Re: They ALL suck! [Was: On Java and C++]
"Jerry Coffin" <jcoffin@taeus.com> wrote in message
news:MPG.1ec52730bfca6d7989790@news.sunsite.dk...
In article <%qJ6g.6812$Fg4.2320@clgrps12>,
owong@castortech.com says...
[ ... ]
<Java>
class NodeToken {
public int beginColumn, endColumn;
}
class Token {
public int startColumn, endColumn;
}
</Java>
I'm trying to merge these two classes together. If they had used accessor
methods, I could have a methods setStartColumn(int) and
setBeginColumn(int)
affect the same private field, so that the changes would be seen by
either
interfaces.
This seems to be almost entirely orthogonal to the user
of accessor functions.
Unfortunately, they didn't use accessor methods, and instead
used public fields, so now I've got to start by adding the accessor
methods
to each seperate classes, mark the fields as deprecated, check for all
access to those fields, change those to invoke the accessor methods, then
merge the class, then simplify the API.
Well, in C++, you could pretty easily do something like
this:
class Mergedtoken {
public:
int beginColumn, endColumn;
int &startColumn;
MergedToken() : startColumn(beginColumn) {}
};
This produces essentially the same effect as you'd be
hoping to get via the accessor functions -- but without
the ugly syntax.
I'll admit I've never had to try this with Java, so I'm
not _sure_ its references will support this like C++
does, but offhand I can't think of any particularly good
reason they shouldn't.
Java doesn't have anything like what C++ calls "references". You can't
alias a variable in Java.
Also, to make things more interesting, the classes I'm trying to merge
actually keep track of something called "SpecialTokens". In one case,
they're implemented as a doubly-linked list, in another as a vector. The
Java code looks something like:
<Java>
class NodeToken {
public int beginColumn, endColumn;
public Vector<NodeToken> specials;
}
class Token {
public int startColumn, endColumn;
public Token nextSpecial, prevSpecial;
}
</Java>
So the problem again comes with two different representations for the
same ideas, and I can't simply take both fields, as their contents need to
be "synchronized" somehow.
- Oliver