Re: General rule for constructors
softwarepearls_com wrote:
I'm a big fan of JB and his Effective Java.. but look at the JDK, and
work out the ratio of public constructors to factory methods. Public
constructors are in an overwhelming majority.. so clearly most people
are perfectly happy with constructors which, yes, hardcode the
implementation type in your logic. Even Bloch's Collections API uses
mostly the constructors approach.
It is only a small part of classes where one will want to be
able to replace the implementation.
Nobody wants to use a factory class for everything. Think Spring - you
want to dynamically load the critical classes not every class.
Last but not least, I would argue strongly that software needs to be
thought of as fluid. With modern refactoring tools, we can quickly
make the kinds of changes to whole codebases which just a few years
ago would have been major headaches.
I disagree.
Changing lots of code to use a specific implementation is a
bad practice even if it is somewhat automated.
Noone will prefer:
Connection con = new MySqlConnection(constr);
over:
Connection con = DriverManager.getConnection(conurl);
just because you have a fancy tool that can change MySqlConnection
to OracleConnection in the entire application.
Arne