Referencing main class from created instances

The quick setup:
My Main class creates a JFrame and adds a few custom JPanels. One of the JPanels has a mouse listener and responses to the mouse clicks, and it works great.
I'd like to know if there's a way to have that JPanel invoke public, non-static methods from the Main class (the class which created it) without passing a reference for the instance of the Main class to the JPanel when it's (the JPanel) is created. Or is that the way you're supposed to do it?
A (sort of) similar question: can a component invoke methods of it's parent container? If so, how?
Thanks so much,
Matt

Hi Rhesus21,
A (sort of) similar question: can a component invoke methods of it's parent container? If so, how?Yes, simply this way :
public class MainFrame extends JFrame {
    private MyPanel panel;
    panel = new MyPanel(this);
public class MyPanel extends JPanel {
    private MainFrame frame;
    public MyPanel(MainFrame frame) {
        this.frame = frame;
}

Similar Messages

Accessing object of the main class from the thread

Hi, I'm having problem accessing object of the main class from the thread. I have only one Thread and I'm calling log.append() from the Thread. Object log is defined and inicialized in the main class like this:
public Text log; // Text is SWT component
log = new Text(...);Here is a Thread code:
...while((line = br.readLine())!=null) {
     try {
          log.append(line + "\r\n");
     } catch (SWTException swte) {
          ErrorMsg("SWT error: "+swte.getMessage());
}Error is: org.eclipse.swt.SWTException: Invalid thread access
When I replace log.append(...) with System.out.println(..) it works just fine, so my question is do the log.append(..) the right way.

This is NOT a Java problem but a SWT specific issue.
It is listed on the SWT FAQ page http://www.eclipse.org/swt/faq.php#uithread
For more help with this you need to ask your question on a SWT specific forum, there is not a thing in these forums. This advice isn't just about SWT by the way but for all specific API exceptions/problems. You should take those questions to the forum or mailing list for that API. This forum is for general problems and exceptions arising from using the "core" Java libraries.

Referencing host class from a thread?

Hello, I need some help with the logic of this. How would I reference the host class (the class that created the thread) from the thread. I want to send a string from a thread (where it is grabbed from the command line) to the class which made the thread.. Thanks!

Just like when any object of one class needs to access another object. Somewhere you'll have to pass the "host class" (actually "host object reference" is more close) to the thing that implements Runnable or extends Thread (however you designed it), so that the object can hold and use a reference to it.

Referencing utility classes from a war file

How do you reference a utility class from a war file? I tried adding the class to the deployment plan descriptor, however I still get a ClassNotFoundException.
Thanks,
Will

To use the utility classes from a war you have to place them under the web-inf/classes directory.
webApplication(WAR directory)--->WEB-INF--> classes (put your utility classes in this directory)

Referencing a class that created another class

Is there a certain way reference the class that created "you" - examples:
public class SomeClass
public SomeClass()
    // blah blah
    SomeOtherClass foo = new SomeOtherClass();
public class SomeOtherClass
public SomeOtherClass()
    // blah
public void SomeMethod()
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}Any ideas?

one way is u can modify ur code this way
public class SomeClass{ public SomeClass() {    // blah blah    SomeOtherClass foo = new SomeOtherClass(String creator); }}
//where string creator u pass the same clasas name i.e someclass
public class SomeOtherClass{ public SomeOtherClass() {
System.out.println("created class name is "+creator );
// blah
} public void SomeMethod() {    // access SomeClass here    TheClassThatCreatedMe.method(); }}

Running one main class from another

Hey, i developed two main class. Each class produce it's one JFrame. One Frame suppose to at one point run the other frame when a start button is press. How should I go about doing it?

You can just call the other class's main method.
However, that's kind of messy. If you have any functionality in your main method other than just bootstrapping your program, it's probably better to refactor it out into a different method. Then your other class can invoke that new method.

Pass parameters to a function in main class from loaded SWF?

I've got a main.as that loads SWF to the stage.
the loaded SWF seppoused to pass a link to the main.as and trigger a javascript function to popUp that photo from that link.
I know there are two ways:
((root as MovieClip).parent.parent as Object).somefunction(parameters);
and to dispatch an event.
inorder to pass parameters throug the event i need to extend it with another class.
isnt the (root as... ) more efficient if all i need is to pass a link?

when a photo from the gallery is selected a javascript popUp shows it enlarged with additioan editing options (kinda like in facebook).
in that popUp ther is also a next button so its kinda bidirectional. (the next calling the loaded SWF throug main to get the next link in the photo array)
the photo is a grandchild of a grandchild of the stage and the loaded swf is a grandchild so using:
((root as MovieClip).root as MovieClip).ExternalInterface.call("ShowPic", link);
is discusting ><

Referencing a Class from a Variable

sorry I also forgot to mention that I'm putting in values for _gameModel.scroll_Vx, and Vy from another class, the scroll class. When I try to reference the var from other classes it works but not the FirstEnemy Class.

Trying to access methods from a .class file by creating instance of class

Hey all,
I'm hoping you can help. I've been given a file "Input.class" with methods such as readInt(), readString(), etc. I have tried creating instances of this class to make use of it, but I receive the error "cannot find symbol : class Input".
If you could help at all, I would greatly appreciate it.
Here's my code. The first is the base program, the second is the driver.
import java.util.*;
public class CarObject
     private String makeType = "";
     private String modelType = "";
     private int yearOfRelease = 0;
     private double numOfMiles = 0.0;
     public void setFilmTitle(String make)
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     public void setMediaType(String model)
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     public void setYearOfRelease(int year)
          yearOfRelease = year;
     public void setNumOfMiles(double miles)
          numOfMiles = miles;
     public String getMakeType()
          return makeType;
     public String getModelType()
          return modelType;
     public int getYearOfRelease()
          return yearOfRelease;
     public double getNumOfMiles()
          return numOfMiles;
The program is used by a rental car company and the object takes on desired attributes.
import java.util.*;
public class TestCarObject
     static Scanner keyboard = new Scanner(System.in);
     public static void main(String[] args)
          System.out.println("Please answer the following questions regarding your rental car order.");
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          String modelType = carinput.readString("Enter your desired model of car: ");
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          double numOfMiles = carinput.readDouble("Enter the highest acceptable number of miles: ");
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          System.out.println("Model: " + makeType);
          System.out.println("Year: " + makeType);
          System.out.println("Mileage: " + makeType);
}

No, I don't know the package name....Is there a way
to import the Input.class by itself without importing
the entire packge?
I tried extending the driver program too...It didn't
work either...
Message was edited by:
BoxMan56How do you know you have a class called Input.class ?
You got a jar file which contains it ? or just a simple .class file ?
You have to set the classpath in either case.
But for the former, you should also need to explicitly telling which package containing the class file you looking for (i.e. Input.class)
e.g. java.util.Vector which is a class called Vector inside java.util package.
You don't have to import the whole package, but you should tell which package this class belongs to.

Coldfusion create instance of class from data element when cosuming a webservice

I am calling the following wsdl via cfobject https://services-staging.labcorpsolutions.com/webservice/services/LabcorpOTS/wsdl/LabcorpO TS.wsdl
I am attempting to call the following method registerDonor(java.lang.String, java.lang.String, com.labcorp.ots.ws.data.CreateRegistrationRequest) which references the CreateRegistrationRequest data element.
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Any assistance would be greatly appreciated in creating instances of methods located in the targetNamespace="http://data.ws.ots.labcorp.com" of the wsdl.
Thanks

Thanks for the explanation and example. At first, I didn't understand what you were getting at, but after reading "Using Top-Level Containers" and "How to Use Root Panes" java tutorials it made much more sense. Unfortunately, the books I've read up to this point, did not cover those topics at all. The books simply stated that the first step in creating a Swing gui was to extend the JFrame, or JApplet, or etc.
Unfortunately, my original problem persists. I continue to get compile-time errors such as:
TestUserInterface.java:5: cannot find symbol
symbol: class UserInterface
location: class projects.web.TestUserInterface
                      UserInterface ui = new UserInterface(); Anyone know why?
Both the classes are in the same named packaged. Below is my code:
package projects.web;
import java.awt.*;
import javax.swing.*;
public class UserInterface extends JFrame{
     JPanel menuPanel = new JPanel();
     JPanel contentPanel = new JPanel();
     JPanel selectionPanel = new JPanel();
     JButton save = new JButton("Save");
     JButton addFiles = new JButton("Add");
     public UserInterface(){
     super("File Upload");
     setSize(500, 500);
     menuPanel.add(addFiles);
     selectionPanel.add(save);
     setLayout(new BorderLayout());
     add(menuPanel, BorderLayout.NORTH);
     add(contentPanel, BorderLayout.CENTER);
     add(selectionPanel, BorderLayout.SOUTH);
     } // end constructor
} // end UserInterface class
package projects.web;
public class TestUserInterface{
     public static void main(String[] args){
          UserInterface ui = new UserInterface();
} // end TestUserInterface class

How to call a method from a class without creating an instance fromthisclas

I want to create a class with methods but I want to call methods from this class without creating an instance from this class. Is this possible?
Is there in Java something like class methods and object methods????

keyword 'static' my friend.
public class foo {
public static void bar {
System.out.println ("hello");
foo.bar()

Instance of a Main Class

Hi guys,
I need to create an instance of the main class in my project.
This main has the standard main method : public static void main (String args[])
,which requires a character by command line.
How to create an instance of this class from another class in the same project passing the required parameter ??
Note : I'm using this to test the class , with Eclipse and Junit
Thanks a lot

Same way you create any other class. Except "main" is a static method, so you don't need to create the class. Just call the following:
Main.main(new String[] {"FirstArg", "SecondArg", "ThirdArg"});Where Main is the class with your "main" method. You can build up the String array separately, and then pass it as the argument to "main" (as you would for any other method that takes a String array).

Creating a Button Class from MC

I have a few simple questions for those who know about
classes. I have been reading the tutorials on creating classes and
specifically extending the MC class. I am pretty sure that an
extended MC_Class might help me get what I need from my project.
I essentially have a bunch of buttons, hundreds to be exact -
and the exact number needs to be dynamic. Each one is currently a
static MC with a bunch of variables assigned to each one via global
variables. Its iis pulling in data taht assign the button values
from XML files and - these XML files may change.
Q1. If I extend the MC class so I can add attributes to MC's
instance (Avoiding global variables) - will it mess with the rest
of the movie clips in my scene? I mean if all I want to do is ad a
a few dynamic string variables - it really shouldnt effect any of
the other clips would it? MC.JumpURL = "newurl.com", MC.Thumnail
="/here/image.jpg" (This would help alot)
Q2. What if I wanted to define actions of the new MC in the
class? If the MC is an extension of the MC class. Would all of my
MC's automatically take on the actions of the custom MC Class? For
instance - I want the movieclip to animate onscreen and have
rollover effects. I could do this easy if it were static - but I
need this to become dynamic. Also - there are now unknown
quantities to deal with
Q3. How exactly would I call and assign the MC its atributes
at the same time? And how do I specify this MC to use the functions
defined in the class and not the other MC's I created elsewhere in
the File.
Example. Currently I have a grid of MCs' created when the
User clicks a menu item (Another type of MC).
Each new MC animates onstage - it calls a
loadMovie(_root.thumb[0], this.Flipper) to assign and embedded MC
an image defined in the XML that was loaded and assigned because I
placed the instance on stage and wrote a MC script on each MC.
Confused - check out what I am creating at
www.vincesidwell.com/Fischer
Click Fabrication or TurboSystems menus. Both menues will
load a new set of Thumbnails at the bottom. They are loaded via an
XML loaded by the menu and a function assigns the jpgs for the main
gallery, Rollover image, and eventually a URL for a downloadable
High Res Image.
The client recently added more than 9 images per menu item. I
will need to create a scrollable thumbnail gallery with dynamic
quantities
I can manually create the MC Scroller item for static number
of buttons. But scripting an unknown for each ones links and images
is insane. So I am looking at Classes. Assign a custom class for
the flipping buttons and I should be able to assign tthem as the
XML loads, and have it automatic. (pray please please please)
Anyhelp?
Thanks
Vince Sidwell

Hi there!
I'll try and give some answers to your questions below...
"vin-E" <[email protected]> wrote in message
news:[email protected]...
>I have a few simple questions for those who know about
classes. I have
>been
> reading the tutorials on creating classes and
specifically extending the
> MC
> class. I am pretty sure that an extended MC_Class might
help me get what
> I
> need from my project.
>
> I essentially have a bunch of buttons, hundreds to be
exact - and the
> exact
> number needs to be dynamic. Each one is currently a
static MC with a
> bunch of
> variables assigned to each one via global variables. Its
iis pulling
> in
> data taht assign the button values from XML files and -
these XML files
> may
> change.
>
> Q1. If I extend the MC class so I can add attributes to
MC's instance
> (Avoiding global variables) - will it mess with the rest
of the movie
> clips in
> my scene? I mean if all I want to do is ad a a few
dynamic string
> variables -
> it really shouldnt effect any of the other clips would
it? MC.JumpURL =
> "newurl.com", MC.Thumnail ="/here/image.jpg" (This would
help alot)
You do not have to create a new MC class to assign local
values or functions
to it. A pseudo code example:
Loop through total buttons you want to make (which can be
number of entries
in an XML file)
Create a new movieclip and load the button graphic into
this, give it a
name like
MyButtonX, where X is an increasing number based on which
button this
is. (Instead of creating
and empty movielcip, you could also attach a movie (or
button) from
library.
Assign the values and create the functions for this button
that you
would like (probably based
on information in the XML file):
MyButtonX.someVariable = node.attribues.someData;
createOnRelease(MyButtonX, someOtherParamters)
(where you have defined the function createOnRelease to do
something
like
function createOnRelease(MC, someOtherParameteres) {
MC.onRelease = function() {
do what you want to do based on someOtherParameteres
Position and resize MyButtonX
In your example you have a 3x3 grid, which might extend to
3xTOTAL,
so you'd have to use some
mathematical formula based on the value X, something like
MyButtonX._x =
(((X-1)%3)*(buttonWidths+hSpaceBetweenButtons)
MyButtonY._y = Math.floor((X-1)/3)*(buttonHeights
+vSpaceBetweenButtons
end of loop.
>
> Q2. What if I wanted to define actions of the new MC in
the class? If
> the MC
> is an extension of the MC class. Would all of my MC's
automatically take
> on
> the actions of the custom MC Class? For instance - I
want the movieclip
> to
> animate onscreen and have rollover effects. I could do
this easy if it
> were
> static - but I need this to become dynamic. Also - there
are now unknown
> quantities to deal with
If you actually create a new class, than all instances of
that class will
have the methods you define for it (just like all instances
of a movieclip
has those methods. At least, have them available. That
doesn't mean they are
always in use ... like for example the onRollOver. But again,
you don't need
to create a class to give all your dynamically created
buttons a rollover
effect. (Check code above).
> Q3. How exactly would I call and assign the MC its
atributes at the same
> time? And how do I specify this MC to use the functions
defined in the
> class
> and not the other MC's I created elsewhere in the File.
You use the instance name of the MC to access that MC and its
attributes/methods. For example button number 10 might look
like this:
trace(MyButton10._x);
trace(MyButton10.someVariableYouHaveDefined);
MyButton10.callSomeFunctionYouHaveDefined();
For a movieclip to access a variable that has been defined
for that instance
of the movieclip, use "this" to point to that particular
instance. So if we
defined the function "callSomeFunctionYouHaveDefined" for
button number 10
and want to access "someVariableYouHaveDefined" for this
particular
instance, then
MyButton10.callSomeFunctionYouHaveDefined = function() {
trace(this.someVariableYouHaveDefined);
> Example. Currently I have a grid of MCs' created when
the User clicks a
> menu
> item (Another type of MC).
> Each new MC animates onstage - it calls a
loadMovie(_root.thumb[0],
> this.Flipper) to assign and embedded MC an image defined
in the XML that
> was
> loaded and assigned because I placed the instance on
stage and wrote a MC
> script on each MC.
>
> Confused - check out what I am creating at
www.vincesidwell.com/Fischer
>
> Click Fabrication or TurboSystems menus. Both menues
will load a new set
> of
> Thumbnails at the bottom. They are loaded via an XML
loaded by the menu
> and a
> function assigns the jpgs for the main gallery, Rollover
image, and
> eventually
> a URL for a downloadable High Res Image.
>
> The client recently added more than 9 images per menu
item. I will need
> to
> create a scrollable thumbnail gallery with dynamic
quantities
>
> I can manually create the MC Scroller item for static
number of buttons.
> But
> scripting an unknown for each ones links and images is
insane. So I am
> looking
> at Classes. Assign a custom class for the flipping
buttons and I should
> be
> able to assign tthem as the XML loads, and have it
automatic. (pray please
> please please)
Again, no need for a class for this. If you load the buttons
into seperate
MCs, and make sure to have all these MCs created inside a
common parent MC
for these buttons (which then _only_ contains these buttons).
You can move
this parent MC up and down on the stage based on the
scrollbar. And you can
read height off this MC to create your scrollbar.
You might want to check out the following tutorials at
http://www.gotoandlearn.com/:
XML Video Playlist
Creating Animated Buttons
Introduction to OOP
Now, I've said many times you don't need to make your own
class to do what
you want. That does not mean you can't make your own class. I
just think
that the main problem you are facing is the dynamic part,
which you will be
facing if you make your own class or not.
/Jensen/
>
> Anyhelp?
>
> Thanks
> Vince Sidwell
>
>
>

How can I assign image file name from Main() class

I am trying to create library class which will be accessed and used by different applications (with different image files to be assigned). So, what image file to call should be determined by and in the Main class.
Here is the Main class
import org.me.lib.MyJNIWindowClass;
public class Main {
public Main() {
public static void main(String[] args) {
MyJNIWindowClass mw = new MyJNIWindowClass();
mw.s = "clock.gif";
And here is the library class
package org.me.lib;
public class MyJNIWindowClass {
public String s;
ImageIcon image = new ImageIcon("C:/Documents and Settings/Administrator/Desktop/" + s);
public MyJNIWindowClass() {
JLabel jl = new JLabel(image);
JFrame jf = new JFrame();
jf.add(jl);
jf.setVisible(true);
jf.pack();
I do understand that when I am making reference from main() method to MyJNIWindowClass() s first initialized to null and that is why clock could not be seen but how can I assign image file name from Main() class for library class without creating reference to Main() from MyJNIWindowClass()? As I said, I want this library class being accessed from different applications (means different Main() classes).
Thank you.

Your problem is one of timing. Consider this simple example.
public class Example {
    public String s;
    private String message = "Hello, " + s;
    public String toString() {
        return message;
    public static void main(String[] args) {
        Example ex = new Example();
        ex.s = "world";
        System.out.println(ex.toString());
}When this code is executed, the following happens in order:
1. new Example() is executed, causing an object to constructed. In particular:
2. field s is given value null (since no value is explicitly assigned.
3. field message is given value "Hello, null"
4. Back in method main, field s is now given value "world", but that
doesn't change message.
5. Finally, "Hello, null" is output.
The following fixes the above example:
public class Example {
    private String message;
    public Example(String name) {
        message = "Hello, " + name;
    public String toString() {
        return message;
    public static void main(String[] args) {
        Example ex = new Example("world");
        System.out.println(ex.toString());
}

Using Class and Constructor to create instances on the fly

hi,
i want to be able to create instances of classes as specified by the user of my application. i hold the class names as String objects in a LinkedList, check to see if the named class exists and then try and create an instance of it as follows.
the problem im having is that the classes i want to create are held in a directory lower down the directory hierarchy than where the i called this code from.
ie. the classes are held in "eccs/model/behaviours" but the VM looks for them in the eccs directory.
i cannot move the desired classes to this folder for other reasons and if i try to give the Path name to Class.forName() it will not find them. instead i think it looks for a class called "eccs/model/behaviours/x" in the eccs dir and not navigate to the eccs/model/behaviours dir for the class x.
any ideas please? heres my code for ye to look at in case im not making any sense:)
//iterator is the Iterator of the LinkedList that holds all the names of the
//classes we want to create.
//while there is another element in the list.
while(iterator.hasNext())
//get the name of the class to create from the list.
String className = (String) iterator.next();
//check to see if the file exists.
if(!doesFileExist(className))
System.out.println("File cannot be found!");
//breake the loop and move onto the next element in the list.
continue;
//create an empty class.
Class dynamicClass = Class.forName(className);
//get the default constructor of the class.
Constructor constructor = dynamicClass.getConstructor(new Class[] {});
//create an instance of the desired class.
Behaviour beh = (Behaviour) constructor.newInstance(new Object[] {});
private boolean doesFileExist(String fileName)
//append .class to the file name.
fileName += ".class";
//get the file.
File file = new File(fileName);
//check if it exists.
if(file.exists())
return true;
else
return false;
}

ok ive changed it now to "eccs.model.behaviours" and it seems to work:) many thanks!!!
by the following you mean that instead of using the method "doesFileExist(fileName)" i just catch the exception and throw it to something like the System.out.println() ?
Why don't you simply try to call Class.forName() and catch the exception if it doesn't exist? Because as soon as you package up your class files in a jar file (which you should) your approach won't work at all.i dont think il be creating a JAR file as i want the user to be able to create his/her own classes and add them to the directory to be used in the application. is this the correct way to do this??
again many thanks for ye're help:)

Referencing main class from created instances

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