Access instance method of a class inside instance method of another class

Hi Friends
I have to use one c1->m1.
c1 is a public instantiation and m1 is a public Instance Method.
I called this m1 method by creating c1 object for class c1.
But problem is inise M1 method,i have a statement
CALL METHOD mo_central_person->if_hrbas_pd_object~read_infty.
here mo_central_person is of type some other class c2.
As without creating the object,i didn't use the above interface method.
Can please suggst me how to handle this.
Regards,
Sree

class a definition.
public section.
methods : display,
            disp.
data : a(10) type c value '10',
         b(5) type c value 'abc'.
endclass.
class a implementation.
method display.
    write : a.
endmethod.
method disp.
    write : b.
endmethod.
endclass.
class b definition inheriting from a.
public section.
methods : display1.
data : c(7) type c value '7'.
endclass.
class b implementation.
method display1.
   call method display( ).
    write c.
endmethod.
endclass.
start-of-selection.
data : o_obj type ref to b.
create object o_obj.
call method o_obj->display1.
the method display is in class a.
we can call this method in class b using the following statement.
method display1.
   call method display( ).
    write c.
endmethod.

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To define a class inside a method

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Iam new to OOPS ABAP.
I had one doubt,
Can we define and implement a new class inside a method... end method (like below)
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Hi Rich Heilman/Naimesh
The requirement is
In XI Proxy(XI proxy is related to creation of materials in SAP),there are macros defined, and my client told us to find out wheather is it possible to replace the macros with the classes and methods.
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Hi,
I have a ClassRoom class that stores a list of Student objects in an array. How would I copy a Student object from the Student[] array in the ClassRoom class to an array in another class?
Is it something like this:
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drew22299 wrote:
Hi,
I have a ClassRoom class that stores a list of Student objects in an array. How would I copy a Student object from the Student[] array in the ClassRoom class to an array in another class?
Is it something like this:
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That being said, you're only moving a single student. This is not something you would use arrayCopy for, as you can just do that with simple assignment. Also, you should consider giving Class a method to add a student to its student list, as the class should know how many students it has and can easily "append" to the array.
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Can I invoke a class that extends JAppl from another class extends JAppl

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Nobody is able to solve this problem, i cant even
think this things. i have hope so plz try and get
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Inner class inside a method - how does it access method's local variable?

hello All:
I've learnt that, an inner class, if defined inside a method, it can access the method's local variables, only when they are defined as "final".
Anyone can help explain the rationale behind it?
Thanks a lot!
Sway

fathomBoat wrote:
In java, everything is about pass-by-reference.
Wrong! Nothing in Java is ever pass-by-reference.
Java uses pass-by-value everywhere.
It makes sense to me if the reason of enforcing a variable to be "final" is to prevent it being messed up.No, the reason is that a copy is made and if the variable weren't final then it could change later on and the developer could be confused because his inner class didn't "see" that change.
The variable being final prevents that scenario.
However, if a copy of the variable is made inside the inner class, i dont see how possible it could affect variables outside of class?Such a copy is made, but the language designers wanted to hide that fact from the developer. By forcing all accessed variables to be declared final the developer has no way to realize that he's actually working on a copy.

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can we write class inside tne main method in java? If yes kindly explain with example.

> can we write class inside tne main method in java? If
yes kindly explain with example.
The Java? Tutorial - Nested Classes
~

Calling a method and setting an ImageIcon with source from anoth class

I am trying to make a simple game, first I am trying to set up a game board, and make it possible to place units on the board. (This game will probably never be possible to play, I am just using it to try to understand Java, GUI, Swing, and using more than one class).
So far I have 4 classes: Board (extends JFrame, sets up a gameboard, on which to place the pieces), Unit (a class from which the specific units types will inherit), Horse (my only type of unit, which extends the Unit class), and Game (which calls methods from the other classes).
(These don't do much now.. this is what they will do, hopefully).
All these classes are in a package called Gamev1.
In the main method of Game, I do:
---code--
public static void main (String[]args){
new Board().show();
Horse horseUnits[] = new Horse[1];
horseUnits[0] = new Horse();
horseUnits[0].moveUnit(squares[0]);
end of code--
when I debug it I get:
myjava/FirstGraphics/Gamev1/Game.java [25:1] cannot resolve symbol
symbol: variable squares
location: class.myjava.FirstGraphics.Gamev1.Game
horseUnits[0].moveUnitsquares[0]);
1 error
---code----
moveUnit(JLabel moveTo)
is a method in Unit class:
public void moveUnit(JLabel moveTo){
target=moveTo;
target.setIcon(this.image);
if (this.position !=null)
this.position.setIcon(noUnit);
this.position=moveTo;
---end of code---------
squares[] is an array of JLabels which is set up in the Board class, whenever a new Board is created:
---code---
JLabel squares[] = new JLabel[100];
for (int s=0; s<100; s++){
squares[s] = new JLabel();
---end of code---
I tried changing the reference from squares[0] to Board.squares[0] but I got the same error message in debug.
Any idea what is wrong?
I have another problem, which is probably similar.
in the Board class I call:
squares[s].setIcon(Unit.noUnit);
and in the Unit class I have:
static ImageIcon noUnit = new ImageIcon("images//none.gif");
I don't get an error message mentioning it, but (without the attempt to place the horse on the board) the program compiles, but doesn't put this image on the labels. Any idea what is the porblem here?
If I have not given enough information for anyone to help me, please tell me what further information I should give.
Thanks to anyone who answers.

I got it to work with
    Board board = new Board();
    horseUnits[0].moveUnit(board.squares[0]);To use Board.squares[0], squares would have to be static.
The ImageIcon seemed to work okay. I noticed that your post had two slashes in the url [/] - that might throw things off . . .
The code below has the icon call at the end of setLabeLProperties.
I got carried away playing with the graphics so the squares don't work very well.
import java.awt.*;
import java.awt.geom.*;
import javax.swing.*;
public class HumaniBlue {
public static void main(String[] args) {
    Board board = new Board();
    board.show();
    JLabel label5 = board.getLabel(5);
    //System.out.println("label5 name = " + label5.getText());
    Horse[] horseUnits = new Horse[1];
    horseUnits[0] = new Horse();
    horseUnits[0].moveUnit(board.squares[0]);
class Unit {
static ImageIcon noUnit = new ImageIcon("images/bclynx.jpg");
public void moveUnit(JLabel square) {
class Horse extends Unit {
public Horse() {}
class Board {
JFrame f;
JPanel gameBoard;
int labelSize;
JLabel[] squares = new JLabel[16];
GridBagConstraints gbc = new GridBagConstraints();
public Board() {
    gameBoard = new JPanel(new GridBagLayout()) {
      public void paintComponent(Graphics g) {
        Graphics2D g2 = (Graphics2D)g;
        g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
                            RenderingHints.VALUE_ANTIALIAS_ON);
        double width = getSize().width;
        double height = getSize().height;
        g2.setPaint(Color.white);
        g2.fill(new Rectangle2D.Double(0, 0, width, height));
        g2.setPaint(Color.black);
        Shape line;
        double
          gridSize = (width < height ? width : height) * 0.8,
          gridUnit = (width < height ? width : height) / 5,
          x = (width - gridSize) / 2,
          y = (height - gridSize) / 2;
        labelSize = (int)gridUnit;
        for(int j = 0; j < 5; j++) {
          line = new Line2D.Double(x, y, x, y + gridSize);
          g2.draw(line);
          x += gridUnit;
        x = (width - gridSize) / 2;
        for(int j = 0; j < 5; j++) {
          line = new Line2D.Double(x, y, x + gridSize, y);
          g2.draw(line);
          y += gridUnit;
      //System.out.println("width = " + width + "\theight = " + height + "\n" +
      //                   "x = " + x + "\ty = " + y + "\n" +
      //                   "gridSize = " + gridSize + "\tgridUnit = " + gridUnit);
    f = new JFrame();
    f.getContentPane().add(gameBoard);
    f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    f.setSize(400,400);
    f.setLocation(600,200);
    //f.setVisible(true);
    setLabelProperties();
private void setLabelProperties() {
    int
      r   = 30,
      g   = 30,
      b   = 0,
      inc = 55;
    //System.out.println("labelSize = " + labelSize);
    for(int j = 0; j < squares.length; j++) {
      squares[j] = new JLabel("Square " + j, JLabel.CENTER);
      squares[j].setOpaque(true);
      squares[j].setPreferredSize(new Dimension(73, 73));
    // add labels
    int index = 0;
    gbc.gridx = 0;
    gbc.gridy = 0;
    for(int y = 0; y < 4; y++) {
      for(int x = 0; x < 4; x++) {
        index = y * 4 + x;
        squares[index].setBackground(new Color(r,g,b,90));
        gameBoard.add(squares[index], gbc);
        gbc.gridx++;
        r += inc;
      gbc.gridy++;
      gbc.gridx = 0;
      r = 90;
      g += inc;
    squares[9].setIcon(Unit.noUnit);
public void show() {
    f.setVisible(true);
public JLabel getLabel(int index) {
    return squares[index];
}

Call a method of a class in a constructor of another class?

Is this good programming or should i do it in another way?
Consider an ordering system, where I have three classes, "Booking", "Table" and "Customer.
My idea is to create a booking assigned to a table and a customer, the fields in the booking class is a Customer and a Table and the constructor assigns values to these field.
In my Table class i have a method that books the table "bookTable(Customer customer)" and sets the availablility to 'false'.
So my question is, is it good programming to call the method 'bookTable()' in the table class from the constructor of the Booking class? Or should i do it in another way?
Edited by: DJHingapus on Jul 6, 2009 5:12 AM

This sounds the wrong way around. What is the return value of bookTable(Customer)?
I'd expect it to return a Booking object that it creates.
Generally, you want the constructor to do as little as possible (while still only ever returning in a valid state, of course!).
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int truncStart = s.indexOf(".java");
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eventListeners are the way to go.
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How to access an attribute(this is referencing to another class) in a class

Dear Gurus,
I have to read an attribute of a class and that attributes type another class.
I have intantiated the class and my question is how to read the attribute. I know I can not dirrectly read the attribute since this is another class. I think I have to first reference the attribute right? Please advise me.
My code looks like below:
data: lo_fpm                                 type ref to if_fpm.
data: lo_msg_mgr                        type ref to if_fpm_message_manager.
data: lo_component_manager    type ref to cl_fpm_component_manager.
lo_fpm = cl_fpm_factory=>get_instance( ).    " cl_fpm_factory is a class which has a static method get_instance
lo_msg_mgr = lo_fpm->mo_message_manager.
lo_component_manager = lo_fpm->mo_component_manager.
The above statement is giving syntax error. I do not know why.
The basic difference b/n the two methods is if_fpm~mo_message_manager    type ref to if_fpm_message_manager    and
mo_component_manager     type ref to cl_fpm_component_manager.
Any help would be appreciated.
Thanks,
GSM

Hello
I cannot test the following coding because I do not get the singleton instance yet it should work:
*& Report ZUS_SDN_CL_FPM_FACTORY
*& Thread: How to access an attribute(this is referencing to another class) in a class
*& <a class="jive_macro jive_macro_thread" href="" __jive_macro_name="thread" modifiedtitle="true" __default_attr="1398429"></a>
REPORT zus_sdn_cl_fpm_factory.
DATA: go_fpm TYPE REF TO cl_fpm. " class implements if_fpm.
DATA: go_msg_mgr TYPE REF TO if_fpm_message_manager.
DATA: go_component_manager TYPE REF TO cl_fpm_component_manager.
START-OF-SELECTION.
BREAK-POINT.
go_fpm ?= cl_fpm_factory=>get_instance( ). " cl_fpm_factory is a class which has a static method get_instance
CHECK ( go_fpm IS BOUND ).
go_msg_mgr           = go_fpm->mo_message_manager.
go_component_manager = go_fpm->mo_component_manager.
END-OF-SELECTION.
Regards
Uwe

Passing a parameter from one class to another class in the same package

Hi.
I am trying to pass a parameter from one class to another class with in a package.And i am Getting the variable as null every time.In the code there is two classes.
i. BugWatcherAction.java
ii.BugWatcherRefreshAction.Java.
We have implemented caching in the front-end level.But according to the business logic we need to clear the cache and again have to access the database after some actions are happened.There are another class file called BugwatcherPortletContent.java.
So, we are dealing with three java files.The database interaction is taken care by the portletContent.java file.Below I am giving the code for the perticular function in the bugwatcherPortletContent.java:
==============================================================
public Object loadContent() throws Exception {
Hashtable htStore = new Hashtable();
JetspeedRunData rundata = this.getInputData();
String pId = this.getPorletId();
PortalLogger.logDebug(" in the portlet content: "+pId);
pId1=pId;//done by sraha
htStore.put("PortletId", pId);
htStore.put("BW_HOME_URL",CommonUtil.getMessage("BW.Home.Url"));
htStore.put("BW_BUGVIEW_URL",CommonUtil.getMessage("BW.BugView.Url"));
HttpServletRequest request = rundata.getRequest();
PortalLogger.logDebug(
"BugWatcherPortletContent:: build normal context");
HttpSession session = null;
int bugProfileId = 0;
Hashtable bugProfiles = null;
Hashtable bugData = null;
boolean fetchProfiles = false;
try {
session = request.getSession(true);
// Attempting to get the profiles from the session.
//If the profiles are not present in the session, then they would have to be
// obtained from the database.
bugProfiles = (Hashtable) session.getAttribute("Profiles");
//Getting the selected bug profile id.
String bugProfileIdObj = request.getParameter("bugProfile" + pId);
// Getting the logged in user
String userId = request.getRemoteUser();
if (bugProfiles == null) {
fetchProfiles = true;
if (bugProfileIdObj == null) {
// setting the bugprofile id as -1 indicates "all profiles" is selected
bugProfileIdObj =(String) session.getAttribute("bugProfileId" + pId);
if (bugProfileIdObj == null) {
bugProfileId = -1;
else {
bugProfileId = Integer.parseInt(bugProfileIdObj);
else {
bugProfileId = Integer.parseInt(bugProfileIdObj);
session.setAttribute(
("bugProfileId" + pId),
Integer.toString(bugProfileId));
//fetching the bug list
bugData =BugWatcherAPI.getbugList(userId, bugProfileId, fetchProfiles);
PortalLogger.logDebug("BugWatcherPortletContent:: got bug data");
if (bugData != null) {
Hashtable htProfiles = (Hashtable) bugData.get("Profiles");
} else {
htStore.put("NoProfiles", "Y");
} catch (CodedPortalException e) {
htStore.put("Error", CommonUtil.getErrMessage(e.getMessage()));
PortalLogger.logException
("BugWatcherPortletContent:: CodedPortalException!!",e);
} catch (Exception e) {
PortalLogger.logException(
"BugWatcherPortletContent::Generic Exception!!",e);
htStore.put(     "Error",CommonUtil.getErrMessage(ErrorConstantsI.GET_BUGLIST_FAILED));
if (fetchProfiles) {
bugProfiles = (Hashtable) bugData.get("Profiles");
session.setAttribute("Profiles", bugProfiles);
// putting the stuff in the context
htStore.put("Profiles", bugProfiles);
htStore.put("SelectedProfile", new Integer(bugProfileId));
htStore.put("bugs", (ArrayList) bugData.get("Bugs"));
return htStore;
=============================================================
And I am trying to call this function as it can capable of fetching the data from the database by "getbugProfiles".
In the new class bugWatcherRefreshAction.java I have coded a part of code which actually clears the caching.Below I am giving the required part of the code:
=============================================================
public void doPerform(RunData rundata, Context context,String str) throws Exception {
JetspeedRunData data = (JetspeedRunData) rundata;
HttpServletRequest request = null;
//PortletConfig pc = portlet.getPortletConfig();
//String userId = request.getRemoteUser();
/*String userId = ((JetspeedUser)rundata.getUser()).getUserName();//sraha on 1/4/05
String pId = request.getParameter("PortletId");
PortalLogger.logDebug("just after pId " +pId); */
//Calling the variable holding the value of portlet id from BugWatcherAction.java
//We are getting the portlet id here , through a variable from BugWatcherAction.java
/*BugWatcherPortletContent bgAct = new BugWatcherPortletContent();
String portletID = bgAct.pId1;
PortalLogger.logDebug("got the portlet ID in bugwatcherRefreshAction:---sraha"+portletID);*/
// updating the bug groups
Hashtable result = new Hashtable();
try {
request = data.getRequest();
String userId = ((JetspeedUser)data.getUser()).getUserName();//sraha on 1/4/05
//String pId = (String)request.getParameter("portletId");
//String pId = pc.getPorletId();
PortalLogger.logDebug("just after pId " +pId);
PortalLogger.logDebug("after getting the pId-----sraha");
result =BugWatcherAPI.getbugList(profileId, userId);
PortalLogger.logDebug("select the new bug groups:: select is done ");
context.put("SelectedbugGroups", profileId);
//start clearing the cache
ContentCacheContext cacheContext = getCacheContext(rundata);
PortalLogger.logDebug("listBugWatcher Caching - removing markup content - before removecontent");
// remove the markup content from cache.
PortletContentCache.removeContent(cacheContext);
PortalLogger.logDebug("listBugWatcher Caching-removing markup content - after removecontent");
//remove the backend content from cache
CacheablePortletData pdata =(CacheablePortletData) PortletCache.getCacheable(PortletCacheHelper.getUserHandle(((JetspeedUser)data.getUser()).getUserName()));
PortalLogger.logDebug("listBugWatcher Caching User: " +((JetspeedUser)data.getUser()).getUserName());
PortalLogger.logDebug("listBugWatcher Caching pId: " +pId);
if (pdata != null)
// User's data found in cache!
PortalLogger.logDebug("listBugWatcher Caching -inside pdata!=null");
pdata.removeObject(PortletCacheHelper.getUserPortletHandle(((JetspeedUser)data.getUser()).getUserName(),pId));
PortalLogger.logDebug("listBugWatcher Caching -inside pdata!=null- after removeObject");
PortalLogger.logDebug("listBugWatcher Caching -finish calling the remove content code");
//end clearing the cache
// after clearing the caching calling the data from the database taking a fn from the portletContent.java
PortalLogger.logDebug("after clearing cache---sraha");
BugWatcherPortletContent bugwatchportcont = new BugWatcherPortletContent();
Hashtable httable= new Hashtable();
httable=(Hashtable)bugwatchportcont.loadContent();
PortalLogger.logDebug("after making the type casting-----sraha");
Set storeKeySet = httable.keySet();
Iterator itr = storeKeySet.iterator();
while (itr.hasNext()) {
String paramName = (String) itr.next();
context.put(paramName, httable.get(paramName));
PortalLogger.logDebug("after calling the databs data from hashtable---sraha");
} catch (CodedPortalException e) {
PortalLogger.logException("bugwatcherRefreshAction:: Exception- ",e);
context.put("Error", CommonUtil.getErrMessage(e.getMessage()));
catch (Exception e) {
PortalLogger.logException("bugwatcherRefreshAction:: Exception- ",e);
context.put(     "Error",CommonUtil.getErrMessage(ErrorConstantsI.EXCEPTION_CODE));
try {
((JetspeedRunData) data).setCustomized(null);
if (((JetspeedRunData) data).getCustomized() == null)
ActionLoader.getInstance().exec(data,"controls.EndCustomize");
catch (Exception e)
PortalLogger.logException("bugwatcherRefreshAction", e);
===============================================================
In the bugwatcher Action there is another function called PostLoadContent.java
here though i have found the portlet Id but unable to fetch that in the bugWatcherRefreshAction.java . I am also giving the code of that function under the bugWatcherAction.Java
================================================
// Get the PortletData object from intermediate store.
CacheablePortletData pdata =(CacheablePortletData) PortletCache.getCacheable(PortletCacheHelper.getUserHandle(
//rundata.getRequest().getRemoteUser()));
((JetspeedUser)rundata.getUser()).getUserName()));
pId1 = (String)portlet.getID();
PortalLogger.logDebug("in the bugwatcher action:"+pId1);
try {
Hashtable htStore = null;
// if PortletData is available in store, get current portlet's data from it.
if (pdata != null) {
htStore =(Hashtable) pdata.getObject(     PortletCacheHelper.getUserPortletHandle(
((JetspeedUser)rundata.getUser()).getUserName(),portlet.getID()));
//Loop through the hashtable and put its elements in context
Set storeKeySet = htStore.keySet();
Iterator itr = storeKeySet.iterator();
while (itr.hasNext()) {
String paramName = (String) itr.next();
context.put(paramName, htStore.get(paramName));
bugwatcherRefreshAction bRefAc = new bugwatcherRefreshAction();
bRefAc.doPerform(pdata,context,pId1);
=============================================================
So this is the total scenario for the fetching the data , after clearing the cache and display that in the portal.I am unable to do that.Presently it is still fetching the data from the cache and it is not going to the database.Even the portlet Id is returning as null.
I am unable to implement that thing.
If you have any insight about this thing, that would be great .As it is very urgent a promt response will highly appreciated.Please send me any pointers or any issues for this I am unable to do that.
Please let me know as early as possible.
Thanks and regards,
Santanu Raha.

Have you run it in a debugger? That will show you exactly what is happening and why.

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Compiling a class from another class

is it possible to compile a class from the code in another class?
i.e I want to check whether code in a .java file will compile before I use it.
Is there any methods that I could use to do this and could anyone give me advice on HOW to use the methods suggested?
thanks in advance
david

i was looking at that but it seems to only run files, not commands
is there a way to use it with command.com or cmd.exe or something to send commands to it?
also if i used a readline on an inputstream it only returned the first line (i tried running a batch file so the only line it returned was ..> javac testscript.java but i spose if i put
@echo off
javac testscript.java
if exist testscript.class (
echo compiled correctly
) else (
echo compiled incorectly
so the first line returned would either be "compiled correctly" or the compile error, but this would be compiling it to see if it compiles so im not sure if this answers the first question anyway =p

Assigning object of one class to object of another class.

Hi,
How will i assign an object of one class to an object of another class?
Ex:
ClassX A=some_method();
Now how will I assign the object A of class ClassX to the object 'B' of another class 'ClassY'.

In java you can only assign a object reference of one class into object reference of another class if the first class is the Second class (in other words the first class is a subclass of second class).
for example if this is a inheritance chart
Car ==========>Mercedes
"===========>Audi
then you can use
Audi a1 = new Audi();
Car c1 = a1;
or Mercedes m1 = new Mercedes();
Car c1 = m1;
but not
a1 = m1;
before assigning a variable into another variable of different class, use:
if(variable1 instanceOf ToBeAssignedIn Class){
variable2 = variable1;
example:
Audi a1;
Car c1;
if(a1 instanceOf Car){
c1 = a1;
Edited by: gaurav.suse on Apr 10, 2012 1:14 PM
Edited by: gaurav.suse on Apr 10, 2012 1:15 PM

Access instance method of a class inside instance method of another class

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