settings: ConverterSett
     public fun convertExpression(expression: PsiExpression?): Expression {
         if (expression == null) return Expression.Empty
 
-        val expressionVisitor = state.expressionVisitorFactory(this)
+        expressionVisitor.reset()
         expression.accept(expressionVisitor)
         return expressionVisitor.result
     }

j2k/src/org/jetbrains/jet/j2k/visitors/ExpressionVisitor.kt

@@ -42,6 +42,10 @@ class ExpressionVisitor(private val converter: Converter,
     public var result: Expression = Expression.Empty
         protected set
 
+    public fun reset() {
+        result = Expression.Empty
+    }
+
     override fun visitArrayAccessExpression(expression: PsiArrayAccessExpression) {
         val assignment = PsiTreeUtil.getParentOfType(expression, javaClass<PsiAssignmentExpression>())
         val lvalue = assignment != null && expression == assignment.getLExpression();

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

@@ -29,6 +29,10 @@ open class StatementVisitor(public val converter: Converter) : JavaElementVisito
     public var result: Statement = Statement.Empty
         protected set
 
+    public fun reset() {
+        result = Statement.Empty
+    }
+
     override fun visitAssertStatement(statement: PsiAssertStatement) {
         val descriptionExpr = statement.getAssertDescription()
         val condition = converter.convertExpression(statement.getAssertCondition())