Great tool for any programming : Logging

I found logging indispensable when I was developing for my software engineering class.
Being ignorant I created my own simple api to achieve my purpose. But as in my internship I discovered log4J an log4net. It was like a bliss when I was debugging.
Gwt natively has only one level of logging: to console using GWT.log().
I discovered this very cool logging api written by allen sauer and fred sauer. It is very much like log4j, but for gwt.
You can find it at
http://code.google.com/p/gwt-log/
and the tutorial to set it up at
http://developerlife.com/tutorials/?p=229
The above tutorial also teaches how to set up third party libraries with gwt.

How to use Enums in Switch (java)

In a small example I am going to tell you how to use enums in switch.

Enums is a good practice of grouping a list of items which fall in similar category. If you want to learn more about enums look in to here.

Now I assume that you know about enums and now lets see how do we swtich on them.

This is my enum set

public static enum Navigation{SCROLL,DROP_DOWN,NONE}

Now you need to switch on the enum.

we write

//choice is

Navigation navigationChoice = Navigation.SCROLL;

switch (navigationChoice) //once decide to switch on the Enumof type navigation choice.

{

Since we already are switching on the Naviagation enum Java knows to look only with the Navigation enum the context is set to Navigation enum so we need not have fully qualified name Navigation.SCROLL . We can just use SCROLL instead.

CORRECT WAY TO DO:

case SCROLL: {...}

CORRECT: We use the unqualified name i.e. SCROLL and Java will automatically know that we are asking for scroll in the navigation options as we are switching on a Navigation enum constant.

WRONG WAY TO DO:

case Navigation.DROP_DOWN: {...}

This will give you error the follwing error

ERROR: The qualified case label Navigation.DROP_DOWN must be replaced with the unqualified enum constant DROP_DOWN

WRONG WAY TO DO:

case (NONE): {...}

This will give you error the follwing error

ERROR: Enum constants cannot be surrounded by parenthesis

}