Hacking so Existing

Here are some notes when I was struggling to develop a web AIM client:

1. Download AIM SDK, both Windows and Linux
In Linux environment, you may already have NSS/NSPR libraries installed, if not following instructions to install it. You only need to run:

cd dist/release/
ln -s /usr/lib/libnspr4.so .
ln -s /usr/lib/libnss3.so .
ln -s /usr/lib/libnssckbi.so .
ln -s /usr/lib/libplc4.so .
ln -s /usr/lib/libplds4.so .
ln -s /usr/lib/libsmime3.so .
ln -s /usr/lib/libsoftokn3.so .
ln -s /usr/lib/libssl3.so .
ln -s /usr/lib/libfreebl3.so .
export LD_LIBRARY_PATH=/usr/local/tomcat/lib/

2. Get a developer key to use AIM SDK. The developer web site does not accept external email account, so create a new one. In fact, more new AIM screen names are needed, as testing AIM requires it.

3. Try to compile and run samples/accjsample:

cd samples/accjsample
javac -cp ../../dist/release/accjwrap.jar AccJSample.java Prefs.java
java -cp ../../dist/release/accjwrap.jar:./ AccJSample username password developerkey

But you may get error messasge like:

UNKNOWNVALUE
com.aol.acc.AccException: IAccSession_SignOn
at com.aol.acc.AccSession.SignOn(Native Method)
at com.aol.acc.AccSession.signOn(AccSession.java:113)
at AccJSample.(AccJSample.java:47)
at AccJSample.main(AccJSample.java:22)

But if you go into dist/release/ directory, where *.so are located, and run:

/usr/local/java/bin/java -cp ../../dist/release/accjwrap.jar:../../samples/accjsample/ AccJSample username password developerkey

You may get things running correctly:

[5/5/08 8:34 AM]: OnStateChange: Connecting, ACC_S_OK
[5/5/08 8:34 AM]: OnStateChange: Validating, ACC_S_OK
[5/5/08 8:34 AM]: OnStateChange: Transferring, ACC_S_OK
[5/5/08 8:34 AM]: OnStateChange: Negotiating, ACC_S_OK
[5/5/08 8:34 AM]: OnStateChange: Starting, ACC_S_OK
[5/5/08 8:34 AM]: OnStateChange: Online, ACC_S_OK
[5/5/08 8:34 AM]: OnUserChange: ACC_S_OK
…

That is because *.so may not be loaded correctly if they are not in the current working directory.

Someone says that inaccurate time may cause problems, so run:

/etc/init.d/ntpd start

to synchronize your server’s time.

4. following, it comes to the time that developing AIM desktop client, and then converting it into Java Servlet based AIM client. So, tutorial “Creating AIM-Enabled Application in Java” series are recommended.

5. And time to deploy your web AIM client to tomcat servlet container.

If your Tomcat 6 server is on Windows, you may need to copy all dist/release/*.dll into your %CATALINA_HOME%/bin/ folder, copy dist/release/accjwrap.jar into %CATALINA_HOME%/lib and restart Tomcat services to get things done. Deploy accjwrap.jar directly into webapps folder is not recommended, because you may want to restart your servlet application frequently while loading and unloading *.dll modules may cause “already loaded in another classloader UnsatisfiedLinkError” problems for Tomcat, which may result that you need to restart your Tomcat server.

If your Tomcat 6 server is on Linux, you also need to copy all dist/release/*.so into your $CATALINA_HOME/bin/ folder, copy dist/release/accjwrap.jar into $CATALINA_HOME/lib. And you need to modify your catalina.sh and add two lines:

LD_LIBRARY_PATH=$CATALINA_HOME/bin
cd $CATALINA_HOME/bin

And then restart Tomcat server.

Related links:

• Tomcat Native library on java.library.path
• Java Native Interface (JNI) - JNI Dll - java.library.path
• Java Linux issues with SDK
• AIM Custom Client Forum

I learned to use JavaCC these days. And I found that JavaCC is a great toolkit.

What is JavaCC?

JavaCC is short for Java Compiler Compiler. It is a parser or scanner generator for Java.

Java Compiler Compiler [tm] (JavaCC [tm]) is the most popular parser generator for use with Java [tm] applications. A parser generator is a tool that reads a grammar specification and converts it to a Java program that can recognize matches to the grammar. In addition to the parser generator itself, JavaCC provides other standard capabilities related to parser generation such as tree building (via a tool called JJTree included with JavaCC), actions, debugging, etc.

You can find a lot of language grammar and AST on its site too. I see that C++ and Java 1.5 grammar are there. JavaScript isn’t there. But I find out that Dojo toolkit’s JSLinker provides an ECMAScript 262 one. That is to say, you can create parser and parse C++, Java or JavaScript sources into your AST for any uses. Lots of great features can be imagined.

I spent about a week learning and using JavaCC. I completed a parser for an IDL language named CAR. I also built an Eclipse editor using the generated AST parser. Bang, all things seems working well: keyword hight-lighting, outline view, error probing, … Great toolkit!

Using JavaCC is quite simple, just download javacc-4.0.zip and unzip it, then following its examples tutorial. I sugguest you to start with JavaGrammars and VTransformer examples, as they are about Java grammar.

I think, later, given opportunity, I will try JavaCC out on other projects. Maybe my Java2Script compiler would be benefited from JavaCC.

P.S. Update:
There is a JavaCC Eclipse Plugin project, you can download the plugin to help you writing your syntax file.

They are really very puzzling. Please check them out:
Advanced Topics in Programming Languages: Java Puzzlers, Episode VI

Here is a task to challenge myself: Find the first k digits prime number. And k would be 16, 32, 64, 256, 1024, 8096, 65536, or even bigger.

And the most challenging thing would be most of key calculations will be performed in JavaScript engine hosted inside browsers. And a distributed algorithm will be designed. Algorithm which is similar to Google’s Map/Reduce will be designed. And Apache Hadoop’s Map/Reduce is also in references.

Any comments about this challenge? Or join me to design the algorithm! Or join the distributed computing game.

Keep tuned for how big the number k would be!

PS: After searching around Internet for existed prime number theories, I find out that k=16 is already a challenge for me! There are algorithms to find prime number in format of 2^p+1, whose digits may be bigger than 1000000. But there are not the 1st k-digits algorithms. According to theories, I should have to find out all prime numbers less than given n. But the count of prime numbers less than n is about n / ln (n), which is huge number already for k=16! So my first challenge would be 16.

Actually, Google Talk Client’s Java SWT desktop copy is the original source for Google Talk Client’s JavaScript copy.

And now it is available for download. Please take a trial.

Sources of Java2Script Google Talk will be available in the next week. Keep tuned.

If you ever use Eclipse trying to debug into Java’s system APIs, such as java.lang.String or java.math.BigInteger, you may find that even you can step over or step in, or have the correct source file open and the correct line of codes highlighted, you still could not see the local variables’ value and method’s parameters are shown in pattern of “arg0″, “arg1″ and so on.

Yes, you are already using JDK instead of JRE. But you still have the above problem. What’s wrong? It’s not a bug of Eclipse. It is all about the rt.jar along with the JDK (1.5 or 1.6). In Sun’s official JDK release, debug symbols are already packed into the rt.jar. But local variables’ debug information is not packed. Sun may consider that it is not OK to includes those local variables’ debugging information. That is the source of problem.

To solve this problem, you may need to upgrade to JDK 1.6. Download DEBUG jar file from
http://download.java.net/jdk6/binaries/
Double click it to install a new JDK. And configure your Eclipse to use the new JDK.

For JDK 1.5, recompiling rt.jar by yourself, or other information, please visit
http://forums.java.net/jive/thread.jspa?threadID=399&tstart=0
for a detailed discussion.

Just have a long waiting time for downloading the *.jar files, and always it comes to a security dialog notifying that the *.jar file is not signed or not signed by known CA while it requires unlimited local access and remote connection access!

How can I accept “Unlimited local access and remote connection access” for unknown *.jar application! Java Applet or Java Web Start really sucks.

http://dev.eclipse.org/newslists/news.eclipse.newcomer/msg13300.html

Add
org.eclipse.core.resources
in the Require-Bundle section in your plugin MANIFEST.MF file
and invoke code:

ResourcesPlugin.getWorkspace().getRoot().getProjects()