final answer to lazy initialization of Java singleton object
main idea: let Java JVM do the synchronization
static class SingletonContainer{
private static Singleton singleton = new Singleton();
public static Singleton getInstance(){
return singleton;
}
}
http://en.wikipedia.org/wiki/Initialization_on_demand_holder_idiom
- posted by Pop @ 12:42 PM
JavaScript Quine
If in a browser, replace the "print" with "alert"
print((function(){return"print(("+arguments.callee.toString().replace(/\s/g,"")+")())";})())
- posted by Pop @ 4:13 PM
write content to iframe
using ifrm.doc.open()/write()/close()
But not perfect for IE7 due to some cross-site issue
function submitFormByAjax(targetId){
var form = dojo.byId("tab_form"); // save ref to form
dojo.xhrPost( {
form: form,
load: function(data) {
// set the form's HTML to be the response
var ifrm = document.getElementById(targetId);
/*
if(ifrm.contentDocument)
ifrm.doc = ifrm.contentDocument;
else if(ifrm.contentWindow)
ifrm.doc = ifrm.contentWindow.document;
else if(ifrm.document)
ifrm.doc = ifrm.document; */
ifrm.doc = ifrm.contentWindow.document;
ifrm.doc.open();
ifrm.doc.write(data);
ifrm.doc.close();
dijit.byId("loadingDialog").hide();
}
});
dijit.byId("loadingDialog").show();
}
--
Pop (Pu Liu)
- posted by Pop @ 3:27 PM
a unified way to display svg in browsers
1. server side
a. using flamingo tool
java -cp flamingo-tst.jar:flamingo.jar:batik-all.jar:xml-apis-ext.jar:xml-apis.jar test.svg.SVGApplicaiton
to convert SVG to Java2D class file
b. The generated Java2D class file can in turn create the JPEG file to be displayed in browser
2. dojo client side
using svg2gfx.xsl (dojox.gfx.demos.data) to convert SVG to JSON file which can be rendered by dojox.gfx
--
Pop (Pu Liu)
- posted by Pop @ 12:37 PM
T42, Ubuntu, Gusty, boot up too slow
Ajust the xres and yres to 1024X768
then run
sudo update-usplash-theme usplash-theme-ubuntu
This should fix the problem
--
Pop (Pu Liu)
- posted by Pop @ 7:44 PM
Re: Ubuntu font problem
Re: Ugly fonts on UTF-8 encoded Chinese webpages, etc.
I just now solved this problem!
You should (don't have to) install the firefly font. Google it. It's
cleaner and does look better.
Then you need to disable antialiasing.
I had to create a file called .fonts.conf and place it in my home
directory.
Here is what the file looks like:
<?xml version="1.0"?>
<!DOCTYPE fontconfig SYSTEM "fonts.dtd">
<fontconfig>
<!-- Disable font alias for Chinese <= 16px -->
<match target="font">
<test qual="any" name="family" compare="eq">
<string>AR PL Mingti2L Big5</string>
<string>AR PL SungtiL Big5</string>
<string>AR PL New Sung</string>
<string>AR PL ShanHeiSun Uni</string>
<string>AR PL ZenKai Uni</string>
<string>Ming(ISO10646)</string>
<string>MingLiu</string>
<string>PMingLiu</string>
<string>Kochi Mincho</string>
<string>Baekmuk Dotum</string>
</test>
<test name="pixelsize" compare="less_eq">
<double>16</double>
</test>
<edit name="antialias">
<bool>false</bool>
</edit>
<edit name="hinting">
<bool>true</bool>
</edit>
</match>
<alias>
<family>serif</family>
<prefer>
<family>Bitstream Vera Serif</family>
<family>Times New Roman</family>
<family>Times</family>
<family>AR PL New Sung</family>
<family>AR PL ShanHeiSun Uni</family>
<family>AR PL Mingti2L Big5</family>
<family>AR PL SungtiL GB</family>
<family>SimSun</family>
</prefer>
</alias>
<alias>
<family>sans-serif</family>
<prefer>
<family>Bitstream Vera Sans</family>
<family>Arial</family>
<family>Verdana</family>
<family>Helvetica</family>
<family>AR PL New Sung</family>
<family>AR PL ShanHeiSun Uni</family>
<family>AR PL kaitiM Big5</family>
<family>AR PL kaitiM GB</family>
</prefer>
</alias>
<alias>
<family>monospace</family>
<prefer>
<family>Bitstream Vera Sans Mono</family>
<family>Courier New</family>
<family>Courier</family>
<family>AR PL New Sung</family>
<family>AR PL ShanHeiSun Uni</family>
</prefer>
</alias>
</fontconfig>
The fonts are no longer blurry and mismatched. This worked for the whole
system, firefox, everything. Let me know if you have any problems.
On Mon, 04 Aug 2008 16:05:03 -0400, Pu Liu <pop.liu@gmail.com> wrote:
> in home directory, create a hidden file .fonts.conf
>
> with the following content
>
>
> <?xml version="1.0"?>
> <!DOCTYPE fontconfig SYSTEM "fonts.dtd">
> <fontconfig>
> <!-- Disable font alias for Chinese <= 16px -->
> <match target="font">
> <test qual="any" name="family" compare="eq">
> <string>AR PL New Sung</string>
> <string>AR PL ShanHeiSun Uni</string>
> <string>AR PL ZenKai Uni</string>
> <string>Ming(ISO10646)</string>
> <string>MingLiu</string>
> <string>PMingLiu</string>
> <string>Kochi Mincho</string>
> <string>Baekmuk Dotum</string>
> </test>
> <test name="pixelsize" compare="less_eq">
> <double>16</double>
> </test>
> <edit name="antialias">
> <bool>false</bool>
> </edit>
> <edit name="hinting">
> <bool>true</bool>
> </edit>
> </match>
> <alias>
> <family>serif</family>
> <prefer>
> <family>Bitstream Vera Serif</family>
> <family>Times New Roman</family>
> <family>Times</family>
> <family>AR PL New Sung</family>
> <family>AR PL ShanHeiSun Uni</family>
> <family>AR PL Mingti2L Big5</family>
> <family>AR PL SungtiL GB</family>
> <family>SimSun</family>
> </prefer>
> </alias>
> <alias>
> <family>sans-serif</family>
> <prefer>
> <family>Bitstream Vera Sans</family>
> <family>Arial</family>
> <family>Verdana</family>
> <family>Helvetica</family>
> <family>AR PL New Sung</family>
> <family>AR PL ShanHeiSun Uni</family>
> <family>AR PL kaitiM Big5</family>
> <family>AR PL kaitiM GB</family>
> </prefer>
> </alias>
> <alias>
> <family>monospace</family>
> <prefer>
> <family>Bitstream Vera Sans Mono</family>
> <family>Courier New</family>
> <family>Courier</family>
> <family>AR PL New Sung</family>
> <family>AR PL ShanHeiSun Uni</family>
> </prefer>
> </alias>
> </fontconfig>
>
>
> On Sun, Aug 3, 2008 at 10:07 AM, yuan <pop.liu@gmail.com> wrote:
>
>> a. subpixel rendering:
>> 1. go to a terminal and type:
>>
>> sudo dpkg-reconfigure fontconfig-config
>> Then select "Autohinter", "Always" and "No" when prompted.
>>
>> 2.
>> Code:
>> sudo dpkg-reconfigure fontconfig
>>
>> 3. restart X and rendering is beautiful!
>>
>>
>> b. System>Prefs>Appearance>Fonts
>>
>> LCD smoothing, then details. Hinting - Slight.
>>
>>
>
>
--
Using Opera's revolutionary e-mail client: http://www.opera.com/mail/
- posted by Pop @ 4:07 PM
Re: Ubuntu font problem
with the following content
<?xml version="1.0"?>
<!DOCTYPE fontconfig SYSTEM "fonts.dtd">
<fontconfig>
<!-- Disable font alias for Chinese <= 16px -->
<match target="font">
<test qual="any" name="family" compare="eq">
<string>AR PL New Sung</string>
<string>AR PL ShanHeiSun Uni</string>
<string>AR PL ZenKai Uni</string>
<string>Ming(ISO10646)</string>
<string>MingLiu</string>
<string>PMingLiu</string>
<string>Kochi Mincho</string>
<string>Baekmuk Dotum</string>
</test>
<test name="pixelsize" compare="less_eq">
<double>16</double>
</test>
<edit name="antialias">
<bool>false</bool>
</edit>
<edit name="hinting">
<bool>true</bool>
</edit>
</match>
<alias>
<family>serif</family>
<prefer>
<family>Bitstream Vera Serif</family>
<family>Times New Roman</family>
<family>Times</family>
<family>AR PL New Sung</family>
<family>AR PL ShanHeiSun Uni</family>
<family>AR PL Mingti2L Big5</family>
<family>AR PL SungtiL GB</family>
<family>SimSun</family>
</prefer>
</alias>
<alias>
<family>sans-serif</family>
<prefer>
<family>Bitstream Vera Sans</family>
<family>Arial</family>
<family>Verdana</family>
<family>Helvetica</family>
<family>AR PL New Sung</family>
<family>AR PL ShanHeiSun Uni</family>
<family>AR PL kaitiM Big5</family>
<family>AR PL kaitiM GB</family>
</prefer>
</alias>
<alias>
<family>monospace</family>
<prefer>
<family>Bitstream Vera Sans Mono</family>
<family>Courier New</family>
<family>Courier</family>
<family>AR PL New Sung</family>
<family>AR PL ShanHeiSun Uni</family>
</prefer>
</alias>
</fontconfig>
a. subpixel rendering:
1. go to a terminal and type:
sudo dpkg-reconfigure fontconfig-config
Then select "Autohinter", "Always" and "No" when prompted.
2.
Code:
sudo dpkg-reconfigure fontconfig
3. restart X and rendering is beautiful!
b. System>Prefs>Appearance>Fonts
LCD smoothing, then details. Hinting - Slight.
--
Pop (Pu Liu)
- posted by Pop @ 4:05 PM
ubuntu, locale generation hangs problem, a fix which works
There's a easy workaround.
The /usr/share/locales/install-language-pack script, used in the postinst of the language-packs packages, invokes /usr/sbin/locale-gen.
locale-gen makes some work and finally it executes localedef, that hangs up. Looking the "ps -aux" output, copying the localedef execution order, deleting the option "--no-archive" it works correcty. It's a mistery, the problem is present when the locale information is stored in locale_country.charset directory inside /usr/lib/locale/, for instance, es_ES.utf-8.
This locale-gen shell script uses the /etc/belocs/locale-gen.conf conffile of belocs-locales-bin package, which has the variable ARCHIVE with the "no" value. By changing this value to "yes", the locale information is stored in one unique file /usr/lib/locale/locale-archive. And the most important, then localedef works, does not hangs up. Now we can install, reinstall language-packs and so on.
Greetings and a lot of luck
--
Pop (Pu Liu)
- posted by Pop @ 2:43 PM
obscured URL
http://email.about.com/gi/dynamic/offsite.htm?site=http://www.pc-help.org/obscure.htm
In Sum
URLs can be obscured at least three ways:
- Meaningless or deceptive text can be added after "http://" and before an "@" symbol.
- The domain name can be expressed as an IP address, in dotted-decimal, dword, octal or hexadecimal format; and all of these formats have variants.
- Characters in the URL can expressed as hexadecimal (base 16) numbers.
--
Pop (Pu Liu)
- posted by Pop @ 3:56 PM
POST redirect issue in HTTP
http://www.theserverside.com/tt/articles/article.tss?l=RedirectAfterPost
t is interesting that PRG pattern exploits non-standard behavior of browsers and web servers. HTTP 1.1 defines several redirect response codes in 3xx range. Some of these codes require browser to use the same request type, some require to change POST to GET, some require to obtain user confirmation when request is redirected. Turns out that many of these requirements are not implemented by popular browsers. Instead, they have common de-facto behavior, like redirecting POST to GET without confirmation if received 302 code. This feature is used by PRG pattern.
This behavior is wrong for 302 ("Found") code, but is absolutely correct for 303 ("See Other") code. Still, few servers return 303 when redirect with GET method is required. HttpResponse.sendRedirect method does not allow to set response code, it always returns 302. It is possible to emulate sendRedirect(url) behavior using the following methods:
res.setStatus(res.SC_SEE_OTHER);
res.setHeader("Location",url);
where SC_SEE_OTHER is the proper 303 code, but sendRedirect provides some additional service like resolving relative addresses, so this is not a direct snap-in. The discrepancy between browser behavior and HTTP standard can be resolved, if 302 and 303 codes considered equal, and another code for proper 302 behavior were created.
In any case, I doubt that browser vendors will change implementation of 302 response code, because too many applications relay on it. The good thing is that modern browsers understand and correctly process 303 code, so if you want to be sure, return 303 instead of 302--
Pop (Pu Liu)
- posted by Pop @ 1:40 PM
