off the blog

Titanium Image Gallery

2011-12-22T21:26:00.000-08:00

Creating an Image Gallery that scrolls side to side isn't terribly difficult with Titanium.

Here is how I did it:

// put this in a file, for instance "ImageGallery.js"
var ImageGallery = {};
(function() {

    ImageGallery.imageViewArray = [];
    ImageGallery.imageNameArray = [];
    ImageGallery.nextImageIndex;
    ImageGallery.Gallery = null;


    ImageGallery.createGallery = function(params) {

        if (params.Images) {
            ImageGallery.imageNameArray = params.Images;
        }
        ImageGallery.init(params);

        ImageGallery.Gallery.addEventListener('click', function(e){});
        for(var i = 0; i < ImageGallery.imageNameArray.length ; i++){
            ImageGallery.Gallery.views[i].image = ImageGallery.imageNameArray[i];
        }
        ImageGallery.nextImageIndex = 1;

        return ImageGallery.Gallery;
    };

    ImageGallery.init = function(params) {
        var imageParams = {
            width:Ti.Platform.displayCaps.platformWidth - 4,
            height:Ti.Platform.displayCaps.platformHeight/2,
            hires:true,
            left:2,
            right:2
        };

        for(var i = 0; i < ImageGallery.imageNameArray.length ; i++){
            ImageGallery.imageViewArray[i] = Titanium.UI.createImageView(imageParams);
        }

        var p = {
            width: 310,
            height: 450,
            top: 5,
            left: 5,
            borderWidth: 2,
            borderColor: '#000',
            showPagingControl: false,
            pagingControlColor: '#fff',
            currentpage:0
        };
        for (var prop in params) {
            p[prop] = params[prop];
        }
        p.views = ImageGallery.imageViewArray;
        p.backgroundColor = "#000";
        ImageGallery.Gallery = Titanium.UI.createScrollableView(p);
    };

})();

Assuming that you include the file above in your view, you then can use it like so:

var gallery = ImageGallery.createGallery(
            {
                // here images is an array of image URLs
                Images:images,
                width:Ti.Platform.displayCaps.platformWidth,
                height:Ti.Platform.displayCaps.platformHeight/2,
                top:null,left:null
            }
        );

What do you think?

PHP and writing to Apache logs

2011-11-03T07:17:00.000-07:00

Printing to STDERR is quite easy, once you figure it out!

file_put_contents('php://stderr', print_r($your_string, TRUE));

Of course, you can also replace 'stderr' with 'stdout'.

You could also use error_log but it truncates long strings ...

Android App Piracy

2011-07-16T12:16:00.000-07:00

As you may know, I have a bunch of apps on the Android market. Recently, I have been fielding questions from users that have had problems with my app. Turns out their contacts were being deleted. Their contacts were receiving lewd photos and messages.

After some digging around, it became clear that they downloaded pirated versions of my apps. Aside from feeling glad that people too cheap to buy something that costs the same as a bag of chips and a soda got what was coming to them, I was inclined to post a message about piracy on my apps home page.

Basically, the gist of what I posted is this:

Would you openly give all of the data on your phone to a third party that you did not know or trust? By downloading applications from sources where the original author did not intend to publish them, you are doing just that.

Most paid applications on the market implement some form of weak licensing that Google endorses. Unfortunately, this licensing is very easy to beat. In order to beat it, pirates must add their own bits of source code to apps.

So ask yourself, what would stop them from injecting more code, to say, read all of your contacts and send them to a third party? Or, reading your banking details?

Some will read this post and assume that I am just trying to protect my interests. Well, of course I am. But understand, my claims are real:

The list could go on and on ... Basically, they all say the same thing; Download applications from sources that you trust (Android Market, App Store, etc) and not pirate web sites.

In the end, is the couple of bucks you save worth all of the headache of having your information stolen, your accounts hacked and your life turned upside down?

A little bit of brain goes a long way.

ServletContextListener: reading init parameters

2011-01-06T12:26:00.000-08:00

Previously, I showed you how to schedule an ongoing task with servlets.

Recently, I needed a way to set the location of a configurable properties file for my web application. This location was to be used by each Servlet/JSP in my web application. You could add an init-param to each servlet declaration, like it is explained here. But why do this if each servlet is going to have the same value?

The better choice is to declare this parameter once and have it read when the web application is loaded by the servlet engine.

To do this, you need to once again implement the interface for ServletContextListener,

public class MyServletContextListener
implements javax.servlet.ServletContextListener

This interface requires you to provide an implemention for

public void contextDestroyed(ServletContextEvent sce), and
public void contextInitialized(ServletContextEvent sce)

Before we get to the implementation for our listener, let's add a context parameter to our web application. This is the 'global' variable our servlets and JSP pages are interested in!
If you open web.xml and add something like the following as a direct child element of the <web-app> element,

<context-param>
   <param-name>some parameter</param-name>
   <param-value>some parameter value</param-value>
</context-param>

And while we have the web.xml open, we will declare our listener (right below our <context-param> declaration):

<listener>
<listener-class>your.package.path.MyServletContextListener </listener-class>
</listener>

Having declared our listener and a context parameter, our contextInitialized() will look something like:

public void contextInitialized(ServletContextEvent sce) {
ServletContext c = sce.getServletContext();
if (c != null) {
    if (c.getInitParameter( "some paramter") != null) {
      c.setAttribute(
       "some parameter",
        c.getInitParameter( "some parameter")
      );
    }
}
}

When the servlet container unloads our web application, we need to clean up after ourselves (not 100% that this is necessary, but it is still a good practice):

public void contextDestroyed(ServletContextEvent sce) {
ServletContext c = sce.getServletContext();
if (c.getAttribute("some parameter") != null) {
c.removeAttribute( "some parameter");
}
}

Now, these attributes are available for each of our individual servlets by calling getServletContext().getAttribute("some parameter").

Nothing to it!

Finding all JAVA imports in a Specified Directory (& sub-directories)

2010-05-06T07:33:00.000-07:00

Here is a little (Li | U)nix command line script that looks through a given directory and extracts all of the JAVA import statements, sorts them and then prints them to STDOUT.

find ./someJavaDir/ -type f -name '*.java' \
-exec grep '^import .*$' '{}' \; | \
sort | uniq | sort | awk '/import/ {print $2 }'

Basically, replace ./someJAVADir/ with the actual directory that you would like to search for JAVA imports.

eCID - Android App

2010-05-01T06:26:00.000-07:00

Please go to our new site: http://www.enhancedsmscallerid.com/

Getting rid of empty XML elements using XML::Simple

2010-04-27T08:30:00.000-07:00

Sometimes it is necessary to remove empty XML elements from XML documents (need a condensed message, etc) and doing so can be a difficult task to achieve! Well, here comes XML::Simple to the rescue...

#!/usr/bin/perl -w
use strict;
use XML::Simple;
use Data::Dumper;
my $xml = <<EOF;
<fullletter>
<CASE_EPIS>00036</CASE_EPIS>
   <letter>
      <IMAGENAME>02_20100423124541</IMAGENAME>
      <RUNDATE>2010-04-23 12:04:41</RUNDATE>
       <LETTERTYPE>LOI2</LETTERTYPE>
   </letter>
    <service> </service>
       <service>
           <NTV_SEQUENCE>26</NTV_SEQUENCE>
           <NTV_DISPLAY_VALUE>Need start date </NTV_DISPLAY_VALUE>
      </service>
       <service> </service>
</fullletter>
EOF

# use XML simple to process the XML
my $xs = XML::Simple->new(

      # remove extra whitespace
      NormaliseSpace => 2,
      # keep root element
      KeepRoot       => 1,
      # force elements to arrays
      ForceArray     => 1,
      # ignore empty elements
      SuppressEmpty  => 1
);
# read in the XML
my $ref = $xs->XMLin($xml);

# print out the data structure
# shows you how to access the data
print Dumper($ref);

# print out the XML minus the empty tags
print $xs->XMLout($ref);

Running this sample code then produces (minus the Data::Dumper text):

<fullletter>
  <CASE_EPIS>00036</CASE_EPIS>
  <letter>
    <IMAGENAME>02_20100423124541</IMAGENAME>
    <LETTERTYPE>LOI2</LETTERTYPE>
    <RUNDATE>2010-04-23 12:04:41</RUNDATE>
  </letter>
  <service>
    <NTV_DISPLAY_VALUE>Need start date</NTV_DISPLAY_VALUE>
    <NTV_SEQUENCE>26</NTV_SEQUENCE>
  </service>
</fullletter>

Firefox (64 bit)

2010-02-16T06:50:00.000-08:00

Just a quick note for those of you wanting a 64bit version of Firefox!

You can obtain a 64bit version here! For those of you that are daring, download and install Firefox.next (version is based on a time stamp).

For those wanting something that works, you should download a version after the list of files for Firefox.next (e.g. Firefox 3.6 below).

JAVA is available (and more stable from what I can tell) in 64bit flavors and I would recommend installing a 64bit version after installing a 64 bit version of Firefox
Note that Flash is not available for 64 bit browsers yet (unless you are on linux).

Posting to Blogger from Perl

2010-01-28T06:17:00.000-08:00

Here is a little snippet that allows you to post to your Blogger blog from Perl:

use Net::SMTP::TLS;
my $mailer = new Net::SMTP::TLS(
    'smtp.gmail.com',    # dont change
    Hello    => 'smtp.gmail.com',         # dont change
    Port     => 587,                      # dont change
    User     => 'your.address@gmail.com', # change to your username
    Password => 'password'                # change to your password
);

# you email address associated with the blog
$mailer->mail('your.address@gmail.com');

# the address to send the post to
$mailer->to('blogid.secretword@blogger.com');
$mailer->data;

# blog post body
$mailer->datasend("Subject: Title of my blog post\n\n")
  ;                                       # keep the trailing \n\n!
$mailer->datasend("The text of my post here\n");

# end blog post
$mailer->dataend;
$mailer->quit;

Let me know how this works for you!

Mapping OWL ontologies into PERL

2010-01-14T07:01:00.000-08:00

Unlike in JAVA, there doesn't exist a way in PERL to generate modules from Web Ontologies (OWL). Well, not until recently!

As part of a bigger effort, the CPAN module, SADI, contains a script for generating fully functional PERL modules from Web Ontologies. The script is called sadi-generate-datatypes.pl and is automatically installed along side the SADI module. Under the hood it is using RDF/OWL parsing code from PLUTO (a module built on from a project from IBM ).

I wont go into the details for how to use this module here (there is ample documentation available on CPAN for this module). I would like to point the interested reader to the documentation for generating the Perl modules. Go to http://search.cpan.org/dist/SADI/ and at the very bottom you will see under the "Other Files" header a link called doc/working_with_datatypes.html. That file should get you going.

Earning rebates when shopping online in Canada

2009-11-26T07:21:00.000-08:00

As someone that enjoys shopping for things online, I thought that I would share a way for Canadian shoppers to earn rebates while shopping for items online.

Great Canadian Rebates is a site that lists various online retailers and offers coupons/rebates (ranging from a flat amount of cash back, to 12%) on items that you buy from retailers that they list. The require you to sign up for an account and then to click through their site to shop the online retailer. With my account, I have received just under $70 back in under a year. They even give you a toonie ($2) for just signing up!

I figure that since I buy stuff online, why not get a little something back!

Perl script to exact packages from multi package Perl module

2009-11-25T11:27:00.000-08:00

Here is a little script that I use to extract the individual modules from a multiple package Perl module.

While the script works, it isn't perfect and if you have any comments, have an addendum, etc, please let me know!

The script is below. Please make sure to edit $file, the input file, and $outdir, the destination directory. Good Luck.


#!/usr/bin/perl -w
use strict;
use File::Spec;
use File::Path qw(mkpath);
my $file   = '/exact/path/to/perl/module.pm';
my $outdir = '/tmp/';
open(my $fh, '<', "$file") or die $!;
my $contents = '';
my $filename = undef;
while (<$fh>) {
       if ( $_ =~ /^package (.*);/g ) {

               # construct a new file
               $contents = '';

               # its filename
               $filename = File::Spec->catfile( $outdir, split( /::/, $1 ) ) . '.pm';

               # its contents
               $contents .= $_;
       } elsif ( $_ =~ /^1;/g ) {

               # put the contents into $filename
               $contents .= $_;
               my ( $volume, $directories, $file ) = File::Spec->splitpath($filename);

               # make the path
               mkpath(
                                  $directories,
                                  {
                                         verbose => 1,
                                         mode    => 0711,
                                  }
               );
               do {
                       open OUT, ">$filename" or die "Can't write to $filename: $!\n";
                       print OUT $contents;
                       close OUT;
               } if $filename;
       } else {
               $contents .= $_;
       }
}
close $fh;

Callback Functions - Scoping

2009-10-12T06:34:00.000-07:00

According to Wikipedia, a callback function is executable code that is passed as an argument to other code. It allows a lower-level software layer to call a subroutine (or function) defined in a higher-level layer.

Callback functions are used very frequently in event driven software systems. Whenever an event happens, a function is called.

The idea is simple, but many people tend to become confused when using these things. The problem that they encounter is that people tend to run into problems with the scope of variables that they are using.

Part of the problem is remembering that the callback function may form a closure. When the callback function is executed, the scope consists of the callback function's code and references to any variables of the function containing the callback function reference. The converse is not true; the function containing the callback function reference cannot use the arguments and variables of the callback function.

Another thing that can confuse people using callback functions is the use of global variables. Since callbacks are usually called in response to events, it may not be clear what the current state of the system is and using any predefined global variable may result in inconsistent results.

In addition to global variables, variables using the same name in the code containing the reference to the callback function and with in the callback can sometimes confusing to people. In this case, the variable within the callback takes precedence.

# example function with closure

function makePowerTo(x) {
 return function(y) {
  var result = y;
  for (var i = 1; i < x;i++)
    result *= y;
  return result;
  };
}
var square = makePowerTo(2);
var cube = makePowerTo(3);
print(square(2)); // 4
print(cube(2));   // 8


square

and cube are both closures. They share the same function body definition, but store different environments. In square's environment, x is 2. As far as cube is concerned, x is 3.

Finding and Deleting Files

2009-10-05T06:00:00.000-07:00

Today, I was trying to remove a bunch of temporary files using the DOS command prompt on Windows Vista. What a pain in the butt!

Let's assume that I have a bunch of unwanted ".tmp" files in the sub-directory "subdir". The directory "subdir" also has other sub-directories containing more files that I would like to delete.

For those of you familiar with Linux, to find and delete files its as easy as the following command:

find ./subdir/ -name '*.tmp'-exec rm -f {} \;

Unfortunately, I couldn't muster something like that up on Windows Vista. I tried stuff like

dir /B /S | find ".tmp"

This produced the full path of the files that I no longer wanted. When I then tried to pipe those files to del, like

dir /B /S | find ".tmp" | del

Vista just said 'The syntax of the command is incorrect.'

To make a long story short, I was finally able to come up with the following:

for /R %i in ("*.tmp") do del %i

Do you have an alternative way of finding and deleting files?

Trim whitespace from string in PERL

2009-10-01T05:47:00.000-07:00

I like Java's String.trim() method, and so I thought I would add one for PERL:


sub trim {
     my ($self, $text) = @_;
     $text = $self
           if ref(\$self) =~ m/^SCALAR/i;
     # return empty string if $text is not defined
     return "" unless $text;
     $text =~ s/^\s+//;
     $text =~ s/\s+$//;
     return $text;
}

That is all that there is to it!

You can add this to your module, and do $self->trim($string) or you can do trim($string) ... If you have anything to add, let me know!

Eclipse.ini / Windows Vista - Don't hardcode Vm; Use JAVA_HOME

2009-08-31T07:30:00.001-07:00

I have a little trick for those of you using Windows Vista (and possibly XP), running Eclipse and fed up of editing your eclipse.ini file each and every time you upgrade your JAVA installation! You know what I mean!

According to Eclipsepedia, you need to tell Eclipse the exact path to your JAVA executable. You cannot use JAVA_HOME or any other variable name in this file!

Here we are going to show you how to make Eclipse use your JAVA_HOME directory so that when new versions (one of the umpteen updates) of JAVA are installed, Eclipse just works!

Assumptions:

You are using Windows Vista (or possible XP).
You know the exact path to your Eclipse installation directory.
You know the exact path of the JVM that your eclipse installation is utilizing.
The variable JAVA_HOME is set up on your computer.

To begin, navigate to the folder, using an elevated comm and prompt, that contains your Eclipse installation. For example, on my machine, that folder is C:\eclipse.

The next step is to enter the following command at the prompt:

mklink /D java %JAVA_HOME%

Basically, we are telling Windows to create a symbolic link from the eclipse home directory, to the JAVA_HOME directory and to call this link java. Windows uses a program called mklink to do this.The output from that command will should resemble something like:

For those of you curious to see what happens when I list the directory contents:

The final step is now to put our symbolic link in the eclipse.ini file. So open up the eclipse.ini file (you can create a backup first if you like) and look for the lines that look like:

-vm
C:\path\to\JAVA_SDK\bin\javaw.exe

and replace them with:

-vm
java\bin\javaw.exe

Remember, that you are editing 2 lines (the -vm is on one line, while the java\bin\javaw.exe is on another)!
To confirm that everything works as promised, save your eclipse.ini file and start up eclipse!

Eclipse, Maven & Jetty

2009-05-27T09:57:00.000-07:00

How to run your web application Maven archetype with Jetty in Eclipse

We will be creating 2 'External Tool Configurations', one to start our web application and one to stop it.

To get started, we need need to bring up the Create, manage, and run configurations window. This can be done by clicking on

Run -> External Tools -> External Tools Configurations...

from the menu bar.

From here, we will context click on Program and choose to create a new configuration. Do this twice and give them the names mvn jetty run and mvn jetty stop.

Now we have to configure our new External Tool!

The configuration for both start and stop are very similar! The only difference is for the Arguments section.

Under Location, we need to enter the absolute path to our maven executable. On windows, this is mvn.bat and can be found in the \maven\bin\ directory. On *nix machines, you are looking for mvn.

For Working Directory, we enter ${project_loc}.

Finally, for Arguments, we enter clean jetty:run for our mvn jetty run configuration and jetty:stop for our mvn jetty stop configuration.

The next thing to configure is the Environment. Here we will set up MAVEN_OPTS so that we can remotely debug our application if the need ever arises! This is only done for the mvn jetty run configuration!

Basically, click on New... and give the variable the name MAVEN_OPTS with the value (all on one line):

-Xdebug -Xnoagent -Djava.compiler=NONE -Xrunjdwp:transport=dt_socket,address=4000,server=y,suspend=n

When we are done, it should look like so:

We are pretty much done. I like to have my configuration handy, so I usually add these external configurations to the favorites menu. This is done from the Common tab. Basically, you just add a check to the check box in the Display in favorites menu.

For the run configuration:

And finally, for the stop configuration:

That really is all there is to it. The only other thing to make sure of is that you have the maven-jetty-plugin added to your POM file.

Here is the plugin XML fragment that I have currently:

    <plugin>
       <groupId>org.mortbay.jetty</groupId>
       <artifactId>maven-jetty-plugin</artifactId>
       <version>6.1.16</version>
       <configuration>
           <stopPort>9966</stopPort>
           <stopKey>foo</stopKey>
       </configuration>
   </plugin>

Let me know if you have any questions!

Google App Engine & Eclipse

2009-04-29T06:40:00.000-07:00

I am going to show you how to run your Google App (Python) in eclipse without any special plugins!

All you need to do is ensure that you have downloaded and installed both the Google App Engine and Python.

The trick to getting Google apps to run within eclipse is to run your app as an 'External Tool'.

From the Eclipse file menu, click on

Run -> External Tools -> External Tools Configuration ...

In the resulting window, choose to create a new program:

Give it a name (I called it 'App Engine') in the Name field. In the Location field, enter the exact path to your Python executable. For the Working Directory, enter the exact path to the Google App Engine.

The Arguments field is the most interesting one! Here we enter:

dev_appserver.py -d ${resource_loc}

The dev_appserver.py is the Python script that Google tells you to run when you want to test your app.

The -d just tells the App Engine to output debug statements. Feel free to use any command line arguments that the App Engine allows!

Finally, the ${resource_loc} tells Eclipse to use the full path of any item currently selected in the Navigator.

The final thing to do is to click on the Common tab and to Select "Display in favorites menu". This will provide you with a shortcut so that running your Google App requires the least amount of clicks!

Set up is complete!

Now choose the root folder of your Google App in Eclipse and click on 'App Engine' (or the name that you named your External Tool).

As you can see, the App Engine is running!

Some Notes:

If the App engine looks like it has hung (froze), click in the Eclipse console and hit the return key on your keyboard. What may have happened is that the App Engine has prompted you to check for updates and Eclipse didn't show you the message.
If you get an Eclipse error, "Problem Occurred", make sure that the root folder for your app is selected in Eclipse (i.e. click on it!).

If you have any other things to add, please post your comments!

for loop using 'find'

2009-04-27T07:49:00.001-07:00

I find myself constantly creating complex loops and forgetting, for a small instance of time, how to construct them again.

In this case, I wanted to list files that passed a certain criteria and loop over them so that I could call a Perl script on them.

For example:

for i in `find . -type f -name '*.pm' -print`; \
do perl some_script.pl $i; \
done

In the above case, I am searching for all files that end in pm, starting from the current directory (.) and once found, I am executing the perl script some_script.pl on them.

Of course, you don't have run a perl script ... you could just echo the output:

for i in `find . -type f -name '*.pm' -print`; \
do echo found $i; \
done

Now, next time I need to run a similar command, I wont forget how to construct the query!

Skipping Maven Tests ... For real!

2009-01-08T06:00:00.000-08:00

For the longest time, I have been trying to figure out how to skip running
the tests that are in a project that I have been working on because they
usually fail!

Usually, I edit the POM file and disable testing, but with a project
containing numerous subprojects, this became very tedious.

All of the documentation points to a variable maven.test.skip and states to
set it to true in order to skip tests; something like:

maven.test.skip=true

This has never worked for me. In case you are wondering, I am using maven
2.0.9 (latest as of January 8, 2009)

Having tried everything, I finally have found a way to get it to work
properly:

maven.test.skip.exec=true

Now when I run the install task for the project, I do it like:

mvn -Dmaven.test.skip.exec=true install

Tests are finally skipped!

Windows and problem playing DVDs

2008-12-28T11:12:00.000-08:00

The other day on a short road trip we tried playing a DVD on our laptop and got the following message:

"Windows Media Player cannot play this DVD because there is a problem with digital copy protection between your DVD drive, decoder, and video card. Try installing an updated driver for your video card."

As soon as I got an internet connection, I tried downloading a driver for my video card. After installing it, I assumed that the DVD would play (after all, the message told me it would!).

No luck. I then downloaded new firmware and drivers for my DVD drive. The message did say something about my DVD drive too ...

Again, no luck. Well, what else is there? Then I noticed the word 'decoder' in the message and decided to pursue that option.

I tried a few things, but the one that actually did the trick was to download the XP Codec Pack. After downloading and installing these codecs, I was finally able to play the DVD that we brought to occupy our time on our short road trip!

Comparing XML Documents Semantically

2008-11-27T13:39:00.001-08:00

I have been interested in comparing the contents of XML documents for some time now.

What I wanted to do is to perform a 'Diff' on 2 XML documents and determine whether or not they are the same document (regardless of whitespace or child element ordering).

In JAVA, I came across XmlUnit. This piece of software is excellent for determining whether or not 2 separate XML documents are equal.

In Perl, I came across XML-SemanticDiff. I thought it was great until I re-ordered the elements in one of my documents. Then this module wasn't so great anymore.

Since I really needed a piece of software equivalent to XmlUnit in Perl, I decided to create my own module and to call it XML-SemanticCompare. This new module really does perform a semantic diff on XML documents:

Child element re-ordering doesn't result in false negatives.
Whitespace is trimmed from text by default when comparing text and attribute values [can be turned off].
Attributes can be ignored [turned off by default].

Using the module is extremely straightforward:

  use XML::SemanticCompare;
  my $x = XML::SemanticCompare->new;

  # compare 2 different files
  my $isSame = $x->compare($control_xml, $test_xml);
  # are they the same
  print "XML matches!\n"
    if $isSame;
  print "XML files are semantically different!\n"
    unless $isSame;

  # get the diffs
  my $diffs_arrayref = $x->diff($control_xml, $test_xml);

  # test xpath statement against XML
  my $success = $x->test_xpath($xpath, $test_xml);
  print "xpath success!\n" if $success;

The only downside to this piece of software is that it isn't very efficient (although, it isn't terribly inefficient either).

If you find yourself trying to compare XML documents DOM trees for equality and you are using Perl, please check out XML-SemanticCompare. If you can make the code more robust and efficient, please do!

A perl script to rename your files

2008-11-25T13:59:00.000-08:00

For those of you looking for a cool way to rename your files, here is a little script that could work wonders for you.

Basically, this scripts takes in a PERL substitution expression and applies it to the filename of interest.

To get started, copy the script below into a file called 'rename.pl'. Once you have done that, then read the usage instructions by running the script with the '-h' option. Of course, you will need perl installed on your machine.

So why write this script? Because I got sick and tired of manually renaming files by hand. Some people have files called 'some_file.txt'. I prefer that file to be called 'SomeFile.txt'.

To accomplish this, all I have to do is run the script like so:

   perl rename.pl -u "s/_/ /g" some_file.txt

followed by

   perl rename.pl "s/ //g" "Some File.txt"

Note: The -u option causes the first letter of each word separated by a space to be capitalized.

Okay, maybe its quicker to manually do this for a single file, but if you are on Windows and have a whole folder full of files like that, then the process is:

   for %v in (*.txt) do perl rename.pl -u "s/_/ /g" "%v" 
   for %v in (*.txt) do perl rename.pl "s/ //g" "%v"

That is all there is to it! All of the files will be renamed with 'camel' text names.

Please make sure that before you attempt to batch rename files, that you have them backed up first!

Script start [hint: dont copy this line ;-)]


#!/usr/bin/perl -w

BEGIN {
 use Getopt::Std;
 use vars qw/ $opt_h $opt_u /;
 getopt;

 # usage
        sub usage {
  print STDOUT <<'END_OF_USAGE';

  Usage: rename [-hu] sub_regex [files]

                sub_regex is any expression that you would like to
                apply to filename. You can use capturing or just 
                matching.

                -h .... shows this message ;-)
                -u .... makes first letter of each word uppercase

  examples:

                1.
         perl rename.pl "s/_/ /g" rename_me.txt
                   This renames rename_me.txt to "rename me.txt"

                2.
         perl rename.pl -u "s/_/ /g" rename_me.txt
                   This renames rename_me.txt to "Rename Me.txt"

                3. MS Windows example
         for %v in (*.mp3) do perl rename.pl -u "s/_/ /g" "%v"
                   This renames all mp3 files in the current directory such that
                   every word begins with a capital letter and all underscores
                   are replaced with spaces.


END_OF_USAGE

}
 if ($opt_h) {
                usage();
  exit(0);
 }

}

# get the substition regex
$op = shift or (usage() and exit(1));

# go through file names
chomp(@ARGV = ) unless @ARGV;
for (@ARGV) {
    $was = $_;
    eval $op;
    die $@ if $@;
    # cap first letter of each word
    my $newname = "";
    my @components = split(/ /, $_);
    foreach (@components) {
      my $x = $_;
      $x = ucfirst lc $x if $opt_u;
      $newname .= " $x";
    }
    rename($was,$newname) unless $was eq $newname;
}

Script End [hint: dont copy this line ;-)]

Freebase & Google App Engine - Write Queries

2008-08-27T05:32:00.000-07:00

If you would like to use Freebase with your application that is hosted with Google App Engine, then you may have run into some difficulties trying to get write queries to work!

Now that I have been able to get writes to work, I am going to write down what it is that I did so that other people don't run into the same problems that I did!

Basically, to get writes to work, I created a proxy between my app engine page and freebase. In other words, I had a form that allows you to modify an entity in freebase and upon submit, the mql write statement was created and sent to the app engine. The app engine then forwarded this request to Freebase and then waited for the response. The response was then forwarded back to the to the client page.

To get this to work, you need to first obtain the cookies that are set when you authenticate with Freebase. To do this, we have a simple python subroutine:

# domain is either sandbox.freebase.com or www.freebase.com
# user is the username
# pass is the password
def login(domain, user, pass):
    result = urlfetch.fetch(
             url='http://'
                  + domain
                  + '/api/account/login?username='
                  + user
                     + '&password='
                  + pass
                  + '&rememberme=true',
                 payload={},
              method=urlfetch.POST,
                 headers={
                 'X-Metaweb-Request':'x-metaweb-request'
                 }
       )
    return result.headers['set-cookie']

This subroutine basically calls the login service for Freebase and returns any cookies that their server says to save.

The next thing that you need to do is to forward your write mql to Freebase. This can be done in a similar manner:


# domain is either sandbox.freebase.com or www.freebase.com
# user is the username performing the write
# pass is the password for the user performing the write
# mql  is the write query wrapped in the query envelope
def write_to_freebase(domain, user, pass, mql):
    form_fields = {
        "queries":mql,
    }
    form_data = urllib.urlencode(form_fields)
    cookies = login(domain, user, pass)
    result = urlfetch.fetch(
                url='http://' + domain+ '/api/service/mqlwrite', 
                payload=form_data,
                method=urlfetch.POST,
                headers={
                    'Content-Type': 'application/x-www-form-urlencoded', 
                    'X-Metaweb-Request':'x-metaweb-request', 
                    'Cookie' : cookies
                }
             )
    return result.content;

This method simply calls the mqlwrite service and forwards the JSON object to you.

The imports required are:

from google.appengine.api import urlfetch
import urllib

That is all that is required in order to get writes to work with google app engine!

Please let me know if I missed anything so that I can update this post!

Thanks and good luck!

My Solaris .profile

2008-06-18T16:13:00.000-07:00

I wanted to post my .profile file online because I have had to re-create it many times and I thought that others might find it useful!

Some of the things that the profile does are:

colors the prompt
adds shortcuts for ll and l (ls -lF and ls -laF)
fixes the delete (among others) key so that delete actually deletes characters, rather than add tildes!
adds mouse support to pico and makes 'nano' refer to pico (our system doesn't have nano)
sets up CDPATH (adds the directories in this variable to the search path when using cd)


# set the term to xterm
export TERM=xterm

# Set up VISUAL, EDITOR for crontab editing
VISUAL=/usr/local/bin/pico
EDITOR=${VISUAL}

# Set up a prompt
PS1="\u@\h:\w# "
export PS1="\e[1;31m$(echo $PS1)\e[m"

# Export all the above
export VISUAL EDITOR PS1

# set up CDPATH
CDPATH=$HOME
export CDPATH

# set up some aliases
alias ll="ls -lF"
alias l="ls -laF"

alias nano="pico -w -m"
alias pico="/usr/local/bin/pico -w -m"


# fix some keys
case $TERM in
xterm*)
    bind '"\e[1~": beginning-of-line'
    bind '"\e[3~": delete-char'
    bind '"\e[4~": end-of-line'
    bind '"\177": backward-delete-char'
    ;;
esac
# eof

All that you need to do is save the above text in your home directory under the filename '.profile'.

I have tested this on Solaris, SuSe Linux and Ubuntu Linux.

Good luck!

Deleting shared memory segments

2008-06-17T08:35:00.000-07:00

Recently, I found myself using IPC in a multi-threaded perl script that I wrote.

After running the script a few times I eventually ran out of memory segments and so the script would just die (turns out that the script wasn't robust enough ;-)

So after searching around, I came up with 2 commands that go through and clean, (read delete) all segments (and semaphores) on the computer. The commands need to be run from the command line.

On Solaris:


ipcs -s | awk ' $5 == "ekawas" {print $2, $5}' | awk '{ print $1}' | while read i; do ipcrm -s $i; done 

ipcs -m | awk ' $5 == "ekawas" {print $2, $5}' | awk '{ print $1}' | while read i; do ipcrm -m $i; done

On Linux/Unix:


ipcs -s | awk ' $3 == "ekawas" {print $2, $3}' | awk '{ print $1}' | while read i; do ipcrm sem $i; done

ipcs -m | awk ' $3 == "ekawas" {print $2, $3}' | awk '{ print $1}' | while read i; do ipcrm -m $i; done

Of course, you will need to change "ekawas" to a more appropriate username. To find out the username that you should be using, run 'ipcs -s' or 'ipcs -m' and see who created the segments.

Please be careful, because all segments created by all users will be listed; so don't delete ones that you didn't create!

dos2unix On Every File in a Dir

2008-04-25T12:20:00.000-07:00

I am by no means a Linux expert and I find myself forgetting obvious commands if I haven't used them for a while.

Today, I found myself needing to apply the app 'dos2unix' on a bunch of files recursively in a directory.

After fumbling for a few minutes, this is what I came up with:

    find . -type f -exec dos2unix '{}' \;

Now hopefully, I wont forget again!

Enabling the Home/End/Delete Keys on a *nix Machine

2008-01-17T10:54:00.000-08:00

Make the Home/End/Delete key function like you would assume that they would!

In your .profile file (create it if necessary in your home directory), if you add the following to the bottom (or top), you can enable the Home/End/Delete keys:


case $TERM in
xterm*)
      bind '"\e[1~": beginning-of-line'
      bind '"\e[3~": delete-char'
      bind '"\e[4~": end-of-line'
      bind '"\177": backward-delete-char'
      ;;
esac

This would enable the hot keys for your profile.

If you want to set them up system wide, then (as root) add the following to the end of your /etc/inputrc file:


"\e[1~": beginning-of-line
"\e[4~": end-of-line
"\e[3~": delete-char
"\177": backward-delete-char

Greasemonkey & Auto Updating Userscripts With Subversion

2007-08-24T08:19:00.000-07:00

Some time ago, I wanted to create a way of auto updating my Greasemonkey userscripts so that I wouldn't have to somehow manually notify everyone when an update occured.

My scripts are kept in a subversion repository with WebDav support. So one of the first things that I did was examine the HTTP headers of my web server when I made a subversion request from my browser:


Date Fri, 24 Aug 2007 16:00:53 GMT 
Server Apache/2.0.54 (Unix) DAV/2 SVN/1.2.0 mod_perl/1.999.22 Perl/v5.8.5 
Etag "1390//some_script.user.js" 
Accept-Ranges bytes 
Content-Length 638 
Keep-Alive timeout=15, max=99 
Connection Keep-Alive 
Content-Type text/html; charset=UTF-8

The one thing to notice is the line with the Etag text. It pretty much displays the subversion version of my script, 'some_script.user.js'. So if I could get this information when my script loads and compare it to any value that I have stored previously, then I can cause my script to update itself quite easily!

So I created a function called check4Update(options) that did just that. In addition to my function, I also used cookie management code that I slighltly modified from webreference.com (included below).

The function that I created has a json object called options with the following parameters:

url - the subversion URL for your userscript

scriptname - the name of your script [defaults to the domain that the script acts upon; this may not be desirable, so please set it!]

delay - the number of page refreshes to wait before nagging the user again [ defaults to 7]

Items in bold are required and items in italics are optional

 
window.check4Update = function(options) {
 var options = options || {}; 
 if (!url) {
  // we need this at least ...
  return;
 }
 var url = options.url;
 var scriptname = options.scriptname || location.host + "_script";
 var delay = options.delay || 7;
 
 // cookie_name is the name of the cookie that we will set with the 
 // value of version
 var cookie_name = scriptname
 
 // the version of the script. Initially, this will be null.
 var version =  getCookie(cookie_name);
 
 // the name of the cookie that indicates when we should nag 
 // about upgrading in case the user didnt want to upgrade their script
 var upgrade_cookie = scriptname+ '_DELAY_UPGRADE'
 
 try {
  GM_xmlhttpRequest({ 
   // head command because we are only interested 
   // in the Headers and not the script!
   method: 'HEAD',
   url: url,
   headers: {
            'User-agent': 'Mozilla/4.0 (compatible) Greasemonkey '+scriptname+'/1.0'
   },
   onload: function(responseDetails) {
            if (responseDetails.status == 200 || responseDetails.status == 202) {
            var headers = (responseDetails.responseHeaders).split('\n');
            for (var i in headers) {
    
            // go through and look for 'Etag'
            if (headers[i].indexOf('Etag') != -1) {
             var s = headers[i];
             
             // create a regular expression to parse the version
             var regx = /^.*Etag: \"(\d+)\/\/.*\"$/;
             regx = regx.exec(s);
             
             // here s will be our version obtained from the svn repository
             s = regx[1]
             
             //  here version would be a previously set version or null
             // if this is the first time running the script
             if (version) {
                      // here we get the nag count
                      var count = getCookie(upgrade_cookie)
                    
                      // if the nag count exists and is greater than 0, then decrement it
                      // and dont prompt to upgrade
                      if (count && count-- > 0) {
                      // user doesnt want to be notified
                     var now = new Date();
                     window.fixDate(now);
                     now.setTime(now.getTime() +  31*24*60*60*1000); // expire in a month
                     deleteCookie(upgrade_cookie);
                     setCookie(upgrade_cookie, count, now,"/", scriptname + ".com");
                     GM_log("Wont nag for " + count +" more reloads ....");
                     return;
                       }
                    
                    // so we have found a newer version of the script prompt to upgrade                    
                    if (s > version) { 
                      // ask the user if they wish to upgrade
                      // if they choose not to, then set a cookie to wait 'delay' page
                      // refreshes and then notify them to upgrade again
                      if (confirm("A newer version of this script exists!\n\tRemote Version: " +s+"\n\tYour Version: "+version+"\nWould you like to upgrade now?")) {
                     setCookie(upgrade_cookie, -1, null, "/", scriptname + ".com");
                     var now = new Date();
                     window.fixDate(now);
                     now.setTime(now.getTime() +  31*24*60*60*1000); // expire in a month
                     deleteCookie(cookie_name,"/", scriptname + ".com");
                     setCookie(cookie_name, s, now,"/", scriptname + ".com");
                     alert("Please reload the page once the script has been updated!")
                     // here we cause the page to refresh with the location of our script
                     // this will cause greasemonkey to prompt the user to install the script
                     location.replace(url)
                      } else {
                     // set a cookie to upgrade later
                     var now = new Date();
                     window.fixDate(now);
                     now.setTime(now.getTime() +  31*24*60*60*1000); // expire in a month
                     deleteCookie(upgrade_cookie,"/", scriptname + ".com");
                     setCookie(upgrade_cookie, delay, now,"/", scriptname + ".com");
                     GM_log("Won't notify of upgrades for a "+delay+" page refreshes!");
                      }
                    }
               } else {
                     // version wasnt previously set so we set the version in the cookie to
                     // be the current version of the script in svn repository
                     var now = new Date();
                     window.fixDate(now);
                     now.setTime(now.getTime() +  31*24*60*60*1000); // expire in a month
                     deleteCookie(cookie_name,"/", scriptname + ".com");
                     setCookie(cookie_name, s, now,"/", scriptname + ".com");
               }
            }
           }          
          }
   }, 
   onerror: function(responseDetails) {
          console.log('GM_xmlhttpRequest error: %s', responseDetails.responseText)
   }, 
   onreadystatechange: function(responseDetails) {
 
   }
  });
 } catch (exception){
  console.log('Error occurred while updating the script %s . The error was: %s', scriptname, exception);
 }
 
}

The code above is commented to indicate the logic behind it. If you need more information, please add a comment and I will explain any discrepancies. Also, if you can think of a better way of doing things, please let me know!

Below are the cookie management functions:


window.setCookie = function (name, value, expires, path, domain, secure) {
  var curCookie = name + "=" + escape(value) +
      ((expires) ? "; expires=" + expires.toGMTString() : "") +
      ((path) ? "; path=" + path : "") +
      ((domain) ? "; domain=" + domain : "") +
      ((secure) ? "; secure" : "");
   
  document.cookie = curCookie;
}


window.getCookie = function (name) {
  var dc = document.cookie;
  var prefix = name + "=";
  var begin = dc.indexOf("; " + prefix);
  if (begin == -1) {
    begin = dc.indexOf(prefix);
    if (begin != 0) return null;
  } else
    begin += 2;
  var end = document.cookie.indexOf(";", begin);
  if (end == -1)
    end = dc.length;
 
  return unescape(dc.substring(begin + prefix.length, end));
}


window.deleteCookie = function (name, path, domain) {
  if (getCookie(name)) {
    document.cookie = name + "=" +
    ((path) ? "; path=" + path : "") +
    ((domain) ? "; domain=" + domain : "") +
    "; expires=Thu, 01-Jan-70 00:00:01 GMT";
  }
}


window.fixDate = function (date) {
  var base = new Date(0);
  var skew = base.getTime();
  if (skew > 0)
    date.setTime(date.getTime() - skew); 
}

This is how one could call the this function from within their userscript.


window.check4Update({'url':'http://someurl.com/my_script.user.js', 'scriptname':'my_script_name', 'delay':7});

Finally, all of the code mentioned above was placed in my Greasemonkey userscript at the end of the onload event handler:


window.addEventListener('load',
  function () {
//... your user script code here ... //

// ... the auto update code here ... //
 }
,true);

Good luck!

Creating a Modular 'Waiting' dialog in javascript

2007-08-01T10:35:00.000-07:00

Have you ever needed to create a modular pop up that displayed a message to the user while you did some processing in the background? I have and I got fed up of constantly creating a new modular pop up each time.

The following javascript code is easy to use and is based upon the grayOut javascript function.

This snippet of code creates a modal dialog box. This is useful for times when you want to make the user wait while you do something in the background or if you would like to make the user aware of something on the page. While the dialog box is active, most interactive elements on the page (links, etc) are inactive.

The dialog box is dynamically created and can be customized to a certain height and width. The dialog box has a high z-index and should be placed above most other elements. Items which have a higher z-index than the dialog box will appear on top of the dialog box.

By default the dialog box has a z-index of 100.

Other default parameters are:

height - 25% of the page height
width - 35% of the page width
opacity - 90% (i.e. semi-transparent)
border style - solid
border color - black
border width - 3px
text alignment - center
many others ...

All of the above can be configured to your liking. Look at the comments in the script for more customization features.

Example. This snippet has been tested in Firefox 2, Safari 3, and Internet Explorer 7.


function modular_waiting(vis, msg, options) {
// Pass true to show the dialogue screen, false to hide
// options are optional.  This is a JSON object with the following (optional) properties
// opacity:0-100         // Lower number implies a more transparent dialog box
// zindex: #             // HTML elements with a higher zindex appear on top of others with a lower number
// height: 0-100         // The height in percentage terms relative to the browser screen
// width:  0-100         // The width in percentage terms relative to the browser screen
// name: text         // A name for your dialog box - this is what you will refer to when showing and hiding the dialog
// align: text         // Should the text be placed in the: center, justify, left or right
// fontcolor: (#xxxxxx)  // Standard RGB Hex color code
// fontweight: 100-900   // The boldness of the text in increments of 100. 900 implies maximum boldness
// bgcolor: (#xxxxxx)    // Standard RGB Hex color code
// borderwidth: #     // The thickness of the border
// bordercolor: (#xxxxxx)// The color of the border in HEX
// borderstyle: text     // The style of the border. One of dashed, dotted, double, groove, inset, none, outset, ridge, solid
// modular_waiting(false); // hide the dialog
// modular_waiting(true, 'my message to show here', {'name':'myName', 'zindex':'50', 'bgcolor':'#0000FF', 'opacity':'70'}); // show the dialog
// Because options is JSON opacity/zindex/bgcolor are all optional and can appear
// in any order.  Pass only the properties you need to set.
var options   = options || {};
var zindex   = options.zindex || 100;
var height   = options.height || 25;
var width   = options.width || 35;
var opacity   = options.opacity || 90;
var opaque   = (opacity / 100);
var bgcolor   = options.bgcolor || '#FFDC75';
var fColor   = options.fontcolor || '#0000FF';
var fWeight  = options.fontweight || 600;
var bcolor   = options.bordercolor || 'black';
var bstyle  = options.borderstyle || 'solid'
var bwidth  = options.borderweight || '3px'
var align   = options.align || 'center';
var __div_id__ = options.name ||  '__modular__popup__';

var dark=document.getElementById(__div_id__ );

if (!dark) {
var tbody = document.getElementsByTagName("body")[0];
var tnode = document.createElement('div');       // Create the layer.
tnode.style.position='fixed';                 // Position absolutely
tnode.style.overflow='auto';
tnode.style.display='none';                      // Start out Hidden
tnode.id=__div_id__ ;                    // Name it so we can find it later
tbody.appendChild(tnode);                        // Add it to the web page
dark=document.getElementById(__div_id__ );       // Get the object.
}

if (vis) {
var txt = document.createElement('font')
txt.setAttribute('color',fColor);
txt.style.fontWeight = fWeight;
txt.innerHTML = msg.replace(/\"/g,""").replace(/\'/g,"'").replace(/\/g,">").replace(/\n/g,"<br/>")

dark.style.border = bwidth + " " + bstyle + " " + bcolor;
dark.setAttribute('align',align);
dark.style.opacity=opaque;    
dark.style.MozOpacity=opaque; 
dark.style.filter='alpha(opacity='+opacity+')';
dark.style.zIndex=zindex;
dark.style.backgroundColor=bgcolor;
dark.style.width= width+'%';
dark.style.height= height+ '%';
dark.style.display='block';
dark.style.cursor = 'wait';
dark.appendChild(txt);
dark.style.left =  '40%'
dark.style.top  =  '50%'
} else {
// TODO - should i remove the element?
dark.style.display='none';
dark.innerHTML = "";
}
}

Activate/Deactivate with a function call to modular_waiting(vis, msg, options).

vis is a true/false variable. If you pass true, the dialog will appear. If you pass false, the dialog will be removed.

"msg" is the message that you would like to display.

options is an optional JSON object this allows you to send only the properties you want modified. You don't have to pass options if you don't want. modular_waiting(true,"Hello world") and modular_waiting(false) will work quite nicely.

To set all of the options, do the following {'opacity':'70', 'bgcolor':'#0000FF', 'zindex':'25', 'height':'50','height':'50', 'name':'myPopUpDialog', 'align':'left', 'fontcolor':'red', 'fontweight':'900', 'bgcolor':'yellow', 'borderwidth':'5', 'bordercolor':'blue', 'borderstyle':'dotted' }. This will create a somewhat transparent dialog box that covers approximately 50% of the window, with text aligned left, colored red and bold on a yellow background and a dotted, blue border!

Feel free to change the values yourself!

Order doesn't matter, mix and match however you wish.

The Dogs of the Dow - Half Year Performance 2007

2007-06-05T06:45:00.000-07:00

Previously, I talked about the dogs of the dow and how you could use that as a strategy. Below is an update for those that are interested in this investment strategy. The table includes the Dow component and it's year to date increase.

Please note that dividends are not re-invested, but are included in the rate of return.

As of June 4, 2007:

Pfizer	5.8%
Verizon Communications	15.9%
Altria	-16.1%
AT&T	19.2%
Citigroup	0.0%
Merck	18.5%
General Motors	4.0%
General Electric	0.3%
Dupont	9.3%
Coca-Cola	9.1%

The overall rate of return for the first 6 months was about 6.6%.
The overall gain for the Dow in the same period was roughly 9.3%.

There were 2 components in negative territory (Citigroup was slightly in the red and Altria was in the red by double digits).

Cheers!

Disclaimer:

I am not be liable for any investment decision made or action taken based upon the information on this page.
I suggest you check with a broker or financial adviser before making any stock investing decisions.
I am not offering financial advise, but rather commenting on widely available investment strategies.
Finally, Caveat emptor!

Gold Stocks - Trade Idea Part 2

2007-05-03T06:00:00.000-07:00

Last time, I talked about naked put selling on gold stocks that you wouldn't mind owning. Let's assume, following the earlier example, that at the end of May you are 'put' into Barrick Gold Corp because the stock traded lower than the strike price of the put options you wrote (i.e. $30 USD).

This means that you are now the proud owner of 500 shares of ABX. What can you do? You could hold the stock and hope it goes up or you could sell the stock for a slight loss (remember, it must be less than $30 because you were 'put' into the stock). Alternatively, you could write covered calls on the stock.

So, what is a 'call'? A call option is an agreement that gives an investor the right (but not the obligation) to buy a stock (or some other other financial instrument) at a specified price within a specific time period. If you sell someone the right to buy stock that you own, then this is a covered call.

Imagine now that you sell 5 call contracts that expire in one months' time at the $30 strike price. Imagine that each contract is trading at $0.75. This would mean that you would receive:

$0.75 x 500 or $375 for selling someone the right to buy your stock in one months' time!

If at the end of next month, the stock is trading below the strike price of $30, then you keep your stock and the $375 that you made on the call options. For argument's sake, if the stock is trading at $50, you are obligated to sell your stock for $30. In other words, if on the day of expiration for your call option, ABX is trading at any price over $30, you must deliver your stock for $30.

Let's assume now that for one year, you write naked put options for ABX, and when you are put into the stock you write covered calls. Moreover, when you called to deliver your stock, you write naked puts for the following month. In other words, every month that goes by, you either own ABX and sell covered calls, or don't own ABX and sell naked puts.

Let's also assume that your monthly premium on the option writing is approximately $0.85. Then each month, you generate about 500 x $0.85 or $425. For the year, you would generate about $5,100. Remembering that you had to initially have $15,000 in your account to cover the naked put options, you are looking at yearly rate of return of about 33%. Not too shabby!

Disclaimer:

I am not be liable for any investment decision made or action taken based upon the information on this page.
I suggest you check with a broker or financial adviser before making any stock investing decisions.
I am not offering financial advise, but rather commenting on widely available investment strategies.
Options trading can be extremely risky.
Finally, Caveat emptor!

Gold Stocks - Trade Idea

2007-04-17T07:45:00.000-07:00

Over the last year, I have benefited from one trading strategy involving gold stocks. First of all, I believe that gold will continue to rise, first as a hedge against inflation and second as a hedge against the falling us dollar.

With that said, it seems that gold stocks would be the place to be. My strategy is simple: write 'in the money' naked put options on gold stocks that I wouldn't mind owning for the amount of shares that I am willing to buy.

The seller of a put option has the obligation to buy shares in a company at a specified price at a certain time. In return for this obligation, a put seller gains a premium. Most gold companies are volatile, thus garnering larger premiums.

As an example, take Barrick Gold Corp (ABX on the NYSE; ABX on the TSX). Currently, this stock is trading at around $30 USD per share. Assuming that you thought this stock was going to follow the price of gold higher and that you wanted to buy 500 shares, then following the strategy above, you would:

sell 5 put contracts (uncovered) for the month of May for a premium of around $1 per contract
ensure that your account has enough money in it to finance the trade (in this example, $15,000)

Doing this, you would gain $500 (minus commissions) and come the third Friday of May, if the stock is trading less than $30, you are obliged to purchase 500 shares at $30 dollars. Otherwise, you keep the $500 and repeat the strategy the next month if you still are bullish on Barrick and the price of Gold.

Keep in mind that there are numerous gold producing companies out there, not just Barrick Gold and that those companies that exhibit wild fluctuations in daily share price, usually garner larger premiums.

Good luck.

Disclaimer:

I am not be liable for any investment decision made or action taken based upon the information on this page.
I suggest you check with a broker or financial adviser before making any stock investing decisions.
I am not offering financial advise, but rather commenting on widely available investment strategies.
Finally, Caveat emptor!

Solving Pesky ssh Issues in Cygwin

2007-03-02T07:51:00.000-08:00

Every time that I re-install cygwin and I use ssh for the first time, I encounter minor annoyances. My biggest annoyance is the fact that no matter how many times I log into a remote machine, cygwins' ssh utility tells me the following:

Could not create directory '/home/ME/.ssh'.
The authenticity of host 'xxx.yyy.zzz.ca (1xx.82.67.xx)' can't be established.
RSA key fingerprint is 6c:59:15:64:ed:c8:67:35:d6:ed:1c:a2:ee:87:2b:3f.
Are you sure you want to continue connecting (yes/no)?

Once I enter 'yes', I get the following:

Failed to add the host to the list of known hosts (/home/ME/.ssh/known_hosts).

So that message occurs every single time that I attempt to login to the remote machine.

So the question is, how do I solve this problem? The solution was actually quite simple!

First locate the file called 'passwd' in your C:\path\to\cygwin\etc directory and open it with wordpad.

Second, replace the text
/home/YOUR_NAME
with
/cygdrive/c/Documents and Settings/YOUR_NAME

Finally, save the file.

In hindsight, the solution is very straightforward, but it took me hours to finally figure out. Hopefully, I can save your time!

Maven, Windows and Deploying to a Remote Location

2007-02-03T08:11:00.000-08:00

If you are a programmer on Windows, some tasks take longer to perform than others. Attempting to set up maven so that you can deploy files to a remote machine is one of those tasks!

Here is what you need to get the job done:

Download plink
Download puttygen
Download pscp

If the above links do not work, use Google and search for "putty download".

Once you download them, place them in a folder called putty and move that folder to your root drive (C:\). The next thing that you should do is add that folder to the PATH. Not sure how to do that?

press the windows key and 'pause break' at the same time.
A system properties panel will appear. Click on the 'Advanced' tab.
Click on the 'Environment Variables' button.
Locate the PATH variable from the System variables portion of the panel and choose 'Edit'.
Append, without quotations, ';c:\putty;' to the end of the PATH value.
close the panels and you are done!

Now you need to create a private key from the remote server that you would like to deploy your files to.

ssh into the remote machine
execute the following command on the remote machine
ssh-keygen -b 1024 -f ssh_host_key -N '' -t rsa
This will create a file called ssh_host_key.
On your local machine, create a folder called c:\ssh and place the file, ssh_host_key, in that folder from the remote machine.

The key that we generated on the remote machine will now be used to create one that is compatible with putty. We will now use puttygen to create a 'putty' private key.

Double click the file puttygen.
Make sure that you select you select 'ssh-2 RSA' at the bottom of the page.
Next choose, Conversion -> import.
Select c:\ssh\ssh_host_key.
Save the generated key (save both the public/private key) in c:\ssh.

Most of the 'hard' stuff is now done. Next we will add our remote server to our local maven configuration. To do this, we will have to modify the file settings.xml.

The settings.xml file is usually located in
c:\Documents and Settings\<user>\.m2.

Before proceeding, you should back up the file. Open settings.xml in Wordpad and add the following fragment of xml into the file:


<server>
 <id>remote-repository-id</id>
 <username>your_username_here</username>
 <password>your password here</password>
 <privateKey>c:/ssh/your_private_key.pkk</privateKey>
 <configuration>
  <sshExecutable>plink</sshExecutable>
  <scpExecutable>pscp</scpExecutable>
 </configuration>
</server>

That piece of xml goes in the servers portion of the file. Add it and modify the bold pieces of the text.

That's really all there is to do. However, if you are lazy, like myself, then create a windows batch file that does the deploying for you!

Below is one that I use. You will have to modify the lines in bold. Run it without arguments first, to have it display the usage!

@echo off
if "%1"=="" GOTO ERROR
if "%2"=="" GOTO ERROR
GOTO DEPLOY

:ERROR
@echo off
echo There was an error deploying file.
echo usage:
echo %0 jar pom [repository_id]
goto END

:DEPLOY
setlocal
set REPO=%3
if "%3"=="" set REPO=remote-repository-id
@echo on
REM should be on one line!
mvn deploy:deploy-file -Dfile=%1 -DpomFile=%2 -Durl=scpexe://remote_server_domain/:/remote/path/to/maven/ -DrepositoryId=%REPO%
REM end one line
endlocal
@echo off
GOTO END

:END
@echo off

Dogs of the Dow for 2007

2006-12-31T10:58:00.000-08:00

This is my first public mention of the stock market, so please bear with me ...

Every year, I find myself worrying about where to place my money for the upcoming year. Last year around this time, I really liked metals and mining stocks. The year before that, it was oil and gas royalty trusts (I am a Canadian investor).

This year, I find myself intrigued with the 'Dogs of the Dow' theory, which according to wikipedia, is where 'an investor should annually select for investment the ten Dow Jones Industrial Average stocks whose dividend is the highest fraction of their price.'

According to the SINLetter, the Dogs faired quite well in 2006 in comparison to the rest of the Dow (and other American markets).

Dogs Of The Dow Performance Vs Major Indices

2006 Dogs of the Dow	24.8%
Dow Jones Industrial Average	16.29%
S&P 500	13.62%
Nasdaq	9.52%
Russell 2000	17%

The 2007 picks for the dogs of the Dow are as follows (Name/Yield):

Pfizer	4.45%
Verizon Communications	4.34%
Altria	4.13%
AT&T	4.00%
Citigroup	3.87%
Merck	3.49%
General Motors	3.27%
General Electric	3.07%
Dupont	3.02%
Coca-Cola	2.80%

I have read about some modifications, for instance, picking the top yielding dogs with the smallest market capitalization with the hopes of higher growth which would translate into higher returns. Some opponents of the Dog strategy mention that some stocks (usually the high tech ones) pay smaller dividends which result from there consistent exclusion from the list.

The 'Pigs of the Dow' is another modification of the Dog strategy that doesn't exclude any members of the Dow. This strategy entails picking the 10 worst performing Dow stocks of the previous year. Of course, you might want to make sure that they didn't underperform for some obvious reason (maybe there was mention of bankruptcy, or have some form of potentially crippling pending litigation).

Anyways, I wish you luck with all your investments in the new year! Please feel free to comment on these strategies and to mention others that people might like.

Disclaimer:

I am not be liable for any investment decision made or action taken based upon the information on this page.
I suggest you check with a broker or financial adviser before making any stock investing decisions.
I am not offering financial advise, but rather commenting on widely available investment strategies.
Finally, Caveat emptor!

Intel ProSet Wireless ... Part 2

2006-12-19T11:05:00.000-08:00

Previously (see here), I had noted some problems that occurred upon performing an upgrade of the drivers for my Dell Intel 2915 ABG Wireless Network Card.

Specifically, I had to downgrade my router from acting as a wireless G router, to acting as a B/G router. This resulted in slower performance (from the router).

I am glad to say that this morning, I upgraded my network cards' drivers (see here) and it seems like Dell finally corrected this problem. I can safely say that the problems that I have encountered in the past have fully been resolved.

The update is for the Intel wireless adapter model number 2915 and 2200. Before upgrading, make sure to backup your 'profiles' that you connect to just in case.

Just thought that I would let you know!

Where is my context.xml coming from!?!

2006-12-06T15:07:00.000-08:00

I recently modified some JSPs that were being served by Tomcat. Specifically, I added some 'Environment Entries' so that I could set some 'global' variables for my webapp.

I added things like the following to my context.xml file in the META-INF directory of my webapp:

<Environment name="maxExemptions" value="10" type="java.lang.Integer"/>

So that during execution I could do load the variable and use it like so:


Context c = new InitialContext();
String maxExemptions =
  ((Integer)c.lookup("java:comp/env/maxExemptions")).intValue();

After I deployed my new code, I tested it and found out quickly that the javax.naming.NamingException were being throw. The error basically stated that the variable was not bound in this context.

At first I thought that I did the whole looking up stored properties incorrectly. What really happened though, was that in my

/${catalina.home}/conf/Catalina/localhost/

directory was a cached copy of my context.xml file under the name of 'my_webapps_name'.xml.

Once I deleted that and restarted Tomcat, everything worked as expected.

If you came here trying to debug javax.naming.NamingExceptions, I recommend that you first try removing that file first!

Good Luck!

Funny EA Sports NHL 2007 Bug

2006-11-22T12:34:00.000-08:00

I came across a bug that I reported to EA but wanted to share since I haven't come across anyone else that has encountered it before.

The basic gist of the bug is that there is an extra goalie on one of the teams. Moreover, the team that has the extra goalie seems to steal this man from the other team because they are one man shy. So not only does one team have an extra goalie, the extra man was taken from the other team!

Oddly, enough, I really like this bug. It's really fun trying to deke out both goalies. Right when you think that you have beat one of them, the other dives across and saves the day. Who knows, maybe EA should add a mini-game in the next installment that allows you to play against a team with an extra on ice goalie.

So how does one re-create this bug?

First of all, I have an Xbox 360, so that is the only platform that I have tried this game on. So all other consoles are out of luck.
Second, the bug has happened to me many times, and only when playing against a friend using the 'play now' mode. The team that always seems to be on the ice when this happens are the Buffalo Sabres. For the screenshots below, they were playing against Colorado.
Thirdly, you have to edit your lines once you have chosen your teams and before loading the game. When changing your lines, try to have as many players listed as 'undefined, undefined, undefined'. If you don't know what I mean, try double shifting players repeatedly until this glitch occurs.
Finally, go on and play the game. During a face off, you will notice that all of a sudden both teams are 4 on 4. After the face off, a player will come off the bench and his team will have an extra goalie.

So below are some screen shots that I took when I encountered the bug. Sorry if they are out of focus, but I am sure that you get the point!

Intel ProSet Wireless Issues and Solutions

2006-11-09T14:58:00.000-08:00

I decided today that I would update the drivers for my Intel Pro/Wireless 2915ABG Network Card. This is the network card that came with my Dell Inspiron 6000.

Downloading the file from Dell's website was no problem at all. The only thing that bothers me is that the file is 100MB. A bit large for something that just handles wireless connections don't you think?

Anyways, in the past all attempts of upgrading my drivers have led to failure. For one reason or another, the upgrade doesn't work and I revert to old drivers. I always wonder what it is that I am missing ...

Back to the story ... I downloaded the drivers and installed them. I wasn't surprised when I was unable to connect to my network. Another upgrade, and another failure... Wait, not this time. I was determined to see it through.

To save you from my ramblings, this is what I found:

My Intel wireless card does not like my wireless router.
To get my router and the wireless card talking, I had to downgrade router. Actually, I went from a purely G router, to a mixed mode B/G setting.
My wireless card likes to beep when it connects to a network

Okay, so point 2 solved my incompatiblity issue. That's great, except I wish that I didn't have to run in mixed mode. To make sure that my wireless card isn't running in B mode, I made sure that the adapters 'Wireless Mode' was set to '802.11g only'. You can modify this setting from the 'Advanced' tab of the wireless card's properties panel (Control + A from within the Intel ProSet/Wireless application window).

As for point 3 above, the beeping, I think that I managed to fix that by modifying a setting in the Intel PROSet/Wireless Application Settings (issue a Control + P from within the application) window. The setting that I changed was to uncheck the 'Show Information Notifications' box. This seemed to work for me.

All in all, I am glad that I finally was able to upgrade my drivers. Hope that you can too.

Scheduling an Ongoing Task in a Servlet

2006-10-30T16:51:00.000-08:00

Recently, I had the need to create a task that had to run hourly, with the stats to be available to clients. I wanted the task to be distributed without having to worry about configuring a database store, etc.

The solution I came up with was to create a JAVA servlet and use a Timer object to schedule a timer task that runs every hour. The task then runs hourly and saves the results in memory.

Usually, creating threads (which is what a TimerTask object is) in a servlet container is frowned upon because the container cannot manage the resources used by the user spawned thread. In addition, whenever your web application is deployed, reloaded, or undeployed you have to ensure that you clean up after your thread.

The first thing that you will do is implement the ServletContextListener interface. This interface consist of 2 methods that you will have to implement, namely,


public void contextInitialized (ServletContextEvent servletContextEvent);
   
     &
   
public void contextDestroyed (ServletContextEvent servletContextEvent);

The contextInitialized(...) method is invoked by the servlet container everytime the servlet is 'started up'. So upon initial deployment, this method is called. Everytime you reload your web application, this method is invoked.

The contextDestroyed(...) method is invoked everytime the web application is shut down, for example, when you reload or un-deploy the web application.

Ideally, anything that you need to do when the web application first starts up should be done in the contextInitialized(...) method, while anything to undo the initialization should be done in the contextDestroyed(...) method.

In the contextInitialized(...) method, the idea is to create a TimerTask object and using the Timer object, schedule it at the desired time interval. Once the scheduling is done, we save the Timer object as an attribute in the ServletContext.

For example, assuming that MyTimerTask extends TimerTask,

  
ServletContext servletContext = servletContextEvent.getServletContext();
try{
 // create the timer and timer task objects
  Timer timer = new Timer();
 MyTimerTask task = new MyTimerTask();

 // get a calendar to initialize the start time
  Calendar calendar = Calendar.getInstance();
 Date startTime = calendar.getTime();

  // schedule the task to run hourly
 timer.scheduleAtFixedRate(task, startTime, 1000 * 60 * 60);

  // save our timer for later use
  servletContext.setAttribute ("timer", timer);
} catch (Exception e) {
 servletContext.log ("Problem initializing the task that was to run hourly: " + e.getMessage ());
}

In the contextDestroyed(...) method, the idea is to clean up after yourself. In our case, this means cancelling any tasks and removing the timer object.


ServletContext servletContext = servletContextEvent.getServletContext();

// get our timer from the Context
Timer timer = (Timer)servletContext.getAttribute ("timer");

// cancel all pending tasks in the timers queue
if (timer != null)
timer.cancel();

// remove the timer from the servlet context
servletContext.removeAttribute ("timer");

The final thing that we have to do now is make sure that our ServletContextListener is added to our web.xml file.

As a child element of the <web-app> element, add the following lines of code:

<listener>
   <listener-class>your.package.declaration.MyServletContextListener</listener-class>
</listener>
Where, your.package.declaration is the package containing the class MyServletContextListener that implements ServletContextListener!

Now everytime the web application starts up and shuts down, our listener will be invoked. Not only did we create an on-going task, but we scheduled the task and made sure that we cleaned up after ourselves too!

Creating Your Own Cat 5 Cable

2006-10-25T07:20:00.000-07:00

The other day I wanted to create an Ethernet outlet in one of my rooms. I bought a network switch, some 'high' quality cat 5 cable, an outlet, some rj45 plug ends and a crimper.

Wiring the outlet was extremely easy, but the cable was another story... For the life of me, I couldn't find what the proper ordering of the cables was supposed to be! Most places that I had found on the internet contradicted each other.

Now that I know how this works, I wanted to post here for my future use and for others to benefit from.

There are 4 pairs of colors, with each pair consisting of a solid and a striped wire. The order of these wires is obviously important for its function and once ordered correctly, they are placed in a RJ45 plug end (shown below).

Using the image above, going from left to right, the order of the wires for a straight through cable (non-crossover, for connecting a computer to a network) is:

orange striped
solid orange
green striped
solid blue
blue striped
solid green
brown striped
solid brown

If you are interested in creating the crossover cable (for connecting a router to a switch, or connecting 2 computers directly through their network adapters), one end of your cable would be wired as stated above and the other end would be:

green striped
solid green
orange striped
solid blue
blue striped
solid orange
brown striped
solid brown

Once you line up the wires and push them into your RJ45 plug end, use your crimper to finish the job off.

Creating the wire is very easy and extremely cost effective. Good luck!

Configuring Tomcat to serve static files

2006-10-11T09:47:00.000-07:00

For a long time now, I have been trying to figure out how to specify a default servlet in Tomcat 5 and still allows for static files to be served.

From all of my readings, I have noticed that in order to have a default servlet and serve static files, I would have to serve the files via my servlet. I didn't like this solution. Finally, I have discovered a work around...

To outline the problem, imagine that your web.xml file contains the following:

<servlet-mapping>
 <servlet-name>My Servlet</servlet-name>
 <url-pattern>/</url-pattern>
</servlet-mapping>

Now all requests to your webapp are going to go through 'My Servlet'. So if you ask for a file like http://localhost:8080/your_app/myStyleSheet.css, Tomcat will look at the request and forward it to 'My Servlet'.

Now unless that particular servlet contains code to handle the case for myStyleSheet.css, nothing will happen (depends on your 'My Servlet' code of course; 404 might be returned, etc).

So one work around that I have found is to enter the following in your tomcat/webapps/your_app/WEB-INF/web.xml:

<servlet-mapping>
 <servlet-name>default</servlet-name>
 <url-pattern>*.css</url-pattern>
</servlet-mapping>

With that code all requests for a file ending in the prefix css will not be sent to 'My Servlet'. Instead Tomcat will look for the file in your web apps home directory and if found, serve it, otherwise a 404 is returned.

Now that I have found this one solution, it seems to me like it was obvious (maybe that's why I couldn't find it in all my web searching with google) ...

Dell & Poor Customer Support

2005-11-30T20:34:00.000-08:00

I am so disappointed with Dell. Up until now, I have been a satisfied customer. I have purchased, in the last couple of years, 2 desktop systems, 4 notebooks, 2 laser printers, 2 flat panel displays and even an ipod wannabe Dell DJ.

So I went to purchase my next notebook, an Inspiron 6000. Got the fastest processor, the highest resolution screen, a big hard disk (100GB). I got the works. Placed my order on the 9th and thought great, I will have a new notebook probably by the end of the week (like most of my previous orders). Great.

Well, a week passes. My 'order status' looks like it has shipped. I will wait a few more days. By the 21st, I figure that it has been a while, so I call their shipping company. Seems like they received something from Dell that states that they will be shipping something for them. As for that something, it isn't there. The shipping company told me to call Dell. I did and I told them that there website says that it has shipped on the 13th and that the shipping company told me that they didnt have it. I was told that I would have it soon. Soon?! I ask, when is soon. Their reply - 'Dont worry sir, your computer is coming.'

So, I wont bore you with the other calls that I made before receiving my notebook on the 26th. But upon opening the box that my computer was in, I noticed that, first it came with no 'support' cds and no operating system cd (i.e. windows XP media edition cd was missing). Okay, no big deal. Oh, what is this? No power adapter. I understand that the computer has a great battery life, but I dont think it will last so long as I wont need to charge it.

So what do I do? I phone Dell. After navigating through the endless maze of menus. I am told that they are closed weekends. Nice, now I have to wait 2 more days to see if I can resolve this mess. On the 28th, I phone customer care. They transfer me to hardware support. I tell the agent that my computer shipped without various components. The agent then asks me, how long have I had this problem? How long have I had this problem!?! Probably since I opened the box. What kind of question is that? These call 'support' agents really need to start thinking for themselves. So, after the agent finally gets it, I ask, how long will it take to get my power supply? The agent replies, 1-2 weeks. All of a sudden, I snapped and I asked to speak to their supervisor. The supervisor then assured me that in a few days I would receive my adaptor. I did, on the 29th. Unfortunately, no discs.

But wait, what is this. I have another item in my order status window. It says that the discs are coming and that the total cost is $25? Now I have to pay for the discs? What a mess. I phone customer support and ask to speak to a supervisor. The agent tries to help me. At the end, I ask for the supervisor. The agent tells me that he will transfer me to him, and he places me on hold.

10 minutes later I hang up. How long can I be placed on hold? I think I will place Dell on hold from now on. I am strongly urging anyone contemplating a purchase from Dell to rethink the purchase. I strongly recommend going to a physical store, where customer representatives (employees) treat you properly. I was told 4 times that a supervisor would be phoning me in a couple of hours. I think that their watch must be slow, because it has been at least a few days since I was told this.

Dell use to be known for customer support. If you do buy from Dell, god forbid that something should go wrong with your order or worse, your computer. You will have to jump through hoops trying to correct it. The worst part is, Dell doesnt think that your time matters and you will be on hold for hours. In total, I must have spent about 29hours on the phone. Do yourself a favor and walk to your local computer store and buy your computer there. You might pay $50 dollars more, but at least you will be taken care of.