fiswidgets getting started

Getting Started

The best way to get started coding with fiswidgets is to look at the example code and take off from there. These notes are very sparse and will be expanded as we get more user feedback.

The fiswidgets API is designed to be very, very easy to code with. (You have traded flexibility and breadth for ease and speed.). To program with fiswidgets, you really should have some experience coding in C, C++, or Java. If you haven't coded in Java before, but at least have an idea of how object oriented coding works, you may be able to extrapolate from the example code and your C, C++ knowledge successfully. We strongly recommend the "JAVA in a Nutshell", by David Flanagan, O'Reilly series book as a reference if you haven't used Java before.

To write a fiswidget application

You need to write 2 Java classes (ie 2 "programs"). First, you write a FisBase class. This is the program where you specify all the widgets that will appear in the GUI. Then, you write a FisRunManager class. This is the program where you specify what happens when the user clicks on the RUN button.

FisBase class
There are 2 methods in this class:
- public application()
  this is the constructor function. There are some standard calls, such as super(), activateRunButton(), and display() that must be made (see Hello1.java). Then, each widget that will appear in the GUI is constructed; the call to the constructor will automatically add the widget to the GUI.
- public static void main(String[] args)
  just copy this main function as is from the example code. It would only change if you wanted to pass parameters to a fiswidget application from the command line.

FisRunManager class
There are 2 methods in this class:
- public applicationRun(application gui)
  this is the constructor function. It takes the associated FisBase object as a parameter. You can copy this method from the example code as is, it doesn't change.
- public void run()
  This is where you have to do all your work. Whatever happens when RUN is clicked, happens here. Typically, this method will pull all the information out of the fields in the FisBase class, (it can do that because the FisBase class is passed as a parameter to the constructor), to determine what selections the user has made. Then, some sanity checking of those selections may be performed using the standard Java language calls. For example, if the user has specified an output file, the Java io package File.exists() call can be used to check if the file already exists. Then, typically, one of three things is done:
  - Usually, a process external to the Java Virtual Machine is spawned. A command line call is constructed, based on the user selections, and, a call to FisRunner() is made to execute the command. This is the case in which the fiswidget application is being used as an interface to an existing program or shell script.
  - In some cases, everything the user has specified can be done using Java language constructs within the FisRunManager run() method.
  - Or, you may need to spawn another Java process, possibly another Java GUI (nonfiswidget) application for the user, by using the Java new construct.
  Once the external call has been spawned, or Java code is done, or the new Java object has been instantiated, the run() method simply returns.

To compile and run a fiswidget application

You need to have both the Fiswidget classes in your CLASSPATH.

The fiswidget components use the Swing components, so you need to install Swing (aka JFC, Java Foundation Classes) on any machine that uses fiswidgets. You should not have to worry about that since Swing comes with the JDK for Java versions 1.2 and higher.

You also need to have the fiswidgets-system and fiswidgets-all jar files in your CLASSPATH. For example, if you have installed fiswidgets in /usr/local/pkg/fiswidgets, you need to add /usr/local/pkg/fiswidgets/fiswidgets-system.jar and /usr/local/pkg/fiswidgets/fiswidgets-all.jar to your path.

Finally, since you are creating a new Java class (your fiswidget) in the current directory, you will need to add the current working directory (.) to your CLASSPATH.

In order to run the Java compiler (javac) and the Java interpreter, (java), you need to add the Java bin directory (usually /usr/java/bin) for your site to your path.

So, the instructions to set up your environment, compile your fiswidget, and run it might look like:

set path = ($path /usr/java/bin)
setenv CLASSPATH /usr/local/pkg/fiswidgets/fiswidgets-system.jar:/usr/local/pkg/fiswidgets/fiswidgets-all.jar:.
javac MyApp.java MyAppRun.java
java MyApp