public PsiElementVisitor buildVisitor()

in comparing_string_references_inspection/src/main/java/org/intellij/sdk/codeInspection/ComparingStringReferencesInspection.java [34:80]

32 lines of code
10 McCabe index (conditional complexity)


  public PsiElementVisitor buildVisitor(@NotNull final ProblemsHolder holder, boolean isOnTheFly) {
    return new JavaElementVisitor() {

      /**
       * Evaluate binary PSI expressions to see if they contain relational operators '==' and '!=',
       * AND they are of String type.
       * The evaluation ignores expressions comparing an object to null.
       * IF these criteria are met, register the problem in the ProblemsHolder.
       *
       * @param expression The binary expression to be evaluated.
       */
      @Override
      public void visitBinaryExpression(@NotNull PsiBinaryExpression expression) {
        super.visitBinaryExpression(expression);
        IElementType opSign = expression.getOperationTokenType();
        if (opSign == JavaTokenType.EQEQ || opSign == JavaTokenType.NE) {
          // The binary expression is the correct type for this inspection
          PsiExpression lOperand = expression.getLOperand();
          PsiExpression rOperand = expression.getROperand();
          if (rOperand == null || isNullLiteral(lOperand) || isNullLiteral(rOperand)) {
            return;
          }
          // Nothing is compared to null, now check the types being compared
          if (isStringType(lOperand) || isStringType(rOperand)) {
            // Identified an expression with potential problems, register problem with the quick fix object
            holder.registerProblem(expression,
                InspectionBundle.message("inspection.comparing.string.references.problem.descriptor"),
                myQuickFix);
          }
        }
      }

      private boolean isStringType(PsiExpression operand) {
        PsiClass psiClass = PsiTypesUtil.getPsiClass(operand.getType());
        if (psiClass == null) {
          return false;
        }

        return "java.lang.String".equals(psiClass.getQualifiedName());
      }

      private static boolean isNullLiteral(PsiExpression expression) {
        return expression instanceof PsiLiteralExpression &&
            ((PsiLiteralExpression) expression).getValue() == null;
      }
    };
  }