> Dr. Hacker, 
> My question is, how do I change the src directory structure so it doesn't
> mirror the entire package structure?  I'm not sure how you changed that when
> you did the demo in class.
>
> -- Resourceful 

> Dr. Hacker,
> 
> I have 2 questions concerning the AccountInfo1 assignment:
> 1. A user could be both, for example Admin AND Faculty?
>     (Yes / No)

> 
> 2. In your assignment you mention:
>     "Clients of the AccountInfo class will want to use it to create, 
>       delete, query, and modify accounts."
>     
> If I wanna change the password of an account, would I do
> a) or b)?
>     
> a) 
> AccountInfo accountInfo = new AccountInfo();
> ...
> accountInfo.setPassword("account313", "newPassword");
> 
> b)
> AccountInfo accountInfo = new AccountInfo();
> ...
> Account account = accountInfo.getAccount("account313");
> account.setPassword("newPassword");
> 
> 
> I think b) is better because a) is kinda redundant. For a) you
> have to program the setPassword function in AccountInfo
> and Account.
> Do I have to take a) or b)?
> 
> -- I like composition

> Dr. Hacker, 
> What do you recommend for the accountinfo1 assignment, interface or
> abstract class?  I'm currently using an abstract class, but you seem to
> hint at using an interface.  So I was just wondering.
>
> -- To abstract, or not to abstract

http://www.javadigest.net/articlecache/article.php?sid=63

>> Dr. Hacker said the following in a previous email:
>> Have you read the instructions for installing Tomcat?
> 
> The problem is that I cannot find the instructions for installing Tomcat.
>
> -- Where in the world is Tomcat San Diego?

> Dr. Java,
> 
> I'm a student in 613 class and am confused with the forward e-mail. I'm
> not sure whether the following quoted message is applied to our Account1
> assignment.
> 
> I'm planning to use Applet. Should I change my mind to use Junit?
>
> -- Choosey GUI 

> Dr. Hacker,
> 
> One question to clarify: This package name is AcountInfo1, but the class
> name is AcountInfo?

> 
> 
> And this is how I implement Acounts:
> 
> AcountInfo is an abstract class. Administrator, Faculty and Student are
> another three classes that extends AcountInfo and implement the abstract
> methods. AcountInfo class has all common attributes and behavior of all
> acounts like name and passwd, the abstract method is about the acount type
> -- whether it is a faculty or student or administrator.
> 
> AcountInfo class has a static vector to store each instance of administrator,
> faculty or student object when it is first created. One manage acounts
> through this vector.
> 
> Is it satisfying your requirements? Thank you!
>
> -- Love those vectors

> Dr. Hacker,
> 
> I have little idea on how to deal with the following statement requirement
> in installing tomcat 3.2.4:
> 
>> Set the environment variable JAVA_HOME to point to the root directory of
>> your JDK hierarchy, then add the Java interpreter to your PATH
>> environment variable.
> 
> 
> I attempted to take care of that by doing the following in the command
> prompt:
> 
>> %set JAVA_HOME=C:\Program Files\JavaSoft\Jre\1.3
>
> -- Environmentally unfriendly

> Dr. Hacker,
>
> Can you give us some hint on how to use ant? I installed Tomcat and JUnit,
> both are working ok. I installed ant too but seems there's some problem.
>
> I downloaded two 414 projects. The intallation of them needs build by ant.
> I failed in this step.
>
> -- Ants not marching

You do NOT need to install JUnit or Ant for any of the 414 projects. Those packages come with the download. If you install Java and Tomcat correctly, and set JAVA_HOME and TOMCAT_HOME correctly, then after running setenv.bat, you should be able to type 'ant' (possibly with some target) to build the system.

> Dr. Hacker,
>
> Is windows 2000 required to use/run tomcat?  I have windows 98 and so far,
> tomcat isn't working.  Also, is there any 414 projects that I can look at
> without tomcat so that I can do the assignment by sunday?
>
> -- 20th century dude

Note the plural "URLs"---the above sentence means I need in the email TWO links, not a link to a page containing links. Those of you who resubmit by midnight tonight will be OK.

> Dr. Hacker,
>
> I had a hard time to make Win2000 work on my new laptop(the proginal OS is
> Win XP home edition).
>
> Do you think I can use WinXP home edition to replace Win2000 for all
> homework in this class?
>
> -- CDs are bugging me

> Dr. Hacker,
>
> When is the papers due?  it says:
> Due date:  Sunday, 1/20/2002, midnight, via email.
>
> does this mean I have all of Saturday but once the clock hits midnight, the
> date changes to 1/20 and its due?  Or does it mean that I also have all of
> Sunday to work on it?  Some people may translate you due date differently.
>
> -- Thank goodness Hawaii doesn't observe Daylight Savings Time

> Dr. Hacker
>
> on the section about prime directive 2, becuase it is on the non-developer's
> point of view, all we have to do is be able to use the software.  So for the
> projects that ics414 did, we don't need to download an install their package.
> The use of the software would just be to go to the homepage and
> register/login  or whatever it says to do, and that would be using their
> software satisfing PD#2.  Downloading and installing the package using the
> steps on their README.html would actually be stuff on PD#3.  Am I viewing this
> assignment correctly?
>
> -- Down and out

> Dr. Hacker,
>
> Should we bring 1 copy of our open source reviews, or sufficient copies for
> everyone in class?  If we need multiple copies, how many?
>
> Or, will you use the links to show the reports on the projection system?
>
> -- Love that xerox machine

> Dr. Hacker,
>   i was wondering what the queryAccount method does.  for now, i made it
> print out the info about the user account.  am i missing anything?  thanks
>
> -- Command shell man

It's possible, even probable, that some of you have started work on AccountInfo but have forgotten about the engineering log. If that's the case for you, then please start immediately. Please *don't* add in retrospective entries to try to "cover your tracks". Just start today. If you haven't yet started the engineering log because you haven't yet started working on the programming assignment, then of course that's good news with respect to the engineering log, but bad news with respect to the assignment. :-)

> Dr. Hacker,
>
> Do you have any hint on ensuring the validity of names and passwords?  I
> wrote two Exception class, InvalidNameException and InvalidPasswordException
> and had methods setName and setPassword throw them.  But I'm only sure on how
> to ensure that the password is at least 6 characters.  How might I check that
> a password have at least one upper case letter, lower case letter, and digit?
> And how to do all the other restrictions of valid names and passwords, I
> currently have no idea except to manual make sure all invalid character are
> not in the String and to check that there is at least one upper case letter
> by checking each Alphabet at a time.  There must be a better way to do this.
> Can you give a hint if there is?
>
> -- Loop de Loop

A meta-level comment: Don't be misled into thinking that the "real work" in this class is writing the accountinfo class, and that creating the stack template and editing the jpx file is just "overhead". The process of creating project structures and integrating tool files into it is just as much "real work" in software engineering as the development of the software itself. So, you are learning something worthwhile while you stumble through this.

>>> A previous question was:
>>>
>>> How might I
>>> check that a password have at least one upper case letter, lower case
>>> letter, and digit?
>
> Dr. Hacker,
>
> It sounds to me like this student is asking about the existence of methods
> like the character tests for isDigit, isLetter, isLetterOrDigit, etc., to
> make the testing easier.
>
> -- Alternative interpretation

> Dr. Hacker,
>
> The assignment write up says, "The test cases should be implemented as a
> set of methods belonging to a class named TestAccountInfo."
>
> But... I think I remember you saying in class today that we shouldn't name
> our main class starting with "Test".  So, should we just call it
> AccountInfoTest or something like that?
>
> --- Name de Plume

Note that if you're using JRefactory, then it's quite simple to rename classes so you could try it either way.

> Dr. Hacker,
> I have a question. Ever since the very first day of class, your
> suggestion to change operating systems to either Windows 2000 or XP scared
> me out of my wits. Since then I've been deliberating for a solution and I've
> finally obtained one. I just recently obtained a refurbished computer,
> however this nice tool came equipped with Windows XP Home Edition. My
> question for you is, is it possible to complete this course successfully
> if I used the Home Edition or would it be better to use either Windows
> 2000 or XP Professional.
> 
> -- Freaked and frustrated

> Dr. Hacker,
>
> I rushed out of class yesterday & forgot to pin you down on the
> .jpx.local and .jpx~ question. What's the deal with files with this extension?
>
> -Jay Builder

OK, at long last, back to the questions: what is *.jpx.local, and what is ~.jpx~? These are clearly JBuilder files. There are two strategies for answering this question yourself. First, read the JBuilder documentation, which is available from within JBuilder. Second, do a google search. For example, I went to google, clicked on the google groups button, typed in "jpx.local", and the very first hit explained exactly what the jpx.local file is. (Note that while I know what jpx~ files are, I didn't know the purpose of jpx.local files until I did the google group search myself. I'd say it took me roughly 15 seconds to find out the answer. And as it's taken me about 15 minutes to type out this response, you can see that I view this issue as quite important since it would have taken far less time to simply answer the silly question directly. :-)

> Dr. Hacker,
>
> Can I adapt my accountinfo1 to stack template by copying those files that my
> accountinfo doesn't have to my current accountinfo1 directory?
>
> - Vice Versa

> Dr. Hacker,
>
> JRefactory's pretty printer tabs 4 spaces while the class standards say we
> should use 2 spaces.  Is it okay to leave pretty printer's formatting of 4
> spaces?
>
> - Indentationally challenged

> Also
>
> What is the different between the two uses of Exception handling:
>     myMethod() throws Exception {
>         try{}catch{}
>     }
>
> and
>
>     myMethod() {
>         try{}catch{}
>     }
>
> I've done both, but seems to be no difference.  Which do you prefer and why?

> Dear Dr. Hacker,
>
> I'm wandering around which collections to use for holding objects. I
> assume you will ask us to add "sorting" and "search" mechanism in. Is this
> assumption correct?
>
> - Informationally hidden

Food for thought, and potential midterm question: under what circumstances would you *have* to actually deploy a solution in order to find out what the optimal choice of internal data structure would be? (In other words, under what circumstances would no amount of pre-implementation design be sufficient to determine the "right" choice of data structure?)

> Dear Dr. Hacker,
>
> are we supposed to write down stuff like converting our accountinfo1 class
> into an Ant-based build in our engineering log?  Or do we just write down
> coding ideas?  Those are the only questions I have for now.  Everything
> seems fine for my project except that when I run "ant test" I get 66
> errors from checkstyle.  I think it's because I didn't use javadoc style
> comments.  It said something about that in the errors.  I've never done
> javadocs, so I'll have to read about that over the weekend.  I hope after I
> do that everything is okay.  By the way, I just wanted to let you know I'm
> really enjoying this class.  Pretty cool stuff.
>
> - Amazed and confused

Glad to hear you're enjoying the class. We aim to please.

> Dear Dr. Hacker,
>
> You mentioned the midterm in a previous email. What should we be doing to
> prepare?
>
> - Looking ahead

> Dear Dr. Hacker,
>
> In reference to the following question from a previous column:
>
>>> What is the different between the two uses of Exception handling:
>>>     myMethod() throws Exception {
>>>         try{}catch{}
>>>     }
>>>
>>> and
>>>
>>>     myMethod() {
>>>         try{}catch{}
>>>     }
>>>
>>> I've done both, but seems to be no difference.  Which do you prefer and why?
>
>
> I've read the Java in a Nutshell and the Sun info you mentioned.  I
> understand that the general objective is to either catch the exception and
> handle it (second situation), or to let it rise to the top and be handled at
> the next level (using throws clause but not catching.)
>
> The other book I use for reference (Deitel, Java How to Program) also
> discusses exception handling and allows for rethrowing an exception that has
> been caught --- and may have been partially handled at the current level, or
> a decision is made to not handle the particular exception and to pass it back
> up the chain.  In that case, the first approach (of course specifying the
> specific exception being thrown, not just Exception as a catchall) would
> apply.
>
> Are you implying that rethrowing an exception is not good form  --- i.e.,
> that exceptions should be exclusively either caught or passed up the line,
> but not both?
>
> -Exceptionally yours,

Finally, one thing that you definitely shouldn't do is simply "swallow" exceptions. If an exception occurs, you have to deal with it somehow. You can't simply catch it and forget about it and hope that the client will somehow rescue you.

> Dear Dr. Hacker,
>
> I can't fit my zip file on to a floppy!  My zip file is 3MB.  Should I
> put it on a CDRW or should I post it on the web?  I don't have a zip
> drive, but if that's what it comes down to, I'm sure I can find one to
> use somewhere.
>
> - Stack overflow

Once we move to CVS, the submission mechanism will be much easier.

> Dear Dr. Hacker,
>
>> (1) Do the simple thing, which is to first check the length for validity and
>> reject passwords that are too long.  If the password passes that test, then
>> do
>
> I didn't find any information about the max length of account name and
> password. Will you specify it?
>
> - Long John

> Dear Dr. Hacker,
>
> The project seems to be working ok, including Ant build/dist.
>
> Next question...should my original (default) constructor using interactive IO
> be deleted, since it's not really tested in the program?
>
> I originally wrote a default constructor using interactive IO to get user
> information for creating the class.  My assumption is/was that new accounts
> should not be created unless/until it is possible to verify all of the
> account information, since I don't want to give someone an account unless
> they give me valid information to start (but I'm not really validating the
> email addresses, just checking for an entry).
>
> I subsequently wrote a parameterized constructor that can be used for testing
> and provides all the user information.  That is the constructor being tested
> exclusively by the test class.
>
> Since the default constructor is not tested by the test class, should it be
> removed from the project (for cleanliness)?  Or should it be left for
> completeness?
>
> - Love that command line input loop

So, the answer is: Yes, you should remove the default constructor for a number of reasons:

	the default constructor should be private
	in general, ADTs should not do any I/O themselves. I/O should be the responsibility of the client classes.
	even viewing your I/O as a "developer level" capability, it is more appropriate to use test cases to exercise the interface. Now that you have them, there is no need to have the interactive output inside the class itself.

Cheers, 
Dr. Hacker

> Dear Dr. Hacker,
> 
> I am busily revising all the stack files to be accountinfo1 files. What
> should I do about the following that appears in several of the .html files?
> 
>        $Id: JBuilder.html,v 1.1 2002/01/23 02:39:47 johnson
>
> - Confused in configuration management land

> Dear Dr. Hacker,
> 
> regarding the sorting stuff, is it part of description that we need to
> include? To my opt, we still can write another sorting function to sort out
> the whole object list as option method. But if we need to create object, add
> into collection list then sort it or pass in the object, sorting the list and
> search it. I think this is unnecessary plus this should not really go faster
> when you do the search with sorting. Even if you have sorted list whenever it
> has create the object, that will even slow down overall speed. For example, I
> just did the linear seach for the modify function or query function for the
> proj. The worst case is still going to be O(n) because just linear for loop,
> but if you add sorting method whenever you create/search, the best case will
> still be like O(nlogn). But if you create bunch of objects without any
> sorting and sort before you close of collection list and next time you create
> object with sort collection list, it indeed will help to search object in
> this way intially. Other than that, I could not find any reason why we need
> to include sorting in search/create function.
>
> - Out of sorts with this assignment

> p.s.
> One thing about your link on my email is broken..maybe just mine but I think I
> still can link up if I type all of linked words. Correct my bad thinking!

> Dear Dr. Hacker,
> 
> If our uhunix account is about to be full and cannot accomadate the 3M
> project, can we put the link to an outside website?
> 
> - Out of space, out of time

> Dear Dr. Hacker,
> 
> I have one question.
> 
> Everything is going on great with my package. However when I use
> "ant test", there is one line indicating a failure:
> 
>     [junit] TEST edu.hawaii.chenx.accountinfo1.TestAccountInfo FAILED
> 
> And when I check the build/test_output result, there is one error:
> 
>     Class edu.hawaii.chenx.accountinfo1.TestAccountInfo has no public
>     constructor TestCase(String name)
> 
> Since we are writing our own TestAccountInfo class, should we include
> a TestCase constructor in it? I guess this is caused by not using JUnit
> this time, so maybe we don't have to pay attention to this little bug
> as you indicated before?

> Dear Dr. Hacker,
> 
> I am a little unsure of how to code the throws clause in a method declaration
> that has more than 80 characters in it.  In Java style, it says to break
> apart long lines and to align the parameter on the next with that of the
> first on the previous line like so:
> 
> public void createAccount(int accountType, String username, String password,
>                           String firstName, String lastName, String email) {}
> 
> My question is when you use a throws clause, how should you align it.
> 
> Like this:
> public void createAccount(int accountType, String username, String password,
>                           String firstName, String lastName, String email)
>   throws AccountInfoException {}
> 
> Or like this:
> public void createAccount(int accountType, String username, String password,
>                           String firstName, String lastName, String email)
>                           throws AccountInfoException {}
> 
> I have tried to look for an example that shows this, but I was unable to find
> one.  I feel that the first one is a little harder to read than the second,
> but Pretty Printer will set it to that first one whenever I run it.  Another
> question...should we always start our throws clause on another line, even if
> the clause can safely fit on the first line?
> 
> Like this:
> public void deleteAccount(String username)
>   throws AccountInfoException {
>   accounts.remove(indexOf(username));
> }
> 
> Or like this:
> public void deleteAccount(String username) throws AccountInfoException {
>   accounts.remove(indexOf(username));
> }
> 
> I just ask this because otherwise, half of my methods will look like the
> createAccount method and the other half will look like the deleteAccount
> method.  I'm pretty sure I should only keep it on one line though since Java
> style says to only break apart long lines.  Just asking for
> confirmation...man, correct coding style and documentation is almost harder
> than the coding itself!! :)
> 
> Thanks,
> Exceptionally Anal :)

* Whenever you have to break up a line and introduce a line break, align the next line with the line immediately above it. So this is the correct one:

> public void createAccount(int accountType, String username, String password,
>                           String firstName, String lastName, String email)
>                           throws AccountInfoException {}

> Dear Dr. Hacker,
>
> Now that I am happily using the prettyprinter, I am wondering what to do with
> this javadoc line the prettyprinter puts in there with "Title" on it.
> Obviously, the Title of the class is the name of the class which is also the
> name of the file, so putting that in there would be utterly redundant. So
> title of what? The whole project?
>
> - Entitled to an explanation

I received the following as part of an email from a former student who is now a developer on the mainland (and who is working with me from there on the open source Hackystat project.) I thought you would appreciate an independent, industrial perspective on the class:

> BTW, I also spent some time at http://csdl.ics.hawaii.edu/~johnson/413s02/. 
> The content of 613 is getting better than ever. I took 613 twice, but if i 
> were in UH now, I would have taken this class again. Ant and junit are the de
> facto tools for java developers. Both my previous job and current job use
> these tools at a daily basis. My current company USUALLY has them in the
> interview questions. The only thing that I found missing is design pattern.
> Almost any job interview for a Java developer position would involve
> questions about design patterns. Thanks for making the slides PDF available
> to public, I went through all of them so far, and learned something from each.

> Dear Dr. Hacker,
>
> I have a question about the constructor of account, student,
> administrator, and faculty.  i have a constructor that takes in all the
> parameters like firstName, lastName, email etc.  Can a constructor throw
> exceptions?  i'm trying to verify a valid password in it but i cant seem
> to get it working.  should i seperate this and make another method to
> create an account w/ the variables?
>
> - Needing constructive criticism

> Dear Dr. Hacker,
> 
> Do we have to write our own README.htm, history.htm, etc from scratch? Or
> can we use what was provided in the Stack system and just change relevant
> areas?  eg. your name to our name, stack to accountinfo, etc..
>
> - Hoping that plagiarism is the sincerest form of flattery

> Dear Dr. Hacker,
> 
> ok, i'm having some problems w/ replacing the stack files w/ accountinfo
> files.  First, where are we suppose to store the ".class" generated?  Also
> if you get the properties of the project window up, what folder is the
> "working directory" suppose to be pointing too?
> 
> - Classically confused

(2) The working directory should be the top-level directory of the distribution. For example, on my system, it's set to 'c:/cvs/stack'.

> p.s.
> the last question is that i was just wondering if we zipped our files and
> whatever up, will our project run on other computers?  because we had to
> set up the file path and what not (class path, source path), and i think
> we all would have put the project in different folders like:
> 
> c:\Documents and Settings\Admin\Destop\accountinfo1\...
> 
> others might just store the project in c drive
> 
> c:\accountinfo1\...
> 
> will this make a difference when taken to another computer?

The answer is that although the paths are displayed as absolute paths, internally they are stored as relative paths in the stack.jpx file. This might be a good time for everyone to actually open up that file (use Notepad or something other than JBuilder for this.) What you'll find is an XML file containing data like the following:

  <node name="stack" type="Folder">
    <file path="../../src/edu/hawaii/stack/Assert.java"/>
    <file path="../../src/edu/hawaii/stack/Debug.java"/>
    <file path="../../src/edu/hawaii/stack/EmptyStackException.java"/>
    <file path="../../src/edu/hawaii/stack/overview.html"/>
    <file path="../../src/edu/hawaii/stack/package.html"/>
    <file path="../../src/edu/hawaii/stack/Stack.java"/>
    <file path="../../src/edu/hawaii/stack/TestStack.java"/>
  </node>
 

Cheers, Dr. Hacker