What is the use of Marker Interfaces?

What is the use of marker interfaces?
As it is not having any methods or fileds what is the benefit I will get by implementing those interfaces?
Servlet implements SingleThread
What it will do behind the scenes exactly as singleThread model is marker interface

The use of marker interfaces is to act as markers (shock horror)
It is quite a common way to tell a program what a class can/can't do: Cloneable, Serializable etc etc
This doesn't change the functionality of the class itself, but is more an indication as to what can be done with this class.
In this case the servlet container can then tell whether or not it implements the interface, and can treat it accordingly. Implementing this interface tells the container you want it to run this servlet in singleThreaded mode.
Thats all there is to it.
It would be along the lines of
Servlet servlet = loadServlet("...")
if (servlet instanceof SingleThreadModel){
// Single threaded servlet - start new process for it
else {
// regular servlet - reuse existing object.

Similar Messages

What is the significance of Marker interface? Why are we using, even though

What is the significance of Marker interface? Why are we using, even though it has no method?

Well, what's the significance of an interface? They can define a set of methods a class may implement but the class could equally well implement these methods without the interface so why having interfaces at all?
The answer is that the most important aspect of an interface is that it constitutes a type (you can declare variables of it). And it's a type regardless of how many methods it defines, including none. So the reason for having a marker interface is that you're interested solely in the type aspect of interfaces.

What is the use of Serializable Interface in java?

Hello friends,
I have one dout and i want to share with u guys:
Why Serializable interface made and actully
what's the use of it?
At which place it become useful ?
It is not contain any method then why it is made?
If anyone have any idea about this then please reply.
Thanks in advace
Regards,
Jitendra Parekh

t is not contain any method then why it is made?To point out to the user of a class (and the programs) that the design of this class is conforming to certain restraints needed for Serialization.

What is the use of Externalizable interface?

What is the use of Externalizable? and what is the diff b/w Serializable and Externalizable interfaces?

What is the use of Externalizable?Read the API docs, they explain it.
and what is the
diff b/w Serializable and Externalizable interfaces?Well, read the API docs of Serializable, too, and then find the difference.

What is the use of marking repair request in the scheduler?

Hi !
what is the use of the option repair full request in the scheduler menu item?

Hi Durai,
You can use a request that was selected as a repair request via Scheduler ® Repair Full Request to carry out a full update in any data target. This also applies to data requests that already contain data from an initialization run or deltas for this DataSource/source system combination, and that have overlapping selection criteria.
Nice post by Roberto:
Bye
Dinesh

Use of marker Interface

can any bdy plz tell me what is the use of marker interface ????

Please search the forums before asking such a common question.

What is the use of Storage loc.ref.in LE-WM Interface to Inventory Managemt

Hi Guys
What is the use of below fields
Special movement indicator for warehouse management and Storage loc. ref.
In the WM configaration LE-WM Interface to Inventory Management
How we can do the below scenario with this configaration
I have 3 scenarios all scenarios have MIGO and placing stock to WM
2 scenarios requres Immediate TO creation after MIGO 101 mvt type
But last scenario does not want Immediate TO ,it is having another Z transaction to create TO
But problem is for the last scenario also creating Immdiate TO after MIGI 101
How to avoid this Immdiate TO for this scenario
And How to allow it for first 2 scenarios
How we can to with that configaration

Hello ,
It is not possible directly in customising as all three cases are using the same Mvt Type.
Alternate Solution :
You may try an by creating a new Mvt Type 901 i.e making a copy of 101.
Thereafter try to link a new Ref Mvt Type to the same .You should use this case for the third scenario.
This may resolve your problem.
Regards
Ramesh Ch

What is the use of interface in the adobe forms

Hi friends,
can any one tell,
what is the use of interface in the adobe forms for desigining the form.

The main purpose of the form interface is to send the application data to the form.
The form interface is created separately from the form, which consists of the form context and layout. When you create a form, you must assign it to a form interface.
please have a look at the link below for more info:
http://help.sap.com/saphelp_nw70/helpdata/EN/96/6ee0d5b39640d68fc0078fc575114a/frameset.htm
http://help.sap.com/saphelp_nw70/helpdata/EN/f2/21021b911f4c0cae11459a4ce0bc62/frameset.htm
hope this helps,
harman

What is the use of with and without marker update?

what is the use of with and without marker update?

Hi,
Marker Update Updates the stock values and NO Marker does not.
Generally BX upload has to be compressed with MU and BF(and UM) delta init has to be compressed with NO MU because Stock was updated with BX. And delta loads of BF and UM has to be compressed with MU because these brings new Material movements which will has to give effect to stock.
With rgds,
Anil Kumar Sharma .P

What is the use of hot key...

what is the use of hotkey in elementary search helps...how to use this in elementary search helps...can anybody send any navigations on these ..

Creating Elementary Search Helps
Procedure
In the initial screen of the ABAP Dictionary, select object class Search help, enter the name of the search help and choose Create.
A dialog box appears in which you must select the type of search help.
Select Elementary search help and choose .
The maintenance screen for elementary search helps appears.
Enter an explanatory text in the field Short text.
You can for example find the search help at a later time using this short text.
In the Definition tab page enter the selection method of the search help.
You can enter the name of a table or a view (database view, projection view or help view) here. If you enter a table that has a text table, the name of the text table is automatically entered in the corresponding field.
Using the input help (F4 help), select fields of the selection method as parameter in the Search help parameter area. Select the fields that should be used in the dialog box for value selection or in the hit list.
If the selection method is a table that has a text table, both the fields of the table and the fields of the text table are offered in the input help.
The data element of the parameter is automatically copied from the selection method. The data element defines the output attributes and the F1 help of the parameter in the hit list and in the dialog box for value selection.
You can assign the parameter another data element. To do so, select the Mod flag. The Data element field is now ready for input. Then select a data element with the input help (F4 help). Only data elements whose data type, length and number of decimal places is the same as those of the previous data element can be assigned.
This removes the link between the data element of the search help parameter and the data element of the selection method field having the same name. If you cancel the Mod flag, the data element of the assigned table field is used again.
Define the attributes of the search help parameters.
Select the IMP flag if it is an import parameter. Select the EXP flag if it is an export parameter.
You can define the dialog for the input help with the fields LPos, SPos and SDis. Enter the parameter position in the hit list in LPos. If you enter nothing or the value 0 here, the parameter is not displayed in the hit list.
Enter the parameter position in the dialog box for value selection in SPos. If you enter nothing or the value 0 here, the parameter is not displayed in the dialog box for value selection.
Set the SDis flag if the parameter should be a pure display field in the dialog box for value selection. The user is thus informed that the contents of the parameter restrict the value, but he cannot change this restriction. This makes sense for example when the parameter is an import parameter or if it has a default value.
You can assign the parameter a default value in the Default value field.
Select the dialog type of the search help.
The dialog type defines how the hit list is displayed in the input help.
Save your entries.
A dialog box appears in which you have to assign the search help a development class.
Choose .
Do not forget to link the search help to a screen field. The search help attachment is not part of the search help definition; it is part of the object definition to which the search help is attached.
Result
The search help is activated. You can find information about the activation flow in the activation log, which you can display with Utilities ® Activation log. If errors occurred during activation, the activation log is automatically displayed.
Other Options
Assign a hot key: If the search help is to be accessed with a hot key, you must enter a one-place ID in the Hot key field. All the elementary search helps contained in a collective search help should have different short cuts.
Assign a search help exit: In exceptions, you might have to change the standard flow defined by the search help with a search help exit. In this case enter the name of the search help exit in the corresponding field.
Test the search help: You can test the flow of an input help defined by the elementary search help with . A dialog box appears in which you can simulate the behavior of the search help under different conditions. You can obtain information about the options provided in this window with .
See also:
Example for Search Helps
Each customer of a carrier (see Flight Model) or of a travel agency has a customer number. You want to find a search option for this customer number.
The user must be offered two different search paths.
The user should be able to search for the customer number using the customer data, such as the name and address.
The user should be able to search for the customer number using existing customer bookings.
You can provide the required search option by creating a collective search help SCUSTOM. Two elementary search helps SCUSTOM_NAME (for searching with the customer data) and SCUSTOM_BOOK (for searching with the existing bookings) are created for the actual search paths. These elementary search helps are included in the collective search help.
Elementary Search Help SCUSTOM_NAME
This elementary search help should enable you to search for the customer number using the name and address (street, city, country). All this data is contained in table SCUSTOM. Table SCUSTOM must therefore be selected as the selection method of the elementary search help.
You now have to decide which fields of the selection method are needed for the input help process. These are the fields that should appear either in the dialog box for restricting values or in the hit list.
In the dialog box for restricting values, the user should be able to restrict values with the customers name and address, i.e. the fields for the street, city and country. These fields as well as the customers number (the information to be found must always be in the hit list) should appear in the hit list. The fields ID, NAME, STREET, CITY and COUNTRY of table SCUSTOM must be included in the search help as parameters.
The parameter ID is declared to be an import parameter. A pattern entered in the corresponding field of a screen template can therefore be used directly for the value selection. Restrictions for the other parameters of the search help must be entered in the dialog box for value selection.
All the parameters of the search help are declared to be export parameters. As a result, all the parameters of the hit list can be returned to the screen template if the corresponding fields are available there.
Elementary Search Help SCUSTOM_BOOK
This elementary search help should enable you to search for the customer number using existing customer bookings. The flight data for the booking (flight number, date of flight, city of departure, city of arrival) and the name of the customer should be used for the search here. This data is distributed on the tables SBOOK (bookings), SCUSTOM (name) and SPFLI (cities of departure and arrival). The following graphic shows the relationship between the relevant tables, that is the existing foreign key relationships.
In this case a database view SCUS_BOOK must be created on these three tables (see Example for Views) as selection method. The tables in the view (join) are linked as defined by the existing foreign key relationships (see Foreign Key Relationship and Join Condition).
In the dialog box for restricting values, the user should be able to restrict the search for booking data with the carrier ID, customer name, city of departure and city of arrival The flight date and of course the customer number should also be displayed in the hit list. Fields CARRID, FLDATE, CUSTOMID, NAME, CITYFROM and CITYTO of view SCUS_BOOK must be included in the elementary search help as parameters of the search help.
The parameter CUSTOMID is declared to be an import parameter. All the parameters of the search help are export parameters.
Collective Search Help SCUSTOM
The two elementary search helps are now included in the collective search help. You must now allocate the parameters of the elementary search helps to the parameters of the collective search help.
The parameter ID of the collective search help is marked as an import parameter. All the parameters are export parameters. The values can thus be copied from the hit list to the screen template.
Attaching the Search Help
In order to be able to use the search help SCUSTOM in screen templates, the attachment of the search help (see Attaching Search Helps with Screen Fields) must be defined.
Attaching to the Check Table SCUSTOM
The search help should be available for all the fields that are checked against table SCUSTOM. The search help therefore must be attached to table SCUSTOM. The search help parameters must therefore be assigned to the key fields of table SCUSTOM.
The parameter ID of search help SCUSTOM is here assigned to the field ID of table SCUSTOM in this field assignment. No assignment is possible for all other parameters of the search help (NAME, CITY and COUNTRY) since table SCUSTOM does not contain this information as key fields.
Attaching to a Field of Table SCUSTOM
In order that the search help is available when the field SCUSTOM-ID is directly copied to the input template, you have to attach the search help to this field.
With this type of attachment, all the parameters of the search help can be assigned to the corresponding fields of the table.
Structure of an Elementary Search Help
An elementary search help defines the standard flow of an input help. You can define the following components of this flow in the search help:
where does the data displayed in the hit list come from (selection method)
what information should be displayed in the dialog box for value selection and in the hit list (search help parameters)
what field contents can be taken into account for hit list selections and which values in the hit list can be returned to the screen fields (search help parameters)
what dialog steps should be executed in the input help (dialog behavior)
Selection Method
The possible input values displayed for a field in the hit list are determined at runtime by database selection.
If all the data required in the hit list comes from one single table, you only have to select this table (or a projection view on this table) as selection method. If there is a text table for the table, its fields are also available in the input help. A table entry is linked with the corresponding text by the existing foreign key.
If the data needed in the hit list comes from more than one table, you must link these tables with a view (database view or help view). This view must be defined as the selection method.
If the underlying tables are client-specific, the client field must be contained in the view. Otherwise selection for the input help would be for all clients.
Search Help Parameters
A search help has an interface consisting of parameters. These parameters define the fields of the selection method that should be used in the input help.
A parameter of the search help must correspond to each field in the dialog box for value selection and to each field of the hit list. The parameters are copied from the corresponding selection method, that is they always have the same name as the corresponding field of the selection method.
If the search is restricted with a parameter of the search help, this is used in the data selection for formulating a WHERE condition for the field of the selection method with the same name. Vice versa, the parameters of the search help are assigned the contents of the fields of the selection method having the same name.
The search help should not contain any parameters for the clients. In the input help, selection is automatically in the logon client of the user.
A data element must be assigned to each search help parameter, that is a type is always defined for the search help parameters.
A search help can contain further parameters that do not correspond to any field of the selection method. This is normally only necessary if the standard flow of the input help described by the search help still has to be modified by with a search help exit.
Import and Export Parameters
When an input help is called, the entries that the user already made in the input template are taken into consideration. For example, if a user calls the input help for the flight number and already specified the carrier, of course only the numbers of flights of this carrier should be offered.
On the other hand, if the user selects one row of the hit list, more than one field of the input template might have to be filled with data from the selected row of the hit list. For example, if the flight number is obtained from the hit list, the city of departure and the destination should also be returned in the screen template.
The interface of a search help defines the context data that can be used in the input help and the data that can be returned in the input template.
A parameter of a search help can be classified as:
Import parameters: Parameters with which context information from the processed input template (screen) may be copied to the help process.
Export parameters: Parameters with which values from the hit list may be returned to the input template.
A parameter can simultaneously be an input and an export parameter. A search help can also contain parameters that are neither import nor export parameters. Such parameters could be required for the internal input help process, for example.
When you attach a search help, you must define where the import parameters of the search help get their values from and the fields in which the contents of the export parameters are returned. See also Value Transport for Input Helps.
Description of the Online Behavior
The online behavior defines the steps executed in the input help process and the structure of the hit list and dialog box for value selection.
The dialog type defines whether or not the dialog box for value selection should be displayed. If you want to skip the dialog box for value selection, the hit list is displayed directly after calling the input help.
When you define an elementary search help, you can define how the dialog box for value selection and the hit list should look. For example, you can define the position of a parameter in the dialog box for value selection here. The column position in which the values of a parameter are displayed in the hit list can also be defined here
Please reward points..
regards

What is the use of initial value in a database table?

Hi can anyone help me in knowing what is the use of initial value which is present besides primary key while creating a table?

Initial Value:
Indicator that NOT NULL is forced for this field
Use
Select this flag if a field to be inserted in the database is to be filled with initial values. The initial value used depends on the data type of the field.
Please note that fields in the database for which the this flag is not set can also be filled with initial values.
When you create a table, all fields of the table can be defined as NOT NULL and filled with an initial value. The same applies when converting the table. Only when new fields are added or inserted, are these filled with initial values. An exception is key fields. These are always filled automatically with initial values.
Restrictions and notes:
The initial value cannot be set for fields of data types LCHR, LRAW, and RAW. If the field length is greater than 32, the initial flag cannot be set for fields of data type NUMC.
If a new field is inserted in the table and the initial flag is set, the complete table is scanned on activation and an UPDATE is made to the new field. This can be very time-consuming.
If the initial flag is set for an included structure, this means that the attributes from the structure are transferred. That is, exactly those fields which are marked as initial in the definition have this attribute in the table as well.
hope it helps,
Saipriya

What is the use of XML file in EJB

Hi,
Generally EJB contains
1) Home Interface
2) Remote Interface
3) Bean class
4) XMl file
In xml file we will mention something like
<home>name of home interface </home>
<remote?name of remote interface</remote>
what is the use of this xml file and how it works.
Thanks.

It's called the deployment descriptor and it's used by the container to support your bean's configuration. For instance, if you want container managed persistence for an entity bean then you need to tell the container which table to use in which database with the column mappings, etc.

What is the use of REUSE_ALV_FIELDCATALOG_MERGE

Hi
in alv's what is the use of REUSE_ALV_FIELDCATALOG_MERGE OTHER THAN ADDING FIELD HEADINGS
Title Edited by: Alvaro Tejada Galindo on Jan 11, 2008 4:20 PM

Hi,
This is the functionality of that FM,
Supports the creation of the field catalog for the ALV function modules
based either on a structure or table defined in the ABAP Data
Dictionary, or a program-internal table.
The program-internal table must either be in a TOP Include or its
Include must be specified explicitly in the interface.
The variant based on a program-internal table should only be used for
rapid prototyping since the following restrictions apply:
o   Performance is affected since the code of the table definition must
    always be read and interpreted at runtime.
o   Dictionary references are only considered if the keywords LIKE or
    INCLUDE STRUCTURE (not TYPE) are used.
If the field catalog contains more than 90 fields, the first 90 fields
are output in the list by default whereas the remaining fields are only
available in the field selection.
If the field catalog is passed with values, they are merged with the
'automatically' found information.
reward points if useful,
seshu.

What is the use of Generic class in java

hi everyone,
i want to know that
what is the use of Generic class in java ?
regards,
dhruvang

Simplistically...
A method is a block of code that makes some Objects in the block of code abstract (those abstract Objects are the parameters of the method). This allows us to reuse the method passing in different Objects (arguments) each time.
In a similar way, Generics allows us to take a Class and make some of the types in the class abstract. (These types are the type parameters of the class). This allows us to reuse the class, passing in different types each time we use it.
We write type parameters (when we declare) and type arguments (when we use) inside < >.
For example the List class has a Type Parameter which makes the type of the things in the list become abstract.
A List<String> is a list of Strings, it has a method "void add(String)" and a method "String get(int)".
A List<File> is a list of Files, it has a method "void add(File)" and a method "File get(int)".
List is just one class (interface actually but don't worry about that), but we can specify different type arguments which means the methods use this abstract type rather than a fixed concrete type in their declarations.
Why?
You spend a little more effort describing your types (List<String> instead of just List), and as a benefit, you, and anyone else who reads your code, and the compiler (which also reads your code) know more accurately the types of things. Because more detail is known, the compiler is able to tell you when you screw up (as opposed to finding out at runtime). And people understand your code better.
Once you get used to them, its a bit like the difference between black and white TV, and colour TV. When you see code that doesn't specify the type parameters, you just get the feeling that you are missing out on something. When I see an API with List as a return type or argument type, I think "List of what?". When I see List<String>, I know much more about that parameter or return type.
Bruce

What is the use of control breaks in reoprts?how can we use them in report?

hello all
what is the use of control breaks in reoprts? and how can we use them in reports?

hi,
check this sample program using control break statements.
*& Report Y777_CBSTABLE
REPORT Y777_CBSTABLE1.
TYPES:
BEGIN OF S_MARKS,
     ROLLNO    TYPE I,
     SCODE(3) TYPE C,
    ROLLNO    TYPE I,
     SNAME(10) TYPE C,
     MARKS     TYPE I,
END OF S_MARKS.
DATA : C TYPE I,
       D(3) TYPE C,
       TOT TYPE I,
       STU TYPE I,
       MARKS TYPE STANDARD TABLE OF S_MARKS,
       WA_MARKS TYPE S_MARKS.
WA_MARKS-ROLLNO = 1.
WA_MARKS-SCODE = 'MAT'.
WA_MARKS-SNAME = 'MATHS'.
WA_MARKS-MARKS = 65.
APPEND WA_MARKS TO MARKS.
CLEAR WA_MARKS.
WA_MARKS-ROLLNO = 1.
WA_MARKS-SCODE = 'SCI'.
WA_MARKS-SNAME = 'SCIENCE'.
WA_MARKS-MARKS = 85.
APPEND WA_MARKS TO MARKS.
CLEAR WA_MARKS.
WA_MARKS-ROLLNO = 1.
WA_MARKS-SCODE = 'COM'.
WA_MARKS-SNAME = 'COMPUTER'.
WA_MARKS-MARKS = 90.
APPEND WA_MARKS TO MARKS.
CLEAR WA_MARKS.
WA_MARKS-ROLLNO = 2.
WA_MARKS-SCODE = 'MAT'.
WA_MARKS-SNAME = 'MATHS'.
WA_MARKS-MARKS = 55.
APPEND WA_MARKS TO MARKS.
CLEAR WA_MARKS.
WA_MARKS-ROLLNO = 2.
WA_MARKS-SCODE = 'SCI'.
WA_MARKS-SNAME = 'SCIENCE'.
WA_MARKS-MARKS = 75.
APPEND WA_MARKS TO MARKS.
CLEAR WA_MARKS.
WA_MARKS-ROLLNO = 2.
WA_MARKS-SCODE = 'COM'.
WA_MARKS-SNAME = 'COMPUTER'.
WA_MARKS-MARKS = 80.
APPEND WA_MARKS TO MARKS.
CLEAR WA_MARKS.
RETRIVAL ************************************
SORT MARKS BY SCODE .
LOOP AT MARKS INTO WA_MARKS.
    AT FIRST .
       ULINE.
       FORMAT COLOR 6 ON.
       WRITE:/ 'SUBJECT CODE', 65 ' ' .
       FORMAT RESET.
       FORMAT COLOR 6 ON INTENSIFIED OFF.
       WRITE:/20 'ROLL NO',
              40 'SUBJECT NAME',
              55 'MARKS',
              65 ' '.
       FORMAT RESET.
       ULINE.
    ENDAT.
    ON CHANGE OF WA_MARKS-SCODE.
       IF SY-TABIX NE 1.
           NEW-LINE.
           ULINE 40(25).
           FORMAT COLOR 5 ON INVERSE ON INTENSIFIED ON.
           TOT = TOT / STU.
           WRITE:/40 'AVERAGE MARKS =', TOT.
           FORMAT RESET.
           CLEAR TOT.
           CLEAR STU.
       ENDIF.
      FORMAT COLOR 6 ON INTENSIFIED ON.
      WRITE:/ WA_MARKS-SCODE.
      FORMAT RESET.
    ENDON.
    FORMAT COLOR 6 ON INTENSIFIED OFF.
    WRITE:/20 WA_MARKS-ROLLNO,
           40 WA_MARKS-SNAME,
           55 WA_MARKS-MARKS,
           65 ' '.
    FORMAT RESET.
    STU = STU + 1.
    TOT = TOT + WA_MARKS-MARKS.
    C = STU.
    AT LAST.
           NEW-LINE.
           ULINE 40(25).
           FORMAT COLOR 5 ON INVERSE ON INTENSIFIED ON.
           TOT = TOT / STU.
           WRITE:/40 'AVERAGE MARKS =', TOT.
           FORMAT RESET.
           CLEAR TOT.
           CLEAR STU.
         ULINE.
         FORMAT COLOR 6 ON INVERSE ON INTENSIFIED ON.
         WRITE:/ ' TOTAL STUDENTS : ', C.
         FORMAT RESET.
    ENDAT.
ENDLOOP.
reward points if hlpful.

What is the use of Marker Interfaces?

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