Compile applications

Compile applications and services.

The goal of this quick start is to create an application and service for testing using the Genero Application Server for Java.

Steps

Start the command line interface and set the environment for your Genero BDL using envcomp.
- On Linux®/macOS™, change to your Genero BDL installation directory and run the script, for example:
```
cd /opt/fourjs/fgl
./envcomp 
```
- On Windows®, change to your Genero BDL installation directory and run the bat file, for example:
```
cd "c:\program files\fourjs\fgl"
envcomp.bat 
```

With a text editor, create an application source file called helloapp.4gl.

In it copy the code shown in the example and save:

IMPORT FGL fgldialog

MAIN
  OPEN FORM f FROM "helloapp"
  DISPLAY FORM f

  MENU "Exit"
    COMMAND "Hello"
      CALL fgl_winmessage("Hello", "Hello World!", "exclamation")
    COMMAND "exit"
      EXIT MENU
  END MENU
END MAIN

Create a per file (the application form) called helloapp.per
Copy the code shown in the example and save:
```
LAYOUT(TEXT="Hello World")
GRID
{
    Hello World!
}
END
```

Create a file called helloservice.4gl

Copy the code shown in the example and save:

IMPORT XML
IMPORT COM

&define L(s) DISPLAY SFMT("(%1:%2) %3", __FILE__, __LINE__, s)
&define LF(s) L(SFMT s)

# Query string parameters
TYPE QSParams DYNAMIC ARRAY OF RECORD
    name STRING,
    value STRING
  END RECORD

MAIN
  DEFINE url,
         qs,
         requestUrl STRING
  DEFINE request com.HTTPServiceRequest

  CALL com.WebServiceEngine.Start()

  WHILE TRUE
    TRY
      #Retrieve the HTTPServiceRequest object to handle the HTTP request in various FUNCTIONs
      LET request = com.WebServiceEngine.GetHttpServiceRequest(-1)

      #Separate the incoming URL from query string
      LET requestUrl = request.readFormEncodedRequest(false)
      CALL splitUrl(requestUrl) RETURNING url, qs
      CALL processRequest(request, requestUrl)
    CATCH
      LF(("Exception %1 - %2", status, SQLCA.SQLERRM))
      L("Got an exception - Exiting")
      EXIT WHILE
    END TRY
  END WHILE
END MAIN

{ Split a url and returns (path, query string) }
FUNCTION splitUrl(url)
  DEFINE url STRING
  DEFINE i INTEGER

  IF url IS NULL THEN
    RETURN NULL, NULL
  END IF

  LET i = url.getIndexOf("?",1)
  IF i >= 1 THEN
    RETURN url.subString(1, i - 1), url.subString(i + 1, url.getLength())
  END IF

  RETURN url, NULL
END FUNCTION

FUNCTION processRequest(request, requestUrl)
  DEFINE request com.HTTPServiceRequest,
         requestUrl STRING

  LF(("processRequest: %1", requestUrl))

  CALL request.sendTextResponse(200, "OK", "Hello World!")
END FUNCTION

Compile the application and service source files (4gl and per).
Run the commands shown at the command line:
```
fglcomp -r -M helloapp.4gl
fglform -M helloapp.per
fglcomp -r -M helloservice.4gl
```
The application and service 42m and 42f files are created.