private static Optional convertIsInExpression()

in flink-connector-kudu/src/main/java/org/apache/flink/connector/kudu/table/utils/KuduTableUtils.java [232:272]
38 lines of code
10 McCabe index (conditional complexity)

    private static Optional<KuduFilterInfo> convertIsInExpression(List<Expression> children) {
        // IN operation will be: or(equals(field, value1), equals(field, value2), ...) in blink
        // For FilterType IS_IN, all internal CallExpression's function need to be equals and
        // fields need to be same
        List<Object> values = new ArrayList<>(children.size());
        String columnName = "";
        for (int i = 0; i < children.size(); i++) {
            if (children.get(i) instanceof CallExpression) {
                CallExpression callExpression = (CallExpression) children.get(i);
                FunctionDefinition functionDefinition = callExpression.getFunctionDefinition();
                List<Expression> subChildren = callExpression.getChildren();
                FieldReferenceExpression fieldReferenceExpression;
                ValueLiteralExpression valueLiteralExpression;
                if (functionDefinition.equals(BuiltInFunctionDefinitions.EQUALS)
                        && subChildren.size() == 2
                        && isFieldReferenceExpression(subChildren.get(0))
                        && isValueLiteralExpression(subChildren.get(1))) {
                    fieldReferenceExpression = (FieldReferenceExpression) subChildren.get(0);
                    valueLiteralExpression = (ValueLiteralExpression) subChildren.get(1);
                    String fieldName = fieldReferenceExpression.getName();
                    if (i != 0 && !columnName.equals(fieldName)) {
                        return Optional.empty();
                    } else {
                        columnName = fieldName;
                    }
                    Object value =
                            extractValueLiteral(fieldReferenceExpression, valueLiteralExpression);
                    if (value == null) {
                        return Optional.empty();
                    }
                    values.add(i, value);
                } else {
                    return Optional.empty();
                }
            } else {
                return Optional.empty();
            }
        }
        KuduFilterInfo.Builder builder = KuduFilterInfo.Builder.create(columnName);
        return Optional.of(builder.isIn(values).build());
    }