Symbols + Base-Class Workflow

I frequently create a lot of Library Symbols, export for Actionscript, letting Flash auto-generate the Class & extending a custom base-class in order to give them all custom functionality w/out having to create a Class for each, and/or without having to create a FactoryClass for instantiating X number of ClassObjects for each Symbol to be added to.
It's really fast for prototyping, and with this workflow I've only hit a few obstacles. Those are:
1 - If the Symbol has children you cannot give the children instance-names, else the compiler gives an error related to automatically declaring stage instances. Two workarounds for this are that you can uncheck automatically declare stage instances, and do it manually in your base-class. or you can avoid using instance-names, and use getChildAt().
2 - If the Symbol is a MovieClip, the timeline doesn't inherit the base-classes imports. I don't have a workaround for this.
My question is, are these limitations that could be addressed by Adobe's Flash team, or are they limitations that are unavoidable without altering the workflow?

Vote for this idea at ideas.adobe.com Flash Professional: http://tinyurl.com/2bxew2x
Problem Description:
Using the Library to export Symbols for Actionscript hits a severe wall when Symbols use auto-generated classes + base-classes. Child instances are declared as their auto-generated class type instead of their base-class. The result is that you cannot create 2 Library Symbols with auto-generated classes which inherit from a user-defined base-class which have named child instances with auto-generated classes & a user-defined base-class.
Steps to Reproduce:
1.     Create 2 Library Symbols, export for Actionscript with base-class "Character" which extends Sprite. Let Flash auto-generate Class names "Character1" & "Character2".
2.     Create 2 more Library Symbols, export for Actionscript with base-class "Head" which extends Sprite. Let Flash auto-generate Class names "Character1Head" & "Character2Head".
3.     Place an instance of Character1 on the stage, and give it a child instance of "Character1Head" named "head".
4.     Place an instance of Character2 on the stage, and give it a child instance of "Character2Head" named "head".
5.     Test Movie or Publish
Actual Result:
Warning: All instances named 'head' will be automatically declared as "Character1Head" in symbols that use "Character" as their base class. In symbols that are linked to user-defined base classes, instances with the same name must be of the same type.
Expected Result:
Flash should declare all instances named "head" as their base-class type "Head" when using auto-generated Classes. Save this workflow!!!

Similar Messages

Is there a way to turn off "automatically declare stage instances" on a per-symbol basis?

This would be an incredibly useful feature, and would eliminate 99% of those "1152: A conflict exists with inherited definition... in namespace public".
Generally, this option is off for my main flash document, but in individual "lesson" swfs that I load into it, most of the content in those are not class-backed, so I leave "automatically declare stage instances" on at the document level (currently the only level to specify this option) for those lesson swfs.
However, in one of those "lesson" swfs, there are two library symbols that I would like to have the same base class. They have the same child instances with the same names, just with different sizes (e.g. one is a main idea with two fields, the other is the same thing, but the fields are bigger). When I set both of these to use the "MainIdea" class as thier "base class" (defined in an external SWC, but not relevant here), I get the confict error, because Flash tries to generate it's own class for each object (inheriting from the base class I specified), but that base class already has those identifiers defined.
So, ideally, I would like to be able to stop flash from trying to atomatically declare stage instances on those particular symbols that specify a base class. In fact, it makes sense to me that for any symbol that's given an explicit base class, Flash Authoring should either never try to automatically declare stage instances (since the presense of a base class would imply the presense of pre-defined instance variables) or should give the developer the option at the symbol-level, so that this conflict would not occur. Even when it does occur, it should be a warning rather than an error, since Flash Authoring could simply not re-define the variable if it already exists in the base class.
A potential work around, which doesn't even work and which defeats the purpose of using a single shared base class for multiple symbols, is to actually define a unique class file for each symbol (which both inherit from the base class), so that Flash doesn't try to automatically declare stage instances for it, but Flash still tries to automatically generate stage instances.
Final recommendation: I really think Flash would be much better off if the "automatically declare stage instances" option would resolve the conflicts itself by simply not declaring already-declared properties for symbols that use a defined class or base class. Instead, it should just show a warning saying "I tried to automatically define a property for this stage instance, but it's base class already defined it, and that's ok!"

Have a look at this YouTube movie, explaining how to replace the simple action by a oneliner standard action to prevent the playhead of being released:
http://www.youtube.com/watch?v=M3nKi-DB6Fw&feature=plcp sorry, but I cannot use the link button (to have a meaningful text) in Chrome.
If you prefer readng:
http://blog.lilybiri.com/why-choose-standard-over-simple-action
Lilybiri

AS3: How to create one base class for classes loaded in multiple swfs?

Our application have 3 different modules and all use
fscommand and ExternalInterface alot. Now the problem is we are
combining all those modules, but they all will reside in different
swfs. Is there any way that they extend to same base class and its
static members have only one instance accessible by all
three?

Hi,
You can achieve this via Workshop 9.2 by using the exported Ant script for your project as follows:
-Ensure that all Jars needed to resolve com.bea.p13n.property.EntityPropertyManager (this particular class is found in weblogic92/common/p13n/lib/p13n_ejb.jar) and all referenced classes are added to the Java build path for your WebLogic EJB project (Properties->Java Build Path->Libraries)
-Export the "Workshop Ant Script" for your WebLogic EJB project (File->Export->Workshop Ant Script); this will generate a "build.xml" Ant script under your project root directory.
-Edit this default build script as follows: in the call to the "ejbgen" task within the "build" target, add the attribute: propertyFile="ejbgen.properties"
-Create a file "ejbgen.properties" under the root of your WebLogic EJB project and add the following entry:
YourSessionBeanClassName.remote.baseClass=com.bea.p13n.property.EntityPropertyManager
-Add a "<path refid="java.classpath"/>" within the "<classpath>" for the "java" task element that calls "weblogic.ejbc" (this will ensure that the p13n classes are resolved by EJBC)
Follow the instructions for executing the Ant build script found here: http://edocs.bea.com/workshop/docs92/ws_platform/ideuserguide/conUseCustomAntBuild.html
For more information on the EJBGen property file support, see: http://e-docs.bea.com/wls/docs92/ejb/EJBGen_reference.html

Warning :: Derived class hides the base class virtual function

We are porting from CC5.3 to CC5.8 compiler with Sun Studio one compiler. After plenty of hurdles we are in the final stage of removing the warning messages... Amoung the plenty the following one is very common and in different files. Why am I getting this error in 5.8 and not in 5.3 compiler....
Warning: derived_Object::markRead Hides the virtual function base_Object::markRead(ut_SourceCodeLocation&) const in a virtual base
From this it is easily understandable that the base class mark read was hidden by derived class markRead... when we drive and override the derived class function.... It is all over the place....
Thank you,
Saravanan Kannan
//public: using xx_Object :: markRead;
virtual void markRead() const;

The Sun C++ FAQ discusses the warning message:
http://developers.sun.com/prodtech/cc/documentation/ss11/mr/READMEs/c++_faq.html#Coding1
Notice that warnings are not necessarily errors. But I applaud your desire to fix the code so that it generates no warnings. I wish more of our customers could be persuaded to do the same. :-)
C++ 5.3 issues this warning, by the way. Example:
struct B { virtual int foo(int); };
struct D : B { virtual int foo(double); }; // line 2
D d;
line 2: Warning: D::foo hides the virtual function B::foo(int).
If for your particular code you do not see a warning with C++ 5.3, it would be due to a bug in C++ 5.3 that was later fixed.

Class override, how to create the child class and then the base class

I started to write a program for a smart DMM, the problem is every version of the DMM the company change the communication commend.
My idea is to write a child class for every DMM version and every SubVI of the child will override the base class SubVI.
My problem is, i want first to create one child class and after i will see every thing is work, start to create the base class. that way i will see if am thinking the right way.
My question is
How can i create a child class and then create the base class and configure the SubVi of the child class to be Override of the base class?
I tried to search in the property of the class but i didn't see nothing.
Thanks
Solved!
Go to Solution.

This can be done and I've done it on occasion.
You simply create the base class with the dynamic dispatch methods you require (connector panes need to be identical to thos of the child class).
Then set the inheritance of the class to inherit from this base class. If your method is defined as a dynamic dispatch method in the parent, you'll most likely now have some errors (unless your child method was already DD in which case you might just be OK already).
To change the inheritance of a class, right-click the properties of the class in your project and select properties. I believe the ineritance tree is at the lower end of the properties. Click on the "change inheritance" (or something similar) to choose the class from which you now wish to inherit.
Say hello to my little friend.
RFC 2323 FHE-Compliant

How to specify a base class for Remote Interface in Workshop 9.2? -- URGENT

Hi,
I am trying to create a UUP EJB in WebLogic 9.2 workshop. I am using @FileGeneration to create my home & remote interfaces. And the generated remote interface is extending javax.ejb.EJBObject;I want my remote interface to extend com.bea.p13n.property.EntityPropertyManager which in turn implements javax.ejb.EJBObject. Can someone tell how i can do it in Workshop?.
I came across Predefined Variable: remote.baseClass and as per docume
ntation..."If specified, the value of this variable will be used as the base class for all generated remote classes. Where i should specify it?. @FileGeneration does nt have any option for it. Any help is grtly appreciated.
Following are my code snippets:
IMPL Class
@FileGeneration(remoteClass = Constants.Bool.TRUE,remoteHome = Constants.Bool.TRUE, localClass = Constants.Bool.FALSE, localHome = Constants.Bool.FALSE,remoteClassName = "MyEntityPropertyManager",remoteHomeName = "MyEntityPropertyManagerHome")
public class MyEntityPropertyManagerImpl extends GenericSessionBean implements
SessionBean {
//code
}

This question was posted to both the bea.workshop.developer.general and weblogic.developer.interest.workshop (I had replied to the later on 10/19); after seeing an identical question today on this list want to include a reference to that reply here:
http://forums.bea.com/bea/message.jspa?messageID=600044925&tstart=0
-Rob

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

Error with instance variable and constructor of base class

I am getting the error on the following statement "protected Point apoint" of by base class. What is causing this problem? See my code:
package Shapes;
public abstract class Shapes
     protected Point apoint; / ****error at this line****/
     public void move(double xdelta, double ydelta)
          apoint.x += xdelta;
          apoint.y += ydelta;
public abstract void distance();
public abstract void show();
public String toString()
return "\nThe starting point is at coordinates ("+x+","+y+")";
package Shapes;
public class Lines extends Shapes
protected Point start;
protected Point end;
     protected double x;
     protected double y;
     double delta;
     public Lines( final Point apoint, final Point bpoint)
start.x = apoint.x;
          start.y = apoint.y;
          end.x = bpoint.x;
          end.y = bpoint.y;
public Lines(double xstart, double ystart, double xend, double yend)
this.xstart = xstart;
          this.ystart = ystart;
          this.xend = xend;
          this.yend = yend;
     public Lines(double x, double y)
          this.x = x;
          this.y = y;
               public void distance(final Lines start, final Lines end)
                    delta = abs(Math.sqrt (super.x - start.x) * (super.x - end.x) +
                    (super.y - start.y) * (super.y - end.y));
               Lines move(Point start, double delta)
                    end.x += delta;
                    end.y += delta;
                    return new Point(end);
public Lines show()
g.drawLine( start.x, start.y, end.x, end.y);
public String toString()
return super.toString()+ "\n moved distance is("
               + start + ") : (" + end + ")"
               +" \n to position(" + start + " ) : (" + end + ")";
package Shapes;
public class Rectangle extends Lines
     double delta;
public Rectangle (Point top_lft_pt, Point bottom_rght_pt)
super(top_lft_pt, bottom_rght_pt);
public Rectangle(double x_top_lft, double y_top_lft, double x_bottom_rght, double y_bottom_rght)
super(x_top_lft, y_top_lft, x_bottom_rght, y_bottom_rght);
     public Rectantgle is_it_diagonal()
          if(top_lft.x > bottom_rght.x && bottom_rght.x < top_lft.x)
               System.out.println("Point are Not Diagonal");
               public void distance(double delta)
                    delta = abs(Math.sqrt (top_lft.x - bottom_rght.x) * (top_lft.x - botton_rght.x) +
                    (top_lft.y - bottom_rght.y) * (top_lft.y - bottom_rght.y));
               public Rectangle move(final Point top_lft_pt, double delta)
                    bottom_rght.x += delta;
                    bottom_rght.y += delta;
                    return new Point(bottom_rght_pt);
               public void get_top_rght_coords()
                    Point top_rght = new Point();
                    top_rght.x = bottom_rght.x;
                    top_rght.y = top_lft.y;
               public void get_bottom_left_coords()
                    Point bottom_lft = new Point();
                    bottom_lft.x = top_lft.x;
                    bottom_lft.y = bottom_rght.y;
     public Rectangle show()
                    g.drawLine(top_lft.x, top_lft.y, top_rght_x, top_rght_y);
                    g.drawLine(bottom_lft.x, bottom_lft.y, bottom_rght.x, bottom_rght.y);
                    g.drawLine(top_lft.x, top_lft.y, bottom_lft.x, bottom_lft.y);
                    g.drawLine(top_rght.x, top_rght.y, bottom_rght.x, bottom_rght.y);
package Shapes;
public class Circles extends Lines
protected double radius;
     public double delta;
     protected Point center;
public Circles(double x, double y, double radians)
super(x, y);
          radius = radians;
     public Circles(Point acenter)
          center.x = acenter.x;
          center.y = acenter.y;
public void distance()
delta = abs(Math.sqrt(super.x - x) * (super.x - x) + (super.y - y) * (super.y -y));
     public Circles move(final Point Circles, double delta)
          return new Point(Circles);
public void show()
g.drawOval(Circles.x, Circles.y, radius, radius);
package Shapes;
import java .math .*;
import java.util .Random ;
public class ShapesDriver
Shapes[] aShape = new Shapes[10];
static double range = 101.0;
static Random r1 = new Random();
public static void main(String [] args)
double[][] coords = new double[10][10];
double[] radians = new double [10];
Shapes anyShape = {
new Circles(radians),
new Lines(coords),
new Rectangle(coords)
Shapes aShape; /***error at this line***/
          for(int i = 1; i <= coords.length; i++)
for(int j = 1; j <= coords.length; j++)
                                                  coords[i][j] = r1.nextDouble () * range;
                                                  radians[j] = r1.nextDouble () * range;
aShape[i] = anyShape[r1.nextInt(aShape.length)];
System.exit(1);

Thanks for your help with this problem. Now I have another problem that I am having a hard time figuring out. My program is using inheritance and polymorphism. I trying to use only one version of methods in the superclass points which extends the shapes class which is the abstract superclass vs. repeating the implementation of the methods (move, show, etc.) in each of the subclasses. The error I am getting is this "declare the class abstract, or implement abstract member 'Point Shapes.move()'. As you see, move is declared abstract and of type point in the Shapes superclass and it's behavior is implemented in the subclass Points extending Shapes. The other subclasses, circle, rectangle and lines will invoke the move method from Points and return a new point object. Why I am I getting the error to declare or implement move when the implementation is in Point?
Below is code, please help?
import java .awt .Point ;
public class ShapesDriver
     public static void main(String args[])
          int count = 0;
          int choice;
          Point start = null;
          Point end = null;
          System.out .println(" 1 i am here");
          start = new Point((int)(Math.random()* 10.0), (int)(Math.random()* 10.0));
          end = new Point((int)(Math.random()* 10.0), (int)(Math.random()* 10.0));
     System.out .println(" 2 i am here");
     System.out.println (start);
     System.out.println(end);
     for(int i = 0; i <= count; i++)
          System.out .println(" 3 i am here");
          choice = (int)(4.0 * Math.random());
          System.out .println(" 4 i am here");
          System.out.println (choice);
     switch(choice)
          case 0: //Lines
          System.out .println(" 5 i am here");
          Lines apoint = new Lines((int)(Math.random()* 10.0), (int)(Math.random()* 10.0),
                              (int)(Math.random()* 10.0), (int)(Math.random()* 10.0));
          Point coords = new Point((int)(Math.random()* 10.0),
                         (int)(Math.random()* 10.0));
          new Point((int)(Math.random()* 10.0),
                         (int)(Math.random()* 10.0));
          break;
          case 1: //Circles
          System.out .println(" 6 i am here");
          Circles center = new Circles((double)(Math.random()* 10.0),
          (double)(Math.random()* 10.0), (double)(Math.random()* 10.0),
          (double)(Math.random()* 10.0),(double)(Math.random()* 10.0));
          Circles centerpt = new Circles((int)(Math.random()* 10.0),
          (int)(Math.random()* 10.0), (int)(Math.random()* 10.0),
          (int)(Math.random()* 10.0), (double)(Math.random()* 10.0));
     break;
          case 2: //Rectangles
     System.out .println(" 7 i am here");
          Rectangle top_lft_pt = new Rectangle ((double)(Math.random()* 10.0),
                         (double)(Math.random()* 10.0), (double)(Math.random()* 10.0),
                         (double)(Math.random()* 10.0), (double)(Math.random()* 10.0),
                         (double)(Math.random()* 10.0));
          Rectangle bottom_rgt_pt = new Rectangle ((double)(Math.random()* 10.0),
               (double)(Math.random()* 10.0), (int)(Math.random()* 10.0),
                         (int)(Math.random()* 10.0), (int)(Math.random()* 10.0),
                         (int)(Math.random()* 10.0));
     break;
     default:
     System.out .println(" 9 i am here");
     System.out.println("\nInvalid shape choice =" + choice);
     System.exit(0);
     break;
     try
               System.in.read();
               catch(java.io.IOException ioe)
import java .awt .Point ;
public abstract class Shapes
     private String shape;
     public Shapes(String ashape)
          shape = new String(ashape);
     public abstract Point move();
     public double distance()
          return 0.0;
     public abstract void show();
     public String toString()
          return "\nThis shape is a" + shape;
import java .awt .Point ;
public class Rectangle extends Points
     protected Point top_lft;
     protected Point top_rgt;
     protected Point bottom_lft;
     protected double top_lft_x;
     protected double top_lft_y;
     protected double bottom_rgt_x;
     protected double bottom_rgt_y;
     protected Point bottom_rgt;
     protected double delta = 0;
     protected String shape = "Rectangle";
     public Rectangle(double x, double y, double top_lft_x,
                         double top_lft_y, double bottom_rgt_x,
                         double bottom_rgt_y)
          super(x, y);
          top_lft_x = top_lft_x;
          top_lft_y = top_lft_y;
          bottom_rgt_x = bottom_rgt_x;
          bottom_rgt_y = bottom_rgt_y;
     public Rectangle( double x, double y, Point bottom_rgt, Point top_lft)
          super(x, y);
          bottom_rgt_x = bottom_rgt.x;
          bottom_rgt_y = bottom_rgt.y;
          top_lft_x = top_lft.x;
          top_lft_y = top_lft.y;
     public String toString()
          return super.toString() + " coordinates top left= " + top_lft_x + "," + top_lft_y + "and bottom right" +
               bottom_rgt_x + "," + bottom_rgt_y + ")";
     public void is_it_diagonal()
          if(top_lft_x < bottom_rgt_x && bottom_rgt_x > top_lft_x)
               System.out.println("Points are Not Diagonal");
          public double distance()
               distance ();
               return delta;
          public Point move(Point top_lft)
               move();
               bottom_rgt_x += delta;
               bottom_rgt_y += delta;
               return top_lft;
          public void get_other_coords()
               top_rgt.x = bottom_rgt.x;
          top_rgt.y = top_lft.y;
               bottom_lft.x = top_lft.x;
               bottom_lft.y = bottom_rgt.y;
          public void show()
               super.show();
               System.out.println("new coords are :");
               System.out .println ("(" + top_lft_x + "," + top_lft_y + ")");
               System.out .println ("top right(" + top_rgt + ")");
               System.out .println ("(" + bottom_rgt_x + "," + bottom_rgt_y + ")");
               System.out .println ("bottom right(" + bottom_rgt + ")");
import java .awt .Point ;
public class Points extends Shapes
     protected double delta = 0.0;
     protected double x;
     protected double y;
     protected String ashape = "Points";
     public Points( double x, double y)
          super("Points");
          x = x;
          y = y;
     public Points( Point start)
          super("Points");
          x = start.x;
          y = start.y;
     public String toString()
          return super.toString() + "References coordinates(" + x + y + ")";
     public double distance(double x1, double y1 )
          return delta =(Math.sqrt(x - x1) * (x - x1) + (y - y1) *
          (y - y1));
     public Point move(Point pts)
          pts.x += delta;
          pts.y += delta;
          return pts;
     public void show()
          System.out.println("This shape is a" + ashape + "(" +
                              "(" + x+ "," + y + ")");
import java .awt .Point ;
public class Lines extends Points
     double delta = 0;
     protected double x;
     protected double y;
     protected String ashape = "Lines";
     public Lines( double x1, double y1, double x, double y)
          super(x1,y1);
          x = x;
          y = y;
     public Lines(Point start, Point end)
          super(start);
          x = end.x;
          y = end.y;
     public String toString(Point end)
          return super.toString() + "line points = (" + x + "," + y +
               "(" + end + ")";
     public double distance()
          distance ();
          return delta;
     public Point move(Point lines)
          move ();
          return lines;
     public void show()
          System.out.println("This shape is a" + ashape + "(" +
                              "(" + x + "," + y + ")");
import java .awt .Point ;
public class Circles extends Points
protected double radius;
protected double xcenter;
protected double ycenter;
protected String ashape = "Circle";
     public Circles( double x, double y, double cx, double cy, double radians)
          super(x, y);
          xcenter = cx;
          ycenter = cy;
          radius = radians;
     public Circles( Point acenter, Point ref, double radians)
          super(ref);
          xcenter = acenter.x;
          ycenter = acenter.y;
          radius = radians;
     public String toString(Point ref)
          return super.toString() + " reference points (" +
               ref + ")" +
               "center coordinates (" + xcenter + "," + ycenter + ")";
          public double distance(Point ref)
               return (Math.sqrt(ref.x - xcenter) * (ref.x - xcenter)
                         + (ref.y - ycenter) *
          (ref.y - ycenter));
          public Point move(Point center)
               move();
               return center;
          public void show()
               System.out.println("This shape is a" + ashape + "(" +
                              "(" + xcenter + "," + ycenter + ")");

Field-symbols as class attribute

Hi Fellas,
Is there a way we can define a field-symbols as a class attribute ? My requirement is that i am dynamically constructing a structure at runtime in my model class and binding the component of this structure to my view fields. I am able to create the structure which is basically ref to cl_abap_structdescr and the problem is when i am binding to the model attribute, i need this to be a structure so that i can address the components as "//model/structure.component".
Please let me know how we can define a field-symbol as a class attribute.
Cheers,
Ram.

Hi Ram,
Field-Symbol as class attribute is not possible. Your way to do this by REF TO DATA is the correct way for that.
By default data binding is only possible like this:
Simple field attribute
value=//<model>/<field name>
Structure attribute
value=//<model>/<structure name>.<field name>
Table attribute
value=//<model>/<table name>[<line index].<field name>
If you want to bind to your data reference you have to implement your own getter and setter methods. Read this <a href="http://help.sap.com/saphelp_nw70/helpdata/en/fb/fbb84c20df274aa52a0b0833769057/frameset.htm">http://help.sap.com/saphelp_nw70/helpdata/en/fb/fbb84c20df274aa52a0b0833769057/frameset.htm</a> for further information. In addition to that, you have to implement your own GET_M_S_xxx to return metadata of your structure. By doing all this it is possible to implement a completely dynamic data binding. In the view it looks like the regular Structure attribute: value=//<model>/<data-ref name>.<field name>
Regards,
Thilo

How to call derived class to base class

Hello everybody,
I create a GUi application in java swing. Now i want to navigate between the screen but the timing between the screen is very slow bcoz i imported the class from package to another package. Now i want to extends one package to another package to reduce the navigation time but it saying error bcoz i cant able to call my derived class to base class. if anyone know the answer for this please answer this immediately.
If any other method is there to optimise the navigation time please tell me
by
(kamal)

Sorry, I've got major difficulties understanding your query:
I create a GUi application in java
ication in java swing. ok
Now i want to navigate between
the screenwhat? switch screens? display a different dialog?
but the timing between the screen is very
slowtiming? do you mean the time it takes to display a different dialog?
bcoz i imported the class from package to
another package.how did you come to the conclusion that that is the reason for the slowness? Did you do any profiling or is this just guess-work?

Set fields of derived class in base class constructor via reflection?

Does the Java Language Specification explicitly allow setting of fields of a derived class from within the base class' constructor via reflection? The following test case runs green, but I would really like to know if this Java code is compatible among different VM implementations.
Many thanks for your feedback!
Norman
public class DerivedClassReflectionWorksInBaseClassConstructorTest extends TestCase {
abstract static class A {
    A() {
        try {
            getClass().getDeclaredField("x").setInt(this, 42);
        } catch (Exception e) {
            throw new RuntimeException(e);
static class B extends A {
    int x;
    B() {
    B(int x) {
        this.x = x;
public void testThatItWorks() {
    assertEquals(42, new B().x);
    assertEquals(99, new B(99).x);
}

why not just put a method in the superclass that the subclasses can call to initialize the subclass member variable?In derived classes (which are plug-ins), clients can use a field annotation which provides some parameter metadata such as validators and the default value. The framework must set the default value of fields, before the class' initializer or constructors are called. If the framework would do this after derived class' initializer or constructors are called, they would be overwritten:
Framework:
public abstract class Operator {
    public abstract void initialize();
}Plug-In:
public class SomeOperator extends Operator {
    @Parameter(defaultValue="42", interval="[0,100)")
    double threshold;
    @Parameter(defaultValue="C", valueSet="A,B,C")
    String mode;
    public void setThreshold(double threshold) {this.threshold = threshold;}
    public void setMode(String mode) {this.mode = mode;}
    // called by the framework after default values have been set
    public void initialize() {
}On the other hand, the default values and other metadata are also used to create GUIs and XML I/O for the derived operator class, without having it instantiated. So we cannot use the initial instance field values for that, because we don't have an instance.

Reflection: attributes from the base class

Is there a way to get the attributes from the base class of a derived class via reflection? I only found methods to get the attributes from the derived class.
Example:
class A
int a = 4;
class B extends A
int b = 5;
Object unknown = new B();
Code/Idea to get all attributes from baseclass A using unknown (here: a=4)?

Thank you all for your hints. The mistake I make, was to use the baseclass, and not the derived class for getting the attributes. By using an extra parameter of type class I got all attributes in their context.
   private StringBuffer getDump(Object obj, Class cl)
         dmp.append(cl.getName() + " {\n");
         Field[] attribute = cl.getDeclaredFields();             <--- only the fields of the current class
         for (int j = 0; j < attribute.length; j++)
            attribute[j].setAccessible(true);
            try
               if (attribute[j].getType().isPrimitive() || attribute[j].getType() == String.class)
                  dmp.append(attribute[j].getName() + "=" + attribute[j].get(obj) + "\n");
               else
                  if (((attribute[j].getModifiers() & Modifier.STATIC) != Modifier.STATIC) &&
                      (attribute[j].getType().getName().startsWith("java.lang") == false) &&
                      ((attribute[j].getModifiers() & Modifier.FINAL) != Modifier.FINAL))
                     dmp.append(getDump(attribute[j].get(obj), attribute[j].get(obj).getClass())); <- recursive call
            catch (IllegalAccessException ex)
               ex.printStackTrace();
         dmp.append("}");
      return dmp;
   }

Base class vs derived class

We have entity classes that we use to access our database. We have subclasses derived from these entity classes that apply business rules. For instance, the base class AddressEntity has a
setAddress2(string) that AddressEntity.select() uses to set a class variable with data retrieved from the database. The derived class Address also has a setAddress2(string) method that puts restrictions on the length of the data. I want the AddressEntity.select() method to use the base class method AddressEntity.setAddress2(). I've tried using this.setAddress2() in AddressEntity.select() but the derived class method is still used. Any suggestions?
Thanks,
Joe

If you need to call some methods on the base class sometimes and some methods on the derived class other times, but using the same object, then yes dubwai is right you should revisit your Object hierarchy.
One simple way to do what you are asking is to have your method(s) look like this:
void setAddress2(String sAddress) { setAddress2(sAddress, true); }
void setAddress2(String sAddress, boolean bRestrictLength) {
// real method
}then you could just look at the variable bRestrictLength to see if you need to restrict the length, and have it default to true. In this way you can use overloading to solve your problem.

How to call a method of a base class if the base class is abstract...

This is my sample code>>>>
abstract class b {
     public void display() {
          System.out.println("I am in Base Class");
class test extends b {
     public static void main(String[] args) {
          test obj = new test();
          obj.display();
     public void display() {
          System.out.println("I am in Derived Class");
I want to call base class version of display with derived class object.........is it possible....

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Enough with the friggin' zombie threads already!

Base class

Hi ,
What will happen if I have a derived class default constructor which does not call the base class constructor as below?
Will this cause any issues?
Thanks,
public class Base{
private String st = null;
public Base (){}
public Base(String str){
st = str;
public class Derived extends Base{
public Derived(){}
}

What will happen if I have a derived class
default constructor which does not call the
base class constructor as below?Another hint: who says the derived class constructor does not call a base class constructor? One very good way to learn about what is happening is to output messages in your constructors. Add the following line to your base class default constructor:
System.out.println("Base default constructor");
Then create an object of your derived class and see what happens.
Will this cause any issues? Why even bother thinking about it? If you always call a base class constructor from your derived class constructors, then you don't have to worry.

Symbols + Base-Class Workflow

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