Array as Instance Variable

Friends,
Hope you can get me on the right track with this. I have an array (that must be an instance variable of type double) :
private double[] myArray;
that stores two values at each index:
double length
char unitOfMeasure
We have to develop a method which will perform a different calculation on the value based on the identity of the unitOfMeasure.
The method I'm working on looks like this:
public double getDistance (int index)
if (myArray[index].unitOfMeasure == 'a')
return ....
else .....
The problem is that I get an error that reads "double cannot be dereferenced" I guess this is b/c you can't make a call with a primitive.
How then, do I get the value of the unitOfMeasure at a particular index (as opposed to the value of length at that same index)?
thanks!

Thanks, I understand - much easier to do this way.Above all it's possible. You can never store more
than one value at an array index position. At least
not at the same time -:)private static int VALUE_INDEX = 0;
private static int UNIT_OF_MEASURE_INDEX = 1;
private double[][] doubles;
doubles = new double[42][2];

Similar Messages

Copying Arrays - Instance Variables - Multiple Animations

Hi All!
Thanks so much, in advance, as always, for your assistance!
So, here's a site I'm working on:
http://www.mediamackenzie.com/cmix/cmix10.html
I have 3 quick questions:
- I tried, when I first started making this site, to load all of the artwork images into an array and then copy the array before resizing them for their specific functions (being seen as thumbnails or as full size pics.) Unfortunately, I ran into the well known issue of Array cloning only creating a pointer to the same group of items. I tried the newArray = oldArray.slice() trick, but it didn't seem to work. Finally, I just loaded the images twice into two separate arrays, and it works, but I hate this solution. Anyone got a better one?
- I'm trying to maintain some sort of connection between the two sets of Arrays so that, for example, when someone clicks on Thumbnail 15, Fullsize Image 15 will open up but I couldn't find anything that worked. Renaming the Instance Name dynamically didn't seem to work and adding an Instance Variable dynamically doesn't seem possible either as I can't make the Class I am working with (Sprite, in this case) dynamic ahead of time. I'm sure there's a simple method for this. Any suggestions?
- Lastly, notice how when the site opens up, the different animations seem to interfere with each other and slow each other down (they also seem to get interference from the time taken to load the image Arrays.) Anyone got any high level suggestions for how to avoid this?
Thanks So Much!
and Be Well
Graham

I'm still stuck, but close, I think. The URL: http://www.mediamackenzie.com/cmix/cmix11.html
Here is the code from frame 1 of my Gallery MovieClip (an instance of which is created dynamically in the main timeline):
stop();
import fl.transitions.Tween;
import fl.transitions.easing.*;
var idealH = 120;
var idealW = idealH + 50;
var loadH = 300;
var loadW = loadH * 2;
var thumb = 0;
var loadNum = 0;
var thumby:Sprite;
var darkStage:Sprite;
var loadSprite:Sprite;
var thumbArray:Array = new Array();
var loadArray:Array = new Array();
var bigLoad:Loader;
var reSized:Boolean = false;
this[thumb] = new Loader();
this[thumb].contentLoaderInfo.addEventListener(Event.COMPLETE, thumbComplete);
this[thumb].load(new URLRequest("images/0.png"));
thumbArray.push(this[thumb]);
function thumbComplete(e:Event):void {
    trace("thumbComplete");
    thumb++;
    this[thumb] = new Loader();
    this[thumb].load(new URLRequest("images/" + thumb + ".png"));
    thumbArray.push(this[thumb]);
    this[thumb].contentLoaderInfo.addEventListener(Event.COMPLETE, thumbComplete);
    this[thumb].contentLoaderInfo.addEventListener(IOErrorEvent.IO_ERROR, thumbError);
function thumbError(e:IOErrorEvent):void {
    trace("thumbError");
    thumb = 0;
    thumbArray.pop();
    loadArray = thumbArray.slice();
    gotoAndStop(2);
Now, here is the code from frame 2:
//stop();
addArrows();
thumbResize();
loadResize();
function thumbResize():void {
trace("thumbResize");
    for (var batch = 0; batch < Math.ceil(thumbArray.length / 8); batch++) {
        trace("batch " + batch);
        var batchSprite: Sprite = new Sprite();
        batchSprite.x = (batchSprite.x + (idealW / 1.5) + (batch * 800));
        //batchSprite.mouseEnabled = false;
        addChild(batchSprite);
        for (var row = 0; row < 2; row++) {
            trace("     row " + row);
            for (var col = 0; col < 4; col++) {
                trace("          col " + col);
                trace("               thumb " + thumb);
                //If the width of the image is greater than the ideal width, OR the height is greater than the ideal height...
                if ( thumbArray[thumb].content.width > idealW || thumbArray[thumb].content.height > idealH) {
                    //And if the width of the image is greater than the height, apply Scaler 1...
                    if ( thumbArray[thumb].content.width > thumbArray[thumb].content.height ) {
                        //Scaler 1 is the ratio of the ideal width to the image width
                        var scaler1 = idealW / thumbArray[thumb].content.width;
                        trace("               scaler1 = " + scaler1);
                        //Apply Scaler 1 to both the width and height of the image
                        thumbArray[thumb].content.scaleX = thumbArray[thumb].content.scaleY = scaler1;
                        trace("               image width:" + thumbArray[thumb].content.width);
                        trace("               image height:" + thumbArray[thumb].content.height);
                        //Otherwise, apply Scaler 2
                    } else {
                        //Scaler 2 is the ratio of the ideal width to the image height
                        var scaler2 = idealW / thumbArray[thumb].content.height;
                        trace("               scaler2 = " + scaler2);
                        //Apply Scaler 2 to both the width and height of the image
                        thumbArray[thumb].content.scaleX = thumbArray[thumb].content.scaleY = scaler2;
                        trace("               image width:" + thumbArray[thumb].content.width);
                        trace("               image height:" + thumbArray[thumb].content.height);
                    //Otherwise... (that is, the image width and height are in both cases less than the ideal)
                } else {
                    //And if the width of the image is greater than the heigh, apply Scaler 3
                    if ( thumbArray[thumb].content.width > thumbArray[thumb].content.height ) {
                        //Scaler 3 is the ratio of the ideal width to the image width
                        var scaler3 = idealW / thumbArray[thumb].content.width;
                        trace("               scaler3 = " + scaler3);
                        //Apply Scaler 3 to both the width and height of the image
                        thumbArray[thumb].content.scaleX = thumbArray[thumb].content.scaleY = scaler3;
                        trace("               image width:" + thumbArray[thumb].content.width);
                        trace("               image height:" + thumbArray[thumb].content.height);
                    } else {
                        //Scaler 4 is the ratio of the ideal width to the image height
                        var scaler4 = idealW / thumbArray[thumb].content.height;
                        trace("               scaler4 = " + scaler4);
                        //Apply Scaler 4 to both the width and height of the image
                        thumbArray[thumb].content.scaleX = thumbArray[thumb].content.scaleY = scaler4;
                        trace("               image width:" + thumbArray[thumb].content.width);
                        trace("               image height:" + thumbArray[thumb].content.height);
                thumbArray[thumb].content.x = - (thumbArray[thumb].content.width / 2);
                thumbArray[thumb].content.y = - (thumbArray[thumb].content.height / 2);
                thumby = new Sprite();
                thumby.addChild(thumbArray[thumb]);
                thumby.y = (row * (idealW + (idealW / 8)));
                thumby.x = (col * (idealW + (idealW / 8)));
                thumby.buttonMode = true;
                thumby.useHandCursor = true;
                thumby.addEventListener(MouseEvent.CLICK, enLarge);
                batchSprite.addChild(thumby);
                thumb++;
function loadResize():void {
    trace("loadResize");
    for (var ex = 0; ex < loadArray.length; ex++) {
        //If the width of the image is greater than the ideal width, OR the height is greater than the ideal height...
        if ( loadArray[loadNum].content.width > loadW || loadArray[loadNum].content.height > loadH) {
            //And if the width of the image is greater than the height, apply Scaler 1...
            if ( loadArray[loadNum].content.width > loadArray[loadNum].content.height ) {
                //Scaler 1 is the ratio of the ideal width to the image width
                var scaler1 = loadW / loadArray[loadNum].content.width;
                //Apply Scaler 1 to both the width and height of the image
                loadArray[loadNum].content.scaleX = loadArray[loadNum].content.scaleY = scaler1;
                //Otherwise, apply Scaler 2
            } else {
                //Scaler 2 is the ratio of the ideal width to the image height
                var scaler2 = loadW / loadArray[loadNum].content.height;
                //Apply Scaler 2 to both the width and height of the image
                loadArray[loadNum].content.scaleX = loadArray[loadNum].content.scaleY = scaler2;
            //Otherwise... (that is, the image width and height are in both cases less than the ideal)
        } else {
            //And if the width of the image is greater than the heigh, apply Scaler 3
            if ( loadArray[loadNum].content.width > loadArray[loadNum].content.height ) {
                //Scaler 3 is the ratio of the ideal width to the image width
                var scaler3 = loadW / loadArray[loadNum].content.width;
                //Apply Scaler 3 to both the width and height of the image
                loadArray[loadNum].content.scaleX = loadArray[loadNum].content.scaleY = scaler3;
            } else {
                //Scaler 4 is the ratio of the ideal width to the image height
                var scaler4 = loadW / loadArray[loadNum].content.height;
                //Apply Scaler 4 to both the width and height of the image
                loadArray[loadNum].content.scaleX = loadArray[loadNum].content.scaleY = scaler4;
        loadArray[loadNum].content.x = - (loadArray[loadNum].content.width / 2);
        loadArray[loadNum].content.y = - (loadArray[loadNum].content.height / 2);
        loadNum++;
function addArrows():void {
    trace("addArrows");
    var batches = Math.ceil(thumbArray.length / 8);
    var m = 0;
    trace("batches = " + batches);
    if (batches > 1) {
        for (var k = 1; k < batches; k++) {
            var triW = 20;
            var startX = (((800 - triW) * k) + (triW * m));
            var startY = (idealW / 2);
            var tri:Sprite = new Sprite();
            tri.graphics.beginFill(0xFFFFFF);
            tri.graphics.moveTo(startX, startY);
            tri.graphics.lineTo(startX, (startY + triW));
            tri.graphics.lineTo((startX + triW), (startY + (triW/2)));
            tri.graphics.lineTo(startX, startY);
            tri.graphics.endFill();
            tri.buttonMode = true;
            tri.useHandCursor = true;
            tri.addEventListener(MouseEvent.CLICK, moveLeft);
            addChild(tri);
            var tri2:Sprite = new Sprite();
            var startX2 = (startX + (triW * 2));
            tri2.graphics.beginFill(0xFFFFFF);
            tri2.graphics.moveTo(startX2, startY);
            tri2.graphics.lineTo(startX2, (startY + triW));
            tri2.graphics.lineTo((startX2 - triW), (startY + (triW / 2)));
            tri2.graphics.lineTo(startX2, startY);
            tri2.graphics.endFill();
            tri2.buttonMode = true;
            tri2.useHandCursor = true;
            tri2.addEventListener(MouseEvent.CLICK, moveRight);
            addChild(tri2);
            m++;
function moveLeft(event:MouseEvent):void {
    var leftTween:Tween = new Tween(this, "x", Regular.easeOut, this.x, (this.x - 800), .5, true);
function moveRight(event:MouseEvent):void {
    var rightTween:Tween = new Tween(this, "x", Regular.easeOut, this.x, (this.x + 800), .5, true);
function enLarge(event:MouseEvent):void {
    darkStage = new Sprite();
    darkStage.graphics.beginFill(0x000000, .75);
    darkStage.graphics.drawRect(0, 0, stage.stageWidth, stage.stageHeight);
    darkStage.addEventListener(MouseEvent.CLICK, reMove);
    darkStage.buttonMode = true;
    darkStage.useHandCursor = true;
    parent.addChild(darkStage);
    var nmbr = thumbArray.indexOf(event.currentTarget);
    bigLoad = new Loader();
    bigLoad = loadArray[nmbr];
    trace("bigLoad: " + bigLoad);
    loadSprite = new Sprite();
    loadSprite.addChild(bigLoad);
    loadSprite.x = (stage.stageWidth / 2);
    loadSprite.y = (stage.stageHeight / 2);
    loadSprite.addEventListener(MouseEvent.CLICK, reMove);
    loadSprite.buttonMode = true;
    loadSprite.useHandCursor = true;
    parent.addChild(loadSprite);
function reMove(event:MouseEvent):void {
    parent.removeChild(darkStage);
    parent.removeChild(loadSprite);
The function enLarge is the source of the issue (I want the enlarged image to show up and it's not.)
Please help if you can!
Thanks,
Graham

Java - Instance variable that can reference an array of integers?

Hello,
I have the following question in my assignment:
Your first task is to declare a private instance variable called cGroups that can
reference an array of integers. You should then write a constructor for GameN. This should
take a suitable array as its argument which should be used to initialise cGroups.
In order to test your code for declaring and initialising cGroups, you should execute
the following code
int[] coin = {2, 8, 5};
GameN aGame;
aGame = new GameN(coins);
and I have complete the code below but it's not working. maybe I'm reading it wrong or
not understandin something. Could someone correct it? or put me on the right lines
private int[] cGroups = new int[]
public GameN(int group1, int group2, int group3)
super();
this.cGroups = {group1, group2, group3};
}

ShockUK wrote:
I've changed it to
private int[] coinGroups = new int[] {1};
public Nim(int group1, int group2, int group3)
super();
int[] coinGroups = {group1, group2, group3};
}But I still get the same error "Constructor error: Can't find constructor: Nim( [I ) in class: Nim"
Look at the line that error is pointing at. You're trying to use a constructor that doesn't exist. This is not a problem with creating an array.

How to use an BPM Instance Variable in JSP page

Hi All,
I am using the JSP Presentation, but i don't know how to use an Instance variable in JSP page, that instance already declared in the process. And Can u explain the syntax that to include the JS file into jsp page
Regards
Vasu.
Edited by bpmvasu at 04/03/2007 10:43 PM

Hi Mariano,
I'm using JSP presentation too. In "Interactive Component Call" active i'm using "Use JSP presentation", but i only can define one instance variable, i need to add more instance variables. In "Advanced" option of this task, i have the argument mapping .. but i don't understand how to use it.
I have a instance variable called "genders" of the type String[Int] (Associative Array) and i'm mapping this instance variable in "Arguments Show In" option of the advanced option of JSP presentation. In JSP presentation i have the code:
<select <f:fieldName att="person.gender"/>>
               <c:forEach var="gender" begin="0" items="${genders}" varStatus="status">
                    <c:choose>
                         <c:when test="${person.gender == gender}">
                              <option value="<c:out value="${gender}"/>" selected="true"><c:out value="${gender}"/></option>
                         </c:when>
                         <c:otherwise>
                              <option value="<c:out value="${gender}"/>"><c:out value="${gender}"/></option>
                         </c:otherwise>
                    </c:choose>
               </c:forEach>
          </select>And in my screenflow i have the code:
genders[0] = "Male"
genders[1] = "Female"But when i run my application, i have the error: "The task could not be successfully executed. Reason: 'java.lang.ClassCastException: java.lang.Integer'."
What's the problem?

Null Instance Variables on Screenflow

Hi,
I have some problems with instance variable of type BPM Objects in a Screenflow.
I always create automatic processes without user interaction, and on server side I have seen that it's not necessary to instantiate an instance variable. Moreover if within a method I write (I use the Java style syntax):
String a;
a.toString(); // just to call a method on a not-instantiated variable
everything works correctly, the "a" variable is automatically instantiated.
But it seems that in an automatic activity of a Screenflow it's different, I need to do the new also for Instance Variables.
Then, in the Screenflow I have an Instance Variable myObject of type MyObject that is a BPM Object. This object has an attribute myStrings that is an array of String.
To instantiate the instance variable I can write:
myObject = new MyObject();
But then I get a java.lang.*NullPointerException* when I call the extend method of its attribute myStrings to add a string.
Do you agree with me that on the Screenflow code it's necessary to instantiate the variables?
How can I instantiate an Array of String?
Thank you.

Thanks Daniel, I'm using ALBPM 6.0,
i know the line where I get the exception, I have a logMessage before and after each line of code, and then in the exception stack there is the PBL Method line indicated:
Caused by: java.lang.NullPointerException
at xobject.Fuego__AutoGen__Screenflows__.__ScreenflowConJsp.automatic1(__ScreenflowConJsp.xcdl:*19*)
19 is the code line where I get the exception. In this line I have this:
myObject.myStrings.extend(arg1 : a);
but the null object is not the array, it's myObject that is an Instance Variable.
In ALBPM60_Studio_ReferenceGuide at chapter Programming Styles paragraph Java Programming Style there is:
This style emulates Java syntax and adds several features to match PBL expressions. These added features include:
• Output arguments
• Input and display statements
• Variable auto-initialization
In fact in my previuos BPM projects I have seen that is not necessary to istantiate the variables, both for Instance Variable and local variable declared within a method. In my previous post I did an example:
String a;
a.toString();
Usually this causes an Exception, but not in ALBPM methods.
My main question is: is it possible that this is true just for Server side methods and not for Screenflow methods? Because in my case I need to instantiate every Instance Variable of my Screenflow (for example the myObject instance variable) in an Automatic Activity I have put as first Activity of the flow.
Thanks again for your help.

Array as instace variable

i wan to declare array as a instance variable.
i am below sample prog. , i get incorrect output.
is there any other way;
class a
     int m[];
     a(int ab[])
          m = new int[3];
          m = ab;
     void print()
          System.out.println(m[0]+" "+m[1]+" "+m[2]);
class test1
     public static void main(String args[])
          int score[] = new int[3];
          a group[] = new a[3];
          int flag=0;
          for (int k=0;k<3;k++)
               for(int i=0;i<3;i++)
                    if(flag==0)
                         score[i] = i+10;
                    else
                         score[i] = i+100;
               flag++;
               group[k] = new a(score);
               group[k].print();
          group[0].print(); // incorrect output as it prints last inputted value
}

// score[k] = i+10;
// it is not my problem, my problem is that the value of group[0] is not printed out of the loop. inside the for loop , its prints allright but outside the loop its get all wrong. i want to know that anything is wrong with class A structure.
class A
     int m[];
     A(int ab[])
          m = new int[3];
          m = ab;
     void print()
          System.out.println(m[0]+" "+m[1]+" "+m[2]);
class test1
     public static void main(String args[])
          int score[] = new int[3];
          A group[] = new A[3];
          int flag=0;
          for (int k=0;k<3;k++)
               for(int i=0;i<3;i++)
                    if(flag==0)
                    score[i] = i+10;                    else
                    score[i] = i+100;
               flag++;
               group[k] = new A(score);
               group[k].print();// print correct output
          group[0].print(); // prints value of group[2]
}

Good practice to initalize all instance variables with type String to emptr

Is it a good practice to initalize all instance variables with
type String to emptry string?
#1 approach:
public class A
{ private String name = "";
private String address ="";
//etc...
rather than
#2 approach:
public class A
{ private String name;
private String address;
//etc...
When I read Java books, the examples don't usually do #1 approach.
The problem is if we don't initialize to empty string, when we call
the getter method of that instance variable, it will return null.
Please advise. Thanks!!

Please advise. Thanks!!It depends on your coding style. If you can avoid lots of checks for null Strings in the rest of the code then why not initialize to "".
You have the same situation when a method returns an array. If you under circumstances return a null array reference then you have to always check for this special case, but if you return a zero length array instead you have no special case. All loops will just run 0 iterations and everything will work fine.
So in general I guess the return of zero objects instead of null references really boils down to whether it simplicates the rest of your code by removing lots of extra checks for the special null case. This usage is especially favourable in the zero length array case. See Effective Java by Bloch, item 27.

Xcode debugger not showing my instance variables!!

I hate asking questions like this.
I set a breakpoint in an IBAction method 'pushed:' inside FooViewController. At runtime I pressed a GUI button and processing stopped in pushed:.
In the data-viewing pane of xcode, I see
{code}
self = (FooViewController *) 0x... etc.
{code}
Indented under this is
{code}
UIViewController = (UIViewController) { ...
{code}
Nowhere do I see any of my instance variables!!
Now, they were synthesized from properties, but that doesn't matter, does it?
The code that proceeds to set some instance variables runs fine.
Why isn't xcode displaying self's instance vars?
Thanks,
Chap

Yes, yours looks like I was expecting mine to look.
Note that viewDidLoad (below) does work correctly, producing the expected results in the simulator!
Hangman3ViewController.h:
@interface Hangman3ViewController : UIViewController {
@property (         nonatomic )           NSInteger wordLength;
@property ( retain, nonatomic )           NSString *alphabet;
@property (         nonatomic )           unichar    guess;
@property (         nonatomic )           NSInteger guessNo;
@property ( retain, nonatomic )           NSMutableString *board;
@property ( retain, nonatomic ) IBOutlet UILabel   *boardLabel;
@property ( retain, nonatomic ) IBOutlet UILabel   *guessNumberLabel;
@property ( retain, nonatomic ) IBOutlet NSArray   *keyboardButtons;
- (IBAction)letter:(id)sender;
- (void)showBoard;
@end
and, Hangman3ViewController.m:
#import "Hangman3ViewController.h"
@implementation Hangman3ViewController
@synthesize wordLength       = _wordLength; // preprocessor command to gen getter/setter and instance variable
@synthesize boardLabel       = _boardLabel; // preprocessor command to gen getter/setter and instance variable
@synthesize guessNumberLabel = _guessNumberLabel; // Guess #n
@synthesize keyboardButtons = _keyboardButtons;   // array of buttons
@synthesize alphabet         = _alphabet;    // A-Z unichars
@synthesize guess            = _guess;       // unichar
@synthesize guessNo          = _guessNo;     // int
@synthesize board            = _board;
- (IBAction)letter:(id)sender
            Get letter from sender - driven when key button is pressed.
            The button's tag is an int from 0-25, identifying what letter of the alphabet it is.
            Extract that unichar from ALPHABET as 'guess'. Then, disable the button,
            which has been defined to have its text turn white (invisible) when disabled.
    UIButton *button = (UIButton *)sender;
    self.guess = [self.alphabet characterAtIndex: button.tag];
    NSLog(@"Received keystroke: %C", self.guess);
    [button setEnabled:NO];
- (void)showBoard
    self.boardLabel.text = self.board;
    self.guessNumberLabel.text = [NSString stringWithFormat:@"Guess #%d", self.guessNo];
- (void)dealloc
    [_boardLabel release];
    [_guessNumberLabel release];
    [_keyboardButtons release];
    [super dealloc];
- (void)didReceiveMemoryWarning
    // Releases the view if it doesn't have a superview.
    [super didReceiveMemoryWarning];
    // Release any cached data, images, etc that aren't in use.
#pragma mark - View lifecycle
// Implement viewDidLoad to do additional setup after loading the view, typically from a nib.
- (void)viewDidLoad
    NSLog(@"Hello from viewDidLoad");
    [super viewDidLoad];
    self.alphabet   = @"ABCDEFGHIJKLMNOPQRSTUVWXYZ"; // unichar string
    self.wordLength = 7; // temp - will be set from flipside later on
    self.guessNo    = 1;
    [self.board setString:@"_______"]; // actually dynamic based on wordLength
    self.board = @"_______";
    [self showBoard];
- (void)viewDidUnload
    [super viewDidUnload];
    // Release any retained subviews of the main view.
    // e.g. self.myOutlet = nil;
- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
    // Return YES for supported orientations
    return (interfaceOrientation == UIInterfaceOrientationPortrait);
@end

Parsing XML and Storing values in instance variable

hi,
i'm new to XML.
here i'm trying to parse an XML and store their element data to the instance variable.
in my main method i'm tried to print the instance variable. but it shows "" (ie it print nothing ).
i know the reason, its becas of the the endElement() event generated and it invokes the characters() and assigns "" to the instance variable.
my main perspective is to store the element data in instance variable.
thanks in advance.
praks
import java.io.*;
import java.net.*;
import java.util.*;
import javax.xml.parsers.*;
import org.xml.sax.*;
import org.xml.sax.helpers.*;
public class mysax extends DefaultHandler
     String ctelement;
     CharArrayWriter contents;
     String vname1,vrcbreg1,vaddress1,vcountry1,vtelephone1,vfax1;
     String vname,vrcbreg,vaddress,vcountry,vtelephone,vfax;
     public mysax()
          vname1 = null;
          vrcbreg1 = null;
          vaddress1 = null;
          vcountry1 = null;
          vtelephone1 = null;
          vfax1 = null;
          contents= new CharArrayWriter();
     public void doparse(String url) throws Exception
          SAXParserFactory spf = SAXParserFactory.newInstance();
SAXParser sp = spf.newSAXParser();
ParserAdapter pa = new ParserAdapter(sp.getParser());
pa.setContentHandler(this);
pa.parse(url);
     public void startElement(String namespace,String localName,String qName,Attributes atts)
          ctelement = localName;
     public void endElement(String uri,String localName,String qName) throws SAXException
     public void characters(char[] ch,int start, int length) throws SAXException
          try
               if(ctelement.equals("name"))
                    vname = new String (ch,start,length);
                    System.out.println("The method "+vname1);
          }catch (Exception e)
               System.out.println("The exception "+e);
     public static void main(String args[])
          try
          mysax ms = new mysax();
          ms.doparse(args[0]);
          System.out.println("the contents name "+ms.vname1);
          catch(Exception e)
               System.out.println("this is exception at main" +e);
my XML looks like
<coyprofile_result>
<company>
<name>abcTech</name>
<rcbreg>123456789</rcbreg>
<address>Singapore</address>
<country>sg</country>
<telephone>123456</telephone>
<fax>123155</fax>
</company>
</coyprofile_result>

I believe that the problem has to do with the value you assign to ctelement. You are assigning the value of localName to ctElement, however for the element: <name>...</name> the localname is empty string i.e. "", but qName equals "name". Because you are assigning empty string to ctElement, when you do the comparison in characters of ctElement to "name" it will always be false. So in startElement change it to ctElement = qName; Try it and see if it works. I have produced similar programs and it works for me.
Hope this helps.

How to convert an array collection instance to a complex object for interaction with webservice

Hi there,
I have a stubborn problem that I am trying to work out the best way to solve the problem. I am interacting with a WebService via HTTPService calling a method called find(String name) and this returns me a List of ComplexObjects that contain general string and int params and also lists of other Complex Objects. Now using the code:
ArrayCollection newOriginalResultsArray = new ArrayCollection(event.result as Array)
flex converts my complex objects results to an arraycollection so that I can use it in datagrids etc. Now up until this part is all good. My problem is when getting a single instance from the results list, updating it by moving data around in a new datagrid for example - I want to interact with the webservice again to do an create/update. This is where I am having problems - because these webservice methods require the complex object as a parameter - I am struggling to understand how I can convert the array collection instance back to my complex object without iterating over it and casting it back (maybe this is the only way - but I am hoping not).
I am hoping that there is a simple solution that I am missing and that there is some smart cookie out there that could provide me with an answer - or at least somewhere to start looking. I guess if I have no other alternative - maybe I need to get the people who built the service to change it to accept an array - and let them do the conversion.
Any help would be greatly appreciated.
Bert

Hi Bert,
According to my knowledge you can use describeType(Object) method which will return an XML... That XML will contain Properties and values just iterate through the XML and create a new Object..   Probably u can use this method...
public function getObject(reqObj:Object,obj:Object,instanceName:String,name:String=null,index:int=-1):Obj ect
            if(!reqObj)
                reqObj = new Object();
            var classInfo:XML = describeType(obj);
            var className:String = instanceName;
            if(name!=null)
                className=name+"."+className;
            if(index!=-1)
                className=className+"["+index+"]";
            for each (var v:XML in classInfo..accessor)
                var attributeName:String=v.@name;
                var value:* = obj[attributeName]
                var type:String = v.@type;
                if(!value)
                    reqObj[className+"."+attributeName] = value;
                else if(type == "mx.collections::ArrayCollection")
                    for(var i:int=0;i<value.length;i++)
                        var temp:Object=value.getItemAt(i);
                        getReqObject(reqObj,temp,attributeName,className,i);
                else if(type == "String" || type == "Number" || type == "int" || type == "Boolean")
                    reqObj[ className+"."+attributeName] = value;
                else if (type == "Object")
                    for (var p:String in value)
                        reqObj[ className+"."+attributeName+"."+p] = value[p];
                else
                    getReqObject(reqObj,value,attributeName,className);
            return reqObj;
Thanks,
Pradeep

How to change value of instance variable and local variable at run time?

As we can change value at run time using debug mode of Eclipse. I want to do this by using a standalone prgram from where I can change the value of a variable at runtime.
Suppose I have a class, say employee like -
class employee {
public String name;
employee(String name){
this.name = name;
public int showSalary(){
int salary = 10000;
return salary;
public String showName()
return name;
i want to change the value of instance variable "name" and local variable "salary" from a stand alone program?
My standalone program will not use employee class; i mean not creating any instance or extending it. This is being used by any other calss in project.
Can someone tell me how to change these value?
Please help
Regards,
Sujeet Sharma

This is the tutorial You should interest in. According to 'name' field of the class, it's value can be change with reflection. I'm not sure if local variable ('salary') can be changed - rather not.

Instance variable to hold the element of a tag in the xml file

Hi I have an xml file that is handled using this parser
<attr id="MY_NAME" >
this parser hanled the above tag but now I want to have it handle
<attr id="MY_NAME" desc="GOOD">
but I need to create an instance variable to handle the desc element in the attr tag .
Can some one help me out as this is not my file and I am having trouble to do please......
import java.util.*;
import java.io.*;
import javax.xml.parsers.*;
import org.xml.sax.*;
import org.xml.sax.helpers.*;
   The SupportMatrix class provides static variables and methods to simplify
   the determination of whether or not a given attribute is supported for a
   certain object type (queue manager, channel, etc.), depending on the version
   and platform of the queue manager to which it belongs.
   The SupportMatrix class may not be instantiated. Its constructor is private.
   An instance of the class is created internally in the static initializer so
   that the XML parsing methods are available.
   A corresponding XML document, SupportMatrix.xml, is parsed to create the various
   HashMaps which contain the version/platform dependency information. A number of
   inner classes are used to represent the various elements of the XML matrix
   definition.
   Here's a sample document:
   
   <supportmatrix>
     
     <object classid="1">
       
       <version cmdlevel="base">
         
         <attr id="MQCA_Q_MGR_NAME">
           
           <support platforms="UNIX,WINDOWS,OS400,VMS,NSK" maxlen="48" type="MQCFST"/>
           <support platforms="MVS" maxlen="4" type="MQCFST"/>
         </attr>
         <attr id="MQCA_Q_MGR_DESC">
           
           <support platforms="all" maxlen="64" type="MQCFST"/>
         </attr>
         
         <attr id="MQIA_PLATFORM"/>
         <attr id="MQIA_COMMAND_LEVEL"/>
       </version>
       
       <version cmdlevel="520" include="base">
       </version>
     </object>
   </supportmatrix>
   The inner classes, and their hierarchical relationships are as follows:
     SupportObject - corresponds to the <object> element. Stored in a static HashMap, and
                     keyed by classid.
       VersionObject - corresponds to the <version> element. Stored in a HashMap instance
                       variable of the SupportObject class, keyed by cmdlevel.
         AttributeObject - corresponds to the <attr> element. Stored in a HashMap instance
                           variable of the VersionObject class, keyed by attribute name.
           PlatformObject - corresponds to the <support> element. Stored in HashMaps belonging
                            to the AttributeObjects, keyed by platform. A single PlatformObject
                            instance is created when the support tag is encountered. The
                            "platforms" attribute of the support element is then processed. For
                            each platform in the comma-delimited list, an entry is added to the
                            collection of PlatformObjects. This is to greatly simplify later
                            lookups.
   In order to support the 'include' feature of object and version elements, certain
   functions are recursive. If the attribute to be validated is not found for the passed
   cmdlevel, the 'parent' VersionObject is consulted by means of the 'include' value. If
   the chain of VersionObjects has been exhausted and the attribute in question has still not
   been located, the next SupportObject in the chain is consulted in a similar fashion.
public class SupportMatrix extends DefaultHandler {
    /** The objects collection holds all the SupportObjects, keyed by classid. */
    private static HashMap objects;
    /** xmlFile will name the xml document to be parsed. Note that using the
        default class loader expects the string to be the path to the file. It must
        NOT begin with the '/' character. */
    private static String xmlFile =
        ResourceManager.getApplicationProperties().getProperty("SupportMatrixFile");
    private Stack stack;
    /** This static initializer allocates the static objects collection, creates an
        instance of the SupportMatrix class for xml parsing purposes, and initiates
        the parse operation to populate the collection. */
    static {
        objects = new HashMap();
        // Create a parser and process the xml doc
        SupportMatrix handler = new SupportMatrix();
        InputSource is = null;
        try {
            is = new InputSource(ClassLoader.getSystemClassLoader().getResourceAsStream(xmlFile));
            XMLReader xmlReader =
                SAXParserFactory.newInstance().newSAXParser().getXMLReader();
            xmlReader.setFeature("http://xml.org/sax/features/namespaces", true);
            xmlReader.setContentHandler(handler);
            if (is == null) {
                System.err.println("No input stream, dammit");
            xmlReader.parse(is);
        } catch(Exception e) {
            e.printStackTrace();
    /** Private constuctor, used only for XML parsing. */
    private SupportMatrix() {
        stack = new Stack();
    /** Add a SupportObject instance to the objects collection. */
    private void addObject(SupportObject obj) {
        String key = obj.getClassId();
        objects.put(key, obj);
    /* DefaultHandler methods                                              */
    /** Not used. */
    public void characters(char[] ch, int start, int length) {}
    /** Not used. */
    public void endDocument() {}
    /** For the version, object, and attr elements, pop the top element of the stack. */
    public void endElement(String uri, String localName, String qName) {
        if (localName.equals("version") || localName.equals("object") || localName.equals("attr")) {
            stack.pop();
    /** Not used. */
    public void setDocumentLocator(Locator locator) {}
    /** Not used. */
    public void startDocument() {}
    /** Most of the work is done here. Create the appropriate inner class instance for
        element; for object, version, and attr, push the element onto the stack so that
        child elements may be added to their collections as needed. */
    public void startElement(String uri, String localName, String qName,
                             Attributes attributes) {
        String include = attributes.getValue("include");
        if (localName.equals("object")) {
            SupportObject obj = new SupportObject(attributes.getValue("classid"), include);
            addObject(obj);
            stack.push(obj);
        } else if ( localName.equals("version")) {
            VersionObject ver = new VersionObject(attributes.getValue("cmdlevel"), include);
            ((SupportObject)stack.peek()).addVersion(ver);
            stack.push(ver);
        } else if ( localName.equals("attr")) {
            AttributeObject a = new AttributeObject(attributes.getValue("id"));
            //String desc = StringFactory.getString(attributes.getValue("desc"));
            //if(desc != null)
               //     a.setAttribute();
            String readonly = attributes.getValue("readonly");
            String exclude = attributes.getValue("exclude");
            if (include != null && exclude != null) {
                Log.log(Log.ERROR, this, "include and exclude are mutually exclusive, exclude value ignored");
                exclude = null;
            if (include != null) {
                a.setCondition(include, true);
            if (exclude != null) {
                a.setCondition(exclude, false);
            if (readonly != null)
                a.setReadonly(readonly.equals("y"));
            ((VersionObject)stack.peek()).addAttr(a);
            stack.push(a);
        } else if (localName.equals("support")) {
            String platforms = attributes.getValue("platforms");
            String readonly = attributes.getValue("readonly");
            String maxlen = attributes.getValue("maxlen");
            String type = attributes.getValue("type");
            int attrType = 0;
            if (type != null) {
                if (type.equals("MQCFIN")) {
                    attrType = CMQCFC.MQCFT_INTEGER;
                } else if (type.equals("MQCFIL")) {
                    attrType = CMQCFC.MQCFT_INTEGER_LIST;
                } else if (type.equals("MQCFST")) {
                    attrType = CMQCFC.MQCFT_STRING;
                } else if (type.equals("MQCFSL")) {
                    attrType = CMQCFC.MQCFT_STRING_LIST;
                } else if (type.equals("EXBIN")) {
                    attrType = MqcConstants.EXCFT_BINARY;
                } else if (type.equals("EXPCF")) {
                    attrType = MqcConstants.EXCFT_PCF;
            PlatformObject p = null;
            if (readonly == null) {
                p = new PlatformObject(platforms);
            } else {
                p = new PlatformObject(platforms, readonly.equals("y"));
            String exclude = attributes.getValue("exclude");
            if (include != null && exclude != null) {
                Log.log(Log.ERROR, this, "include and exclude are mutually exclusive, exclude value ignored");
                exclude = null;
            if (include != null)
                p.setCondition(include, true);
            if (exclude != null)
                p.setCondition(exclude, false);
            if (attrType != 0)
                p.setType(attrType);
            if (maxlen != null)
                p.setLen(Integer.parseInt(maxlen));
            ((AttributeObject)stack.peek()).addPlatform(p);
    public static boolean isExported(int attribute, TopologyModelNode node) {
        String name = ResourceManager.getAttributeName(attribute);
        return isExported(name, node);
    public static boolean isExported(String attribute, TopologyModelNode node) {
        // Find the qmgr node to fetch platform and cmdlevel
        TopologyModelNode qmgr = node.getModel().getQMgrNode(node.getAddress());
        // If there's no qmgr for this node, it must be one of 'ours'.
        if (qmgr == null)
            return false;     // None of 'our' objects can be exported to MQSC.
        String classId = node.getClassId();
        String cmdLevel = qmgr.getAttributeValue("MQIA_COMMAND_LEVEL");
        String platform = qmgr.getAttributeValue("MQIA_PLATFORM");
        return isExported(attribute, classId, cmdLevel, platform, node);
    public static boolean isExported(int attribute, String classId, String cmdLevel, String platform,
                                     TopologyModelNode node) {
        String name = ResourceManager.getAttributeName(attribute);
        return isExported(name, classId, cmdLevel, platform, node);
    /** Determine if an attribute is exportable. The attribute name, the classid of the object to
        which it belongs, plus the command level and platform of the queue manager are all needed
        to make this determination.
        Start by finding the AttributeObject for the combination of attribute, classid, and
        command level. If we can't find the AttributeObject, we assume that the attribute
        is not exported. Otherwise, find out if it is exportable for the selected platform.
    public static boolean isExported(String attribute, String classId, String cmdLevel, String platform,
                                     TopologyModelNode node) {
        AttributeObject attr = getAttributeObject(attribute, classId, cmdLevel);
        if (attr == null) {
            return false;
        } else {
            return attr.isExported(platform, node);
    public static boolean isSupported(int attribute, TopologyModelNode node) {
        String name = ResourceManager.getAttributeName(attribute);
        return isSupported(name, node);
    public static boolean isSupported(String attribute, TopologyModelNode node) {
        // Find the qmgr node to fetch platform and cmdlevel
        TopologyModelNode qmgr = node.getModel().getQMgrNode(node.getAddress());
        // If there's no qmgr for this node, it must be one of 'ours'.
        if (qmgr == null)
            return true;
        String classId = node.getClassId();
        String cmdLevel = qmgr.getAttributeValue("MQIA_COMMAND_LEVEL");
        String platform = qmgr.getAttributeValue("MQIA_PLATFORM");
        return isSupported(attribute, classId, cmdLevel, platform);
    public static boolean isSupported(int attribute, String classId, String cmdLevel, String platform) {
        String name = ResourceManager.getAttributeName(attribute);
        return isSupported(name, classId, cmdLevel, platform);
    /** Determine if an attribute is supported. The attribute name, the classid of the object to
        which it belongs, plus the command level and platform of the queue manager are all needed
        to make this determination.
        Start by finding the SupportObject for the classid. If it isn't there, we make the assumption
        (for now) that the attribute is supported. The only classids for which this can occur are
        broker, agent, and the various container objects.
        Propagate the isSupported request to the chain of SupportObjects (based on 'include' values)
        until we get a 'true' result or we run out of SupportObjects. */
    public static boolean isSupported(String attribute, String classId, String cmdLevel, String platform) {
        if (attribute == null)
            return false;
        SupportObject obj = (SupportObject)objects.get(classId);
        // If the object type isn't even in the support matrix, we interpret that to
        // mean that it's a Broker or Agent, in which case all attributes are supported
        // at present.
        if (obj == null)
            return true;
        boolean result = false;
        while (result == false && obj != null) {
            result = obj.isSupported(attribute, cmdLevel, platform);
            if (result == false && obj.getInclude() != null) {
                obj = (SupportObject)objects.get(obj.getInclude());
            } else
                obj = null;
        return result;
    /** Locate an AttributeObject for a given attribute name, object type, and command level.
        This is a helper function for the getMaxLen and getType methods. */
    private static AttributeObject getAttributeObject(String attr, String classID, String cmdLevel) {
        AttributeObject result = null;
        SupportObject obj = (SupportObject)objects.get(classID);
        while (result == null && obj != null) {
            result = obj.getAttr(attr, cmdLevel);
            if (result == null && obj.getInclude() != null) {
                obj = (SupportObject)objects.get(obj.getInclude());
            } else
                obj = null;
        return result;
    /** Determine the maximum length for a given combintation of attribute name, object type,
        command level, and platform. If the AttributeObject can't be found, or if the length
        hasn't been set, return -1. */
    public static int getMaxLen(String attr, String classId, String cmdLevel, String platform) {
        AttributeObject a = getAttributeObject(attr, classId, cmdLevel);
        if (a == null)
            return -1;
        return a.getMaxLen(platform);
    /** Determine the PCF parm type for a given combintation of attribute name, object type,
        command level, and platform. If the AttributeObject can't be found, or if the length
        hasn't been set, return -1. */
    public static int getType(String attr, String classId, String cmdLevel, String platform) {
        AttributeObject a = getAttributeObject(attr, classId, cmdLevel);
        if (a == null)
            return -1;
        return a.getType(platform);
    /** Inner class to contain platform-specific info for an attribute. */
    class PlatformObject {
        /** This instance variable will contain the comma-delimited string of all
            platforms to which this object applies. */
        private String platform;
        private int maxlen;
        private String condition = null;
        private boolean include;
        private boolean readonly;
        private boolean lenSet;
        private int attrType;
        private boolean typeSet;
        public PlatformObject(String p, boolean readonly) {
            platform = p;
            this.readonly = readonly;
            lenSet = false;
            typeSet = false;
        public PlatformObject(String p) {
            this(p, false);
        public void setCondition(String condition, boolean include) {
            this.condition = condition;
            this.include = include;
        public boolean isReadonly() {
            return readonly;
        public boolean isExported(TopologyModelNode node) {
            if (condition != null) {
                boolean test = false;
                try {
                    test = Utilities.evaluateCondition(node, condition);
                } catch (Exception e) {}
                if (include ^ test)
                    return false;
            return !readonly;
        public void setLen(int len) {
            maxlen = len;
            lenSet = true;
        public void setType(int type) {
            attrType = type;
            typeSet = true;
        public String getPlatform() {
            return platform;
        public int getMaxLen() {
            if (!lenSet)
                return -1;
            return maxlen;
        public int getType() {
            if (!typeSet)
                return -1;
            return attrType;
    /** This class represents a specific MQSeries attribute. It can optionally contain
        instances of the PlatformObject class as needed. When the 'platforms' collection
        is empty, the attribute is supported on all platforms. It is also possible to
        include a PlatformObject for the 'all' platform, if specific attribute characteristics
        need representation. When the 'platforms' collection is non-empty, it will include one
        entry for each platform where the attribute is supported. */
    class AttributeObject {
        private String attribute;
        private String attrValue;
        private HashMap platforms;
        private String condition = null;
        private boolean include;
        private boolean readonly = false;
        public AttributeObject(String a) {
            this(a, false);
        public AttributeObject(String a, boolean readonly) {
            attribute = a;
            platforms = new HashMap();
            this.readonly = readonly;
        public void setCondition(String condition, boolean include) {
            this.condition = condition;
            this.include = include;
        public void setReadonly(boolean readonly) {
            this.readonly = readonly;
        public boolean isReadonly() {
            return readonly;
        public void addPlatform(PlatformObject p) {
            for (StringTokenizer st = new StringTokenizer(p.getPlatform(), ","); st.hasMoreTokens() ;) {
                platforms.put(st.nextToken(), p);
        public PlatformObject getPlatform(String platform) {
            PlatformObject p = (PlatformObject)platforms.get(platform);
            if (p == null)
                p = (PlatformObject)platforms.get("all");
            return p;
        public String getAttribute() {
            return attribute;
        public int getMaxLen(String platform) {
            PlatformObject p = getPlatform(platform);
            if (p == null)
                return -1;
            return p.getMaxLen();
        public int getType(String platform) {
            PlatformObject p = getPlatform(platform);
            if (p == null)
                return -1;
            return p.getType();
        public boolean isSupported(String platform) {
            if (platforms.isEmpty()) {
                return true;
            if (platforms.containsKey(platform)) {
                return true;
            if (platforms.containsKey("all")) {
                return true;
            return false;
        public boolean isExported(String platform, TopologyModelNode node) {
            if (readonly) {
                Log.log(Log.DEBUG, this, attribute + " is readonly, returning false");
                return false;
            if (condition != null) {
                Log.log(Log.DEBUG, this, "Testing condition = " + condition);
                boolean test = false;
                try {
                    test = Utilities.evaluateCondition(node, condition);
                    Log.log(Log.DEBUG, this, "Condition result is " + test);
                } catch (Exception e) {
                    Log.log(Log.ERROR, this, "Condition through an exception");
                if (include ^ test)
                    return false;
            if (platforms.isEmpty()) {
                return true;
            PlatformObject p = getPlatform(platform);
            if (p == null) {
                Log.log(Log.DEBUG, this, platform + " not found for " + attribute + ", returning false");
                return false;
            return p.isExported(node);
    /** This class represents a specific value of a queue manager's command level. A
        given instance of this class may 'include' a 'parent' instance through its
        include instance variable. The traversal of the parent/child hierarchy is
        delegated to the SupportObject class, since that is where the collection of
        VersionObjects lives. */
    class VersionObject {
        private String cmdLevel;
        private String include;
        private HashMap attributes;
        public VersionObject(String cmdLevel, String include) {
            this.cmdLevel = cmdLevel;
            this.include = include;
            attributes = new HashMap();
        public void addAttr(AttributeObject attr) {
            attributes.put(attr.getAttribute(), attr);
        public AttributeObject getAttr(String attr) {
            return (AttributeObject)attributes.get(attr);
        public String getCmdLevel() {
            return cmdLevel;
        public String getInclude() {
            return include;
        public boolean isSupported(String attr, String platform) {
            AttributeObject obj = (AttributeObject)attributes.get(attr);
            if (obj == null) {
                return false;
            } else
                return obj.isSupported(platform);
    /** This class represents an MQSeries object type, as identified by its classid, e.g.
        queue manager or local queue. This class implements an include facility similar to
        that described for the VersionObject. The traversal of that hierarchy is delegated
        to the static isSupported method, because the collection of SupportObject instances
        is a static variable of the SupportMatrix class. */
    class SupportObject {
        private String classId;
        private String include;
        private HashMap versions;
        public SupportObject(String classId, String include) {
            this.classId = classId;
            this.include = include;
            versions = new HashMap();
        public void addVersion(VersionObject obj) {
            String key = obj.getCmdLevel();
            versions.put(key, obj);
        public String getClassId() {
            return classId;
        public String getInclude() {
            return include;
        public boolean isSupported(String attr, String cmdLevel, String platform) {
            boolean result = false;
            VersionObject obj = (VersionObject)versions.get(cmdLevel);
            if (obj == null)
                obj = (VersionObject)versions.get("base");
            // I don't actually know what it means if obj is null at this point.
            // It probably can't happen.
            if (obj == null)
                return false;
            while (result == false && obj != null) {
                result = obj.isSupported(attr, platform);
                if (result == false && obj.getInclude() != null) {
                    obj = (VersionObject)versions.get(obj.getInclude());
                } else
                    obj = null;
            return result;
        public AttributeObject getAttr(String attr, String cmdLevel) {
            AttributeObject result = null;
            VersionObject obj = (VersionObject)versions.get(cmdLevel);
            if (obj == null)
                obj = (VersionObject)versions.get("base");
            // I don't actually know what it means if obj is null at this point.
            // It probably can't happen.
            if (obj == null)
                return null;
            while (result == null && obj != null) {
                result = obj.getAttr(attr);
                if (result == null && obj.getInclude() != null)
                    obj = (VersionObject)versions.get(obj.getInclude());
                else
                    obj = null;
            return result;
}

Are you the one who commented out the code you're looking for ?//String desc = StringFactory.getString(attributes.getValue("desc"));You just have to modify you AttributeObject class to hold a new field : String description. And then, it's up to you to create a new constructor or a new setter method.
Btw, this is not a Swing related question.

How can I use evaluate to get the instance variable in customized tag

1.
At first , I create a class called bean,and declared several params in it and do not define any getter function for the param.
class bean{
String param = "test";
SomeClass scObj = new SomeClass();
2.
The second ,I use
request.setAttribute("beanObj",new bean());
3.
And then I wanna use the customized tag to show a text box , then initialize it's value.
<salt:text name="param" value="beanObj.param">
<salt:text name="obj" value="beanObj.scObj.func()">
4.
I tried the evaluator provided by JexlContext ,Struts, JSTL and it seems that if I do not define the getter for the variable ,I can not get the bean's instance variable's value.
Expression e = ExpressionFactory.createExpression( value );
JexlContext jc = JexlHelper.createContext();
jc.getVars().put(strInitBeanName, request.getAttribute("beanObj"));
Object obj = e.evaluate(jc);
the result of the obj is null....
Can anybody recommand some other evaluator can get the value of a instance variable from an object?

do you have any other suggestion ? Nops, somebody else may have though. AFAIK, all lookups of the type
beanName.propertyNameuse reflection on the getXXX() methods to access the property.
Having said that, I guess you could write one though in a custom tag, using the same - reflection (you will ahve to rely on the java.lang.reflect.Field class quite heavily) - but that would be reinventing the wheel for most other functionality that you would have to include (like looking up the bean in scope etc)
cheers,
ram.

Not able to access parent instance variable in outside of methods in child

Hi,
I am not getting why i am not able to access parent class instance variable outside the child class intance methods.
class Parent
     int a;
class Child extends Parent
     a = 1; // Here i am getting a compilation error that Syntax error on token "a", VariableDeclaratorId expected after this token
     void someMethod()
          a = 1; // Here i am not getting any compilation error while accessing parent class variable
}Can any one please let me know exact reason for this and what is the error talks about?
Thanks,
Uday
Edited by: Udaya Shankara Gandhi on Jun 13, 2012 3:30 AM

You can only put assignments or expressions inside methods, constructors or class initializors, or when declaring a variable.
It has nothing to the with Child extending Parent.
class Parent {
    int a = 1;
    { a = 1; }
    public Parent() {
        a = 1;
   public void method() {
       a = 1;
}

Binding: Instance variable loses value.

Hi all,
Just making my first steps into Objective-C, I've done a lot of C, C++ and C# on win & linux. Anyhow, I've been hacking away happily and discovered a peculiar behaviour, and I'm not sure if it's my code or some obscure bug in Xcode.
1. I have a Check Box(NSButton) directly bound to a BOOL instance variable called "checkValue" using KVC. The containing class is a custom NSView subclass.
2. I manually implemented the setter according to KVC naming rules "setCheckValue".
3. When debugging the UI (check box) calls the setter perfectly with the correct value, which shows up in the NSLog output.
4. I hooked up the action for the check box as well, and inside the action handler the instance variable reports the value correctly. Everything looks fine.
5. Now here's the rub. I put a mousedown event handler into the class as well, and it is called flawlessly when I click on the custom view. However, "checkValue" does not report the correctly set value.
So, how can a class instance variable, which is set and reports correctly elsewhere in the same scope, all of the sudden take on a nonsense value in a event handler? If a variable has a value set, it should be the same everywhere within the same scope!
Below is simplified code extracted from the original project for clarity. It produces exactly the same behaviour as the more complex project without the distracting code.
#import "CheckBoxHandler.h"
@implementation CheckBoxHandler
@synthesize checkValue;
//Apparently this is required for binding in NSView based classes
//The same behaviour occurs even if you remove this.
+(void)initialize
[self exposeBinding:@"checkValue"];
-(id)initWithFrame:(NSRect)frameRect
self = [super initWithFrame:frameRect];
if(!self)
return nil;
[self setCheckValue:YES];
return self;
//manual impelementation of KVC setter
-(void)setCheckValue:(BOOL)v
checkValue = v;
NSLog(@"Setter Called: checkValue is %d", checkValue);
//The action works fine as evidenced by Log output
//Check and uncheck the box a few times.
-(IBAction)checkBoxAction:(id)sender
NSLog(@"UI State:%d Ivar State: %d", [checkBox state], checkValue);
//Mouse clicking on the view calls into this event.
//The problem is the value reported by [self checkValue] OR checkValue directly
//do not match the UI state. In fact it always reports some nonsense value.
-(void)mouseDown:(NSEvent *)event
NSLog(@"Inside Mousedown: checkValue is: %d", [self checkValue]);
@end
I have a workaround, but it really bends my head when something doesn't behave as expected!

I have synthesized against "checkValue", although I manually implemented the setter so I could set a breakpoint and observe the value. I thought [self checkValue] and self.checkValue both simply call the same getter, just different syntax.
The setting of the value using the UI checkbox happens outside of the event call chain. I can check and uncheck the checkbox and the value changes correctly. The checkbox is in a separate space on the window, so clicking it does not activate mousedown on the view, this is correct behaviour. Clicking on the view does activate the mousedown event, this is done after I've set the checkbox so the value has been set well before the mousedown event. Thus it should already have the correct value in the event.
For completeness this is the interface file:
#import <Cocoa/Cocoa.h>
@interface CheckBoxHandler : NSView {
IBOutlet NSButton *checkBox;
BOOL checkValue;
-(IBAction)checkBoxAction:(id)sender;
@property (assign, readwrite) BOOL checkValue;
@end
I'll change everything to self.checkValue just for the excercise. Ok, done. checkValue still reports a value of 1 in the mousedown event regardless of the value set elsewhere.

Array as Instance Variable

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