Creating the Natural Code

This document contains the following exercises:

Content of the Adapter
Creating the Main Program
Testing the Completed Application

Content of the Adapter

When you saved your page layout, the Natural adapter HELLO-A was created for your page. This is the name that you have specified earlier in this tutorial. Your application program will use the adapter to communicate with the page.

The adapter code looks as follows:

* PAGE1: PROTOTYPE       --- CREATED BY Application Designer --- /*<RO>>
* PROCESS PAGE USING 'XXXXXXXX' WITH
* NAME RESULT
DEFINE DATA PARAMETER
/*( PARAMETER
1 NAME (A) DYNAMIC
1 RESULT (A) DYNAMIC
/*) END-PARAMETER
END-DEFINE
*
/*( PROCESS PAGE
PROCESS PAGE U'/MyFirstUI/helloworld' WITH
PARAMETERS
 NAME U'name'
  VALUE NAME
 NAME U'result'
  VALUE RESULT
END-PARAMETERS
/*) END-PROCESS
*
*  TODO: Copy to your calling program and implement.
/*/*( DEFINE EVENT HANDLER
* DECIDE ON FIRST *PAGE-EVENT
*  VALUE U'nat:page.end',U'nat:browser.end'
*   /* Page closed.
*   IGNORE
*  VALUE U'sayHello'
*   /* TODO: Implement event code.
*   PROCESS PAGE UPDATE FULL
*  NONE VALUE
*   /* Unhandled events.
*   PROCESS PAGE UPDATE
* END-DECIDE
/*/*) END-HANDLER
*
END /*<<RO>

Creating the Main Program

You will now create the main program which uses the adapter to display the page and which handles its events. The name of the program will be HELLO-P and you will store it in the library CISHELLO.

To create the main program

Open the NaturalONE perspective.
In the Navigator view or in the Natural Navigator view, go to the SRC folder of the library CISHELLO.
Invoke the context menu for the adapter HELLO-A and choose Generate Main Program.
In the resulting dialog box, enter "HELLO-P" as the name of the new program and choose the OK button.

The program with the specified name is now created.
Initialize the page data. In the page layout definition, the property name has been bound to the FIELD control with the label Your Name. For the property name, a parameter NAME has been generated into the parameter data area of the adapter. Thus, in order to preset the FIELD control, we will preset the variable NAME with the value "Ajax Developer".
```
DEFINE DATA LOCAL
1 NAME (A) DYNAMIC
1 RESULT (A) DYNAMIC
END-DEFINE
*
NAME := 'Ajax Developer'
PROCESS PAGE USING 'HELLO-A'
WITH NAME RESULT
```
Handle the events that can occur on the page. A template for the event handler code has been generated as a comment block into the page adapter HELLO-A.
```
DEFINE DATA LOCAL
1 NAME (A) DYNAMIC
1 RESULT (A) DYNAMIC
END-DEFINE
*
NAME := 'Ajax Developer'
PROCESS PAGE USING 'HELLO-A'
WITH NAME RESULT
*
DECIDE ON FIRST *PAGE-EVENT
  VALUE 'nat:page.end',U'nat:browser.end'
  /* Page closed.
    IGNORE
  VALUE 'sayHello'
  /* TODO: Implement event code.
    PROCESS PAGE UPDATE FULL
  NONE VALUE
  /* Unhandled events.
    PROCESS PAGE UPDATE
END-DECIDE
*
END
```
After the page has been displayed, the user raises events on the page by using the controls. The name of the raised event is then contained in the system variable *PAGE-EVENT. Depending on the event, the program modifies the page data, resends it to browser with a PROCESS PAGE UPDATE FULL statement and waits for the next event to occur.

The predefined events nat:page.end and U'nat:browser.end' are raised when the user closes the page or closes the browser. The event sayHello is raised when the user chooses the Say Hello button. Previously in this tutorial, you have bound the event sayHello to this button while designing the page. The NONE VALUE block should always be defined as above. It contains the default handling of all events that are not handled explicitly.

When the event sayHello occurs, we want to display a greeting in the FIELD control with the label Result. Therefore, we modify the variable RESULT (which is bound to the corresponding FIELD control in the page layout) accordingly before we resend the page data.

DEFINE DATA LOCAL
1 NAME (A) DYNAMIC
1 RESULT (A) DYNAMIC
END-DEFINE
*
NAME := 'Ajax Developer'
PROCESS PAGE USING 'HELLO-A'
WITH NAME RESULT
*
DECIDE ON FIRST *PAGE-EVENT
  VALUE 'nat:page.end',U'nat:browser.end'
  /* Page closed.
    IGNORE
  VALUE 'sayHello'
  /* TODO: Implement event code.
    COMPRESS 'Hello, ' NAME '!' TO RESULT
    PROCESS PAGE UPDATE FULL
  NONE VALUE
  /* Unhandled events.
    PROCESS PAGE UPDATE
END-DECIDE
*
END

The main program is now complete.

Save your changes and use the Build Natural Project command to update the Natural server and catalog the sources of the current project.

Note:
When Build Natural projects automatically is selected in the Natural preferences, the Natural server is automatically updated each time you save a source or add a new source. The source is uploaded to the Natural server and is cataloged there.

Testing the Completed Application

You will now execute the program and check whether it provides the desired result. If it contains errors, you can debug it.

To execute the program

In the Navigator view or in the Natural Navigator view, select the program HELLO-P.
Invoke the context menu and choose NaturalONE > Execute.

The program is executed and the output is shown in the browser.
Enter your name and choose the Say Hello button.

The page should now successfully "talk" to your adapter.

To debug the program

In the Navigator view or in the Natural Navigator view, select the program HELLO-P.
Invoke the context menu and choose NaturalONE > Debug.

The Debug perspective is opened. In the editor window, the debugger waits at the first executable source code line. You can now use the standard Eclipse functionality to debug the Natural program.

You have now completed this tutorial. See the remaining section of these First Steps for some background information.