RE: (Java) Dealing With a Rogue Null Pointer Exception at Runtime
- From: "Sina Bahram" <sbahram@xxxxxxxxx>
- To: <programmingblind@xxxxxxxxxxxxx>
- Date: Wed, 12 Mar 2008 16:42:01 -0400
Really quick: The two standard rules of thumb are ... capitolize every word
in all classes and interfaces, and capitolize only every word past the first
one in all object names, method names, and so on.
I'll look for a java style guideline, but I'm sure this is easily
googleable.
Take care,
Sina
-----Original Message-----
From: programmingblind-bounce@xxxxxxxxxxxxx
[mailto:programmingblind-bounce@xxxxxxxxxxxxx] On Behalf Of Jared Wright
Sent: Wednesday, March 12, 2008 3:54 PM
To: programmingblind@xxxxxxxxxxxxx
Subject: Re: (Java) Dealing With a Rogue Null Pointer Exception at Runtime
Hi Sina, Your point is taken. I confess it's not the biggest thing I'm
worrying about right now, but if you could point me towards any primers on
elements of style for OOP or have any individual tips you feel would be
appropriate, I'll certainly take a look at them and try and modify my coding
practices accordingly. I am, as of now, exclusively a speech user when
programming, and I bet there's plenty of things like this I do "incorrectly"
as a byproduct of the speech medium.
Best,
JW
Sina Bahram wrote:
> He does ... they are of type room. Why room is not capitilized , since it
is
> a class, I think is a further major big deal ; however.
>
> Take care,
> Sina
>
> -----Original Message-----
> From: programmingblind-bounce@xxxxxxxxxxxxx
> [mailto:programmingblind-bounce@xxxxxxxxxxxxx] On Behalf Of Michael Malver
> Sent: Tuesday, March 11, 2008 6:19 PM
> To: programmingblind@xxxxxxxxxxxxx
> Subject: RE: (Java) Dealing With a Rogue Null Pointer Exception at Runtime
>
> Look up the proper declaration for arrays. I think you have to explicitly
> state the object type that is going to go in each element. I haven't had
to
> declare an array in quite some time, so I may be wrong about this.
>
> -----Original Message-----
> From: programmingblind-bounce@xxxxxxxxxxxxx
> [mailto:programmingblind-bounce@xxxxxxxxxxxxx] On Behalf Of Jared Wright
> Sent: Tuesday, March 11, 2008 3:20 AM
> To: programmingblind@xxxxxxxxxxxxx
> Subject: (Java) Dealing With a Rogue Null Pointer Exception at Runtime
>
> Hi all, The following constructor keeps giving me a null pointer exception
> if called at runtime. I guess the easiest place to start is with a code
> exerpt. The context is that this class, cave, is made up of an array of
> rooms. Each room has a number, three adjacent rooms, a description, etc.
It
> also tracks what the current room is, per the user's direction in the
larger
> scope of the program. The constructor gets its info from a text file, and
> the amount of rooms in the cave could vary based on this text file's
> contents. I think it is this flexible length of the array of rooms for
each
> cave object that's the trouble spot, but beyond that I am admittedly
stuck.
> Note that TextReader serves much as the Scanner class would, this one just
> has a couple of extra quirks that I like, thus I'm using it instead.
>
> public class cave {
> private int current; private int numrooms; // Variables for the current
room
> the user is in and the number of rooms in the cave.
> private room myroom[]; // The array of room objects for the cave.
> public cave(String filename) throws IOException {
> current = 1;
> TextReader file = new TextReader(new FileInputStream(filename));
//
> numrooms=file.readInt(); // Reads in the first integer of the
file,
> which is the number of rooms the cave must hold.
> myroom = new room[numrooms-1]; // Attempt to populate the myroom
> array with the appropriate number of rooms. This is the line the exception
> actually references, along with the line that called the constructor (from
> another file).
> }
>
> The constructor actually goes on to fill the room objects with more
specific
> data (room number, description, etc.). Is there a better way to go about
> this? Will I have to somehow explicitly define the array length, or is
there
> a way that the constructor can make the array the appropriate size based
on
> the data in the file? Might I be looking in the wrong place for the source
> of this error?
>
> More code available on request. I didn't want the snipet to get too big.
> I hope I've made things clear, and thanks for any guidance, everyone.
>
> Jared
>
>
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