What is a "Helper" class?

I come across this a lot in my readings, but don't know what it is? What exactly is a "Helper" class? What defines one?
Thanks.

A class that is created to offload some part of a responsibility from another class. Usually used to manage complexity. Helper's don't have a separate reason for existing than to 'help' implement another class. Usually 'package' visible rather than protected or public.
Chuck

Similar Messages

What's the naming convention for Helper Class?

Hi Experts,
What's the naming convention for helper class?
cl_util? or cl_heper?
Thanks in advance!

Hi.,
Normally in JAVA the naming convention for Helper Class is <EventID>Util.java. The Naming convention for helper class must start with EventID.
here Event ID is the event Name , Util.java is the helper class for java.
I believe the same will be followed in ABAP OO too..
here the helper class is cl_uitl.,
so <EventID><ABAP hepler class> is the naming convention.
wait for experts reply..,
hope this helps u.,
Thanks & Regards,
Kiran

How to construct table in jsp for the resultset from helper class

Hi Dudes!!!
Want to construct table in jsp for the resultset, but the resultset are retrieved at the helper class.I constructed Table in Helper class Using StringBuffer and return it as string from the helper class.Is their any other feasible and efficient way to construct table in Jsp for the resultset from Helper class.Solution will be highly appreciated.Thanx in Advance.

no, we can't.
Certainly noone can with such vague specifications even if they had the intent to do so.
"the computer", which computer?
"attach to our current page", what is meant by that?
And noone should ever help you if you're planning to breach security anywhere.

Including helper classes in java proxy jar file

I must not be using the right header search criteria because I'm sure this question
has been asked before. In a Web Service File (.jws) I've imported a couple of
helper classes that function as data transfer objects. I did this to maintain
consistency with other portions of the application. The Java Proxy jar file generated
by Workshop does not include these files. Is there a way of including these dependencies
or do I need to distribute another jar file with my helper classes?

Hi Naichen,
I was able to successfully run both the autotype and clientgen Ant task, on the
WSDL you provided. The code behind those Ant tasks are pretty much what the WebLogic
Web Services test page run. Are you using WLS 8.1 SP2? If not, you might want
to try with that version.
Regards,
Mike Wooten
"Naichen Liu" <[email protected]> wrote:
>
>
>
Hi,
I am having a warning message when trying to generate java proxy jar
file on weblogic8.1
webservice test web app, the message is as follows:
"Warning Failed to generate client proxy from WSDL definition for this
service.
Prescription Please verify the <types> section of the WSDL."
in the mean time, on weblogic starting terminal, I saw the following
exceptions,
C:\DOCUME~1\u252738\LOCALS~1\Temp\wlwproxy37508.jar1533409921\com\ual\www\rcc\cb
t\schema\modifypnr\AlphaLength4Deserializer.java:36: cannot resolve symbol
symbol : class FacetUtils
location: package binding
weblogic.xml.schema.binding.FacetUtils.checkLengthFacet(__typed_obj,4L);
^
C:\DOCUME~1\u252738\LOCALS~1\Temp\wlwproxy37508.jar1533409921\com\ual\www\rcc\cb
t\schema\modifypnr\OSIFieldAnonTypeDeserializer.java:36: cannot resolve
symbol
symbol : class FacetUtils
location: package binding
weblogic.xml.schema.binding.FacetUtils.checkMaxLengthFacet(__typed_obj,69L);
^
C:\DOCUME~1\u252738\LOCALS~1\Temp\wlwproxy37508.jar1533409921\com\ual\www\rcc\cb
t\schema\modifypnr\AlphaLength2Deserializer.java:36: cannot resolve symbol
symbol : class FacetUtils
location: package binding
weblogic.xml.schema.binding.FacetUtils.checkLengthFacet(__typed_obj,2L);
^
C:\DOCUME~1\u252738\LOCALS~1\Temp\wlwproxy37508.jar1533409921\com\ual\www\rcc\cb
t\schema\modifypnr\FreeFormAnonTypeDeserializer.java:36: cannot resolve
symbol
symbol : class FacetUtils"
Can anybody help me about this issue? I attached WSDL file, also United
Airlines
got an enterprise weblogic license deal with BEA, any help will be highly
appreciated.
Thanks!!!
Naichen

Obtaining principal in EJB helper classes

I have a pretty typical EJB setup where the actual EJBs delegate a lot of work
off to helper classes which are simple java classes. Some of these helpers need
access to the principal currently executing on this container thread. Currently,
I am passing the principal as a parameter in every method signature on the helpers
which need it. But as you can probably guess that approach is quickly becoming
unweildy.
Ideally, what I would like to do is to have access to the principal associated
with the currently executing thread. I can mimic this by setting thread-local
variables in the EJB prior to calling helpers. But I was wondering (ok, hoping)
that there was already a way to access this information (either through weblogic
classes or MBeans). At this point, I dont even care if it is not portable.
P.S., I use WL6.1
Thank you in advance,
Steve

>
The helper methods do database querries etc and return results that the EJB sends onwards to clients. If these methods
are NOT synchronized (and the ejbs share the static class) won't it cause concurrency errors? I think most of our methods are not
synchronized (and it doesn't seem to cause any concurrency errors so far... though the system have not beeen stressed test that much,
and concurrency bugs tends to pop up later and randomly :P).
>
No, if you dont have any static data variables in the Java classes, static method as such will not cause concurrency errors, and the methods should not be synchronized.
If you have any synchronized methods and they take a while to execute, that could become a bottleneck in itself, because different threads waiting for each other,
so make sure you dont have any synchronized methods where it is not explicitly needed.
Think of a static method (without static data in the class being manipulated) as a plain function in another programming-language.
>
We have some scaleability problems with the EJBs... It seems as if they do not run concurrently. If we do a stress test with several threads calling the EJBs their response time increases by a too large factor to feel comfortable...
>
Apparently, you do have a some scaling/concurrency problem, which could have many causes -- transaction locking and clashes in the database, poorly configured database, network congestion, problems in the EJB architecture, etc -- can be many reasons...
The general idea to debug, is first to find out exactly what calls in your code that take longest time to execute (profiling, logging, System.out.println's are useful) when you put parallel load on your system -- rather than just seeing "the whole application seems slow" -- from there you can move on, "divide&conquer" the problem, etc...

Urgent...Help Needed.1. Helper Class 2. Connection Pool

Hello,
1. There are few helper classes which has to be
shared b/w session and entity beans. But it
seems,state of the object is not transfered to entity
bean though the class has implemented Serializable
interface. I have archived all the helper class and
copied to j2ee\home\lib directory. The same jar file
is made accessible to server via updating <library-
path> in j2ee/home/config/application.xml file.
2. How can i utilise connection pooling in oc4j. In data-sources.xml, i am using
"OracleConnectionPoolDataSource" class. But i feel that connection pool is not utilised coz server hangs in the middle of the retrieval.
The value of max-connections is 50.
We are actually migrating from Weblogic 5.1.0 to Oracle 9i AS. In weblogic, we had given 10 max connections in weblogic.properties,it is working fine. But i dont understand why it is not working in 9i AS though the max-connections is 50.
Kindly let me know the solution at the earliest as it is very urgent to get the program running...
Thanx and Regards,
Achyuth

Hi,
hopefully I can help you.
1. There are few helper classes which has to be ...We have just the same constellation. We have put the HelperClasses in the
J2EE/home/lib dir, NOT specifying it in the application.xml. So everything works fine.
The only thing: never, again: never put these files within WEB-INF and the lib-dir.
With the HelperClasses in both we have only faced massive problems, mostly ClasCastExceptions.
We had once all the helperClasses within J2EE/home/applications/lib, but this requires to
specify this dir within the orion-application.xml within the appl dir in applications-deployment.
It also worked fine.
2. How can i utilise connection pooling in oc4j. In data-sources.xml, i am using ...I'm not sure of this, but I think, the container handles Connection Pooling, no matter what Factory you
specify. But I think, the Class hasn't to be OracleConnectionPool ... but I have to check this (right now
I have no access to our datasource.xml ..)
cu
ed

Add helper class public parts as used DC in EJB DC

Hi Experts,
I have created a JAVA DC project containing the helper classes.
For this helper classes i have created a Jar file.
I have also created two public parts
1) with an option Can be packaged into other build results (e.g. SDAs)
2) with an option Provides an API for developing/compiling other DCs
Now i want to use these public parts in my EJB DC.
I have added the API public part in my EJB DC as build time design time and run time.
Now when i am getting java.lang.NoClassDefFoundError: for the class defined in JAVA DC helper class.
Can you help me in resolving this?
Regards,
Ashish Shah

Hi
I have done following things:
1) I have a java DC containing helper classes and an EJB DC referring to it.
2) Now to access this EJB DC, I have created a java command bean DC.
3) And I am using this command bean Java dc in my WebDynpro application.
4) Now for deploying the helper class, I have created a library project.
5) To this library project I have added the SDA and API public part of helper class as used dc.
6) I have added this java library file as used DC in WebDynpro DC and in EJB DC.
7) I have added the library reference to the WebDynpro DC for J2ee server component library DC As pg.comaptsc~dc_aptjl
8) When i checked in Visual admin i could see the Assembly (SDA) helper class jar file.
In my helper class files, I am getting this warning.
Checking package reservation
Warning: Package pg.com.apt.help.cls is not reserved for DC : apt/sc/dc_apthc.
Now in my webdynpro DC when I refer to the helper class through the EJB, I get this error.
java.lang.NoClassDefFoundError: pg/com/apt/help/cls/TargetMarket at pg.com.atos.WebModuleProject.FetchSDCDataBean.SearchGTINTMDataEJB(FetchSDCDataBean.java:133) at pg.com.atos.WebModuleProject.FetchSDCDataObjectImpl0.SearchGTINTMDataEJB(FetchSDCDataObjectImpl0.java:119) ... 35 more ; nested exception is: java.lang.NoClassDefFoundError: pg/com/apt/help/cls/TargetMarket
Can you please guide on what I am missing.
Thanks in advance.
Regards,
Ashish Shah
Edited by: ashish shah on Dec 18, 2007 3:23 PM

EJB environment question (static helper classes)

We're using JBoss as AS containing several stateless session beans.
Now, we have certain helper classes that are abstract and contain static methods. Is this a problem for the EJBs? All of them use these helper classes all over their methods. Are they sharing the static class and will slow down somehow? Or is each EJB using its version of the class and can run concurrently?
Should we rethink this and put an INSTANCE of each helper class in each ejb instead of using static methods in the helper class?
Now in EJB method:
Helper.calculateStuff();
Should it be?
Helper h = new Helper(); // defined when ejb is created
helper.calculateStuff();
Edited by: JAeon on Sep 8, 2008 12:21 AM
Edited by: JAeon on Sep 8, 2008 12:22 AM

>
The helper methods do database querries etc and return results that the EJB sends onwards to clients. If these methods
are NOT synchronized (and the ejbs share the static class) won't it cause concurrency errors? I think most of our methods are not
synchronized (and it doesn't seem to cause any concurrency errors so far... though the system have not beeen stressed test that much,
and concurrency bugs tends to pop up later and randomly :P).
>
No, if you dont have any static data variables in the Java classes, static method as such will not cause concurrency errors, and the methods should not be synchronized.
If you have any synchronized methods and they take a while to execute, that could become a bottleneck in itself, because different threads waiting for each other,
so make sure you dont have any synchronized methods where it is not explicitly needed.
Think of a static method (without static data in the class being manipulated) as a plain function in another programming-language.
>
We have some scaleability problems with the EJBs... It seems as if they do not run concurrently. If we do a stress test with several threads calling the EJBs their response time increases by a too large factor to feel comfortable...
>
Apparently, you do have a some scaling/concurrency problem, which could have many causes -- transaction locking and clashes in the database, poorly configured database, network congestion, problems in the EJB architecture, etc -- can be many reasons...
The general idea to debug, is first to find out exactly what calls in your code that take longest time to execute (profiling, logging, System.out.println's are useful) when you put parallel load on your system -- rather than just seeing "the whole application seems slow" -- from there you can move on, "divide&conquer" the problem, etc...

Is there any practical reason to use DB helper class?

Is there any practical reason to use database helper class ( e.g. database.bookDB in Duke's bookstore)in servlet design? What if I setup a DB connection for every servlet?

to ken_robinson
I am currently setup DataSurece in servlet init().Usually (I know WebLogic is this way), if you configure the DataSource through the app server's configuration app, it is available to all applications.
The most efficient way to look up the DataSource in a particular app is have a ServletContextListener lookup the DataSource from JNDI and set it in the Context as an Attribute. Each servlet would then, in it's init() method, get the DataSource from the ServletContext (faster than using JNDI for each Servlet. The ServletContextListener requires the container you are running in support the 2.3 spec. If it does not, simply use a startup servlet (servlet that is loaded when the app is loaded) and do the same thing.

Class/member variables usage in servlets and/or helper classes

I just started on a new dev team and I saw in some of their code where the HttpSession is stored as a class/member variable of a servlet helper class, and I was not sure if this was ok to do or not? Will there be problems when multiple users are accessing the same code?
To give some more detail, we are using WebLogic and using their Controller (.jpf) files as our servlet/action. Several helper files were created for the Controller file. In the Controller, the helper file (MyHelper.java) is instantiated, and then has a method invoked on it. One of the parameters to the method of the helper class is the HttpServletRequest object. In the method of the helper file, the very first line gets the session from the request object and assigns it to a class variable. Is this ok? If so, would it be better to pass in the instance of the HttpServletRequest object as a parameter to the constructor, which would set the class variable, or does it even matter? The class variable holding the session is used in several other methods, which are all invoked from the method that was invoked from the Controller.
In the Controller file:
MyHelper help = new MyHelper();
help.doIt(request);MyHelper.java
public class MyHelper {
    private HttpSession session;
    public void doIt(HttpServletRequest request) {
        session = request.getSession();
        String temp = test();
    private String test() {
        String s = session.getAttribute("test");
        return s;
}In the past when I have coded servlets, I just passed the request and/or session around to the other methods or classes that may have needed it. However, maybe I did not need to do that. I want to know if what is being done above will have any issues with the data getting "crossed" between users or anything of that sort.
If anyone has any thoughts/comments/ideas about this I would greatly appreciate it.

No thoughts from anyone?

Servlet cannot find helper class

Hello
Under WEB-INF/classes I put ServletExample and SingletonExample. Compiling ServletExample, that makes use of SingletonExample, works.
In the directory WEB-INF/classes I also have another direcotry, test. And in WEB-INF/classes/test I put again ServletExample and SingletonExample.
Here I have tried in several ways to compile the servlet, but I always get an:
Cannot find symbol class SingletonExample.
I tried writing package test at the top of both files, and even at the top of only one of these two.
I even tried to make WEB-INF/classes/test/ServletExample make use of SingletonExample residing in WEB-INF/classes, but I didnt succeded.
What happens when you have subdirectory in WEB-INF/classes/? I think this is a MUST, to have subdirectory in large webapplication, so I really dont want to put everything in the classes directory.
Do you how to resolve this prolem? And: if Im in WEB-INF/classes/test and want to referr from a servlet residing in this direcory to a Singleton/helper class residing in WEB-INF/classes/, which approach do I have to use?
Thanks
Paolo

Jeez, you aren't gonna get very far in Java like this.
CLASSPATH is wrong - again. You're supposed to give JARs and paths where the class loader is supposed to look, not the actual .class file.
Also, you're not telling the compiler to put the .class file in the package directory structure.
Your example is pretty awful. Try this:
Put this code into c:\common
package common;
import common.test.TestDown; // What the hell is this? There is no package test, but there is a package named common.test
public class TestUp
   public void sayHello()
      System.out.println("Hello.....");
}Put this code into c:\common\test
package common.test;
import common.TestUp;
public class TestDown
   public TestDown()
        TestUp testUp = new TestUp();
        testUp.sayHello();
   public static void main(String[] args)
        new TestDown();
}Open a command shell and navigate to c:\, then do the following:
Directory of c:
07/01/2005 03:43 PM    <DIR>          .
07/01/2005 03:43 PM    <DIR>          ..
07/01/2005 03:45 PM    <DIR>          common
               0 File(s)              0 bytes
               3 Dir(s) 74,909,675,520 bytes free
C:\>javac -d . common\*.java
C:\>javac -d . common\test\*.java
C:\>java -classpath . common.test.TestDown
Hello.....Once you've got your head around this, go learn Ant and have it compile your projects properly.
%

Problem in generating Helper class

Hi All,
I have generated Helper classes using rmic -iiop tool of JDK 1.4. But the Helper class which is generating doesnot contain any bind method. So in my application, when i am trying to bind CORBA ORB with this helper class bind method, it is giving compilation error.
When i was using Borland Server i was able to generate Helper class with bind method also using java2iiop and now i am not using Borland as we are migrating to JBoss. So i am using rmic -iiop tool.
Can anybody suggest me what should i do for this.

I don't think many of us could help you with such a limited description. Try to be more descriptive, and please include relevant source code if possible.

What is the standard class used to create SALES ORDER in SAP CRM?

Hello Experts,
Can anyone suggest me what is the standard class used for creating sales order.
I have created sales order using the BAPI 'BAPI_SLSTRANSACT_CREATEMULTI' in my report program.
Now, I have to create sales order using standard classes and methods(my assignment).
Please suggest the suitable class.
Regards
DNR Varma

Hi Varma,
You can create crm documents like sales order using BOL interfaces.
You can check one example at the following thread:
Create OrderThro BOL
Check if it helps you a little more.
Kind regards,
Garcia

What file types get classed as 'Movies' in Macbook Pro?

I'm creating space on my Macbook hard drive by moving movies onto a hard drive. I've moved virtually all of them over, and emptied the trash can. However a system storage report is still showing 59GB of movies. What else does macbook class as movies? Could it class podcasts .mp3 as Movies and count them towards the 59 GB?

This web site may be a good place to start:
http://www.fileinfo.com/filetypes/common
There are other places that you may search on the Internet that may help close the gap.
Ciao.

What's this Help

I am switching my appl in VC++ 2005 from winhelp to chm.
winhelp works fine with .hlp file. Now, with html, context
sensitive (F1) works fine, but What's this help doesn't work. In my
CMainFrame class, he is my code tha takes care of that.
void CMainFrame::WinHelp(DWORD dwData, UINT nCmd)
DWORD myarray[]={
ID1, IDH_1, ...and so on};
if(!m_InContextHelpMode){
::HtmlHelp(m_hWnd,AfxGetApp()->m_pszHelpFilePath,
HH_HELP_CONTEXT,dwData); // this works fine
else{
CPoint CurPos;
GetCursorPos(&CurPos);
CWnd *pWnd=WindowFromPoint(CurPos);
//Find the window under cursor
if(pWnd !=NULL){
CSHContextHelp(pWnd->GetParent()->m_hWnd,pWnd->m_hWnd,0);
// works fine for win help, Don't for Html
//::HtmlHelp(pWnd->m_hWnd,".chm::/.TXT",HH_TP_HELP_WM_HELP,(DWORD)
(LPVOID) array);
Q1) for the Ids I use in the array, they work fine, but how
can I use the Html call without calling the array, as I thought
Robo help does the mapping and spits out chm file which is the only
thing I need I think. Besides, I can't map 4000 Ids in my
application, how do I get to make the what's this help Ids to work
without any manual mapping? What do I pass for that call, or what
do I pass instead of the array ?
Q2) When I click on ? in dialogs, nothing happens, if I
switch back to winhelp, it works fine using CSHContextHelp call
above, I am hoping this comes alive if I get any of this to work.
For the ? handling, I don't do any, I just return TRUE for BOOL
ONHELPINFO function in the dialogs, and it works fine for winhelp
but not for html..........
I appreciate your feedback and comments.
Thanks

No problem. We all live and learn. I've added a link between
the posts so you don't have to delete it. Try posting your query
here.
This is not a pure RoboHelp forum so you'll have to give a bit more
detail but at least it is frequented by likeminded people. Best of
luck.

What is a "Helper" class?

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