Decorator Design Pattern

Hi all,
Have anybody a example of how to utilize the Decorator Design Pattern?
Whats the functionallity of this pattern?
Thanks.

Check this url:
http://www.castle-cadenza.demon.co.uk/decorate.htm
It gives you a pretty good insight on the Decorator pattern.

Similar Messages

Resizing button Decorator design pattern

I am having the problem in doing the resizing of a button using the Decorator Design Pattern. Plz anyone who is having idea about this please send me the source code for me. I am having very less time to submit.plese replay me as early as possible

Ever heard of Google?

Design Patterns, The Decorator

When trying to implement the classic decorator design patterns your decorator executable might look like this: 
<pre>
METHOD validate.
 DATA: Validator TYPE REF TO validation_manager.
 CREATE OBJECT:
 Validator TYPE validation_manager.
 ,Validator TYPE validate_format EXPORTING x_validator = Validator
 ,Validator TYPE validate_values EXPORTING x_validator = Validator
 ,Validator TYPE validate_relation_input EXPORTING x_validator = Validator
 ,Validator TYPE validate_relation_database EXPORTING x_validator = Validator.
 me->lst_result = validator->validate( me->lst_data ).
 WRITE: / 'Processing Validate Activity'.
ENDMETHOD. "validate</pre> 
The validate method ends up in endless resurcion in the memory. The reason is that I'm using the same variable as the resulting instanse and as parameter. It seems like the constructor treats both the result and the parameter as the same field/instanse regardless import parameter such as VALUE/REFERENCE. If I change the method to use an extra field in the method validate like:
 <pre>
METHOD validate.
 DATA:
 validator TYPE REF TO validation_manager
 ,recursive TYPE REF TO validation_manager.
 CREATE OBJECT validator TYPE validation_manager.
 recursive ?= validator.
 CREATE OBJECT validator TYPE validate_format
 EXPORTING x_validator = recursive.
 recursive ?= validator.
 CREATE OBJECT validator TYPE validate_values
 EXPORTING x_validator = recursive.
 recursive ?= validator.
 CREATE OBJECT validator TYPE validate_relation_input
 EXPORTING x_validator = recursive.
 recursive ?= validator.
 CREATE OBJECT validator TYPE validate_relation_database
 EXPORTING x_validator = recursive .
 recursive ?= validator.
 me->lst_result = validator->validate( me->lst_data ).
 WRITE: / 'Processing Validate Activity'.
ENDMETHOD. "validate</pre> 
Now the decorator engine works, but why does the first implementation not work when the same one executes fine in php, c++, delphi, java and other languages. 
If you do not know what I'm trying to discuss, look up "Design Patterns - Simply", and jump to the chapter about the decorator design pattern. I'm trying to use this design pattern for a validation manager within my Business Process Engine, which needs to be able to configure what types of validation needed for on specific process (BPMN). 

Hi Matt, Thanks for the formatting..:) I will post the complete program as it's only a prototype program. Trying to get the format under control.
</body>
Report ZDP_DECORATOR_XMP01
REPORT zdp_decorator_xmp01.
parameters: bestimpl TYPE boolean_01 default 0.
TYPES:
BEGIN OF processdata
 ,name TYPE char30
 ,street TYPE char30
 ,zip TYPE char5
 ,city TYPE char30
 ,email TYPE char50
 ,phone TYPE char20
,END OF processdata
,BEGIN OF result
 ,msgid TYPE msgid
 ,msgtyp TYPE msgty
 ,msgno TYPE msgno
 ,status TYPE char1
,END OF result.
CONSTANTS:
true TYPE boolean_01 VALUE 1
,false TYPE boolean_01 VALUE 0.
CLASS validationmanager DEFINITION
CLASS validation_manager DEFINITION.
PUBLIC SECTION.
 METHODS:
 validate
 IMPORTING
 x_data TYPE processdata
 RETURNING
 value(y_result) TYPE result.
ENDCLASS.
CLASS validationmanager IMPLEMENTATION
CLASS validation_manager IMPLEMENTATION.
METHOD validate.
 WRITE: / 'Common validation'.
ENDMETHOD. "validate
ENDCLASS.
CLASS Validate_Decorator DEFINITION
CLASS validate_decorator DEFINITION INHERITING FROM validation_manager ABSTRACT .
PUBLIC SECTION.
 DATA: validator TYPE REF TO validation_manager.
ENDCLASS.
CLASS validate_format DEFINITION
CLASS validate_format DEFINITION INHERITING FROM validate_decorator.
PUBLIC SECTION.
 METHODS:
 constructor
 IMPORTING value(x_validator) TYPE REF TO validation_manager
 ,validate REDEFINITION.
ENDCLASS.
CLASS validate_format IMPLEMENTATION
CLASS validate_format IMPLEMENTATION.
METHOD constructor.
 CALL METHOD super->constructor( ).
 me->validator = x_validator.
ENDMETHOD. "constructor
METHOD validate.
 y_result = validator->validate( x_data ).
 IF y_result-status IS INITIAL.
 WRITE: / 'Now doing the format checks'.
 ENDIF.
ENDMETHOD. "validate
ENDCLASS.
CLASS validate_values DEFINITION
CLASS validate_values DEFINITION INHERITING FROM validate_decorator.
PUBLIC SECTION.
 METHODS:
 constructor
 IMPORTING value(x_validator) TYPE REF TO validation_manager
 ,validate REDEFINITION.
ENDCLASS.
CLASS validate_values IMPLEMENTATION
CLASS validate_values IMPLEMENTATION.
METHOD constructor.
 CALL METHOD super->constructor( ).
 me->validator = x_validator.
ENDMETHOD. "constructor
METHOD validate.
 y_result = validator->validate( x_data ).
 IF y_result-status IS INITIAL.
 WRITE: / 'Now doing the values checks'.
 ENDIF.
ENDMETHOD. "validate
ENDCLASS.
CLASS validate_relation_input DEFINITION
CLASS validate_relation_input DEFINITION INHERITING FROM validate_decorator.
PUBLIC SECTION.
 METHODS:
 constructor
 IMPORTING value(x_validator) TYPE REF TO validation_manager
 ,validate REDEFINITION.
ENDCLASS.
CLASS validate_relation_input IMPLEMENTATION
CLASS validate_relation_input IMPLEMENTATION.
METHOD constructor.
 CALL METHOD super->constructor( ).
 me->validator = x_validator.
ENDMETHOD. "constructor
METHOD validate.
 y_result = validator->validate( x_data ).
 IF y_result-status IS INITIAL.
 WRITE: / 'Now doing the relation input checks'.
 ENDIF.
ENDMETHOD. "validate
ENDCLASS.
CLASS validate_relation_database DEFINITION
CLASS validate_relation_database DEFINITION INHERITING FROM validate_decorator.
PUBLIC SECTION.
 METHODS:
 constructor
 IMPORTING value(x_validator) TYPE REF TO validation_manager
 ,validate REDEFINITION.
ENDCLASS.
CLASS validate_relation_database IMPLEMENTATION
CLASS validate_relation_database IMPLEMENTATION.
METHOD constructor.
 CALL METHOD super->constructor( ).
 me->validator = x_validator.
ENDMETHOD. "constructor
METHOD validate.
 y_result = validator->validate( x_data ).
 IF y_result-status IS INITIAL.
 WRITE: / 'Now doing the relation database checks'.
 ENDIF.
ENDMETHOD. "validate
ENDCLASS.
CLASS process_execution DEFINITION
CLASS process_execution DEFINITION.
PUBLIC SECTION.
 METHODS:
 startevent
 ,getdata
 ,validate
 ,process
 ,endevent.
PRIVATE SECTION.
 DATA:
 lst_data TYPE processdata
 ,lst_result TYPE result.
ENDCLASS. "process_execution DEFINITION
CLASS process_execution IMPLEMENTATION
CLASS process_execution IMPLEMENTATION.
METHOD startevent.
 WRITE: / 'Processing startevent'.
ENDMETHOD. "startevent
METHOD getdata.
 me->lst_data-name = 'Hans Andersen'.
 me->lst_data-street = 'H.C Andersens Boulevard 112'.
 me->lst_data-zip = '1557'.
 me->lst_data-city = 'København'.
 me->lst_data-email = 'hcATandersen.dk'.
 me->lst_data-phone = '0045-31162211'.
 WRITE: / 'Processing Get_Data Activity'.
ENDMETHOD. "getdata
METHOD validate.
 DATA:
 validator TYPE REF TO validation_manager
 ,recursive TYPE REF TO validation_manager
 IF bestimpl = true.
 CREATE OBJECT:
 validator TYPE validation_manager
 ,validator TYPE validate_format EXPORTING x_validator = recursive
 ,validator TYPE validate_values EXPORTING x_validator = recursive
 ,validator TYPE validate_relation_input EXPORTING x_validator = recursive
 ,validator TYPE validate_relation_database EXPORTING x_validator = recursive.
 ELSE.
 CREATE OBJECT validator TYPE validation_manager.
 recursive ?= validator.
 CREATE OBJECT validator TYPE validate_format
 EXPORTING x_validator = recursive.
 recursive ?= validator.
 CREATE OBJECT validator TYPE validate_values
 EXPORTING x_validator = recursive.
 recursive ?= validator.
 CREATE OBJECT validator TYPE validate_relation_input
 EXPORTING x_validator = recursive.
 recursive ?= validator.
 CREATE OBJECT validator TYPE validate_relation_database
 EXPORTING x_validator = recursive .
 recursive ?= validator.
 ENDIF.
Recursive call of the validate and it's successors
 me->lst_result = validator->validate( me->lst_data ).
 WRITE: / 'Processing Validate Activity'.
ENDMETHOD. "validate
METHOD process.
 WRITE: / 'Processing Process Activity'.
ENDMETHOD. "process
METHOD endevent.
 WRITE: / 'Processing endevent'.
ENDMETHOD. "endevent
ENDCLASS.
CLASS mainapp DEFINITION *
CLASS mainapp DEFINITION.
PUBLIC SECTION.
 CLASS-METHODS:
 main.
ENDCLASS.
CLASS mainapp IMPLEMENTATION *
CLASS mainapp IMPLEMENTATION.
METHOD main.
 DATA:
 p89 TYPE REF TO process_execution.
 CREATE OBJECT p89.
 p89->startevent( ).
 p89->getdata( ).
 p89->validate( ).
 p89->process( ).
 p89->endevent( ).
ENDMETHOD.
ENDCLASS.
START-OF-SELECTION.
mainapp=>main( ).
Edited by: Matt on Dec 22, 2009 2:03 PM Fixed formatting

J2EE Decorating Filter Design Pattern

I have been reading a little bit about J2EE patterns on Sun's web site
          (URL at bottom). The design pattern called "Decorating Filter" involves
          creating servlets that are always executed before and/or after all
          servlets.These always-executed servlets do things such as request
          logging and security.
          The idea sounds really nice to me. You can do a lot, without putting
          code for logging or security in the servlet that people actually
          requested. So, you could request a servlet, but these other servlets are
          executed before/after it automatically.
          Is there a way to do this in WebLogic? Is this "servlet chaining"?
          Thanks,
          Mike


Mike,
          Checkout 6.1 it has filters implemented as part of servlet2.3 spec.
          http://e-docs.bea.com/wls/docs61///////webapp/filters.html
          Kumar.
          Michael Olivieri wrote:
          > I have been reading a little bit about J2EE patterns on Sun's web site
          > (URL at bottom). The design pattern called "Decorating Filter" involves
          > creating servlets that are always executed before and/or after all
          > servlets.These always-executed servlets do things such as request
          > logging and security.
          >
          > The idea sounds really nice to me. You can do a lot, without putting
          > code for logging or security in the servlet that people actually
          > requested. So, you could request a servlet, but these other servlets are
          > executed before/after it automatically.
          >
          > Is there a way to do this in WebLogic? Is this "servlet chaining"?
          >
          > Thanks,
          > Mike

What is the best design pattern for this problem?

No code to go with the question. I am trying to settle on the best design pattern for the problem before I code. I want to use an Object Oriented approach.
I have included a basic UML diagram of what I was thinking so far.
Stated simply, I have three devices; Module, Wired Modem, and Wireless Modem.
In the Device Under Test parent class, I have put the attributes that are variable from device to device, but common to all of them.
In the child classes, I have put the attributes that are not variable to each copy of that device. The attributes are common across device types. I was planning to use controls in the class definition that have the data set to a default value, since it doesn't change for each serial number of that device. For example, a Module will always have a Device Type ID of 1. These values are used to query the database.
An example query would be [DHR].[GetDeviceActiveVersions] '39288', 1, '4/26/2012 12:18:52 PM'
The '1' is the device type ID, the 39288 is the serial number, and the return would be "A000" or "S002", for example.
So, I would be pulling the Serial Number and Device Type ID from the Device Under Test parent and child, and passing them to the Database using a SQL string stored in the control of the Active Versions child class of Database.
The overall idea is that the same data is used to send multiple queries to the database and receiving back various data that I then evaluate for pass of fail, and for date order.
What I can't settle on is the approach. Should it be a Strategy pattern, A Chain of Command pattern, a Decorator pattern or something else.
Ideas?

elrathia wrote:
Hi Ben,
I haven't much idea of how override works and when you would use it and why. I'm the newest of the new here.
Good. At least you will not be smaking with a OPPer dOOPer hammer if I make some gramatical mistake.
You may want to look at this thread in the BreakPoint where i trie to help Cory get a handle on Dynamic Dispatching with an example of two classes that inherit from a common parent and invoke Over-ride VIs to do the same thing but with wildly varying results.
The example uses a Class of "Numeric" and a sibling class "Text" and the both implement an Add method.
It is dirt simple and Cory did a decent job of explaining it.
It just be the motivation you are looking for.
have fun!
Ben
Ben Rayner
I am currently active on.. MainStream Preppers
Rayner's Ridge is under construction

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.

Design patterns implemented in java API

Hi,
I have some questions on design patterns implemented in core java class or in general in java API.
1)Whether
java.util.Collections, the checkedXXX(), synchronizedXXX() and unmodifiableXXX() methods.
can be considered as a decorator pattern?
2) Whether
LinkedHashMap(LinkedHashSet<K>, List<V>) which returns an unmodifiable linked map which doesn't clone the items, but uses them
can be considered as a Bridge pattern?
3) Whether Facade pattern is implemented in java ? If so which API uses it?
4) Whether
• All non-abstract methods of java.io.InputStream, java.io.OutputStream, java.io.Reader and java.io.Writer.
• All non-abstract methods of java.util.AbstractList, java.util.AbstractSet and java.util.AbstractMap
can be considered as a Template method pattern?
5) Whether
• java.util.Comparator#compare(), executed by among others Collections#sort()
can be considered as a Stratergy pattern?
6)
Whether State pattern is implemented in java ? If so which API uses it?
7)
All implementations of java.lang.Runnable are considered as a Command pattern.
8)
Whether
• java.io.InputStreamReader(InputStream) (returns a Reader)
• java.io.OutputStreamWriter(OutputStream) (returns a Writer)
can be considered as an Adapter pattern?
Please clarify.
Thanks.

What do you think, and why?

Design Patterns in Dynamic Programming

I mentioned this on a thread some time ago - that many of the GoF patterns disappear in languages such as Lisp, but didn't have the reference handy. Came across it again today so I thought I'd post the link:
http://www.norvig.com/design-patterns/
Pete

hi sourdi
Below are the list of Design pattern in abap .
Singleton: ensuring single class instantiation
Adapter: making class interfaces compatible
Factory: encapsulating object creation
MVC: decoupling business logic from the view
Facade: providing a simplified interface
Composite: treating individual objects and compositions uniformly
Decorator: forming a dynamic chain of components to be used as one by the client
regards
chinnaiya P

Design Patterns in ABAP.

Hi,
I want to know about the Design Patterns in ABAP.
Regards,
Sourav

hi sourdi
Below are the list of Design pattern in abap .
Singleton: ensuring single class instantiation
Adapter: making class interfaces compatible
Factory: encapsulating object creation
MVC: decoupling business logic from the view
Facade: providing a simplified interface
Composite: treating individual objects and compositions uniformly
Decorator: forming a dynamic chain of components to be used as one by the client
regards
chinnaiya P

Design Patterns that are used in standard j2se/j2ee classes/interfaces

Hi All,
I am understanding following design patterns (used within standard j2se/j2ee):
Adapter
Facade
Composite
Bridge
Singleton
Observer
Mediator
Proxy
Chain of Responsibility
Flyweight
Builder
Factory Method
Abstract Factory
Prototype
Memento
Template Method
State
Strategy
Command
Interpreter
Decorator
Iterator
Visitor
I want to see if/where these design patterns are used in j2se/j2ee classes/interfaces. i am looking for few examples of standard java classes/interfaces/cases where these design patterns are used by jdk developers.
for e.g.
WindowAdapter class is an example of Adapter DP.
JOptionPane is an exmple of Facade DP.
MouseListener is an example of Observer DP.
Similarly, where can find examples of jdk classes/interfaces of the remaining DPs.
I searched a lot of books, but they explain the DPs by creating their own classes/interfaces.
I would like to see where these DPs are already utilised in std j2se/j2ee
thanks,
Madhu_1980

877316 wrote:
I searched a lot of books, but they explain the DPs by creating their own classes/interfaces.
I would like to see where these DPs are already utilised in std j2se/j2eeWell, you can go through the javadocs first, they sometimes mention the pattern used.
Then you can get the sources for the jdk and go through the classes yourself, identifying the patterns.

How can I develop a web application using EJB design pattern?

I have searched over the web and found quite a lot of tutorials on how to use the EJB design pattern.
I know that there will be a home interface, EJB object interface and a SessionBean.
But the tutorials often only cover a single class, this made me unable to get a complete picture of how EJB design pattern can be implemented into a whole system.
I am now required to devleop an online shopping web application using EJB and JSP page.
I think I will need to create a lot of classes: Member, ShoppingCart, Product...etc.
What I want to ask is that, do I need to create a home interface, EJB object interface and a SessionBean for each of these classes?
I really need some ideas on how to develop this system using EJB + JSP pages.
Many thanks to you all.

For every EJB that you want to create, you will need to code a home and remote interface and a bean class.
You could start getting your ideas here
http://www.theserverside.com/books/wiley/masteringEJB/
http://www.coreservlets.com

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

Business delegate and Session facade design patterns

Does any one tell me, what is the difference between business delegate and session facade design patterns.

1. Session Facade decouples client code from Entity beans introducing session bean as a middle layer while Business Delegate decouples client code from EJB layer ( Session beans).
2. SF reduces network overhead while BD reduces maintenance overhead.
3. In SF any change in Session bean would make client code change.
While in DB client is totally separate from Session bean because BD layer insulate client from Session beans(EJB layer).
3. In only SF scenario, Client coder has to know about EJB programming but BD pattern no EJB specialization needed.
4.SF emphasizes on separation of Verb, Noun scenario while BD emphasizes on separation of client(presentable) and EJB layer.
Anybody pls suggest more differences ?

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?
#2.2 If there is not,Does the following way work?I put every tabledata's property as corresponed component.if user choosed the row in the table,My Listener will syncronize the row data to the components.But
#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 for updating a fact table

I have a fact table and about 10 dimensions.
One of these dimensions can be missing values, so the fact table row will link to an UNKNOWN value.
When the correct value is finally entered in the dimension table i want to update any associated fact rows.
Whats the most efficient way of doing this?

I know i have to use a lookup transformation ;-)
I wouldnt be at teh stage of even having a fact table if i didnt know that! I was looking for a design pattern, not the name of a shape!
The solution i went with was to take a hard line on any rows with unknown values. If when importing the data there are unknown values for two of the most important dimensions, those rows are not inserted into the fact table, but instead pushed to an ErrorLog
table.
Users run a report that shows what this table contains and if they really want those rows, they insert the correct dimension values and rerun the import, which will only import any rows not already in the fact table.
This way:
1. all sorting & filtering issues are resolved as there will be no unknown rows for the most important dimensions used in sorting and filtering.
2. we can quickly see any rows with unknown values and figure out whats wrong. its always missing reference data that the client didnt think to give us. a quick insert of the dimension data and import and the rows get imported.
thanks for the replies.

Decorator Design Pattern

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