The Genero Browser Client (GBC) provides a mechanism for applications to be run as child programs that execute in the background. That is, the parent program can continue to run without waiting for the child program to finish.

Before you begin

It is recommended you complete the topic regarding Stacked windows prior to completing this demonstration.

Start the standalone dispatcher from the command line using httpdispatch.

$ httpdispatch

Launch the Genero Workplace Window to ensure an environment suitable for Genero commands.

Open the demos application in your browser by entering the URL: http://localhost:6394/ua/r/gwc-demo.

Run without waiting demonstration

For this demonstration, you need to write and compile a Genero application.

This example starts an application with stacked windows. It gives you the option to use a RUN WITHOUT WAITING command to start another instance of the application as a background process.

1. Create the Navigation app source

Copy and save the following Genero source as a file named Navigation.4gl.

MAIN
  DEFINE cw STRING
  DEFINE i INT

  IF num_args() = 0 THEN LET i=1 ELSE LET i=arg_val(1) END IF

  OPEN FORM f FROM "Navigation"
  DISPLAY FORM f
  DISPLAY "screen" TO fname

  OPEN WINDOW w1 WITH FORM "Navigation"
  CALL fgl_setTitle("Window w1 - " || i)
  DISPLAY "w1" TO fname

  OPEN WINDOW w2 WITH FORM "Navigation"
  CALL fgl_setTitle("Window w2 - " || i)
  DISPLAY "w2" TO fname

  OPEN WINDOW w3 WITH FORM "Navigation"
  CALL fgl_setTitle("Window w3 - " || i)
  DISPLAY "w3" TO fname

  WHILE 1
    DISPLAY "YES" TO info
    MENU "Test"
      COMMAND "w1"      LET cw="w1" EXIT MENU
      COMMAND "w2"      LET cw="w2" EXIT MENU
      COMMAND "w3"      LET cw="w3" EXIT MENU
      COMMAND "screen"  LET cw="screen" EXIT MENU
      COMMAND "RWW"     RUN "fglrun Navigation " || i+1  WITHOUT WAITING
      COMMAND KEY(INTERRUPT) "Exit" EXIT PROGRAM
    END MENU
    DISPLAY "NO" TO info
    CASE cw
      WHEN "w1" CURRENT WINDOW IS w1
      WHEN "w2" CURRENT WINDOW IS w2
      WHEN "w3" CURRENT WINDOW IS w3
      OTHERWISE CURRENT WINDOW IS SCREEN
    END CASE
    DISPLAY "YES" TO info
  END WHILE
END MAIN

NOTE: The "RWW" menu command contains the instruction which allows you to start another instance of the application:

COMMAND "RWW" RUN "fglrun Navigation " || i+1  WITHOUT WAITING

2. Create the Navigation app form

Copy and save the following Genero form definition as a file named Navigation.per.

# Property of Four Js*
# (c) Copyright Four Js 1995, 2015. All Rights Reserved.
# * Trademark of Four Js Development Tools Europe Ltd
#   in the United States and elsewhere
#
# Four Js and its suppliers do not warrant or guarantee that these
# samples are accurate and suitable for your purposes. Their inclusion is
# purely for information purposes only.

LAYOUT
GROUP(text="Test Current Window")
GRID
{
Window name [fw         ]
Is current  [info       ]
}
END
END
ATTRIBUTES
  LABEL fw=formonly.fname;
  EDIT info=formonly.info;
END

3. Compile the Navigation app

From the command line, compile the source code modules you have created (Navigation.4gl and Navigation.per) by typing the following commands:

$ fglcomp Navigation.4gl
$ fglform Navigation.per

Compiled files are created, Navigation.42m and Navigation.42f.

4. Create the Navigation app configuration file

Create an application configuration file for your application. Save the configuration file (named Navigation.xcf) in your $(res.appdata.path)/app directory.

<?xml version="1.0" encoding="UTF-8" ?>
<APPLICATION Parent="defaultgwc" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
      xsi:noNamespaceSchemaLocation="http://www.4js.com/ns/gas/3.00/cfextwa.xsd">
 <EXECUTION>
      <PATH>*path_to_your_directory*</PATH>
      <MODULE>Navigation.42m</MODULE>
 </EXECUTION>
 <UA_OUTPUT>
    <PUBLIC_IMAGEPATH>$(res.public.resources)</PUBLIC_IMAGEPATH>
    <GBC>_default</GBC>
 </UA_OUTPUT>
</APPLICATION>

5. Run the Navigation app

Request the Navigation application in your browser by entering the URL: http://localhost:6394/ua/r/Navigation

The current window at the top of the stack (w3-1) is displayed.

The current window's menu button options are: w1, w2, w3, screen, RWW, and Exit.

The Window name field displays w3 for the current window.

The Is current field displays "YES" for the current window.

The sidebar panel is not displayed, as there is only one running application.

6. Run another instance of the Navigation app

To have another instance of the Navigation application running at the same time: In the current window's Test menu panel, click RWW. The sidebar displays, listing the two running applications.

From the sidebar, switch between the instances of the Navigation application.

You should see that both applications have current windows. The first instance of the Navigation application you started (the parent program) continues to run without waiting for the second instance of Navigation (the child program) to finish.

Select the different windows from the window list in the chromebar. The result of your selection will depend on the following:

• If the selected window is the current window, the Is current field value is "YES" and the Test menu panel is displayed.
• If the selected window is not current, the Is current field value is "NO" and the Test menu panel is not displayed.