Re: correct usage for @SuppressWarnings("unchecked")

From:
Thufir <hawat.thufir@gmail.com>
Newsgroups:
comp.lang.java.help
Date:
Thu, 22 Apr 2010 05:36:42 GMT
Message-ID:
<KfRzn.156608$y13.4916@newsfe12.iad>
On Mon, 19 Apr 2010 13:34:24 -0500, Chris Riesbeck wrote:

Thufir wrote:

    @SuppressWarnings("unchecked")
    private List<Beatle> populateBeatles() {
        ...
        ArrayList<ArrayList<String>> table = database.getTable();


Is getTable() defined to return ArrayList<ArrayList<String>>?


for some reason it was, rather than:

List<List<String>>

I was working from:

public ArrayList<ArrayList<Object>> Results2Array(ResultSet rs)
                throws SQLException {
        ResultSetMetaData metaData = rs.getMetaData();
        int columns = metaData.getColumnCount();

        ArrayList<ArrayList<Object>> al = new ArrayList<ArrayList<Object>>
();

        while (rs.next()) {
                ArrayList<Object> record = new ArrayList<Object>();

                for (int i = 1; i <= columns; i++) {
                        Object value = rs.getObject(i);
                        record.add(value);
                }
                al.add(record);
        }
        return al;

}

http://stackoverflow.com/questions/1685038/convert-java-resultset-to-
string-array

(don't ask me why this person capitalizes the method name, pls.)

and, while I don't have my code at the moment, I wasn't able to get it to
return what I wanted, which was a List of List of String. So, I went to
a List of Foo (in my case, Beatle). However, that didn't seem
particularly "generic", as it only applies to Foo's (or Beatles). Hence,
the question.

Even a List<List<String>> is returned, there's going to have to be an
unchecked cast, it seems -- unless each String is sent to a Foo
constructor or factory of some variety. Perhaps that would be more
extensible?

I suppose Foo could extend List<String>, but that seems to lock down the
design of Foo a bit.

-Thufir

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