RE: java question
- From: "Sina Bahram" <sbahram@xxxxxxxxx>
- To: <programmingblind@xxxxxxxxxxxxx>
- Date: Sun, 21 Aug 2011 12:06:17 -0400
Give class an accessibility identifier of public, just for good coding
practices.
Return false in your catch because you have failed to make the connection, and
currently your code has a bug where it will fail to
make the connection, then promptly output a message and return true, as if it
succeeded.
Regarding your imports, it's extremely bad practice to import anything.*, so
instead explicitly import the things you need. Yes,
this can sometimes create a long list, but for those cases, usually one is in
an IDE. Even if one isn't, it's better practice, both
for namespace pollution avoidance, as well as just explicit notes to the
reader, to not do .*.
You are naming your methods with capital letters. This is best avoided for best
practice. Per the defacto community style guidelines
of java: Classes are initial caps camel case, packages are all lower case,
methods are initial lower case camel case, variables are
all lower. If you go back and change this, don't forget to correct your string
in your catch.
Java has two kinds of exceptions: checked and unchecked. You only have to catch
checked exceptions. IOException is a checked
exception, so yes you have to either catch it, or throw it up the chain. You
can throw it up the chain by simply saying throws
IOException after the method declaration but before the opening brace
Like this:
Public Boolean listen(int port) throws IOException {
I would not recommend doing that, and instead would do what you are doing,
which is handling that particular exception right then
and there in listen, so no need to pass it up the chain.
This brings us to your final question/problem, which you didn't explicitly ask,
but some might find confusing.
You are in fact catching IOException, so why the heck is your java compiler
complaining that Listen isn't passing that IOException
up the chain, and that's because of one of two things.
Either A. you modified this program inadvertently in terms of ignoring newlines
or not pasting the whole code in, because the error
is really on line 15, not 19.
Or B. your java compiler is super screwy.
It's complaining that .close's IOException is not getting caught in finalize,
not the one thrown in listen, which you do catch
successfully, so address it in finalize, and you're done.
Oh, and I wouldn't split that string across two lines, if I were you. some
compilers are quite iffy about newline splitting of
strings like that.
Take care,
Sina
-----Original Message-----
From: programmingblind-bounce@xxxxxxxxxxxxx
[mailto:programmingblind-bounce@xxxxxxxxxxxxx] On Behalf Of Littlefield, Tyler
Sent: Sunday, August 21, 2011 11:11 AM
To: programmingblind@xxxxxxxxxxxxx
Subject: java question
Hello:
I have the following code. When I try to compile, i get a really odd error.
import java.net.*;
import java.io.*;
class Server
{
private ServerSocket _listener;
public Server()
{
_listener = null;
}
protected void finalize()
{
if (_listener != null)
{
_listener.close();
}
}
public boolean Listen(int port)
{
if (port < 0 || port > 65535)
{
return false;
}
try
{
_listener = new ServerSocket(port);
} catch(IOException e) {
System.out.println("IOException caught in Server.Listen:
"+e.getMessage());
}
return true;
}
}
First, I"m curious if I have done this right, or if there's a better way
to set this up. Second, here's the error I get:
Server.java:19: unreported exception java.io.IOException; must be caught
or declared to be thrown
so this means that I have to catch -all- exceptions? sort of makes some
sense.
--
Take care,
Ty
my website:
http://tds-solutions.net
my blog:
http://tds-solutions.net/blog
skype: st8amnd127
My programs don't have bugs; they're randomly added features!
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