Re: How to implement jcombobox with name value pair from database?

From:

Lew <lewbloch@gmail.com>

Newsgroups:

comp.lang.java.help

Date:

Thu, 29 Nov 2012 16:08:13 -0800 (PST)

Message-ID:

<77e23a07-f99f-4c04-b4f7-88f0e4b099e7@googlegroups.com>

Knute Johnson wrote:

Lew wrote:

'Employee' needs to override 'equals()' to be consistent with 'compareTo()'.

From what I can read in the docs Employee only needs to be "consistent
with equals" if it is to be used in a Set or as a key in SortedMap. I'm

This is fine if 'Employee' never leaks outside its current use.

not using Sets. Employees are values in the HashMap and so neither

So far.

compareTo() nor equals() would be called if the map were sorted.
Collections.sort() uses the compareTo() to accomplish the sort and
doesn't need equals() as far as I can tell.

So maybe it would have been better to create a Comparator instead of

Yes. The problem with internal inconsistency in the class is that it is fragile
the instant you expand the type's use. With an external 'Comparator' that does not
happen.

making Employee Comparable. Employee would still need an equals()
method if it were to be used in a Set.

Or any other context where you don't want identity equality.

There was another recent question in this forum that looks like someone fell afoul
of the 'equals()'/'==' dichotomy.

--
Lew