Events in classes.

Hi all
Can any one explain me the functionality about events and event handlers in ABAP OO??
Thanks and Regards,
Arun Joseph

Hi there
Whilst the SENDER doesn't know about the RECEIVER the reverse is not true. Some people might (wrongly) infer from the comment about the sender that the receiver doesn't know either. I'm only adding the comment below hopefully to clear this up for some people who perhaps a new to OO programming and OO ABAP in particular.
By using the parameter SENDER the receiver can know what object triggered the event. This is of course useful where you have say multiple grid displays on the screen and an action needs to be performed depending on what object triggered it.
class lcl_event_handler definition.
* CLASS     cl_event_receiver
* DEFINITION
public section.
    methods:
*--To add new functional buttons to the ALV toolbar
handle_toolbar for event toolbar of cl_gui_alv_grid
importing e_object e_interactive
          sender,
*--To implement user commands
handle_user_command
for event user_command of cl_gui_alv_grid
importing e_ucomm
          sender,
class lcl_event_handler implementation.
*--Handle Toolbar
method handle_toolbar.
*    PERFORM handle_toolbar USING e_object e_interactive .
endmethod .
*--Handle Hotspot Click
method handle_hotspot_click .
*    PERFORM handle_hotspot_click USING e_row_id e_column_id es_row_no .
create object go_handler.
    set handler go_handler->handle_user_command
    for go_grid1.
set handler go_handler->handle_user_command
    for go_grid2.
form handle_toolbar
case g_sender
when go_grid1
etc
sorry if this info is a case of "stating the obvious" but reading the forums there's quite a bit of confustion surronding event generation and handling in OO ABAP.
Cheers
jimbo

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Events in classes LabVIEW 8.6

i have class with some member (counter of something)
and i want to generate a user event when this member has specific values.
currently i manage to generate the event only if i register the event of the class
in the Top Vi that use this class
can i register the event inside the class itself, let say inside the initilize vi that i ave for the this class ?
thanks
Solved!
Go to Solution.

The question is a little confusing. You can register for the event anywhere you like, but somewhere you pretty much need to have an Event Structure in a running VI waiting for that event to occur.
What should be aware of these events? Class members
P.S. On second reading, it seems you might just be asking if you can register the event in a class VI, instead of having to register it in the top-level VI. If that's the case, then yes you can. Just have the Register for Events function inside the Initialize VI of your class and have it output the Event Registration Refnum corresponding to your event.
Message Edited by Jarrod S. on 11-02-2008 08:48 PM
Jarrod S.
National Instruments

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A typical singleton OO design pattern involved a protected (or private)
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(from http://e-docs.bea.com/wls/docs61/webapp/app_events.html#178593)
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Hi Matt,
This sounds like a case where you will need to have two classes -- your
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Dennis Munsie
Developer Relations Engineer
BEA Support
"Matt Hembree" <[email protected]> wrote in message
news:[email protected]..
A typical singleton OO design pattern involved a protected (or private)
no-arg
constructor and a public instance() method that manages a private static
variable
referencing the single instance, internally invoking the no-argconstructor.
>
A class designated in web.xml as a <listener> must have a public no-arg
constructor.
(from http://e-docs.bea.com/wls/docs61/webapp/app_events.html#178593)
Anyone thoughts on how to accomplish both goals?

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I have a list of proxyNames which are stored in a Vector.
These proxy names are then displayed as Tabs accordingly.
For every tab there is a specific action to be performed.
I want to write a single event handling class for handling all events.
What I have is this:
while(eNum.hasMoreElements()){
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How do I have a single event listener?

Yikes! Is that a minimal program? When I am trying to do something new, or facing a problem that causes me to get stuck for more than an hour, I create a short program to solve just that problem. In time, you create a directory of test programs that's useful, and with practice, solving a problem in isolation is a faster (and generally better) way to go about things that doing it all in a larger application.
Any way, here is your code, with a change listener added in method makeSubpanel. If you don't want the listener called the very first time, add it at the end of this method. I also fixed some bugs in createProxyList.
import java.awt.*;
import java.awt.event.*;
import java.io.*;
import java.util.*;
import javax.swing.*;
import javax.swing.event.*;
public class TrialTabbed extends JPanel {
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    private Vector v,v1;
    JTabbedPane tabbedPane,tabbedPane2;
    Object proxyName;
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        // Instantiate the Vector.
        v1 = new Vector();
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        tabbedPane.addTab("Normal Mode", null, panel2, "Normal");
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                else {
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                    File file = new File("..", filename); //brittle!
                    if (file.isDirectory()) {
                        String[] contents = file.list();
                        int size = contents == null ? 0 : contents.length;
                        System.out.println(filename + " contains " + size + " files");
                    } else
                        System.out.println(filename + " has length " + file.length());
        //end of new code
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        return panel4;
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    private Vector createProxyList(){
        String dirName = "..";
        File file = new File(dirName);
        if(file.isDirectory()){
            String[] s = file.list();
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} // End for.
} // End of if.
return v1;
} // End createProxyList().
class ItemHandler implements ChangeListener{
public void stateChanged(ChangeEvent e){
System.out.println(v.size());
System.out.println("IN CHANGE LISETENER" + proxyName.toString());
} // End actionPerformed.
} // End Inner class ItemHandler.
public static void main(String[] args) {
JFrame frame = new JFrame("TabbedPaneDemo");
frame.addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent e) {System.exit(0);}
frame.getContentPane().add(new TrialTabbed(),BorderLayout.CENTER);
frame.setSize(500, 425);
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Broadcast events between classes (objects)

Hello,
I'm can't figure out how to broadcast an event to another
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In the defintion of your custom event I miss the isEnabled
part (don't know if that has anything to do with the issue though).
Below a custom event that works for me
package Components {
import flash.events.Event;
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public var maxvalue:Number = 0;
public var zoomfactor:Number = 0;
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public override function clone():Event {
return new ZoomEvent(type, isEnabled);
Furthermore I have somewhere read in the documentation that
using custom event should go together with adding an embedded
statement like: [Event(name="update",
type="Components.UpdateEvent")] in the class where you use the
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And is your class XMLData a subclass from a class that
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Hi,
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There is a web part method called WebPart.OnUnload method, you can override this method and add the custom code to the override method.
Here are some detailed articles for your reference:
https://msdn.microsoft.com/en-us/library/microsoft.sharepoint.webpartpages.webpart.onunload(v=office.14).aspx
http://www.codeproject.com/Articles/25019/Developing-SharePoint-WebParts
Thanks
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Regards,
Guddan

Hi- My suggestion is, let the WF be triggered using std BO and event. For additional custom methods, you create a new WF based class
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Events in Class Constructors

Hi All,
I would like to know if events (instance/static) can be raised within class constructors. My understanding is that events can be raised but not of the same class as the class constructor belongs to.
Please clarify.
Thanks and Regards,
Vidya.

Hi Vidya,
Welcome to SDN.
see this link
http://help.sap.com/saphelp_nw04/helpdata/en/41/7af4eca79e11d1950f0000e82de14a/content.htm
http://help.sap.com/saphelp_nw04/helpdata/en/0a/b552f7d30911d2b467006094192fe3/frameset.htm
http://help.sap.com/saphelp_nw04s/helpdata/en/41/7af4eca79e11d1950f0000e82de14a/frameset.htm
http://help.sap.com/saphelp_nw04/helpdata/en/08/d27c03b81011d194f60000e8353423/content.htm
for Implementing constructor outside class implementation..
use this code
codeREPORT zkarthik.
CLASS counter DEFINITION
CLASS counter DEFINITION.
PUBLIC SECTION.
*METHODS CONSTRUCTOR.
CLASS-METHODS: set IMPORTING value(set_value) TYPE i,
increment,
get EXPORTING value(get_value) TYPE i.
PRIVATE SECTION.
CLASS-DATA count TYPE i.
NO explicit constructor
*METHOD CONSTRUCTOR.
*WRITE:/ 'I AM CONSTRUCTOR DUDE'.
*ENDMETHOD.
ENDCLASS. "counter DEFINITION
CLASS counter IMPLEMENTATION
CLASS counter IMPLEMENTATION.
METHOD set.
count = set_value.
ENDMETHOD. "set
METHOD get.
ENDMETHOD. "get
METHOD increment.
ENDMETHOD. "increment
ENDCLASS. "counter IMPLEMENTATION
DATA cnt TYPE REF TO counter.
START-OF-SELECTION.
Implicit constructor is called
CREATE OBJECT cnt.
CALL METHOD counter=>set
EXPORTING
set_value = 5.
END-OF-SELECTION.[/code]
happy learning.
thanks
karthik

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When the following two event gets trigger in execution.
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Hello Amit
In order to understand the event DATA_CHANGED in more detail you may have a look at Get edited data ou of grid back into internal tabel
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right, it's a little tricky. Offhand, you could choose from:
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hello
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Check out the java tutorials. There are great examples that show you how to do what you want to do

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APPLICATION
<?xml version="1.0" encoding="utf-8"?>
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]]>
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Events in classes.

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