Dependancy of Appliacation Performance on Package Design Patterns ??

Hi
Recently one of my collegue have suggested us to change the data base package design pattern ., i.e to design the package as per the database functionality but not as per the application functionality.
Example to say ., to integrate all the Data retrivel Sp's into a single Package , All the Update functionality into another package so on... i was totally refused to do so as i never find as such practice in my career.,
We design the packages as per the Application functionality i.e for each module we design one or more packages so that the developer working on that particulor module can access the Packaged objects very easily and also this will improve the Application modularity & effeciancy.
Can any one say, what will be impacts on the Appliacation Performance prospective if i design the package as per my collegue's suggestion., and which is best approch in the application development area.
We are working on Oracle 10gR1 and the front end is .Net .,
Regards
Sekhar

I don't think the performance are the biggest problem here. I do think however the code maintenance could be a problem. Especially if your app is large, then somehow logically grouping procedures/functions with similar requirements in packages and having these groups as subsystems/modules in your application is more flexible because as your app grows, you can add another subsystem/module and another package. If you create some fixed number of packages e.g retrieval, update, insert, delete, then what you'll do for a large application? Create package Retrieval1, retrieval2 etc? Seems quite illogical.
So I doubt there are big gains/losses from pure perfomance point, but the biggest problem is maintainability of your code.
Gints Plivna
http://www.gplivna.eu

Similar Messages

J2EE design patterns vs SAP component model

Hello,
does anyone have documentation or articles which makes a link between the J2EE design patterns and the SAP component model ?
Thanks

Hi Thierry,
> What do you mean by assembling DC's into another DC ? Do you mean by using child DC's? Also , the J2EE server DC will have to be in a SC.
If you create "Java" DC that DC will not have a deployable result on its own. Typically you create a public part with purpose "compilation" (API) and a public part with purpose "assembly". If you define a dependency from an EAR DC or a J2EE Library DC to that assembly public part then the Jar file contained in that public part will be assembled into your (deployable) .ear file or the J2EE library.
Child DCs are just a means of limiting visibility/scope, similar to ACLs.
As long as you are working with a "track" each and every DC will be part of an SC. You define a track, you add "developed" SCs, you get a "compartment" where you can create DCs. So each DC automatically belongs to an SC. (But not all DC types produce deployable results, EJB Module/Web Module also need to be assembled into an EAR).
> is it typical to have an SC dedicated to utility classes?
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SERVICE LOCATOR ?? Is it really an interesting Design pattern??

Hi everybody,
i've a problem with the J2EE Design Pattern "Services locator" (it's a singleton).
It is said that by making use of a Service Locator we can :
- hide to the client the complexities of initial context creation, EJB home object lookup,and EJB objectre-creation.
- multiple clients can reuse the Service Locator object to reduce code complexity, provide a single point of control, and improve performance by providing a caching facility.
But i would like to understand at which side should that service locator object reside??!!??
If it is at server side then the clients need well an initial context in order to make a lookup on that object.
Conclusion :
the service locator doesn't hide the complexities of initial context!!
Furthermore the client has to perform a look-up on that service locator object!! The only advantage left is caching facility.
If it is at client side, each client needs his own services locator object
Conclusion :
multiple client don't reuse the same service locator. What's the advantage to be a singleton ???
There is certainly something that i don't understand so help me please!! Thanks.

Hi Yves,
But i would like to understand at which side should
that service locator object reside??!!??
If it is at client side, each client needs his own
services locator object
Conclusion :
multiple client don't reuse the same service locator.
What's the advantage to be a singleton ???The service locator resides on the client side and is implemented as
a singleton. Since it is possible that there could be multiple
class loaders/JVMs on the client side, and therefore, multiple
instances of the "singleton" service locator. This is typical
in a distributed environment (e.g. servlets/JSPs in a web-tier
cluster using service locator). Thus service locator is not
a truly "distributed singleton" object. But, the empahsis
is to design the service locator such that it does not hold
any state that needs to be replicated across multiple
instances across different JVMs as mentioned. Thus, there
is no need for multiple clients to use the "same" service locator,
but still the benefits of implementing this pattern is realized.
By making it a singleton, and keeping it from holding state
that needs to be replicated, we realize the benefits of this pattern.
You may also want to visit the J2EE Pattern interest list
and see these relevant discussions :
Topic: Service Locator and passivation
http://archives.java.sun.com/cgi-bin/wa?A2=ind0106&L=j2eepatterns-interest&F=&S=&P=1026
Topic: Caching EJBHome interfaces
http://archives.java.sun.com/cgi-bin/wa?A2=ind0106&L=j2eepatterns-interest&F=&S=&P=9226
Topic: Using Service Locator for Data Source caching
http://archives.java.sun.com/cgi-bin/wa?A1=ind0106&L=j2eepatterns-interest#31
hope this helps,
thanks,
-deepak

Does any body have any design patterns of JSF Web Application Developping?

Can any one answer me some questions?
#1.I am an amatuar of people who develop Web Application.For some reason,We choose the JSF to develop our item.through some introduction,I know the UI component of JSF is resided in Server side,is it right?but I am a little confused that:if there are many users who are exploring our jsf website.(to simplify my question,image I had just one web page and just one button)How many UI components(buttons) will be there?How it(they?) works?
#2.Does any body have the success experience (for example design pattern)to develop web applications?if We just concern about the Add,Delete,Modify,Query operations of some data.
I just do my job according to my feeling.
I will give every page a pagebean(backing bean),and I am not sure how to combine the business data with the pagebean.some one suggested that I should use delegate pattern to separate my business log and page logic.But I am still confused by following things:
#2.1 does JSF have the same ability to help us construct the model dialog just like swing to
help us control the operation flow?
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#2.2.1 if JSF has the components according to the web users' number,how can My Listener tell which component should be update?Should I maintain the map?
#2.2.2 If the problem I imaged above is false,Does any body can tell me how to custom the ListDataModel,so I can use it like Swing?because now I can just use some view data to insert into ListDataModel,but after some selection operation,my business object must be find according to the selected data,it is not an interesting job!
I am waiting for your advice!

Ok I'll try to explain Step by step please correct me if I make any mistake because I have not played much with shared variables.
To create a shared variable to an RT target go to the target if tou have already otherwise add an RT target by right clicking the Project>>Add targets and Devices
Then in the target Right clikc and select the variable as shown below.
Then once the Shared variable settings window opens Enter a variable name and then Select the type "Network Published"
In the right side you can select the data type for the shared variable and even you can choose your custome controls.
After selecting the data type go for the Network and select buffering if required else leave it if you are planning to use the variable just for display purpose.
Then you can enable the RT FIFO if required (Not able to explain how it works and why it is used).
Then after completing the Shared variable setup you can access the variable in the VI in both the Host and the RT.
You can bind the variable to a control so that if any data from the RT is coming you can read the data from that control.
Once you have placed your shared variable in the BD you can change the access typr to read or write depending on your need.
This might not explain the complete shared variable concept but I believe that this would defenelty give you a kick off to start using the shared variable. Please correct or add more comments if anybody know better.
Good luck.
The best solution is the one you find it by yourself

Design Patterns/Best Practices etc...

fellow WLI gurus,
I am looking for design patterns/best practices especially in EAI / WLI.
Books ? Links ?
With patterns/best practices I mean f.i.
* When to use asynchronous/synchronous application view calls
* where to do validation (if your connecting 2 EIS, both EIS, only in WLI,
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* performance issues
Anyone want to share his/her thoughts on this ?
Kris

          Hi.
          I recently bought WROX Press book Professional J2EE EAI, which discusses Enterprise
          Integration. Maybe not on a Design Pattern-level (if there is one), but it gave
          me a good overview and helped me make some desig decisions. I´m not sure if its
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          Oskar

Producer/Consumer Design Pattern + DAQmx + Event Structure

Dear community users,
at the moment I try to implement the Producer/Consumer Design Pattern into my current project. For this purpose I am trying to make a "minimal-example" in which I use the Producer/Consumer Design Pattern for the data acquisition and analysis (display in GraphXY, calculation etc..) process. In the Producer Loop I perform the data readings via DAQmxRead.VI and in the Consumer Loop, in this example only, I display the data in a GraphXY. At the same time I want to control the data acquisition via an Event Structure, for example Start Measurement/Stop Measurement Buttons. To configure the measurement time, for example if the user only wants to measure 150 sec, I use the Time Out Event of the Event Structure. This is a technique which is often used, when data acquisition and Event Structures are used at the same time (Excuse me if this is wrong!). Due to understand the Producer/Consumer Design Pattern I looked up in the Template\Framework of LabVIEW.
In the attachment you will find my "minimal-example", which -sadly-, not working. What should I do ?
Thank you.
Best regards,
tugrul öztürk
Attachments:
daqEngine_PCP.vi ‏35 KB

Your VI will never stop due to the Ok Button that stops the producer loop is read OUTSIDE of the loop. Add an event case for it.
Move the Start and the Ok Button inside of their respective event cases. This will allow the latch to reset when they are read.
Change the Ok Button to a stop button.
Use a Greater Or Equal instead of Equal for the measurement time comparison. What if somebody randomly changes it to 0 on you? Again, you will never stop.
Is the DAQ only supposed to read for "Measurement Time". Right now, it constantly reads. So if you don't use the DAQmx Read, you will get a buffer overflow error. You need to put the DAQmx Start Task inside of the Start event case and then the Stop DAQmx Task inside of the Timeout event case when the measurement time is exceeded. You should also perform the read regardless inside of the Timeout event case.
I HATE telling the consumer loop to stop by destroying the queue. You can look data that way. Instead, send something an empty array. In the consumer, check for an empty array. If it is empty, stop. Destroy the queue only AFTER BOTH LOOPS HAVE COMPLETED.
You should also report your errors in some way. Simple Error Handler at the minimum.
Since you are using Continous Samples, don't limit the buffer. Leave the Samples per Channel unwired on the DAQmx Timing VI.
There are only two ways to tell somebody thanks: Kudos and Marked Solutions
Unofficial Forum Rules and Guidelines

The search for a perfect design pattern

The search for a perfect design pattern
I am searching tip to upgrade a labview program used. I am looking for the best approach to make
my program more robust and scalable.Software and hardware.
Today the system consists of :
GPS, weather station, ultrasound wind sensor, echosounder and a webcamera, all connected to a computer.
The computer OS is XP pro with Labview version 2009 installed. Except for the webcamera all peripherals have serial communication interface.
The webcamera interface is ethernet.
Device                           Data type                 Interval                    Interface
GPS                                NMEA string                1 second                   Serial rs232
Ultrasound wind sensor   NMEA string                1 second                   Serial rs232
Weather, temp,humid     NMEA string               35 seconds                 Serial rs232
Echosounder                  NMEA string               500ms-5 seconds       Serial rs232
                                                                      (depending of depth)
Webcamera                    Jpg                           Snapshot on demand Ethernet
The tasks to be solved
All the data have to be stored.
All the data have to be displayed in real time.
Weather history data must be buffered to be plotted in a graph (pop-up windows).
Absolute wind speed and direction have to be calculated.
Option to send navigation data attached to email at desired time intervals.
Image snapshot at desired time intervals.
The data wich streams into the serial ports are not synchronized and vary in intervals . Would it be a good idea to put all the serial peripherals into a serial device server. Is it possible to let the server place a event in my software, to trigger reading of the data, from the the server. Or how could that be done in other ways?
The perfect design pattern
In version one of the software I use 4 parallel loops to read data at the serial ports, inside these loops the data was separated and outputted to a datasocket server. I used datasocked read in other loops to present and store data. But it did not look good, and yes it was a mess, a really rat nest. I am looking for a better design pattern.
Could some kind of producer/ consumer pattern be the way to go?
Comments and tips are wanted.
TIK

Nice Project! Congratulations ;-)
I am not an expert for large applications. But your project looks nice and manageable. Here my straightforward ideas:
I would build a GUI, with menu bar, pop-up graph display thing.
THen low level tasks with each one handling a RS232 device and feeding queues or fireing notifications.
Maybe handle the snapshots in an event structure on the GUI blockdiagramm.
When GUI and producer tasks are running, close the gap with a middle layer which captures the data and actualizes GUI by reference. For instance the graph-thing-dialogue triggers a "flush queue" and displays the last 200 entries of the array of data.
I often run into issues when having defined too many userevent structures. I guess i am too stupid for that. Thats why i rather use queues (when i dont want to loose data) or notifiers (data is up-to-date). Nevertheless I like a "stop-all-tasks" user event...traditionally.
My team is actually developing a large application. We are using LabVIEW classes and objects.
So have fun!
Yours
RZM

Choice of design pattern for data acquisition system

Hello all
I have a trouble about selecting the suitable design pattern / architecture for a data acquisition system.
Here is the details of the desired system:
There is data acquisition hardware and I need to use it by observing parameters on User interface.
the data acquisiton period, channel list to scan should be chosen on User interface. Besides, there are many user interface interactions. e.g. if user selects a channel to add scanlist, then I need to enable and make visible some other parts on user interface.
When user completes the channel selection, then he will press the button to start data acquisition. Then I also need to show the scanned values on a graph in real time and log them in txt file.
I know that I cannot use producer consumer pattern here. because the data acquisition loop should wait for parameters to scan channels. and it works in a given period by user. so the user interface loop performs higher rate then consumer loop (data acquisition loop). it means queue will be bigger bigger. if I use notifier it will loss some data come from user interface.
is there any idea about that ? is there any suitable design pattern for this case ?
Thanks in advance
best regards
Veli BAYAR
Embedded Systems Software and Hardware Engineer
"You live in a graphical world. Why not program in one?"
Solved!
Go to Solution.

johnsold wrote:
Veli,
I recommend the Producer/Consumer model with some modifications.
You might need three loops. I cannot tell for sure from your brief description.
The User Interface loop responds to the user inputs for configuration and start/stop of acquisition. The parameters and commands are passed to the Data Acquisition loop via a queue. In this loop is a state machine which has Idle, Configuration, Acquisition, and Shutdown states (and perhaps others). The data is sent to the Processing loop via a different queue. The Processing loop performs any data processing, displays the data to the user, and saves it to file. A notifier can be used to send the Stop or shutdown command from the User Interface loop to the other loops. If the amount of processing is minimal and the file write times are not too long, the Processing loop functions might be able to occur in the Timeout case of the UI loop Event structure. This simplifies things somewhat but is not as flexible when changes need to be made.
I am not sure that a Design Pattern for this exact setup exists but it is basically a combination of the Producer/Consumer (Events) and Producer/Consumer (Data) Design Patterns.
Lynn
Check out this thread: http://forums.ni.com/t5/LabVIEW/Multiple-poll-case-structures-to-event-help/td-p/2551309
There are discussions there about a 3-loop architecture that may help you.
Jeff
Jeffrey Zola

SAP Fiori - Layout Design patterns

Dear All Gurus,
This may be a layman question but expecting your expert advice and perspective on this.
I am creting a fully customized fiori application -" Purchase Order Creation " and User wants to have the UI design very simillar to SAP screens(ME21n) adding only required fields into that.
I know that fiori has a design pattern(Ex : Main items in left and details in right side , 'back' button etc..) which gives me a good impression. But if I go ahead with user's requirement will there be an impact ? Ex : performance / run on mobile.
Thanking you all in advance..
Tags edited by: Michael Appleby

Hi Masayuki,
Thank you for the reply..
+Target device: windows desktop(mainly) and mobile
+Who will use: Employees (mainly)/MRP specialist
+Number of users: 500
+Is there Purchase Requisition process before Purchase Order : NO . Direct PO creation. But PO Approval is there using srtandard Fiori App.
+PO will be created entering everything manually
+Where is the data source for creating PO? : Original data is on paper

Design pattern / data loading solution

Hello all!
I have been working on a few projects which involve loading data, sometimes remotely, sometimes local, sometimes JSON, sometimes XML. The problem I am having is that due to the speed of development and the changing minds of various clients I am finding my designs are too rigid and I would like them to be more flexable. I have been trying to think of a reusable solution to data loading, and would like some advice as I imagine many of you out there have had the same problem.
What I would like to do is to create a generic LoadingOperation abstract class, which has member variables of type Parser and Loader, which have parse() and loadData() methods respectivly. The Parser and Loader classed are interfaces and classes that implement these could be XMLParser and JSONParser, LocalLoader and RemoteLoader etc. With something like this i would like to have a new class which extends LoadingOperation for each thing to be loaded, weather thats a local XML file, or remote JSON, or whatever.
The problem is is that specific Parser implementation cannot return custom data types without breaking the polymorphic behavior of the LoadingOperation class. I have been messing around with generics and declaring subclasses of LoadingOperation like
class SpecificLoader extends LoadingOperation<CustomDataType>
and doing similar things with Parser classes, but this seems a bit weird.
Does anyone have any suggestions on what im doing wrong / could be doing better. I want to be able to react quickly to changing specifications (ignoring the fact that they shouldnt be changing that much!) and have a logical seperation of code etc...
thanks for any help!
psi have also asked this question here [http://stackoverflow.com/questions/4329087/design-pattern-data-loading-solution]

rackham wrote:
Hello all!
I have been working on a few projects which involve loading data, sometimes remotely, sometimes local, sometimes JSON, sometimes XML. The problem I am having is that due to the speed of development and the changing minds of various clients I am finding my designs are too rigid and I would like them to be more flexable. I have been trying to think of a reusable solution to data loading, and would like some advice as I imagine many of you out there have had the same problem.
What I would like to do is to create a generic LoadingOperation abstract class, which has member variables of type Parser and Loader, which have parse() and loadData() methods respectivly. The Parser and Loader classed are interfaces and classes that implement these could be XMLParser and JSONParser, LocalLoader and RemoteLoader etc. With something like this i would like to have a new class which extends LoadingOperation for each thing to be loaded, weather thats a local XML file, or remote JSON, or whatever.
The problem is is that specific Parser implementation cannot return custom data types without breaking the polymorphic behavior of the LoadingOperation class. I have been messing around with generics and declaring subclasses of LoadingOperation like
class SpecificLoader extends LoadingOperation<CustomDataType>
and doing similar things with Parser classes, but this seems a bit weird.
Does anyone have any suggestions on what im doing wrong / could be doing better. I want to be able to react quickly to changing specifications (ignoring the fact that they shouldnt be changing that much!) and have a logical seperation of code etc...That depends on the specifics.
The fact that it seems like processes are similar doesn't mean that they are in fact the same. My code editor and Word both seem to be basically the same but I am rather sure that generalizing between the two would be a big mistake.
And I speak from experience (parsing customer data and attempting to generalize the process.)
The problem with attempting to generalize is if you generalize functionality that is not in fact the same. And then you end up with conditional logic all over the place to deal with differences dependent on the users. Rather than saving time that actually costs time because the code becomes more fragile.
Doesn't mean it isn't possible but just rather that you should insure that it is in fact common behavior before implementing anything.

Design Pattern / Best Practice Question

Hi,
I have been using Flex for a while now, but there is a
scenario which I still have not found a solution I'm entirely happy
with. I'm wondering if anyone else out there might have suggestions
on a design pattern or best practice.
Suppose I have a view which depends on model data which
resides in some back end systems. That model data may or may not
have been loaded (e.g. via a web service or remote object call) at
the time the view is displayed.
I don't know if the user will ever visit this part of the
application so I would prefer to defer retrieval of the data until
the user actually navigates to this view. Or I want to retrieve the
data each time the view is displayed because the data is dynamic
and could change between one presentation of the view and the next.
Because the data comes from several systems, I cannot simply
make one service call and display the view when it completes and
all the data is available. I need to call several services which
could complete in any order but I only want to display my view
after I know all of them have completed and all of the model data
is available. Otherwise, I can present the user an incomplete view
(e.g. some combo boxes are empty until the corresponding service
call to get the data completes).
The solution I like best so far is to dispatch a single event
(I am using Cairngorm) handled by a single command which acts as
the caller and responder for all of the services. This command then
remembers which responses it has received and dispatches another
event to navigate to the view once all the results have returned.
If the services being called are used in different
combinations on different screens, this results in proliferation of
events and commands. An event and command for each service and
additional events and commands to bundle the services and the
handling of their responses in the right combinations for each of
the views.
Another approach is to have some helper class listen for all
of the model changes and only display the view when the model
enters some state that is acceptable. It is sometimes difficult to
determine just by looking at the model whether it is in the right
state (e.g. how can I tell that a collection is the new collection
that should just have been requested versus an old one lingering
from a previous call). The logic required can get kind of
convoluted and brittle.
Basically, all of the solutions I've come up with so far seem
less than ideal and a little hackish. I keep thinking there is some
elegant solution out there that I am just missing ... but so far,
no luck finding it. Thoughts?
Thanks.
Bill

i think a service class is right - to coordinate your calls.
i would have 1 event per call (so you could listen to individual
responses if you wanted to).
then i would use a flag. if you want to check for staleness,
you would probably want two objects to map your service flag to
lastRequested and lastCompleted. when you check, check if it's
completed, and if it's not stale and that your lastRequested is
less than lastCompleted (meaning that you're not currently waiting,
i.e. you've returned since making a request). then make the request
and update your lastRequested.
here's a snippet of what i mean.
./paul
public static const SVC1_LOADED:int = 1;
public static const SVC2_LOADED:int = 2;
public static const SVC3_LOADED:int = 4;
public static const SVCALL_LOADED:int = 7;
private var completedFlag:int = 0;
then each call would have it's own callback.
private function onSvc1Complete( evt:Event):void {
completedFlag |= SVC1_LOADED;
lastCompleted[ SVC1_LOADED ] = getTimer();
dispatchEvent( new Event("svc1complete") );
checkDone();
private function checkDone():void{
if( completedFlag == SVCALL_LOADED )
dispatchEvent(new Event( "allLoaded" ));

Best architecture and design pattern to use

I am currently designing a moderately sized LabView application and cannot decide on the best architecture/design pattern or combinations thereof to implement.
The program basically polls an instrument connected to a serial port continuously at a 2-10Hz rate. When operator clicks a button to start a run, the polled data is then filtered, has math functions performed on the data, writes collected data to files, and produces reltime graphs and calculates point-by-point statistics. At the completion of a run, some additional data files are written. I pretty much know how to accomplish all these tasks.
What is also required is main-vi front panel interaction by the operator to access a database (via a C# dll with .Net) to query for specifications to apply in order to determine pass/fail status. Setup conditions also need to be changed from time to time by the operator and applied to the data in real time (ie- a measurement offset). I have prototyped the database portion successfully thus far.
For the main vi, I started off using the Top Level Application Using Events design pattern (Event structure within a while loop). Copious use of bundled clusters and shift registers keep the database data updated. I cannot figure out how to have the top level vi concurrently poll the serial device as outlined above. The Event structure is only active when defined control values change, and use of a timeout is no help since it prevent data from being collected while the user is accessing the database. All database and setup parameters must be applied to the data as it comes in from the serial port. Error trapping/recovery is a must.
I believe what I need is two parallel processes running under my main vi (one for database and setup, the other for polling and data processing/display, but what would be the preferred choice here?
Revert back to a polled loop in lieu of Events, use notifiers, occurrences, user-defined events, Producer-consumer loops?
It�s been about 3 years since I have had an application on this level (which used a state machine architecture), and a lot has changed in LabView (using 7.1 Prof Devel). I am currently having a mental block while trying to digest a lot of features I have never used before.
Suggestions Welcome!
Thanks.
~~~~~~~~~~~~~~~~~~~~~~~~~~
"It’s the questions that drive us.”
~~~~~~~~~~~~~~~~~~~~~~~~~~

I suggest a (3) state machine(s) architecture. The first is the user interface. Your main VI is a good start. Another state machine handles the instrument I/O (your serial polling). The third handles all data processing. The three loops run independently. Each has a wait to allow LV's scheduler to share CPU time among the loops. I like queues or functional globals for inter-loop communications.
This allows a lot of flexibility. Each portion can be tested alone. Each can have different timing and priority.
Spend some time thinking about what needs to be done and plan the structure carefully before you do any coding (except for little test programs to try new ideas).
I also like Conway and Watts "A Software Engineering Approach to LabVIEW", published
by Prentice Hall.
Lynn

What is command design pattern? what is the problem that it solves?

Hi i have been reading few articles on command design pattern but was unable to understand what it is and what problem does it solve. As far as my understanding goes if there is a pre specified method in an object that could execute and perform the necessary activities then it is called as command design pattern. Why is it named as command design pattern, it is because in a shell we use commands to retrieve output. For example when we type "dir" in dos command prompt it returns the list of files. so here we have to remember a preexisting exe file named "dir" which does something when used. So here like we call it command because when "dir" is passed to the computers it returns something that is expected. may be the computer obeys the command issued and return something back. So like wise if there is a method that is defined as as the command, for example in struts framework the action class must have a method "execute()" which is called by the framework to execute the necessary action mapped to it. So if there is a predefined method like "execute" in struts then the object is said to be followed command design pattern. So what actually does it solve?
What ever i have written is my understanding from the articles i have read about the design pattern. So kindly correct me if i am wrong. Help me understanding what actual problem does this pattern solves. Thanking you in advance.

This is really off-topic for these forums. You might do better on StackOverflow.com. I'll just say that although the first Design Patterns book came as a revelation to me, it was more for (a) the nomenclature (decorator, factory, facade, etc) which is still with us and (b) about five of the original patterns, which told me things I didn't already know. I've never used any of the others, including Command, and the whole design patterns thing quickly degenerated into farce with what seemed like a sustained attempt to reduce the whole of computer science to design patterns, which really isn't the point. As an example, there is one in another book called Type Object, which is nothing but 3rd normal form, which can be defined roughly in a couple of sentences. This pattern went on for dozens of pages with a very artificial example. I wrote to the mailing list about it: 'Type Object considered hilarious'. I got a rude reply from the original author, which I guess I expected, but also an incredible response from the list owner, saying I should recast my objections in the form of a design pattern. That lost it for me. True story. Moral: don't take this religion, or any IT religion, too seriously. They come around every 18 months or so with the regularity of the next bit of Moore's Law. I've seen dozens of them come and go since 1971, all with something to say, all 90% nonsense.
See here for a longer version of this incident.

EJB and Design Patterns

Hi all,
Which design patterns could be applied in coding EJB? I don't know if my question is clear enough, but what I really want to know is which design patterns I could use with EJB and how could I use them this way? (Some example situation)
Regards,
Filipe Fedalto

i think it depends of what u intend to do..
e.g. i think (maybe i'm wrong, any relevant replies are welcome!) that u could use a stateless session bean to implement some facade, delegating entities creation to some non-bean classes? or why not a stateful session bean to implement a factory (when entities creation depend on client preferences)?

Which Design Pattern and how to design using OOP this scenario

I am having trouble designing a module, can anybody help me?
Because it will be hard to maintain this kind of module, I also think that this can test my skill of design pattern usage.
Requirement
This is basically an agricultural project (web application). I need to design a module where some calculation takes place.
There are different crops involved like maize, tomato, okra etc. Each of these crops has different traits.
Each trait has a measurement scale which lies in integer like 200-1000. Now let's say I have planted the crop and done measurement noted down the traits. Now I want to do some sort of measurement. Some measurements are simple and some are complex.
Example
Lets take an example of crop maize. I have recorded observations for 15 traits. (We'll use trait1-trait15 as examples, the actual name can be like plt_ht, yld, etc.)
I recorded 5 observations for each trait:
trait1 trait2 trait3 trait5 trait6..... trait15
01,02,03,04 01,02,03,04 01,02,03,04
User logs into system and selects his crops and enters data for these observations. I have to calculate either average or sum of the data entered for each trait.
Complexity / centre of the problem
So far it's simple but complexity comes when I have some different formulas for some of the traits.
Example: trait YLD has a formula based on which I have to calculate its value, which may also depend on some other traits. Each different crop can have different traits.
All this I am able to do - whenever user selects crop I will check for those specific traits and do calculations (if it's not a special trait then I either average or sum it, based on db entry), but there is a lot of hard coding.
I would like to have suggestions on a better way of handling this.
My code needs to handle both simple and complex calculations.
Simple calculations are easy, I have take average of value entered for trait.
The problem comes when I have to do complex calculations, since each crop have different traits with their own formulas, so to calculate I have to check for crop and then for complex trait. So I have to hardcode the trait name of complex traits.
Can any tell me how I can design this using Java oops [?!?] so that I can make it generic?
I have about 10 different crops. Some calculations are specific to crops, so there will be lot of code like the if below:
hasZeroValue = (HashMap<String, ArrayList<String>>) dataValues[1];
} else if(cropId.equalsIgnoreCase("MZ") && traitName.equalsIgnoreCase("Shelling")) {
    avg=HybridTestDataUtility.calculateAvg(traitName, dataPoint, dataTraits, traitValues,dataPvalues, dataPoint, type);
    avg=avg*dataPoint;
    traitAvg=getMaizeYeild(traitName, traitAvg, population, avg, hybrid, area);
} else if(cropId.equalsIgnoreCase("OK") && traitName.equalsIgnoreCase("YLDGM")) {
    avg=HybridTestDataUtility.calculateAvg(traitName, dataPoint, dataTraits, traitValues,dataPvalues, dataPoint, type);
    //avg=avg*dataPoint;
    Object[] dataValues=getOKRAYield(traitName, traitAvg, population, avg, dividend,hasZeroValue,hybrid,repl);
    traitAvg = (HashMap<String, Float>) dataValues[0];
    hasZeroValue = (HashMap<String, ArrayList<String>>) dataValues[1];
} else if(cropId.equalsIgnoreCase("HP") && traitName.equalsIgnoreCase("w1-w10")) {
    avg=HybridTestDataUtility.calculateAvg(traitName, dataPts, dataTraits, traitValues,dataPvalues, dataPoint, type);
    avg=avg*dataPoint;
    Object[] dataValues=getHotPepperYield(traitName, traitAvg, population, avg,dividend,hasZeroValue,hybrid,repl);
    traitAvg = (HashMap<String, Float>) dataValues[0];
    hasZeroValue = (HashMap<String, ArrayList<String>>) dataValues[1];
} else if(cropId.equalsIgnoreCase("TO") && traitName.equalsIgnoreCase("TLSSG_70")) {
    traitAvg=calculateTLCV(traitName, traitAvg,dataPoint, dataTraits, hybrid, repl, traitValues, dataPvalues,50);
} else if(cropId.equalsIgnoreCase("TO") && traitName.equalsIgnoreCase("TLSSG_100")) {
    traitAvg=calculateTLCV(traitName, traitAvg,dataPoint, dataTraits, hybrid, repl, traitValues, dataPvalues,50);
} else if(cropId.equalsIgnoreCase("TO") && traitName.equalsIgnoreCase("YVMV_60")) {
    traitAvg=tomatoYVMVCalculation(traitName, traitAvg,dataPoint, dataTraits, hybrid, repl, traitValues, dataPvalues);
} else if(cropId.equalsIgnoreCase("TO") && traitName.equalsIgnoreCase("YVMV_90")) {
    traitAvg=tomatoYVMVCalculation(traitName, traitAvg,dataPoint, dataTraits, hybrid, repl, traitValues, dataPvalues);
} else if(cropId.equalsIgnoreCase("TO") && traitName.equalsIgnoreCase("YVMV_120")) {
    traitAvg=tomatoYVMVCalculation(traitName, traitAvg,dataPoint, dataTraits, hybrid, repl, traitValues, dataPvalues);
} else if(cropId.equalsIgnoreCase("TO") && traitName.equalsIgnoreCase("ELCV_60")) {
    traitAvg=tomatoYVMVCalculation(traitName, traitAvg,dataPoint, dataTraits, hybrid, repl, traitValues, dataPvalues);
} else if(cropId.equalsIgnoreCase("TO") && traitName.equalsIgnoreCase("ELCV_90")) {
    traitAvg=tomatoYVMVCalculation(traitName, traitAvg,dataPoint, dataTraits, hybrid, repl, traitValues, dataPvalues);
} else if(cropId.equalsIgnoreCase("TO") && traitName.equalsIgnoreCase("ELCV_120")) {
    traitAvg=tomatoYVMVCalculation(traitName, traitAvg,dataPoint, dataTraits, hybrid, repl, traitValues, dataPvalues);
} else if(cropId.equalsIgnoreCase("OK") && traitName.equalsIgnoreCase("YVMV_60")) {
    traitAvg=tomatoYVMVCalculation(traitName, traitAvg,dataPoint, dataTraits, hybrid, repl, traitValues, dataPvalues);
} else if(cropId.equalsIgnoreCase("OK") && traitName.equalsIgnoreCase("YVMV_90")) {
    traitAvg=tomatoYVMVCalculation(traitName, traitAvg,dataPoint, dataTraits, hybrid, repl, traitValues, dataPvalues);
} else if(cropId.equalsIgnoreCase("OK") && traitName.equalsIgnoreCase("YVMV_120")) {
    traitAvg=tomatoYVMVCalculation(traitName, traitAvg, dataPoint, dataTraits, hybrid, repl, traitValues, dataPvalues);
} else if(cropId.equalsIgnoreCase("OK") && traitName.equalsIgnoreCase("ELCV_60")) {Can anybody think of a way to make a generic approach to this?

There are crops and each crop have traits , traits are actually a mesuremet
scale to decide growth of a seed of a particular crop.
This module is to for planters to observe growth of seeds sowed of certain
crops and take down n no of observation for each trait and upload in csv format.Once they enter
data i have to either avg out the values or sum the values or sometimes
there are more complex function that i have to apply it may differe for each
trait .This is the whole module about.Just to give an idea about how they
will enter data
Hyubrid(seed) trait1 trait2 trait3 trait5 trait6..... trait15
Hybrid1 01 02 03 04 01
HYbrid2 04 06 08 04 01
HYbrid2 04 06 08 04 01
HYbrid2 04 06 08 04 01
HYbrid2 04 06 08 04 01
Once they enter data in this format i have to give result something like
this.
Here avg colum does not necessaryly mean avg it can be sum or any formula
based resutl.Hybrid is the seed for which they record the observation.
I have shown avg column only for two tratis it is actually for all the
traits.
Hyubrid(seed) trait1 Avg trait2 avg trait3 trait5 trait6..... trait15
Hybrid1 01 01 02 04 03 04 01
HYbrid2 04 04 06 10 08 04 01
HYbrid2 04 04 06 12 08 04 01
HYbrid2 04 04 06 14 08 04 01
HYbrid2 04 04 06 12 08 04 01
Hope this clarifies atleat a but
The data are not correctly indented but there is no way i can format it.

Dependancy of Appliacation Performance on Package Design Patterns ??

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