Frequently Asked Questions About lGantt

(add your own)

1.- Why the name?

R: The name comes from "little gantt", but I like to think of it like elegant...

2.- How can I print the diagram?

R: Right now the only way to print a diagram is to export the image into a file (Tools/Export) and then print the image file or include the image in a document and then print the doc.

3.- Is the Gantt rendering component available as a stand-alone AWT component?

R: You can use it as a component if you want to, but you will have to extract the functionality you want from the code. Using something like this (MainFrame.java).

 File source = new File("file.lgantt");
 project = IOManager.loadFrom(source);
 pvModel = new ProjectViewModel(project, file);
 ganttDisplay = new GanttDisplay(pvModel);
 
 GanttActionListener mainListener = pvModel.getMainActionListener();
 mainListener.setup(this, ganttDisplay);
 getContentPane().add(ganttDisplay, BorderLayout.CENTER);

If you take a look at the code, there is only one package for the MODEL and two packages (with subpackages) for presentation. If you want to get only the main graph engine... then you are looking for a class called jgantt.view.gantt.GanttGraph that uses internally a Viewer a Header and a ConstraintHelper (for mouse interaction).

4.- I am having trouble installing lGantt. It says JRE jarfile association is not as expected.

R: The installation program just associates .lgantt files with the lgantt program. This is done by looking in the windows registry for:

HK_CLASSES_ROOT\jarfile\shell\open\command

Normally this item contains something like: java -jar %1. This key defines is the command used to launch .jar files (as of lgantt.jar file) if the key is not found, it is probably because there is no JRE installed. Still the application will asume that java is on the windows PATH environment variable and try to use the standard command to launch lgantt when a .lgantt file is open:

javaw.exe -jar

Assuming javaw.exe is on the windows PATH may produce a working application and the open option for .lgantt files.

The lgantt application is associated with .lgantt files by using the following windows registry keys and values:

  [HKCR\.lgantt]
  (default) = lGantt

  [HKCR\lGantt]

  [HKCR\lGantt\DefaultIcon]
  (default) = "c:\folder\...\lgantt.ico"

  [HKCR\lGantt\shell]

  [HKCR\lGantt\shell\open]

  [HKCR\lGantt\shell\open\command]
  (default) = javaw -jar  "c:\folder\...\lgantt.jar" %1

It is not necessary to install(register) lGantt for it to work as a command line program because a command like:

 javaw -jar lgantt.jar

Will lauch lgantt (if java is in the windows PATH), but is nice to seee the lgantt icon for .lgantt files.

Note : To remove the file association just execute:

 lgantt_register.exe -u

5.- Error: Could not find the main class. Program will exit.

When I tried to LGantt I got the error above.

I created a short cut (in windows) with this command:

%windir%\system32\javaw.exe -jar C:\lgantt-0.4\lgantt.jar "%1"

Is there anything else I should do?

R:

You can test the following

• jdk 1.4 (or newer) installed
• lgantt.jar should be the latest binary version (there were a coupe of versions with an invalid main class defined).
• The parameter %1 is only used for file association or in command files (.CMD or .BAT). If you created a shortcut, then this parameter is not needed.
• use the lgantt_install.exe to register the file association automatically.