private static PsiClassType createDefaultConsumerType(Project project, PsiParameter parameter) {
   final JavaPsiFacade psiFacade = JavaPsiFacade.getInstance(project);
   final PsiClass consumerClass =
       psiFacade.findClass("java.util.function.Consumer", GlobalSearchScope.allScope(project));
   return consumerClass != null
       ? psiFacade.getElementFactory().createType(consumerClass, parameter.getType())
       : null;
 }
 private static String createMapperFunctionalExpressionText(
     PsiParameter parameter, PsiExpression expression) {
   String iteration = "";
   if (!isIdentityMapping(parameter, expression)) {
     iteration += ".map(";
     iteration +=
         compoundLambdaOrMethodReference(
             parameter,
             expression,
             "java.util.function.Function",
             new PsiType[] {parameter.getType(), expression.getType()});
     iteration += ")";
   }
   return iteration;
 }
 private static String createFiltersChainText(
     PsiStatement body, PsiParameter parameter, PsiIfStatement ifStatement) {
   final List<String> filters = new ArrayList<String>();
   while (ifStatement != null && PsiTreeUtil.isAncestor(body, ifStatement, false)) {
     final PsiExpression condition = ifStatement.getCondition();
     if (condition != null) {
       filters.add(
           ".filter("
               + compoundLambdaOrMethodReference(
                   parameter,
                   condition,
                   "java.util.function.Predicate",
                   new PsiType[] {parameter.getType()})
               + ")");
     }
     ifStatement = PsiTreeUtil.getParentOfType(ifStatement, PsiIfStatement.class);
   }
   Collections.reverse(filters);
   return StringUtil.join(filters, "");
 }