log4j good logging tool

It is a very good logging tool. You only need to add log4j.properties or log4j.xml to configure.
Reference web page:
http://my.so-net.net.tw/idealist/Java/Log4j.html (chinese)
http://wiki.apache.org/logging-log4j/Log4jXmlFormat

Quartz Basic structure: (referenece book: Quartz Job Schedule Framework)

Classes:

1. Job - interface class

• provide method execute(JobExecutionContext c)
• JobExecutionContext - getJobDetail() to get the JobDetail instance.
• JobDetail contain the job name and JobDataMap instance from getJobDataMap.
• JobDataMap can help pass the data inside the Job.

Sample:

Create JobDetail, JobDataMap and Trigger.

JobDetail jobDetail = new JobDetail("ScanDirectory", Scheduler.DEFAULT_GROUP, ScanDirectoryJob.class);

// Configure the directory to scan
jobDetail.getJobDataMap().put("SCAN_DIR", "c:\quartz-book\input");

// Create a trigger that fires every 10 seconds, forever
Trigger trigger = TriggerUtils.makeSecondlyTrigger(10); trigger.setName("scanTrigger");

// Start the trigger firing from now
trigger.setStartTime(new Date());

// Associate the trigger with the job in the scheduler scheduler.scheduleJob(jobDetail, trigger);

For CronTrigger

It could be help to develop a more complex trigger than SimpleTrigger.

Table 5.1. Quartz Cron Expressions Support up to Seven Fields

Name	Required	Allowed Values	Special Characters
Seconds	Yes	059	, - * /
Minutes	Yes	059	, - * /
Hours	Yes	23	, - * /
Day of Month	Yes	131	, - * ? / L W C
Month	Yes	112 or JAN-DEC	, - * /
Day of Week	Yes	17 or SUN-SAT	, - * ? / L C #
Year	No	Blank or 19702099	, - * /
The names of months and days of the week are not case sensitive. FRI is the same as fri.

Understanding the Special Characters

As with UNIX cron, Quartz cron expressions support special characters that can be used to create more complicated execution schedules. However, Quartz supports many more than the standard UNIX cron expression.

The * Character

Using the asterisk (*) in a field indicates that you want to include all legal values for that field. For example, using this character in the month field means to fire the trigger for every month.

Example expression:

0 * 17 * * ?

Meaning: Fire the trigger every minute, every day starting at 5 PM until 5:59 PM. It stops at 5:59 PM because the value 17 is in the hour field, and at 6 PM, the hour becomes 18 and doesn't agree with this trigger until the next day at 5 PM.

Use the * character when you want the trigger to fire for every valid value of the field.

The ? Character

The question mark (?) character can be used only in the dayofmonth and dayofweek fields, but not at the same time. You can think of the ? character as "I don't care what value is in this field." This is different from the asterisk, which indicates every value for the field. The ? character says that no value was specified for this field.

The reasons a value can't be specified for both fields are tough to explain and even tougher to understand. Basically, if a value was specified for each, the meaning would become ambiguous: Consider if an expression had the value 11 in a field for the day of the month and a value of WED in the field for the day of the week. Should that trigger fire only on the 11th of the month if it falls on a Wednesday? Or should it fire on both the 11th and every Wednesday? The ambiguity is removed by not allowing a value in both fields at the same time.

Just remember that if you specify a value in one of the two fields, you must put a ? in the other.

Example expression:

0 10,44 14 ? 3 WED

Meaning: Fire at 2:10 PM and 2:44 PM every Wednesday in the month of March.

The , Character

The comma (,) character is used to specify a list of additional values within a given field. For example, using the value 0,15,30,45 in the second field means to fire the trigger every 15 seconds.

Example expression:

0 0,15,30,45 * * * ?

Meaning: Fire the trigger on every quarter-hour.

The / Character

The slash (/) character is used to schedule increments. We just used the comma to increment every 15 minutes, but we could have also written it like 0/15.

Example expression:

0/15 0/30 * * * ?

Meaning: Fire the trigger every 15 seconds on the hour and half-hour.

You can't increment beyond the fields range. For example, you can't specify 30/20 in the second field and expect the scheduler to fire correctly.

The Character

The hyphen (-) character is used to specify a range. For example, 3-8 in the hour field means "the hours 3, 4, 5, 6, 7, and 8." The fields will not wrap, so values such as 50-10 are not allowed.

Example expression:

0 45 3-8 ? * *

Meaning: Fire the trigger on 45 past the hours 3 AM through 8 AM.

The L Character

The L character represents the last allowed value for the field. It is supported by the dayofmonth and dayofweek fields only. When used in the dayofmonth field, it represents the last day of the month for the value specified in the month field. For example, when the month field has JAN specified, using L in the dayofmonth field would cause the trigger to fire on January 31. If SEP was specified as the month, then L would mean to fire on September 30. In order words, it means to fire the trigger on the last day of whatever month is specified.

The expression 0 0 8 L * ? means to fire the trigger at 8:00 AM the last day of every month. The * character in the month field gives us the "every month" part.

When the L character is used in the dayofweek field, it indicates the last day of the week, which is Saturday (or, numerically, 7). So if you needed to fire the trigger on the last Saturday of every month at 11:59 PM, you could use the expression 0 59 23 ? * L.

When used in the dayofweek field, you can use a numerical value in conjunction with the L character to represent the last X day of the month. For example, the expression 0 0 12 ? * 2L says to fire the trigger on the last Monday of every month.

Don't Use Range or List Options with the L Character Although you can use a day of the week (17) value in conjunction with the L character, you're not allowed you to use a range of values or a list with it. This will produce unpredicted results.

The W Character

The W character stands for weekday (MonFri) and can be used only in the dayofmonth field. It is used to specify the weekday that is nearest to the given day. Most business processes are based on the work week, so the W character can be very important. For example, a value of 15W in the dayofmonth field means "the nearest weekday to the 15th of the month." If the 15th was on a Saturday, the trigger would fire on Friday the 14th because it's closer to the 15th than Monday, which would be the 17th in this example. The W character can be specified only when the day of the month is a single day, not a range or list of days.

The # Character

The # character can be used only in the dayofweek field. It's used to specify the nth XXX day of the month. For example, if you specified the value 6#3 in the dayofweek field, it would mean the third Friday of the month (6 = Friday and #3 means the third one in the month). Another example of 2#1 means the first Monday of the month (2 = Monday and #1 means the first one of the month). Note that if you specify #5 and there is no 5 of the given day of the week in the month, no firing will occur that month.

Howtoforge

It is a very good site to talk about the Linux configure and some news.
http://www.howtoforge.com/

A very good article for install Internet Explorer on Ubuntau
http://www.howtoforge.com/ubuntu_internet_explorer

JBoss rules

JBoss rules is a library. It provide the DRL file to store the rules.
DRL file is represent one package.
Under DRL file it contains many rule with a identify name with package.

JBoss IDE for JBoss rules (necessary install in Eclipse 3.2.x) . It just add some views and DRL and DSL Editor. (so i think it just good for help you to check the syntax).

the programming steps:
1. PackageBuilder -> Package
2. RunBaseFactory -> RunBase -> add -> Package
3. RunBase -> new -> WorkingMemory
4. WorkingMemory -> assertObject for fireAllRules().

It will use all assertObjects in WorkingMemory to run for all rules except you have add filter for call method of fireAllRules();

DRL sytax:
rule :
rule "name"
while "condition"
then "process"
end

e.g.
rule "Your First Rule"
salience 10
when
$m : Man(age <> 25)
then
System.out.println("first : " + $m.getName());
mans.add($m);
end

rule "Your Second Rule"
salience 5
when
$m : Man(age > 25, $name : name)
then
System.out.println("second : " + $name);
end

note: if miss salience .. then all rule by default salience = 0.
If fireAllRules() "Your Second Rule" execute first and then "Your First Rule"

query:
query "name"
"condition"
end

e.g. DRL
query "test"
$man Man(age > 25);
end

e.g. Java
QueryResults qrs = WorkingMemory.getQueryResults("test");
qrs.size();

It could return all valid the query objects.

Personal comment:
From example most rule only check about the assertObject and update the state of object ... but never return anything ..... such as only true/false.
If you have other thing out of set state, you need to define global object to return.

oracle reverse enginee and select sql query with case

It is a important page to talk oracle walk though which table to reverse.
http://www.eveandersson.com/writing/data-model-reverse-engineering#columns

use Select sql query with case:
syntax
case when then
when then
...
else
end

sample:

select sal, case when sal < style="font-family: monospace;">'category 1'
                 else 'category 4' 
            end 
from emp;

Open source free Java docking framework and discovery new DB Engine

MyDoggy . Open source free Java docking framework
http://mydoggy.sourceforge.net/
I tried the tutorial. It is a very simple docking framework. It cannot place more than panel on the same dock.

H2 Database Engine. it seems better than hypersonic SQL database
http://www.h2database.com/html/frame.html

oracle 10g FlashBack function

It is a simple function act as recycle bin to store the drop table ... etc.
http://dbaoracle.itpub.net/post/901/271132

• Issue one of the following statements:

  ALTER SESSION SET recyclebin = ON/OFF;
  

SELECT object_name, original_name FROM dba_recyclebin

The recycle bin table name is "dba_recyclebin"

How to purge the recycle bin:

PURGE TABLE BIN$jsleilx392mk2=293$0;
or
PURGE RECYCLEBIN;

Maybe you also can append PURGE after drop table statement.
DROP TABLE ABC PURGE;
then the table will direct delete not add to recycle bin.

Spring JDBC connection

Download Spring.jar version 2.0

- configure the xml
- DriverManagerDataSource class help you to configuration and get the connection from database
- DataSourceTransactionManager class that help to create the transaction when you want to insert or update the database.
- Create your own Dao Class, it just like a class represent a table but i do not help you to maintain the Has-a relationship.

In my sample project (you can import to Eclipse)
App.java - contain main method to execute (but i am connecting SQL Server... you can teach the concert)
OrderDao - interface class to represent what method contain in OrderDaoImpl
OrderDaoImpl - contain code to process
Order - Order represent the table Orders in Database
OrderRowMap - It help you to mapping value from resultset to create the object instance

It contain the method call "public Object mapRow(ResultSet rs, int index)" from the name you know it for mapping.

Use single value to store multiple settings

example use binary compare:

static final int problem1 = 0x1;
static final int problem2 = 0x10;
static final int problem3 = 0x100;

- when user selected problem1 and problem2
we can store the value like that

int userSelVal;
userSelVal = userSelVal | problem1;
userSelVal = userSelVal | problem2;

-then you will ask how to know the user is selected problem1 and problem2

if((userSelVal & problem1) == problem1){
//represent user select problem1
System.out.println("User is selected problem1");
}

if((userSelVal & problem2) == problem2){
//represent user select problem2
System.out.println("User is selected problem2");
}

if((userSelVal & problem3) == problem3){
//represent user select problem3
System.out.println("User is selected problem3");
}

- via to compare the binary position value, each position represent one setting then we can store int binary size setting in one int.

Create a signed jar

Create a signed Jar file

description:
need to use keytool and jarsigner

C:\> keytool -genkey -validity
C:\> keytool -selfcert -validity -keypass
C:\> jarsigner test.jar mykey

http://www.ccw.com.cn/htm/center/prog/02_7_8_4.asp
http://www.owasp.org/index.php/Signing_jar_files_with_jarsigner#Create_a_new_DSA_Key_Pair_for_Bob

Not all the detail, it will be edit later but you can use the upper command to finish it.

signed jar for web start application.

Ant jar file ( Do you remember the script? )

Very simple Ant to create jar file

*project name="XDoclet Generator" default="jar"*
*target name="jar" description="Create binary distribution after xxx"*
*!-- Create application JAR file --*
*mkdir dir="MyJarDir"*
*jar jarfile="MyJarDir/MyJarFile.jar" basedir="classes"*
*/jar*
*/mkdir*

Simple easy under stand but let me write down.... thx. I easy forget

readExif php script

It is very simple sample only a few lines of code.

- description
It read the JPEG file's EXIF information, and use the DateTime value to separate the image file to different folder.

-execution
1. Set php installed folder in envirnment variable.
2. then you can directly type "php" to execute php script on local computer.
3. enable the in php.ini (it may locate on Windows / WINNT folder):
extension=php_mbstring.dll
extension=php_exif.dll

4. put readExif.php into the image folder.
5. type "php readExif.php"
6. It will process.

convert number to English words

I am finding the sample code to convert number to words.
I find one java sample:

reference: site
my own copy and modify code: my modify source file

It is quite simple to convert, just use a little bit time to understand

I think it can help to ppl no need to convert number when write cheque.

one-to-one bidirectional (in hibernate example) xDoclet

create xDoclet tag both one side
1. assume each user only have one car

user class reference car
car class reference user

2. identify From & To direction

assume that user (from) - car (to)
then user primary key store to car table (foreign key)

3. xDoclet tag

== code ==
car class:
/**
* @hibernate.many-to-one
* class = "local.sample.oo.User"
* column = "userId"
*/
public User getUser()
{
return _user;
}
== code ==

car is to --> so that is many-to-one relationship (from logic it is one-to-one but if both side one to one cannot be identify to & from)
column -> represent the user primary key store column on car table

== code ==
user class:
/**
* @hibernate.one-to-one
* cascade = "save-update"
*/
public Car getCar()
{
return _car;
}
== code ==

user is from -> so that is one-to-one relationship
cascade -> when update user, it also request car to update (if car is modified)

Simple Sample to use Spring, xDoclet and Hibernate

I just revision how to use Hibernate, you need to understand about the one-to-one, one-to-many, many-to-many before use the Hibernate. Hibernate is not very complicate but you don't use any tools to help develop the application with Hibernate, you will feel hard.
In my experience, I suggest to use Eclipse 3.1.x & JBoss IDE plugins to develop the Hibernate and Spring application.

I will provide the simple project. It demo how to create one-to-one, one-to-many, many-to-many.
You need to pay attention on :

1. persistent classes xDoclect's Hibernate tag.
2. Spring configuration xml file ( hibernate.xml) - datasource, hbm config, bean of spring
   
3. xDoclet configuration. Project > right click > property > XDoclect configuration

Hope this example can give you idea to use Spring and Hibernate.
** Sample download**

Useful resource to futher study Hibernate.
- HibernateGossip

Any problem, please feel free to contact me:
mingkit@gmail.com

Mylar is eclipse plugin for project management

Interest! I will read about it and write some article.
http://www-128.ibm.com/developerworks/java/library/j-mylar1/?ca=dgr-jw01Mylar-1

http://www.hibernate.org/43.html

MySQL add new user account

It is a very simple procedure but i usually forget. We also can search ther result from MYSQL homepage. Please login by root account.
mysql -u root

1. create user account.
- CREATE USER mingkit IDENTIFIED BY 'password';

2. grant right for the accout.
- for localhost
GRANT ALL PRIVILEGES ON *.* TO 'mingkit'localhost'IDENTIFIED BY 'password' WITH GRANT OPTION;

- for worldwide or certain ip
GRANT ALL PRIVILEGES ON *.* TO 'mingkit'%'IDENTIFIED BY 'password' WITH GRANT OPTION;