cat Llorllale | grep -v '/BS/'

Closures

2011-11-05T20:27:00.002-04:00

Wikipedia's article still makes me somewhat dizzy whenever I have another go at it. Here are three useful links:

Closures – A Simple Explanation (Using Ruby)
Closures Explained using JavaScript. The most illustrative of all three, imho.
Closures using Lua.

Read it, can it, add it to your bat belt. ;)

Oracle's JDBC BLOB support sucks....

2011-08-05T18:57:00.001-04:00

Exception in thread "main" : java.lang.ClassCastException: javax.sql.rowset.serial.SerialBlob cannot be cast to oracle.sql.BLOB
...
Caused by: java.lang.ClassCastException: javax.sql.rowset.serial.SerialBlob cannot be cast to oracle.sql.BLOB
        at oracle.jdbc.driver.OraclePreparedStatement.setBlob(OraclePreparedStatement.java:6634)
        at oracle.jdbc.driver.OraclePreparedStatementWrapper.setBlob(OraclePreparedStatementWrapper.java:126)

The "infringing" code is this:

     SerialBlob sb1 = new SerialBlob(value);
     stmt.setBlob(5, sb1);   //column 5 is a blob, in case you're wondering

Really, why not code against standards?

EDIT 8/5/2011 19:35: Issue worked around like so:

      ByteArrayInputStream bais1 = new ByteArrayInputStream(value);
      stmt.setBinaryStream(5, bais1, value.length);

More Vim goodness: The Power of g

2011-07-21T10:03:00.000-04:00

The Power of g

I was in particular need of: 0"ay0:g//y A

Editting zip files with Vim...

2011-06-30T17:42:00.003-04:00

Woah

Screenie:

Files like .jar and .xpi, themselves just renamed zip files, can also be opened using Vim
(right click -> View Image to view in full size)

You can even edit the files with Vim! So long jar xvf/uvf! Seriously, with Vim, the possibilities are endless...

Vim - End of line characters!

2011-06-17T21:10:00.001-04:00

There are some dtds created with XmlSpy that are used by the system at work and for some reason they have mac style line endings (I really hope this isn't XmlSpy's doing...). Found the following link hugely helpful: http://vim.wikia.com/wiki/File_format

Excerpt:

A common problem is that you open a file and see ^M at the end of many lines. Entering :set ff? will probably show that the file was read as unix: the problem is that some lines actually end with CRLF. To fix this, you need to tell Vim to read the file again using dos file format. When reading as dos, all CRLF line endings, and all LF-only line endings, are removed. Then you need to change the file format for the buffer and save the file. The following procedures will easily handle this situation, but they only work reliably on reasonably recent versions of Vim (7.2.40 or higher).

Convert from dos/unix to unix

To convert the current file from any mixture of CRLF/LF-only line endings, so all lines end with LF only:

:update Save any changes.

:e ++ff=dos Edit file again, using dos file format ('fileformats' is ignored).^{[A 1]}

:setlocal ff=unix This buffer will use LF-only line endings when written.^{[A 2]}

:w Write buffer using unix (LF-only) line endings.

In the above, replacing :set ff=unix with :set ff=mac would write the file with mac (CR-only) line endings. Or, if it was a mac file to start with, you would use :e ++ff=mac to read the file correctly, so you could convert the line endings to unix or dos.

Convert from dos/unix to dos

To convert the current file from any mixture of CRLF/LF-only line endings, so all lines end with CRLF only:

:update Save any changes.

:e ++ff=dos Edit file again, using dos file format ('fileformats' is ignored).^{[A 1]}

:w Write buffer using dos (CRLF) line endings.

JFreeChart: PiePlot.getSectionPaint()

2010-10-26T18:07:00.002-04:00

I am starting to consider replacing the JFreeChart API with some other one in future projects - gotta start looking for it.

Anyway, today's annoyance with this tool happens to be the fact that charts don't assign colors until they're drawn.

[EDIT] I forgot to add that this small detail is not mentioned in the javadoc. :) [/EDIT]

My requirement was simple: assign the same color of each pieplot section to its respective series in an xychart. Sounds extremely simple, right? Well, after having it not work and me scrambling around, adding some ridiculous debugging messages I finally saw that PiePlot.getSectionPaint(Comparable key) was returning null. At that point I wanted to do additional debugging but getSectionKey() is protected for reasons beyond my understanding. So I gave up debugging this myself and turned to google and got slapped in the face with the above.

Damn man.

JDBC and Oracle: setNULL

2010-10-06T10:14:00.001-04:00

I was surprised (and disappointed) by this behaviour (using Sun JVM 1.4 with Oracle DB 10g):

String sql = "select count(distinct seq_no) from tmp_table where time_stamp = to_date('29/09/2010 07:00:00', 'DD/MM/YYYY HH24:MI:SS') and err_code = ?";
PreparedStatement pstmt = conn.prepareStatement(sql);
pstmt.setNull(1, Types.NULL);
result = pstmt.executeQuery();
result.next();
System.out.println("Result: " + result.getInt(1));

The output is: Result: 0

Zero? But there are rows with err_code set to null!!!

Substituting Types.NULL for Types.VARCHAR produces the same result.

Googled around a bit and according to this the jdbc driver is actually sending a string 'null'. Wow. So now I will need to have a second sql/preparedstatement just for this scenario... takes away some of the benefits of preparedstatements... oh well. :/

VIM - Code Completion

2010-10-02T23:21:00.002-04:00

It's been a while!

Anyway, this post's catalyst occurred this morning during my first day of a Java course I'm attending (an attempt at keeping my teeth sharp). As is custom, use of an IDE is not supported and instead attendants are to use a "normal text editor" (we all know Vim is far from "normal text editor" but bare with me here :P).

It suddenly struck me: it was time to fiddle around with code completion in Vim.

Quickly dug around and found that Vim already had code completion for some common languages (from version 7 onwards)! Java was unfortunately not on the list so I had to look for a third party solution. So far I have come across eclim, VJDE and java complete. I didn't like eclim's design (running a server with which vim would interface), and I couldn't make VJDE work for some reason, but java complete has so far been working wonders:

Just one more reason to love Vim! :D

The Tao of Programming

2009-12-15T10:49:00.002-04:00

The master programmer moves form
program to program without fear.
No change in management can harm
him. He will not be fired, even
if the project is cancelled.Why
is this? He is filled with Tao.



The novice programmer stares in
wonder at the bird, for he
understands it not. The average
programmer dreads the coming of
the bird, for he fears its
message. The master programmer
continues to work at his terminal,
for he does not know that the
bird has come and gone.

Classic!

PS: Not to be confused with the blog.

Java String.split() and the "|" (pipe) character

2009-12-02T18:32:00.001-04:00

I came across this issue today and someone else already blogged about it: http://hoskinator.blogspot.com/2006/11/trouble-using-pipe-with-stringsplit.html. Some of the comments are really good!

The pipe character is not mentioned in the Pattern javadoc.

Basically, just escape the pipe character with double backslashes like so "\\|" and you're set.

This post merely provides redundancy in case the above link goes extinct...

Vim Tip of the Day

2009-07-23T15:13:00.001-04:00

Copying lines containing search hits (source):

1.- Clear a register (eg 'a'): qaq
2.- Append all matching lines to that register: g/pattern/y A
3.- Copy contents of register a to clipboard (register '+'): let @+ = @a

Enjoy.

Some Windows "magic"

2009-07-22T23:05:00.011-04:00

Script to get number of lines in a file:

REM %1 is the file name to be parsed, passed at command line

@set count=0
for /f %%a in (%1) do (
@set /a count+=1
)

@echo %count%

Script that will look at each entry (no spaces) in a file (called seq_no_t3.csv in my example) and search for lines that have an exact match with the string (ie "^string$") in a list of files (specified by adroms*_replies.txt in my example) and output the string "string,file_name" followed by an extra \n in an output file (called loc_matches_2.txt in my example). Also, it will constantly echo to the screen the line number on which it is currently working on from input file.

@echo off
@setlocal

set count=0
for /f %%i in ('type .\seq_no_t3.csv') do (
set /a count+=1
set count
<nul (set /p tmp=%%i) >> loc_matches_2.txt
<nul (set /p tmp=,) >> loc_matches_2.txt
for /f %%j in (\findstr /m /r "^%%i$" adroms*_replies.txt') do (
<nul (set /p tmp=%%j) >> loc_matches_2.txt
)
@echo. >> loc_matches_2.txt
)

@endlocal
@echo on

This script has several interesting things going on. Apart from the use of the relatively powerful for loop (where in this case the default delimiter of or is being used), the lines starting with will pipe a nul response to set /p so that the variable remains unchanged. Due to the quirky way set works, set /p prints the value to the right of the equals sign, not the value of the variable itself. Therefore, you're not changing the value of the %tmp% variable yet you are appending %%i/,/%%j to the file with no CRLF! (see source).

Pending fixes:
1.- Fix issue where blank lines (actually they have space characters) are printed to output file
2.- Fix issue where if the input string is matched in several files, a list of files (where delim=CRLF) is appended to the line corresponding to the input string. Hence there will be lines with no comma separation - instead they will have a file name where the last input string was found.

Vim column mode

2009-07-17T18:59:00.009-04:00

Today I found myself in the need of Vim's column mode (using regex for what I wanted to do would have been hard).

I googled real quick but the first few hits weren't of much use/very clear and and so after figuring out how it works I think it's worthy of posting here as a) a reminder for myself :) and b) so others who google this may get to see this - faster, hopefully.

Let's say you have sql statements like in the 1st screenshot. Look closely - they are missing a cast of the date fields with to_date. If you are stuck at 10PM at the office on a friday night, like me, and need to perform this, I really think substitution with regular expressions is the least preferable option at this point.

Enter column mode.

Move the cursor to the position where you would like to insert text:

Hit Ctrl+q. This will make Vim go into 'visual block' mode. Select the intersection of columns and rows where you would like to insert your text. In my case, I wanted to insert some text right before the single quote selected:

Now hit Shift+I. This will bring the cursor to the first coordinate selected before in mode. Type in the text you want to enter. Don't fret when you see that you're only updating that line. Once you finish, press ESC - this is where the magic happens:

Isn't vim the greatest text editor in the world? :)

Enjoy!

`:update`	Save any changes.
`:e ++ff=dos`	Edit file again, using dos file format (`'fileformats'` is ignored).^{[A 1]}
`:setlocal ff=unix`	This buffer will use LF-only line endings when written.^{[A 2]}
`:w`	Write buffer using unix (LF-only) line endings.