Event handlers execute code from a seperate class

i am having difficulties linking my event handlers to another piece of code in a seperate class. basically i want my event handler to execute a code which is in another class. how do i do this?

while adding listener to the component for which u want to handle event add listener with the name of class where u r going to write the event handling code and declare that class as implementing the type of listener and handle the event in that class by implementing the definitions for the methods in the interface

Similar Messages

Accessing interface components from a seperate class

Hi there,
I've just been given a Java project to build, that involves writing an applet to allow text based communication between pairs of people. I've always thought the best way to go about it was to divide code into functional units, i.e. put the user interface code in one class and the code that responds to user interface interactions in other classes (of the same package).
The problem is getting the other classes to access the interface components created in the interface class.
So for brevity, here is my interface Applet class;
package name;
import statements here;
public class Communicate extends Applet {
declare all variables, strings, labels, combo boxes etc
//Construct the applet
public Communicate() {
try {
jbInit();
} catch (Exception ex) {
ex.printStackTrace();
//Initialize the applet
public void init() {
try {
jbInit();
} catch (Exception e) {
e.printStackTrace();
private void jbInit() throws Exception {
add components here
//Now the problem. In the interface there are combo boxes. When the user clicks a button it constructs a jframe that asks the user for a string. The idea is that the string be added to a combobox using add item. If I leave this code in the applet class it works fine, e.g.
public void jButton5_actionPerformed(ActionEvent actionEvent) {
JFrame f = new JFrame();
f.setSize(200, 200);
f.setLocation(200, 200);
f.setVisible(false);
//Add those boxes to the JFrame
JTextField titleField = new JTextField();
String title = "Please enter the title";
int result = JOptionPane.showOptionDialog(f,
new Object[] { message },
"New title", JOptionPane.OK_CANCEL_OPTION,
JOptionPane.QUESTION_MESSAGE,
null, null, null);
String title = titleField.getText();
jComboBox2.addItem(title);
//as jComboBox2 is decalred in the applet above, it adds the string no problem.
But what I'd like is the following, a title class on its own to make it easier to update and modify,
e.g.
public void jButton5_actionPerformed(ActionEvent actionEvent) {
try {
Title title = new Title();
catch (Exception ex) {
ex.printStackTrace();
with the Title class written as such:
package name;
import statements;
class Title {
Title() {
//Set the new title
JFrame f = new JFrame();
f.setSize(200, 200);
f.setLocation(200, 200);
f.setVisible(false);
//Add those boxes to the JFrame
JTextField titleField = new JTextField();
String title = "Please enter the title";
int result = JOptionPane.showOptionDialog(f,
new Object[] { message },
"New title", JOptionPane.OK_CANCEL_OPTION,
JOptionPane.QUESTION_MESSAGE,
null, null, null);
String title = titleField.getText();
*** Here is the problem: How do I reference jComboBox2 which is declared in the original applet class?
jComboBox2.addItem(title); (this wont work!)
public static void main(String[] args) {
Title title = new Title();
I'd thought perhaps I needed to create an instance of the applet and pass it to the second class to use it, so it can reference the components, but I'm not sure how to do this with an applet.
Thanks
Maria

I'm not going to look at your unformatted code, but I'll give you some general hints:
Have one set of classes being the GUI
Have one set of classes being the data (the chat history, basically)
Have one set of classes being the logic
Have one interface for the logic to manipulate the data (e.g. addNewMessage(String)
Have one interface for the GUI to get the data that's to be displayed (e.g. getLastTenMessages())
Have one interface for the logic to notify the GUI of changed data (refresh())
Have one interface for the GUI to notify the logic of user input (e.g. sendMessage(String))
The logic will receive data either from the user and send it, as well as storing it in your chat log, or it will receive it from the network and add it to the data model, both times notifying the GUI of changes afterwards.

Executing code from a Bean only once when page loads

Hi all,
I have a method in a BackingBean which access UI Bindings from my fragment: xxx.jsff.
So that method has to be invoked from a inside that fragment since access Bindings from xxxPageDef.xml
I need to execute that code one and only one time when that fragment loads.
What is the best approach to my case????

Thanks Pino for your reply.
Since the fragment does not have OnLoad event, I have no option than to find a work around.
That is exactly what I am doing.
I have a PageFlowScope variable which is set to true or false depending if I have input parameter value or not.
That variable is re-sated when the user pressed a button.
The problem was where to stick to code that will disable components if needed.
So I used one component and in its Rendered method I put the code that will disable components if needed (based on my PageFlowScope variable value).
Works perfectly fine, but it would be much nicer if there was more natural way of doing it (with OnLoad event on fragment).
Regards.

How to execute code from a text file?

Hello all!
How to execute some code lines from a text file? For example my file is:
String varname = "somecontents";
JFrame frame = new JFrame();
frame.setVisible(true);How can I get contents of this file and parse them if I want get new JFrame and access to the variable varname?

I mean the PHP would generate a readable Java source,
for example some variables with some data, and I just
dont know what to do with file if I want generate the
xls file from my saved data, could You help? :)Some variables, some data, PHP, Java, XLS file??? Al rather vague.
You need to explain in more detail what it is you're trying to do if you want an answer to your question!

Execute code from a string?

I have a Java program that draws lots of different types of curves.
I need to program how to save a drawing to a file.
It would be easiest to make a file that has the string of the code which recreates the drawing.
Is it possible to execute the content of a string?
A trivial example would be you declare an integer
int number
and you execute the string
"number = 10"
so that the value of number becomes 10.
Is this possible?

However, how does your program draw the curve in the first place? What I mean is, if it draws the curve in response to some informatiion from the user, why not save that information as text and then draw the curve the same way when the text is read again later.

Execute code from a text file ...

Hello , Would like to know whether it is possible to have my ABAP code in a text file in desktop and then execute the code by reading it into an ITAB in another ABAP program .
Note : Pl. dont suggest how to upload and create a new program . I dont want to create a new program after uploading into ITAB using INSERT or function modules . I want to execute the code as part of the uploading program only . So that once the execution is complete the uploaded code will not be available in the SAP system.
Thanks in advance ,
Jee.R

>
jeeva R wrote:
> Note : Pl. dont suggest how to upload and create a new program . I dont want to create a new program after uploading into ITAB using INSERT or function modules . I want to execute the code as part of the uploading program only . So that once the execution is complete the uploaded code will not be available in the SAP system.
Oh dear. The only solution to your requirement is, sadly, to upload and create a new program, and then one further step. There is no other way. So it looks like you'll have to do without.
matt

Updating Jlabel from a different class?

Hi,
Im in the middle of developing a program but swing is making it very hard for me to structure my code. The problem is I want to update the text of a Jlable from a different class when a button is pressed. THe event handling is done by a different class than the where the Jlabel is initiated which is why i think it doesnt work. But when the button is pressed it does execute a method from the main class that has the .setText() in it. Why wont the Jlabel update? Thank you

Thanks for your help but i am still having trouble.
This is the code from the button handler class
public void actionPerformed(ActionEvent e)
       if ("btn3_sender".equals(e.getActionCommand()))
            JLabel j = temp2.getlblQuestion();
           j.setText("NEW TEXT");
       This is the code from the main class where the JLabel is created:
public JLabel getlblQuestion()
    return lblQuestion;
}How come this does not work??

How to expose and code the event handlers of a base class?

I have created a class that inherits NumericUpDown. When I instantiate an object from that class, I can make it visible and have it appear on my form just like any other NUD. How can I get that instantiated object to expose the event handlers of its base
class, the NUD in this case, so that, for example, I can tell the client what action to take when the value of the instantiated object changes?
Thanks for your help.

I am not sure exactly what you mean. Are you adding your NUD controls to the Form at design time from the toolbox or adding them in code at run time? If you are adding them to the form from the toolbox then you access the events the same way
you would a standart NUD control. If it is at runtime and you have a fixed amount of them you are going to add then you can declare them Class Scoped using the
WithEvents keyword which will let you access all their events.
Public Class Form1
Private WithEvents Nud1 As New NUD
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
Me.Controls.Add(Nud1)
End Sub
Private Sub Nud1_ValueChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles Nud1.ValueChanged
Me.Text = Nud1.Value.ToString
End Sub
End Class
Public Class NUD
Inherits NumericUpDown
'Your custom code to make it work how you want...
End Class
If this is not what you are doing then you may need to explain a bit more and show the code you are using so we understand better.
If you say it can`t be done then i`ll try it

OIM11 event handlers: How to avoid firing the same code in both pre+post

Hi everyone,
I have a question around event handlers. My experiments so far have gleaned the following:
Manual updates of user form in admin interface -> Fires: pre-insert + Post-insert
Reconciliation trusted creates -> Fires: Post-insert
Reconciliation trusted updates -> Fires: pre-insert + Post-insert
Now I have various handlers that trigger to update fields coming in from trusted recon. Formatting telephone numbers, setting custom user attributes.. etc. I am using the same code in both the post and pre handlers as wherever the update comes from it needs to be processed in the same way. Problem is if a handler fires twice I can't be sure exactly how the system is going to behave (updating the same field again etc), never mind it is unneeded processing.
We have to keep the pre handlers because otherwise changes completed via the admin interface won't be seen until you refresh.
Can anyone please advice how to go about ensuring a handler is only fired once? i.e. if pre fires don't fire post. Have I missed something key here?
Edit: I know I've worded this badly. They will always fire as that's how OIM behaves, what I want is some way to work out in the underlying code if a field has already been modified in pre process... or something like it.
Thanks,
Wayne.
Edited by: wblacklock on 27-Feb-2012 05:38

I am sorry but I am not agree with your design.
However there is no chance to avoid this according to my knowledge. As both class has separate thread under different process, so there is no way to implement thread lock on entity operation.
Alternate way to acheive your requirement:
You can have hidden UDFs. Update hidden UDFs in prepost handler with some data (hardcoded).
"You can have the value this hidden filed like :- "NAME_UPDATE|EMAIL_UPDATED|MANGER_UPDATE"
Now in Post - Process handler check the value of hidden UDF.
Get the value of hidden UDF, tokenize with String Tokenizer. Check which filed is not updated in Pre handler.
*If it is already updated - do not update.* else Update.
Thanks,
Kuldeep

How move code from one class to other?

I have a .fla file.
There i have some keyframes with labels.
On .fla file in property in Class field i adde MyMatching class.
Also i have main code:
package
     import flash.display.MovieClip;
     import flash.events.MouseEvent;
     import flash.text.TextField;
     public class MyMatching extends MovieClip
          var play_btn:MyButton = new MyButton();
          var kyky:MyTimer;
          public function MyMatching():void
               welcomeScreen();
          public function welcomeScreen():void
               stop();
               trace("working");
               play_btn.x = 210;
               play_btn.y = 300;
               addChild(play_btn);
               play_btn.addEventListener(MouseEvent.CLICK, goToLevel_1);
          public function goToLevel_1(event:MouseEvent)
               trace("level 1");
               play_btn.visible = false;
               gotoAndStop('Level1Screen');
               if (kyky==undefined) {
                    kyky = new MyTimer();
And i have other class:
package
     import flash.display.MovieClip;
     import flash.display.Stage;
     import flash.utils.getTimer;
     import flash.text.TextField;
     public class MyTimer extends Stage
          import flash.utils.getTimer;
          var gameStartTime:uint;
          var gameTime:uint;
          var gameTimeField:TextField;
          function mainFunction():void
               gameTimeField = new TextField();
               addChild(gameTimeField);
               gameStartTime=getTimer();
               gameTime=0;
               addEventListener(Event.ENTER_FRAME,showTime);
          function showTime(event:Event)
               gameTime=getTimer()-gameStartTime;
               gameTimeField.text="You plaing: "+clockTime(gameTime);
          function clockTime(ms:int)
               var seconds:int=Math.floor(ms/1000);
               var minutes:int=Math.floor(seconds/60);
               seconds-=minutes*60;
               var timeString:String=minutes+":"+String(seconds+100).substr(1,2);
               return timeString;
Ho i can play code from class MyTimer in goToLevel_1 function(this function stand in my main class MyMatching) ?
Thank you.

First of all your MyTimer class is written wrong and sloppy.
Why does it extend Stage? The most compact class to extend under the circumstances is Sprite.
Also, it is very important to get into habit of datatype declarations. Not only it is good practice, in your case good compiler will throw error because although you return String, function doesn't return anything.
In addition, it is important to declare namespaces like private public and protected inside classes. Not function clickTime():String but private function clockTime():String or public function clickTime():String.
As for how to show your time elsewhere - you just need to create instnace of it and add it to disaply list:
var myTimer:MyTimer = new MyTimer();
addChild(myTimer);
With that said, your class should look like this:
package
     import flash.display.Sprite;
     import flash.events.Event;
     import flash.display.MovieClip;
     import flash.utils.getTimer;
     import flash.text.TextField;
     public class MyTimer extends Sprite
          private var gameStartTime:uint;
          private var gameTime:uint;
          private var gameTimeField:TextField;
          public function MyTimer()
               gameTimeField = new TextField();
               addChild(gameTimeField);
               gameStartTime = getTimer();
               gameTime = 0;
               addEventListener(Event.ENTER_FRAME,showTime);
          private function showTime(event:Event):void
               gameTime = getTimer() - gameStartTime;
               gameTimeField.text = "You playing: " + clockTime(gameTime);
          private function clockTime(ms:int):String
               var seconds:int = Math.floor(ms / 1000);
               var minutes:int = Math.floor(seconds / 60);
               var timeString:String = minutes + ":" + String(seconds + 100).substr(1, 2);
               return timeString;

Error: ORA-03113 while executing complex java code from Oracle PL/SQL

Hi,
I am trying to execute a complex java code from Oracle PL/SQL. The classes were resolved successfully. But in the middle of execution, I am getting the following error:
ERROR:
ORA-03114: not connected to ORACLE
begin
ERROR at line 1:
ORA-03113: end-of-file on communication channel
Process ID: 13685
Session ID: 21 Serial number: 20
Is there a way to debug the Java classes loaded into oracle? Or is there any utility to find out why the connection was lost?
Regards,
Saravana

Hi Saravana:
You could use simply System.out.println(..) at your Java code and see the output at the .trc files generated for your Oracle session.
Or better than this adding Java Util Logging messages at your code, to see how to use JUL API at the OJVM please see this blog post [Using JUL API inside the OJVM|http://marceloochoa.blogspot.com/2007/11/getting-logging-entering-exiting-and.html].
Best regards, Marcelo.
PD: ora-0600 generally are associated with RDBMS bugs, but these bugs can be bypassed by replacing the code which throws the exception by other with a workaround.

Main method not found and how to put event handlers in an inner class

How would I put all the event handling methods in an inner class and I have another class that just that is just a main function, but when i try to run the project, it says main is not found. Here are the two classes, first one sets up everything and the second one is just main.
mport java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.io.*;
public class JournalFrame extends JFrame {
private JLabel dateLabel = new JLabel("Date: ");
private JTextField dateField = new JTextField(20);
private JPanel datePanel = new JPanel(new FlowLayout());
BorderLayout borderLayout1 = new BorderLayout();
JPanel radioPanel = new JPanel();
JPanel statusPanel = new JPanel();
JPanel textAreaPanel = new JPanel();
JPanel buttonPanel = new JPanel();
GridLayout gridLayout1 = new GridLayout();
FlowLayout flowLayout1 = new FlowLayout();
GridLayout gridLayout2 = new GridLayout();
GridLayout gridLayout3 = new GridLayout();
JRadioButton personalButton = new JRadioButton();
JRadioButton businessButton = new JRadioButton();
JLabel status = new JLabel();
JTextArea entryArea = new JTextArea();
JButton clearButton = new JButton();
JButton saveButton = new JButton();
ButtonGroup entryType = new ButtonGroup();
public JournalFrame(){
try {
jbInit();
catch(Exception e) {
e.printStackTrace();
private void initWidgets(){
private void jbInit() throws Exception {
this.getContentPane().setLayout(borderLayout1);
radioPanel.setLayout(gridLayout1);
statusPanel.setLayout(flowLayout1);
textAreaPanel.setLayout(gridLayout2);
buttonPanel.setLayout(gridLayout3);
personalButton.setSelected(true);
personalButton.setText("Personal");
personalButton.addActionListener(new JournalFrame_personalButton_actionAdapter(this));
businessButton.setText("Business");
status.setText("");
entryArea.setText("");
entryArea.setColumns(10);
entryArea.setLineWrap(true);
entryArea.setRows(30);
entryArea.setWrapStyleWord(true);
clearButton.setPreferredSize(new Dimension(125, 25));
clearButton.setText("Clear Journal Entry");
clearButton.addActionListener(new JournalFrame_clearButton_actionAdapter(this));
saveButton.setText("Save Journal Entry");
saveButton.addActionListener(new JournalFrame_saveButton_actionAdapter(this));
this.setTitle("Journal");
gridLayout3.setColumns(1);
gridLayout3.setRows(0);
this.getContentPane().add(datePanel, BorderLayout.NORTH);
this.getContentPane().add(radioPanel, BorderLayout.WEST);
this.getContentPane().add(textAreaPanel, BorderLayout.CENTER);
this.getContentPane().add(buttonPanel, BorderLayout.EAST);
entryType.add(personalButton);
entryType.add(businessButton);
datePanel.add(dateLabel);
datePanel.add(dateField);
radioPanel.add(personalButton, null);
radioPanel.add(businessButton, null);
textAreaPanel.add(entryArea, null);
buttonPanel.add(clearButton, null);
buttonPanel.add(saveButton, null);
this.getContentPane().add(statusPanel, BorderLayout.SOUTH);
statusPanel.add(status, null);
this.pack();
setDefaultCloseOperation(EXIT_ON_CLOSE);
private void saveEntry() throws IOException{
if( personalButton.isSelected())
String file = "Personal.txt";
BufferedWriter bw = new BufferedWriter(new FileWriter(file,true));
entryArea.getText();
bw.write("Date: " + dateField.getText());
bw.newLine();
bw.write(entryArea.getText());
bw.newLine();
bw.flush();
bw.close();
status.setText("Journal Entry Saved");
else if (businessButton.isSelected())
String file = "Business.txt";
BufferedWriter bw = new BufferedWriter(new FileWriter(file,true));
bw.write("Date: " + dateField.getText());
bw.newLine();
bw.write(entryArea.getText());
bw.newLine();
bw.flush();
bw.close();
status.setText("Journal Entry Saved");
void clearButton_actionPerformed(ActionEvent e) {
dateField.setText("");
entryArea.setText("");
status.setText("");
void saveButton_actionPerformed(ActionEvent e){
try{
saveEntry();
}catch(IOException error){
status.setText("Error: Could not save journal entry");
void personalButton_actionPerformed(ActionEvent e) {
class JournalFrame_clearButton_actionAdapter implements java.awt.event.ActionListener {
JournalFrame adaptee;
JournalFrame_clearButton_actionAdapter(JournalFrame adaptee) {
this.adaptee = adaptee;
public void actionPerformed(ActionEvent e) {
adaptee.clearButton_actionPerformed(e);
class JournalFrame_saveButton_actionAdapter implements java.awt.event.ActionListener {
JournalFrame adaptee;
JournalFrame_saveButton_actionAdapter(JournalFrame adaptee) {
this.adaptee = adaptee;
public void actionPerformed(ActionEvent e) {
adaptee.saveButton_actionPerformed(e);
class JournalFrame_personalButton_actionAdapter implements java.awt.event.ActionListener {
JournalFrame adaptee;
JournalFrame_personalButton_actionAdapter(JournalFrame adaptee) {
this.adaptee = adaptee;
public void actionPerformed(ActionEvent e) {
adaptee.personalButton_actionPerformed(e);
public class JournalApp {
public static void main(String args[])
JournalFrame journal = new JournalFrame();
journal.setVisible(true);
}

Bet you're trying "java JournalFrame" when you need to "java JournalApp".
Couple pointers toward good code.
1) Use white space (extra returns) to separate your code into logical "paragraphs" of thought.
2) Add comments. At a minimum a comment at the beginning should name the file, state its purpose, identify the programmer and date written. A comment at the end should state that you've reached the end. In the middle, any non-obvious code should be commented and closing braces or parens should have a comment stating what they close (if there is non-trivial separation from where they open).
Here's a sample:
// JournalFrame.java - this does ???
// saisoft, 4/18/03
// constructor
private void jbInit() throws Exception {
    this.getContentPane().setLayout(borderLayout1);
    radioPanel.setLayout(gridLayout1);
    statusPanel.setLayout(flowLayout1);
    textAreaPanel.setLayout(gridLayout2);
    buttonPanel.setLayout(gridLayout3);
    personalButton.setSelected(true);
    personalButton.setText("Personal");
    personalButton.addActionListener(new JournalFrame_personalButton_actionAdapter(this));
    businessButton.setText("Business");
    status.setText("");
    entryArea.setText("");
    entryArea.setColumns(10);
    entryArea.setLineWrap(true);
    entryArea.setRows(30);
    entryArea.setWrapStyleWord(true);
} // end constructor
// end JournalFrame.java3) What would you expect to gain from that inner class? It might be more cool, but would it be more clear? I give the latter (clarity) a lot of importance.

Execute Javascript from our JAVA code

Hi all,
I have a question:
It's possible to execute a javascript code from the back bean page. For example , we execute a button action (Conect to a db, insert data) and if all it's ok we execute a simple alert ("The insert is ok!!");
Any way to do this??
Thx!

I don't know enough about Javascript, but I don't think it can be executed from within Java code.
If you can't, an alternative is to provide a status code and/or status message that is accessible to the page. There are a number of ways to do this. One option is to put the information in a hidden field. Another option is to put the information in a session bean and add appropriate JSP code to your page to get that information.
You can link a Javascript function to the page's onLoad event. The function can get the status code/status message and create the alert.

How can i execute byte code from remote location.

I want my program to execute byte code from some remote location.Should i ransfer class files to my pc and then execute it but i would it to be executed from remote location.

... but i would it to be executed from remote location.Sounds like you want to use RMI (Remote Method Invocation).
Allows you to have a remote machine execute code.
Start here:
http://developer.java.sun.com/developer/onlineTraining/rmi/index.html

Need help moving my code from the timeline into classes

Hello everybody,
A few months ago I made a simple flashgame with the help of a tutorial (http://www.flashgametuts.com/tutorials/as3/how-to-create-a-brick-breaker-game-in-as3-part- 1/) as a school assignment. When I turned it in to my teacher, his biggest complaint was that the code was written onto the timeline instead of in seperate classes. I know virtually nothing of programming (dealt with agoraphobia while the classes took place ), so I was wondering if someone could help me move the code into classes.
Here's the complete package for the game: https://www.dropbox.com/sh/xhjuhz04z8g129m/0nSwf1wngu
Thanks!

You will need to learn about classes. I suggest that for the moment you set your actual project to the side--but keep it in mind--and work on some smaller chunks. Do some tutorials and learn a bit. Then try and apply what you have learned to your project.
http://www.untoldentertainment.com/blog/2009/08/25/tutorial-understanding-classes-in-as3-p art-1/
Work on the individual bits and post more specific questions when you run up against them.
It will require shifting your thoughts a bit on how to design and structure things. For me the really key concept is encapsulation--the idea that your classes are self-contained and have very specific routes of communication for receiving and sending information. To achieve this you need to think about methods, properties, and events. If you've done regular timeline coding you probably recognize properties (x, alpha, htmlText, etc.) and events (MouseEvent.CLICKED). Methods is a fancy word for function. So when you do something like myMovieClip.gotoAndStop(5) the gotoAndStop is a method of the MovieClip class and that just means somewhere there is code like this:
function gotoAndPlay(frame:Object, scene:String=null):void{
// code that tells flash how to move the movieclip to a frame
That is a bit of a simplification, but conceptionally it is what you will do for the methods of your classes.

Event handlers execute code from a seperate class

Similar Messages

Maybe you are looking for