Saturday, June 21, 2008

Changes in the main window

Version 1.3 changes something in the main window:

  1. The buttons that are highlighted with a green rectangle hide or show trees. For example the first button hides the Matrix tree. Clicking it once again the Matrix tree is displayed again.
    The second button toggles the Function tree visibility, the third the Presentation tree, the 4th the Chart tree and 5th the Timer tree.
  2. On the top of each tree, together with the tree menu, there is a search bar, highlighted with a red rectangle.
    Writing a part of the name/package of the item to search (matrix, function...) and clicking on the green arrow button, the next item with name-package containing that text is selected and showed in the tree.
    For example the text ding.pri finds the item trading.price.

Friday, June 06, 2008

Exception stack trace for final users

In Matrex, like in other programs, it is not always possible to show a simple message box when an error occurred.
Sometimes what I have is an exception occurred deep down in the code, may be in a library.
Nevertheless something has to be shown to the user to let him understand that an error has occurred and give him all the available information to decide what to do.
A classic exception stack trace is not an option: together with the exception text it contains a lot of information to localize the code that generated the exception.
This information, that is precious for the developer, is probably unuseful and confusing for the final user.
For this reason I wrote a small function that transform the exception in a string that contains only the texts of the exception and of all contained (cause) exceptions. Here is the code:

public static String flatException(Throwable e)
StringBuilder b = new StringBuilder();
while(e != null)
e = e.getCause();
return b.toString();

Even if the number of contained exception is large, the message is generally simple and gives immediately an idea of what happened.
This is not intended as a substitute of the classic stack trace, which is written in the application log file so that if needed it can be examined by the developer.

Sunday, June 01, 2008

Fit Columns

A new feature that will be released with version 1.3 is the possibility to fit the width of the columns of the table in a matrix viewer or in a presentation viewer.

This has been a problem from the moment I started to use virtual tables for the two viewer.
Virtual tables have the advantage that they can show tables with a huge amount of rows (> 10000) instantly, because they load only the rows of the table that are displayed in that moment, not the whole table.
As a side effect, there is no way to automatically set the width of the columns so that they can fit the text displayed in the columns' cells.
Because of this, before version 1.3 the use has to manually change the width of the columns.
In version 1.3 I added a menu in the two viewers, called Fit Columns:

This menu calls a function that takes a sample of the table's content: a fixed amount of rows. It measures the lengths of the texts contained in the cells of these rows, and with them it calculates an estimation of the columns' width. Then sets the columns' with to this value.

In conclusion there is no automatic columns' width calculation. The user decides when to calculate them. And that is a good thing, because if the matrix or the presentation change (because matrices get recalculated in Matrex), he can click the menu when he wants to update the width accordingly.