Scope a private variable
Hi,
Is it possible scoping a private param?
Function Execute-vctest {
[CmdletBinding()]
Param (
[Parameter(Mandatory=$false)]
[ValidateNotNullorEmpty()]
[string]$private:LogName
execute-vctest -logname "test"
That script is just failing saying it cannot find LogName...
All parameters are local to the function or script they are defined in. There is no point to declaring them private. Parameters cannot be scoped.
¯\_(ツ)_/¯
Similar Messages
-
Accessing a private variable from a public method of the same class
can anyone please tell me how to access a private variable, declared in a private method from a public method of the same class?
here is the code, i'm trying to get the variable int[][][] grids.
public static int[][] generateS(boolean[][] constraints)
private static int[][][] sudokuGrids()
int[][][] grids; // array of arrays!
grids = new int[][][]
{Are you sure that you want to have everything static here? You're possibly throwing away all the object-oriented goodness that java has to offer.
Anyway, it seems to me that you can't get to that variable because it is buried within a method -- think scoping rules. I think that if you want to get at that variable your program design may be under the weather and may benefit from a significant refactoring in an OOP-manner.
If you need more specific help, then ask away, but give us more information please about what you are trying to accomplish here and how you want to do this. Good luck.
Pete
Edited by: petes1234 on Nov 16, 2007 7:51 PM -
Hello,
While studying I have come up with this problem a few times and was wondering if you could help me.
I am currently working with linked list examples and the variables used have default package access. I am however told that the variables should normally be declared private.
So I made a kinda dummy class which shows my problem.
public class Private
private Private unreachable;
private String greating="hello";
public Private()
unreachable = null;
greating="";
public String getGreating()
return greating;
public Private getReach()
return unreachable;
public class PrivateWork
private String differentGreating;
private Private reachMe;
public PrivateWork()
differentGreating="";
reachMe=null;
public void changeGreating(String change)
Private p = new Private();
p.greating = change; //produces "greating has private access in the class Private" error
p.getGreating() = change; //produces "unexpected type" error
reachMe = p;
public class TestPrivate
public static void main(String[]args)
PrivateWork p = new PrivateWork();
p.changeGreating("Good Morning");
}I know that by making the Private class an inner class of PrivateWork I can keep the variables declared private and the "p.greating = change;" will work.
However is there another way I can access the "greating" variable from the changeGreating(String change) method in the PrivateWork class.I am currently working with linked list examples and the variables
used have default package access.What variables are you referring to?
p.greating = change; //produces "greating has private access in the class Private" error That one should be pretty obvious because it is the definition of private: you can't use objects of the class to access private variables.
By the way, "greating" is spelled greeting.
p.getGreating() = change; //produces "unexpected type" errorI'm not sure about that one. But, you can split that statement up into two lines and you won't get a compile error:
String gr = p.getGreating();
gr = change;However, I don't think that is going to do what you expect. Try to predict the output of this example:
class Private
private String greeting="hello";
public String getGreeting()
return greeting;
public class AATest1
public static void main(String[]args)
Private p = new Private();
String gr = p.getGreeting();
gr = "Goodbye";
System.out.println(p.getGreeting()); //Output??
} -
Enforce setting private variable in subclass with abstract method
Hi,
Is this something that is common usage/practice?:
public abstract class Base {
private int importantPrivateVariable = setImportantPrivateVariable();
protected abstract int setImportantPrivateVariable();
}I would like to enforce the extender of the class to set a private variable, but as there is no abstract variable in java, I can only use a method for it.
Thanks,
lemonboston
Edit: the variable could be protected as well, I suppose this is not important here, but correct me if I am wronglemonboston wrote:
Hi,
Is this something that is common usage/practice?:I don't think that's so common, but that's code easily understandable. However there are several problems with this approach:
public abstract class Base {
private int importantPrivateVariable = setImportantPrivateVariable();
protected abstract int setImportantPrivateVariable();
}I would like to enforce the extender of the class to set a private variableThat's no what your code implements: your base class forces the subclasses to return an int value, and the Base class uses that value to assign it to the variable.
Therefore the method should be called get<Something> (e.g. <TT>getInitialValueOfImportantVariable()</TT>+ to have a naming consistent with its signature (it returns a value, whereas a regular setter method should declare a void return type: <TT>protected abstract void setImportantPrivateVariable(int someValue);</TT>).
Edit: the variable could be protected as well, I suppose this is not important here,Well, yes, this is "important" - at least, there a noticeable difference: the variable being private, the base class is free to handle it as it sees fit (e.g., assign the value at construction time and never modify it afterwards). If the variable was protected, the subclass could modify in ways and at times not known by the base class.
but correct me if I am wrongThere's a trap in this construct: the method is called in the variable initializer, that is, behind the scenes, approximately during the execution of the Base class constructor, so before the subclass constructor. So, you are calling a method on an object that is not fully initialized (e.g. some of its attributes may still be <TT>null</TT> at this stage). There is a rule that discourages such situations, that goes something like "don't call non-private and non-final methods from a constructor".
To avoid this trap, two options:
- require an int argument in the Base class's constructor , as was suggested above
- don't get and set the value of the important variable in the initializer or constructor code, but from a special method in the base class instead:
public abstract class Base {
private int importantPrivateVariable; // default value is zero
// or alternatively:
// private int importantPrivateVariable = ...; // Some default value
protected abstract int getImportantPrivateVariable();
public void initializeImportantPrivateVariable() {
importantPrivateVariable = getImportantPrivateVariable();
}That construct is a degenerate form of a common design pattern known under the name of Template Method (where a base class method calls generally several subclass methods in a specified order and with a specified chaining, leaving it to the subclass to implement the details of the methods).
The drawback is that the client code (the one that uses the Base instance) has to know when to call that initialization method, whereas the constructor-based initialization lets the client code free to not care at all.
Much luck,
J. -
Scope of Presentaion variable in DBPrompt?
Hi All,
If i have dbprompt with "colA" assigned Presentation variable "prsn_a" . on the same db i have master report which i can drill to detail level.
master and details reports have filter on colA prompted. If i click on master report i am unable to see any data on details report.
i.e the value i chose at master level for colA is not propagated to detail report. Can you people tell me work around for this.?
Please ask me if i am unable to convey my problem clearly.
Thanks
user642877To answer the implied question in your title "Scope of Presentation variable in DBPrompt?" based on your explanation in the details of your post, the problem in not the scope of presentation variables. They will work if you set them up correctly in the type of scenario you describe.
Since you didn't answer one of Sandeep's question about whether you are "drilling down" or "navigating" using Value Interaction, I will make an educated guess.
Since you said that...
master and details reports have filter on colA prompted. ...I will assume that you have done the latter, i.e., that you have Value Interaction>Navigation as your method since you can't put an "Is Prompted" filter on the detail report if you are using drill down.
My question is if you have a prompt on the date value, then the Master report will be filtered for that date. Why would you then put Navigation on the date value to go to your detail report? The report is already filtered on that date from the prompt? Why don't you just put the detail report underneath the Master report since both reports are filtered by the same thing, the date prompt?
But to answer your specific question, try using the presentation variable explicitly as the filter instead of "Is Prompted." -
[svn] 3438: Forgot to change a private variable to protected in my previous check-in.
Revision: 3438
Author: [email protected]
Date: 2008-10-01 08:27:31 -0700 (Wed, 01 Oct 2008)
Log Message:
Forgot to change a private variable to protected in my previous check-in.
Modified Paths:
blazeds/trunk/modules/core/src/flex/messaging/services/messaging/ThrottleManager.javaHi Ignacio ,
To change the username you should follow these steps ;
1-You should have to use nQUDMULGen command to export your rpd into a file.Go to ...OracleBI\server\Bin
ex. nQUDMULGen -u Administrator -p Administrator -r C:\OracleBI\server\repository\paint.rpd -o c:\paint.txt
2-After importing try to find your user and change its settings.
3-Then import it back to your rpd.
ex. nQUDMLExec -u Administrator -p Administrator -i c:\paint.txt -b C:\OracleBI\server\repository\paint.rpd -o C:\OracleBI\server\repository\paint2.rpd
The new rpd is going to be created (paint2).Test the new rpd.If its OK.Then replace with your original rpd.
I hope this method works... -
Can one obj access a private variable of another obj of the same class
Can one object access a private variable of another object of the same class?
If so, how?Declaring variable private means you can not access this variable outside class
But other objects of same class can access it. Because each object have separate copy of variable and may have diff. contents for same variable. -
Are private variables of VO/AM/...also passivated?
Hi,
In my JClient application in order to avoid the transaction becomming "dirty" when setting transient attributes => display field, I did the following:
Transient attribute: AttrTransient
Added a private variable Number attrTransient
public Number getAttrTransient()
// return (Number)getAttributeInternal(ATTRTRANSIENT);
// here I call my calculation method
return this.attrTransient;
public void setAttrTransient(Number value)
// setAttributeInternal(ATTRTRANSIENT, value);
this.attrTransient = value;
In my JClient environment it works ok.
Question:
In a STRUTS-ADF where the connection management is different, will my variable attrTransient be part of the passivation mechanism?
In other words will the user get the value of attrTransient when using the same ViewObject instance?
If yes, is this also true for added variables to application modules or Entities?
Thanks
FredHi guys,
Thanks for your help. I really was drowning in a glass of water. Although now I am looking forward to learn and understand all about passivation, the issue was not related with that.
The logic implemented checks certain characteristics for the logged in user. With this particular user the logic applied was different in term that, programatically, there was being applied a ViewCriteria. After researching and consulting I realized that when a VC is applied programatically , all the others view criteria (already applied for that VO in the AM) are lost. Hence, no matter that I was executing with all the params, at the end, the querybuilder would just bind the variables for the VC assigned to the VO. In my case, just the one I've applied programatically.
Regards -
Multithread & private variables ?
Hi,
I would like to know if we can have private variables when we have multiple threads from the same class : in fact even if i declare a variable private when it is changed it is for all threads together, and for the future thread too : how can this be done please ???Hi !
I'm sorry but really it doesn't work : i'm calling this servlet many times using get and st is everywhere set to carine...then I'm calling the post method that set up st to canard in all threads...but if i call a get again then st is set to carine again and everywhere : that means it is not private variables for each threads, I'm sorry but really I would like to know to do that properly....what's wrong ????
Thank you for your help
package servlettest;
import javax.servlet.*;
import javax.servlet.http.*;
import java.io.*;
import java.util.*;
public class carine
extends HttpServlet {
private static class ThreadState {
public String owner;
private static ThreadLocal state = new ThreadLocal() {
protected Object initialValue() {
return new ThreadState();
ThreadState st;
public void init() throws ServletException {
public void doGet(HttpServletRequest request, HttpServletResponse response) throws
ServletException, IOException {
st = (ThreadState) state.get();
st.owner = "carine";
synchronized (this) {
while (true) {
System.out.println("st contains : " + st.owner);
try {
this.wait(2000);
catch (InterruptedException ex) {
public void doPost(HttpServletRequest request, HttpServletResponse response) throws
ServletException, IOException {
System.out.println(st.owner);
st.owner = "canard";
} -
Doubt about scope of instance variable
Hi All,
i have a doubt about scope of instance variable.
if i declare a instance variable in servlet , i want to know whether it can be shared(means everywhere ) or not.
thanks in advance
GopalThe servlet container will create one servlet object, and run multiple threads through its service() / doGet() / doPost() methods.
That means that any instance variables of the servlet are shared between multiple requests, and can cause problems with threads accessing the same variable..
To make your servlets thread-safe
1 - have no instance variables - only use local variables in the doGet/doPost method.
2 - use the session scope for storing variables you need over multiple calls.
Cheers,
evnafets -
I'm a little confused. I know that using private instance variables is good practice, and that the appropriate way to access those variables is with accesser methods (getXXX(), etc.). Since the variables are private, you can't access them by just referring to "testClass.variable", right?
Well, I was reading up on the Comparable interface today, and found a code example where a class implemented a compareTo() method like this:
public int compareTo(Object o) {
if (privateVariable < (TestClass) o.privateVariable) {
return -1;
} else {
return 1;
}But privateVariable is declared as a private variable. So why is it that you can refer to o.privateVariable in the compareTo() method? Is it just because o is cast as a TestClass object, and the compareTo() method is inside of the TestClass class? Even if that's the case, it still seems weird to me; if privateVariable is declared private, I'd think that any reference to a TestClass.privateVariable variable would throw an exception, even if the reference is within the TestClass. This just seems different to me than referring to the privateVariable variable within TestClass, because that obviously refers to the member of the current instance, not a different instance.
Anyway, any explanation would be appreciated.
RichYes, 'private' means 'private to this class', not 'private to this object'.
In this way, it behaves somewhat like a 'friend' variable. The basic idea of making variables private is to hide the implementation behind a class, which still holds even with the compareTo method (you can't use it to figure out that there's a variable called 'privateVariable', when using it from outside your class.) -
Scope of instance variables in servlets..
Hi all,
Sorry for asking a dumb question..
What is the scope of instance variables in a servlet? Is the scope is
limited to thread?
In other words, in the following example, i am setting "testStr", in one
request and when i tried to access the same instance variable from another
request, i am getting it as null. Does it mean instance variable is limited
to that particular thread/request?
thanks in advance..
-ramu
Oops ... I had misunderstood and had the problem backwards ;-)
> Is it known behavior? With registered servlet its working fine (a
> instance variable is shared by all requests)
I believe so; I typically deploy in a WAR so have not seen the problem that
you describe. Servlets can be reloaded, so what you saw could have been
caused bye a date/time mismatch between the .class file and the server's
current time. On the other hand, that could be how WebLogic works.
Peace,
Cameron Purdy
Tangosol, Inc.
http://www.tangosol.com
+1.617.623.5782
WebLogic Consulting Available
"Ramu" <[email protected]> wrote in message
news:[email protected]...
> Hi Purdy,
>
> I got it. I am testing the servlet as a unregistered servlet, which is
> creating instance for every new request!!!, which created this whole
> confusion. Is it known behavior? With registered servlet its working fine
(a
> instance variable is shared by all requests)
>
> > What theory? ;-) Instance variables are on the object, and the object
can
> > be used by multiple threads, thus allowing multiple threads to access
the
> > same instance variables.
> what i mean by theory here is, all instance variables in servlet should
be
> shared by all requests. Now i got it sir.
>
> Thank you..
> -ramu
>
>
> >
> > Peace,
> >
> > --
> > Cameron Purdy
> > Tangosol, Inc.
> > http://www.tangosol.com
> > +1.617.623.5782
> > WebLogic Consulting Available
> >
> >
> > "Ramu" <[email protected]> wrote in message
> > news:[email protected]...
> > > Hi,
> > >
> > > > No, an instance variable in a servlet class is not limited to a
> thread.
> > > There
> > > > is exactly one copy of the servlet created in memory and all
requests
> > pass
> > > > through the same instance, thus sharing any instance variables. A
> > couple
> > > of
> > > > things to remember:
> > > I totally agree with you, But i am wondering why my sample servlet(i
am
> > > attaching the file) is not sharing the instance variables across
> > > threads/reqs. (in 1st request set some string to "testStr" instance
> > > variable, in next request if you read the same instance variable, you
> will
> > > get null!!)
> > > Our current code is having instance variables. But right now we are
not
> > > getting any problems. But as per theory, instance variables should be
> > shared
> > > across threads/requests..
> > >
> > > Any how we are changing our code to remove all instance variables.
> > >
> > > thanks,
> > > -ramu
> > >
> > > >
> > > > 1.) Using instance or class variables in servlets that are not
> read-only
> > > is not
> > > > a good thing to do. This makes the servlet not thread-safe. To
> > maintain
> > > > variables across requests, sessions, etc., use the servlet-defined
> > objects
> > > to
> > > > store the state (e.g., request, session, etc.).
> > > >
> > > > 2.) If you modify the servlet class on disk, WebLogic will reload
the
> > > servlet
> > > > class thus discarding the old instance and creating a new one (of
> > course,
> > > this
> > > > depends on some configuration parameters for servlet reloading).
> > > >
> > > > Hope this helps,
> > > > Robert
> > > >
> > > > Ramu wrote:
> > > >
> > > > > Hi,
> > > > > thanks for quick reply.
> > > > > I am not at all using SingleThreadModel. See the following code.
> > > > > In first request i am passing "abc" value to testStr. But in
second
> > > request,
> > > > > I am getting null for testStr in second request. It looks like
(for
> > me)
> > > for
> > > > > non single threaded model also, scope of instance variables is
> > limited
> > > to
> > > > > Thread/Request.. But as per theory, because its not single
threaded
> > > model,
> > > > > only one instance should be there AND testStr(instace variables)
> > should
> > > be
> > > > > shared across the all threads. But i am not able see that
behaviour
> > > here.
> > > > > But if declare instance variable as static, o am able to share
it
> > > across
> > > > > all threads/requests.
> > > > >
> > > > > note:
> > > > > From browser i am setting testStr to "abc" with URL like
> > > > > "localhost/test1?testStr=abc"
> > > > > And 2nd req from browser is like "localhost/test1" (on server
> output
> > i
> > > am
> > > > > getting null for testStr)
> > > > >
> > > > > Any ideas?
> > > > >
> > > > > thanks,
> > > > > -ravi
> > > > >
> > > > > import java.io.*;
> > > > > import javax.servlet.*;
> > > > > import javax.servlet.http.*;
> > > > >
> > > > > public class test1 extends HttpServlet
> > > > > {
> > > > > public String testStr;
> > > > >
> > > > > public void doGet (HttpServletRequest req, HttpServletResponse
res)
> > > > > throws ServletException, IOException
> > > > > {
> > > > > doPost(req, res);
> > > > > }
> > > > >
> > > > > public void doPost (HttpServletRequest req,
HttpServletResponse
> > res)
> > > > > throws ServletException, IOException
> > > > > {
> > > > > try {
> > > > > res.setContentType("text/html");
> > > > > PrintWriter out = res.getWriter();
> > > > > if(req.getParameter("testStr") != null)
> > > > > {
> > > > > testStr = req.getParameter("testStr");
> > > > > System.out.println("set testStr = " + testStr);
> > > > > }
> > > > > else{
> > > > > System.out.println("get testStr = " + testStr);
> > > > > }
> > > > >
> > > > > }
> > > > > catch(Exception e){
> > > > > e.printStackTrace();
> > > > > }
> > > > >
> > > > > }
> > > > > }
> > > > >
> > > > > "Cameron Purdy" <[email protected]> wrote in message
> > > > > news:[email protected]...
> > > > > > Yes or no, depending on if your servlet implements
> > SingleThreadModel.
> > > > > >
> > > > > > See the servlet 2.2 spec for documentation on how many instances
> of
> > a
> > > > > > servlet will be created. See the doc for the SingleThreadModel
> > > interface.
> > > > > >
> > > > > > Peace,
> > > > > >
> > > > > > --
> > > > > > Cameron Purdy
> > > > > > Tangosol, Inc.
> > > > > > http://www.tangosol.com
> > > > > > +1.617.623.5782
> > > > > > WebLogic Consulting Available
> > > > > >
> > > > > >
> > > > > > "Ramu" <[email protected]> wrote in message
> > > > > > news:[email protected]...
> > > > > > > Hi all,
> > > > > > >
> > > > > > > Sorry for asking a dumb question..
> > > > > > >
> > > > > > > What is the scope of instance variables in a servlet? Is the
> scope
> > > is
> > > > > > > limited to thread?
> > > > > > >
> > > > > > > In other words, in the following example, i am setting
> "testStr",
> > in
> > > one
> > > > > > > request and when i tried to access the same instance variable
> from
> > > > > another
> > > > > > > request, i am getting it as null. Does it mean instance
variable
> > is
> > > > > > limited
> > > > > > > to that particular thread/request?
> > > > > > >
> > > > > > > thanks in advance..
> > > > > > >
> > > > > > > -ramu
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > >
> > > > > >
> > > >
> > >
> > >
> > >
> >
> >
>
>
-
Scope of instance variables clarification requested
under the topic "Scope of instance variables" in the class notes for the course i'm doing it is stated:
inside the class definition, the name can be prefixed by the keyword "this".
e.g. available = this.balance + overdraft;
in simple words, please explain what it means
or:
what is a class definition? and what does using "this" mean?
i'll gladly take internet links on where i can find the answer to my own question if you don't have time.
thanks a million!this can be regarded simply as a reference variable which points to the intance of the class it's used in.
So this.fieldOne referer to the instance field fieldOne withing the current instance just as theOther.fieldOne refers to the instance field in another object. -
Storage of Private Variables...
I know u all are right but the thing here is that ... when we instantiate a sub class memory for every inherited member is allocated(including private) to its object in heap.
I just want to know that why private members are inherited if they are simply inaccessible by the sub class......are they inherited just to waste memory........The thing that u are saying is very much correctbut
the point is that the private variable name used
within the base class but why it comes to the sub
class........and then it is invisible to it...Read this agani (posted by warneja):
A subclass instance is still an instance of thebase class too
(the same object, not another one).It sounds like you don't understand what he is trying
to say. There aren't two objects in memory. I.e it's
not one object for the base class, and another for
the subclass. There is only one object in memory, and
that object has all fields and methods from both
classes.
Kaj(All in that post was directed at the OP, even though it looks like I'm talking to warneja) -
This is such a basic question I decided to post it here.
Does a subclass get its superclass's private variables?So, a subclass cannot changeyes it can but not directly
cannot accessyes it can but not directly
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