I recently wanted to redirect the output of Log4j to a JTextPane, so as to output messages to the JTextPane using a different color depending on the severity.
I spent some time searching for information and I quickly put together a small example. The following screenshot shows the output.
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Today I finished a beta version of a simple java program that collects the statistics from a subversion repository. I have created a website for the program: http://www.freewebs.com/subvstats/
It currently works by checking the whole history of the repository, finding how many lines have been added/removed in each file by using the “svn diff” command and creating an HTML report.
A sample of the report can be found here: http://www.freewebs.com/subvstats/samplereport.html
The program should work for relatively small repositories. As soon as I have time I will document it more and generate more statistics. And yes, I am thinking of making it opensource, but not in its current state. I first need to find some time to document the code properly and have a stable version.
Keywords: Subversion, statistics, package, tool, program, software, java, subvstats.
For the past two days I have been working with MS Access to create an application. One of the features I wanted to create, was a parametric query that would take the value from a combobox on a form and create a report.
To be more precise I had a form with a combobox populate with IDs and names and when the user selected a specific item from the combo and clicked on a button I wanted to have a report that showed some information of related to the selected ID.
One way to do it is to create some vb code and create a select query with a “where” clause. But, that is not too flexible, caz if I want to change the query, I have to change the code.
Today I came across a more flexible solution. Parametric queries. I knew how to use parametric queries, but not in conjunction with forms. So if you want to create a parametric query related to a form, all you have to do in the query is define the parameter at the beginning like:
PARAMETERS [Forms]![formName]![ControlName] ParameterType;
In the where clause you also have to use the same notation. So for example:
where Id = [Forms]![formName]![ControlName]
and that’s it!
As I was searching for something on google, I saw an ad at the bottom of the page. The ad was about the Davinci code new movie that is coming out. I clicked and found a sudoku like puzzle, related to the movie. The puzzle is explained in the following two pictures (description can also be found on: http://student-rant.blogspot.com/2006/04/googles-da-vinci-code-quest-1.html)
Well… it is clearly a very simple problem for a constraint solver, like Alloy Analyzer! I created the following model (took me half an hour, so no comments or too much thought about it).
module testopen util/ordering[Natural] as ord
abstract sig Natural{}
one sig One extends Natural{}
one sig Two extends Natural{}
one sig Three extends Natural{}
one sig Four extends Natural{}
abstract sig Symbol{}
one sig Cross extends Symbol{}{}
one sig Fi extends Symbol{}{}
one sig Blade extends Symbol{}{}
one sig Star extends Symbol{}{}
sig Cell{
symbol: one Symbol,
rowIndex: Natural,
columnIndex: Natural,
inRange: Natural
}
fact Numbers{
ord/first() = One
ord/next(One) = Two
ord/next(Two) = Three
ord/last() = Four
}
pred defineRange(row:Natural,column:Natural,r:Natural){
all c:Cell |
c.rowIndex = row && c.columnIndex = column => c.inRange = r
}
fact DefineRange{
defineRange(One,One,Two)
defineRange(One,Two,One)
defineRange(One,Three,One)
defineRange(One,Four,One)
defineRange(Two,One,Two)
defineRange(Two,Two,Two)
defineRange(Two,Three,Three)
defineRange(Two,Four,One)
defineRange(Three,One,Four)
defineRange(Three,Two,Two)
defineRange(Three,Three,Three)
defineRange(Three,Four,Three)
defineRange(Four,One,Four)
defineRange(Four,Two,Four)
defineRange(Four,Three,Four)
defineRange(Four,Four,Three)
}
pred staticSymbols(row:Natural, column:Natural, s:Symbol){
all c:Cell |
c.rowIndex = row && c.columnIndex = column =>
c.symbol = s
}
fact{
staticSymbols(One,Four,Fi) &&
staticSymbols(Two,Two,Cross) &&
staticSymbols(Four,Two,Blade) &&
staticSymbols(Four,Three,Star)
}
// No two same symbols in the same Range
fact{
all disj c,c’:Cell |
c.inRange = c’.inRange =>
c.symbol != c’.symbol
}
// All cells have different rowIndex and columnIndex
fact{
no disj c,c’:Cell | (c.rowIndex = c’.rowIndex && c.columnIndex = c’.columnIndex)
}
//No two same symbols in the same row Column
fact{
all disj c,c’:Cell |
c.rowIndex = c’.rowIndex =>
c.symbol != c’.symbol
all disj c,c’:Cell |
c.columnIndex = c’.columnIndex =>
c.symbol != c’.symbol
}
pred solution(){
#Cell = 16
}
run solution for 16 Cell
Alloy Analyzer came up with a solution in 3 seconds, on the dual core 2GB RAM opteron server running linux!
The solution is the following one:
symbol= { (Cell_0 Blade_0) (Cell_1 Blade_0) (Cell_2 Blade_0) (Cell_3 Blade_0) (Cell_4 Fi_0) (Cell_5 Fi_0) (Cell_6 Fi_0) (Cell_7 Fi_0) (Cell_8 Cross_0) (Cell_9 Cross_0) (Cell_10 Cross_0) (Cell_11 Cross_0) (Cell_12 Star_0) (Cell_13 Star_0) (Cell_14 Star_0) (Cell_15 Star_0) }
rowIndex = { (Cell_0 One_0) (Cell_1 Two_0) (Cell_2 Three_0) (Cell_3 Four_0) (Cell_4 One_0) (Cell_5 Two_0) (Cell_6 Three_0) (Cell_7 Four_0) (Cell_8 One_0) (Cell_9 Two_0) (Cell_10 Three_0) (Cell_11 Four_0) (Cell_12 One_0) (Cell_13 Two_0) (Cell_14 Three_0) (Cell_15 Four_0) }
columnIndex = { (Cell_0 One_0) (Cell_1 Four_0) (Cell_2 Three_0) (Cell_3 Two_0) (Cell_4 Four_0) (Cell_5 Three_0) (Cell_6 Two_0) (Cell_7 One_0) (Cell_8 Three_0) (Cell_9 Two_0) (Cell_10 One_0) (Cell_11 Four_0) (Cell_12 Two_0) (Cell_13 One_0) (Cell_14 Four_0) (Cell_15 Three_0) }
It is quite straightforward! The symbol of Cell_0 is Blade, its row is One and column One. The symbol of Cell_1 is Blade again, he row is Two and Column Four etc.
The symbol names are not related to the movie or book symbol names. In my model Blade is the pyramid like shape, Fi is the Greek letter fi, Cross is the symbol that looks like a cross and Star is the symbol that looks like a star. I know that I spent half an hour to solve a problem that would have taken me around 10 minutes to solve manually, but as a proper nerd I prefer to use my (few) grey cells to think how to use a computer to solve a problem for me, instead of solving the problem myself.
Well.. that’s it! I don’t want to spend more than 1 hour on this!
There are a couple of blogs with solutions to the puzzles.
Links to solutions:
http://student-rant.blogspot.com/2006/04/warning-solution-to-google-da-vinci.html
http://googlefact.blogspot.com/
UPDATE: I used the model on my P4 running @ 2.8G with 712 MB ram and took AA 23 seconds to solve the problem. Not bad at all! But for bigger problems the state space will be increased by too much. Looks like an AI technique should be used to find a solution.