Develop Reference

Getting the selectionLayer.getSelectedCells() as empty but not always

When I select a cell and start typing any value it edits the cell.
But when I am sorting few columns(2 to 3) by default using this code below,
natTable.doCommand(new SortColumnCommand(sortHeaderLayer, i, true, sortColumn.getSortDirection()));
and then select cell and start typing for first time or maybe first few times it edits then it won't.
When I debug the code I found that I was getting the selected Cells as empty after few successful editing, and that happens randomly like sometimes after 1 or 2 or 4 .. successful editing, then the selected Cell becomes empty. The cell is selected and is clearly visible but still we get empty in the code.
ActivateEditorAction.run()
The above code is used for the Action for the cell editing on selection. In the else block of the synchronized block when we are checking for isSelectionAndTypedKeyValidForEditing(), there the selected cells is coming as empty, not always but once it starts coming as empty then it keeps on coming as empty all the time even though selection is visible on the table.
Code for the function isSelectionAndTypedKeyValidForEditing()

There are certain events that cause a selection clearing. By default sorting is causing such an event.
If you are using GlazedLists you should also be aware that there are multiple events that are fired in case of sorting. The GlazedListsEventLayer tries to squash those events to a single event, but for huge lists it can happen that still multiple events are fired if the time frame in which GlazedLists is firing events is longer than the squashing time.
Maybe you are hitting a concurrency issue somewhere. There is not enough information about your NatTable setup and too much custom code that overrides the default configuration.
Apart from this information it seems to be a quite specific issue that depends on your configuration and your custom code. And that seems to be much more complicated than to be solved easily via Stackoverflow. IMHO you need professional support in this area. Some project members offer sponsored support in that area.

Is there a much simpler or shorter version of this code using a button

I'm sorry if the title is vague. It's because I don't know exactly what it is called.
I am creating a program for a school project and I'm trying to figure out a shorter version of a code that I already got.
The interface looks like this:
Interface
The other parts of the program are not really necessary to put on here. They just input texts/strings in the first row textfields and shifts down one column every time new info is put in the first row.
The buttons on the right (the ones with the [x]) are the ones that are coded. They remove the text/string in the row next to them and shifts up the texts from below (if there are any) by one column.
The code for the first button is such:
CC01.setText(CC02.getText());
SC01.setText(SC02.getText());
SU01.setText(SU02.getText());
SD01.setText(SD02.getText());
SR01.setText(SR02.getText());
CC02.setText(CC03.getText());
SC02.setText(SC03.getText());
SU02.setText(SU03.getText());
SD02.setText(SD03.getText());
SR02.setText(SR03.getText());
CC03.setText(CC04.getText());
SC03.setText(SC04.getText());
SU03.setText(SU04.getText());
SD03.setText(SD04.getText());
SR03.setText(SR04.getText());
CC04.setText(CC05.getText());
SC04.setText(SC05.getText());
SU04.setText(SU05.getText());
SD04.setText(SD05.getText());
SR04.setText(SR05.getText());
CC05.setText(CC06.getText());
SC05.setText(SC06.getText());
SU05.setText(SU06.getText());
SD05.setText(SD06.getText());
SR05.setText(SR06.getText());
CC06.setText(CC07.getText());
SC06.setText(SC07.getText());
SU06.setText(SU07.getText());
SD06.setText(SD07.getText());
SR06.setText(SR07.getText());
CC07.setText(CC08.getText());
SC07.setText(SC08.getText());
SU07.setText(SU08.getText());
SD07.setText(SD08.getText());
SR07.setText(SR08.getText());
CC08.setText(CC09.getText());
SC08.setText(SC09.getText());
SU08.setText(SU09.getText());
SD08.setText(SD09.getText());
SR08.setText(SR09.getText());
CC09.setText(CC10.getText());
SC09.setText(SC10.getText());
SU09.setText(SU10.getText());
SD09.setText(SD10.getText());
SR09.setText(SR10.getText());
CC10.setText("");
SC10.setText("");
SU10.setText("");
SD10.setText("");
SR10.setText("");
So, yes, I have ten of these buttons. And the code for each button reduces by one 5-line code. For example, Button1's code is the one you see up top, then Button2's code starts from the [CC02...], the Button3 starts from [CC03], etc.
I think I used the brute force method of this code which I don't think is efficient and makes my code too long (the code for the ten [x] buttons alone is around 400 lines).
I asking of there is a much shorter way of doing this method.
Thanks.

Java GUI architecture for larger project

I want to make an app, which will work as interface to several servers.
Why: In web iface provided by default (and we cannot change it) are few things we miss, few could be done better and for sure automation of some stuff would make the job easier.
What do I have: almost finished classes for communication with web interface of a server app.
GUI description:
For some kind of version 0.1: text field for username, radio button to select server and one "go" button. Then several (4-12) action buttons to operate on data, 2x text area with results, one label with some text data - I can manage this.
Then I need to view the data - grid MxN which will load the data, expected size: 7-15 columns, usually 10 rows or less, but rarely it can go over 1k (or even more, but I don't need all to be visible to the user in that case).
What I need: simply an advice.
I wish to start with a simple version (and I'm working on that already, but I'm stuck on too many things - 95% cos and absolutely new to GUI and 5% cos I'm new to java).
I've checked many tutorials, but they're all simple.
Real questions:
1) Verify. In MVC controller should handle all user actions - is it done by view's method which is something like button.addActionListener(param); anotherButton.addActionListener(paramp; ...?
1b) I've seen all implemented via one (nested) class, which was then checking source or smth - is that ok? There will be a lots of buttons etc.
2) How to implement the data grid, when I need to take actions on click / dbl click?
4) First row is header, the rest should be scroll able - should it be in the grid or outside (its own grid):
4a) How to make sure header's size (width) will be the same as in data (I don't want to set up straight size)
4b) I failed to create anything scrollable so far, but thats my bad I guess. How to ensure header will hold on a place and the rest can be scrolled?
5) How should be "data update" implemented? I've got JPanel from which I remove grid component and then I make new one and add data into it (simple, but perhapss there is another way). One of first enhancements will be sorting - use the same way I used for new content?
Thanks a lot for any answer, I know this is not very specific, but example I've found are too simple.
I plan a lots of enhancements, but thats in the future and I don't mind to rework GUI/Controller several times, at least, I'll practise, but I don't want to finish one part of the code and realise I've got to rewrite half of a controller and 1/4 of a view to make it possible.
Note: I plan to use this at work as my tool (if things go right, I could make 25-50% of my work by few clicks :-)
So I really mean this).
Note#2: I'm not new to programing, but I've never created GUI (which is why I've got GUI with menu bar with 2 items and 3 components and almost done web-iface connections).
Note#:3 dragable data header, tabbed data view - thats the plan for the future :-)

MVC in Swing is examined here; use nested classes for ease in prototyping and creating an mcve for future questions; as the need arises, nested classes can be promoted to separate classes having package-private access.
Use JTable; its flyweight implementation of renderers is good for organizing data by row and column.
Item three does not exist, but "always remember to translate cell coordinates" if you plan to drag columns or sort rows.
Use a JScrollPane to keep the table header stationary.
Update the TableModel, and the listening view will update itself in response.

If you are interested not only from the event/messaging architecture, but also on handling mouse/keyboard input, hovering detection, widgets, temporary menus, form re-sizing with widget alignment, dragging and dropping etc. I can advice you to look at this question and my answer with helpful resources.

Tracking data offset of data in a table to retrieve the previous/next subset on table scroll

I am writing a browser based application using GWT and making use of websql (yes, I know it is deprecated). I have created a custom table widget (based on FlexTable) and enabled it to scroll with the help of some CSS trickery. What I am striving to achieve (without much success) is that when the user scrolls to the start/end of the current data in the table, an event is fired and the next subset of X rows is returned from the websql DB and replaces the data currently in the table. In order for this to work, I need to keep track of the data offset in the table widget so that I can pass this to the query and use the limit and offset functions of SQL to return the required data. However, I just cannot seem to get the logic right to implement the data offset tracker within the widget. Another complication is that I need the table to be able to scroll 'into the past' (so to speak), so that it can retrieve data from before the initial start point when the table loads.
I have been at this for a number of days now and just cannot seem to get it right. So I was wondering/hoping that someone might be able to point me in the right direction (PLEASE!).
Thanks in advance
Tim

I am not sure why this is causing a problem.
int page = 0;
// when you hit the bottom
page++;
loadData(page);
// when you hit the top
if (page > 0) {
page--;
loadData(page);
}

Tim I think it is not a good idea controlling the scroll with CSS trickery.
I have done something similar soon and controlling all the logic (pagination, scroll positions,...).
What I suggest to use is a gwt's scrollPanel, a HasData widget (like a cellList) your custom AbstractCell (class which is rendered for each row of your list) and asyncDataProvider ( which gives you the onRangeChange handler for asking to your server when the range data display has changed).
You can force/fire that event when in scrollPanel.addScrollHandler detects you are arriving to the end.
If you want to see all of this in action have a look into (click on source code): http://gwt.googleusercontent.com/samples/Showcase/Showcase.html#!CwCellList
EDIT [according comment below]:
A. If you want to override the data (in the example is X+X+X...) with the new retrieved just maintain always the same range of data displayed [display.setVisibleRange(0, newPageSize);], and start from 0 when you render the new data (on your RangeChange listener).
B. If you need to have control over up and down scrolls instead of taking advantage of the used events internally on the cellList (basically onRangeChange), you can create your custom events and fire them (this option could be easier for your colleagues for understanding everything). And do not worry about controlling up and down scrolls, inside the ShowMorePagerPanel.java you can see a simple example of knowing up and down controls.
Anyway, I did not explain more detailed because I did not see you very convinced to use CellList approach (and I was using my tablet :D ).
If you change your mind, just let me know and I write for you a proper example step by step (this part could be tricky, so if you are lost it is normal ;) ).

Printing data to a pre printed form/stationery

We have a requirement where we already have pre printed stationery and want user to put data in a HTML form and be able to print data on that form. Alignment/text size etc are very important since the pre-printed stationery already has boxes for each character. What could be a good way to achieve this in java? I have thinking of using jasper reports. Any other options? May be overlay image with text or something?
Also we might need to capability to print on plain paper in which case the boxes needs to be printed by our application and the form should match after the printed with the already printed blank stationery containing data.
Do we have some open source framework to do such stuff?

Jaspersoft reports -- http://sourceforge.net/projects/jasperreports/
You will then create XML templates, then you will be able to produce a report in PDF, HTML, CSV, XLS, TXT, RTF, and more. It has all the necessary options to customize the report. Used it before and recommend it.
You will create the templates with iReport then write the code for the engine to pass the data in different possible ways.
check http://www.jaspersoft.com/jasperreports
Edit:
You can have background images and overlay the boxes over it and set a limit on the max character size ... and many more
It is very powerful and gives you plenty of options
Here is one of iReport's tutorial for a background image http://ireport-tutorial.blogspot.com/2008/12/background-image-in-ireport.html

The big problem when printing form content that has been filled in electronically, is aligning it correctly on the pre-printed form. You may get content to align for one printer, but when you use another it is completely misaligned.
Fly Software have a form design product called InForm Designer that gets around the problem nicely by allowing users to specify and save vertical and horizontal offsets for printers. This ensures filled in form content is always aligned. I've tried it and it works perfectly. Take a look for yourself here...
http://www.flysoftware.com/products/inform_designer/overview.asp
It might be worth implementing a printer offset similar to InForm's in your own application (if possible).

Some things to think about.
First in terms of the web page, do you want use the stationery as the form layout?
Does it have to be exact?
Combed boxes (one for each character)
Do you want to show it like that on the web page, or deal with the combing later.
How are you going to deal with say a combed 6 digit number. Is this right aligned. What if they enter 7 digits. Same for text. what if it won't fit.
Font choices, we had a lot of fun with W...
How aligned do you want the character within the box, what font limitations does that imply, some of the auto magic software we looked at did crap like change the size of each character.
Combed editing is a nightmare, we display combed, but raise an edit surface the size of the full box on selection.
Another thing that might drive you barking mad, you find find small differences in the size and layout of the boxes, so they look okay from a distance but a column of boxes sort of shifts about by a pixel. Some of testing guys had to lend us their electron microscopes, so we could see how many ink molecules we were out by. :(
Expect to spend a lot of time in the UI side of things, and remember printed stationery changes, so giving yourself some sort of meta description of the form to start with will save you loads of trouble later on.