CODEWITHSUNDEEP
javaclassrefactoring
Alex
Alex

Reputation: 51

How to abstract out same method with different return types in multiple classes

I apologize if I didn't ask the question correctly in advance.

I have about 15 related classes using the same code but different return types. How would I abstract that out to avoid code duplication in all these classes? 

    public ChargeResponse findByTransactionId(final String txId) {
        ChargeResponse chargeResponse = null;
        try (Connection connection = dataSource.getConnection()) {
            PreparedStatement preparedStatement = connection.prepareStatement(VIEW_SERVICE_TRANSACTION_CHARGE_QUERY);
            preparedStatement.setString(1, txId);
            final ResultSet resultSet = preparedStatement.executeQuery();
            chargeResponse = parseQueryResults(resultSet);

        } catch (SQLException e) {
            e.printStackTrace();
        }
        return chargeResponse;
    }

    public EventsResponse findByTransactionId(final String txId) {
        EventsResponse eventsResponse = null;
        try (Connection connection = dataSource.getConnection()) {
            PreparedStatement preparedStatement = connection.prepareStatement(VIEW_SERVICE_TRANSACTION_EVENTS_QUERY);
            preparedStatement.setString(1, txId);
            final ResultSet resultSet = preparedStatement.executeQuery();
            eventsResponse = parseQueryResults(resultSet);
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return eventsResponse;
    }

and so on..

Upvotes: 0

Views: 68

Answers (2)

Volker Stolz
Volker Stolz

Reputation: 7402

If the XXXResponse types share a common super-type (class or interface), you can even solve it without generics, similar to @dubilyer's solution. (And for the love of future generations of programmers, do something about that silly catch-block ;-)

Upvotes: 0

Eduard Dubilyer
Eduard Dubilyer

Reputation: 1013

public <T> T findByTransactionId(final String txId) {
    T chargeResponse;
    try (Connection connection = dataSource.getConnection()) {
        PreparedStatement preparedStatement = connection.prepareStatement(VIEW_SERVICE_TRANSACTION_CHARGE_QUERY);
        preparedStatement.setString(1, txId);
        final ResultSet resultSet = preparedStatement.executeQuery();
        chargeResponse = parseQueryResults(resultSet);

    } catch (SQLException e) {
        e.printStackTrace();
    }
    return chargeResponse;
}

Do the same with parseQueryResults. Then move those methods to parent class.

Upvotes: 2

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