The function Interface Object Generation provides the option to generate single interface objects online on a separate screen. You either type in the parameter definitions required or read them in from an existing subprogram or a parameter data area (PDA).
Generating an interface object from a PDA saves you the effort of creating a subprogram and defining an inline parameter data area.
This section covers the following topics:
Interface objects are generated into the current Natural
library in the current system file. Therefore, we strongly recommend that you
log on to the application library (or one of its steplibs) used by the client
at execution time of the remote CALLNAT
.
Wichtig:
The function Interface Object
Generation overwrites any data contained in the source work area.
When you invoke the function, a corresponding message will warn you not to
delete any existing data unintentionally: choose PF12 to cancel or
choose ENTER to confirm the action and overwrite the contents of the
source work area.
To generate a single interface object
Before you invoke the SYSRPC utility, consider the following:
Log on to the library into which you want to generate the interface object.
If you generate an interface object from a PDA: Rename or copy the
PDA from which you want to generate the interface object if there are objects
on the client side that still reference this PDA. The new name of the PDA must
be identical to the name of the remote CALLNAT
program.
In the Code field of the Client Maintenance menu, enter the following command:
IG
Choose ENTER.
The Generate Interface Object screen appears.
In the Program Name field, enter the name of the interface object to be generated.
The name of the interface object must be identical to the name of the
remote CALLNAT
program.
The Library field is preset to the name of the current library and cannot be changed.
In the Compression field, enter compression type
0
, 1
or 2
(default is 1
);
see Using
Compression described in Operating a Natural RPC
Environment in the Natural RPC (Remote Procedure Call)
documentation.
Choose ENTER.
If the name entered in the Program Name field corresponds to the name of an object that already exists in the assigned library, a window appears with an appropriate message:
Enter an N
(No) and choose ENTER if you
want to cancel the operation. You will return to the Client
Maintenance menu.
Or:
Enter a Y
(Yes) and choose
ENTER if you want to continue with generating interface objects.
If the specified name is identical to a cataloged object of the type subprogram or PDA, the parameter definitions of the respective subprogram or PDA are displayed on the Interface Generation screen.
If the specified name is identical to an already generated
interface object for which also a source object exists, all field attributes
(see also Specifying
Parameters) are retained. Otherwise, all field attributes
are set to M
(modifiable).
If the string entered in the Program Name field, does not match the name of an object that already exists in the assigned library, an empty Interface Object Generation screen is displayed.
On the Interface Object Generation screen, add or modify the parameters to be used in the interface object as described in Specifying Parameters.
The commands provided on the Interface Object Generation screen correspond to the commands described in Commands and PF Keys in the section Service Directory Maintenance.
Exceptions:
Attribute | Values | ||||||
---|---|---|---|---|---|---|---|
EXPIRATION |
Not applicable to interface object generation. |
||||||
COMPAT |
Anmerkung: |
||||||
LIMIT |
|
Choose ENTER to generate the interface object and to exit. The interface object is generated into the assigned library.
The SYSRPC - Information window appears which indicates the size of the interface object requires for sending data from the client to the server or vice versa. The size includes internal RPC information used for the interface object. The indication of the size helps you configure the middleware layer used; for example, the Broker attribute file when EntireX Broker is used.
The following message appears in the SYSRPC - Information window when you generate an interface object from the example subprogram TESTS5 (see Example 1 below):
Interface Object TESTS5 is generated in library SAGTEST (99,49). It requires: Send length: 2249 bytes Receive length: 2221 bytes
If dynamic parameters, X-arrays or X-group arrays are used, this
message only indicates the minimum length requirements. The actual length
requirements can only be determined during program execution and may be
different from call to call. If the Send length
or the
Receive length
exceeds the Entire Net-Work limit of 32000 bytes, a
window appears with a corresponding warning:
Enter a Y
(Yes) to continue, or an N
(No)
to cancel the generation. If you enter a Y
, this setting is kept
for the entire SYSRPC session, that is, you can continue generating interface
objects without receiving further warnings.
If the total data (without internal RPC information) sent or received exceeds the limit of 1073739357 bytes (which is 1 GB minus 2467 bytes of internal RPC information), SYSRPC stops processing and issues a corresponding error message. This error message displays the subtotal of the data in bytes that could be transferred at the field up to which the subtotal was calculated. The corresponding field is then marked. In this case, reduce the amount of data before you continue the generation.
If the interface object was generated in the Natural system library SYSRPC, you have to move it to the application library or steplib using the Natural transfer utility SYSMAIN or the Object Handler. Note that you may have to recatalog the source of the interface object in the target environment.
In the input fields provided on the Interface Object Generation screen, you can enter the parameter definitions that are used in the interface object. You can specify a maximum of 5000 parameters. Unless indicated in the table below, input in the fields is mandatory.
Field | Description |
---|---|
Level |
The level of the field. A level can be a number in the range from See also Defining Groups and Example 2 for an example of a group definition. |
Attr |
The attribute of the parameter:
Parameters assigned a level number of If an interface object has been generated from a subprogram or from a PDA, the attribute is If an interface object has been generated from another interface object, the attribute values specified for the original object are retained. The generated interface object contains a comment that indicates
the attribute specified for the parameter: |
Type |
A Natural data format such as For a description of Natural data formats, see Format and Length of User-Defined Variables and Special Formats in the section User-Defined Variables in the Programming Guide. |
Length |
The length of the parameter or This field does not apply to the following Natural data formats:
The Natural data format |
Prec |
Only applies to Natural data formats The precision of the parameter, that is, the number of digits after the decimal point. |
Dimension 1/2/3 | Only applies to arrays. Optional.
The first, second and third dimension of the parameter. An X-array or an X-group array is specified by entering an asterisk (*) for a dimension. See also Defining X-Arrays and X-Group Arrays. |
The section below contains information on:
You only need to define a group structure for a client Natural object that calls a non-Natural object located on an EntireX RPC server. The group structure must correspond to the IDL definition in EntireX (see Special Considerations for Calling EntireX RPC Servers). A group structure is not required for a client Natural object that calls a subprogram located on a Natural RPC server.
Group arrays and X-group arrays passed from a client Natural object to an interface object must be contiguous. Therefore, we strongly recommend that you always pass a complete array to the object by using asterisk (*) notation for all dimensions. We also strongly recommend that you use identical data definitions in the client Natural program, the interface object and the server program.
See also Example 2 for an example of a group definition.
If any dimension of a parameter is extensible, all other dimensions of the parameter are also extensible. If you define extensible and fixed dimensions for a parameter in a subprogram, the Interface Object Generation function issues a warning and automatically changes the fixed dimension to an extensible dimension as demonstrated in Example 3. In a group structure, you can define either an extensible or a fixed dimension for each level. There is no automatic change of a fixed dimension to an extensible dimension between levels.
Natural RPC only supports extensible upper bounds. All X-arrays and
X-group arrays in the generated DEFINE DATA PARAMETER
area of the
interface object are therefore defined as (1:*)
.
Warnung: If you generate an interface object from a subprogram or a PDA that contains an X-array or X-group array with an extensible lower bound, the extensible lower bound will be converted to an extensible upper bound. |
For an example of a group with an extensible dimension, see Example 3.
If you want to use reliable RPC and your parameter definitions do not
contain group structures, you have to set COMPAT
IDL
before generating the interface
object.
The attribute definitions on the Interface Object Generation screen reflect the perspective of the client. Conversely, the parameter direction in the IDL definition reflects the perspective of the server. This means:
OUT
on the Interface Object
Generation screen corresponds to IN
in the IDL
definition.
IN
on the Interface Object
Generation screen corresponds to OUT
in the IDL
definition.
If you want to call an EntireX RPC server and the parameter definitions on the Interface Object Generation screen contain group structures, group structure and attribute definitions on the Interface Object Generation screen must correspond to the group structure and parameter direction in the IDL definition.
If you want to call an EntireX RPC server and the corresponding IDL
file does not contain group structures, it is recommended to set
COMPAT
IDL
before generating the interface object.
In this case, the attribute definitions on the Interface Object
Generation screen must correspond to the parameter direction in the
IDL definition.
This section provides examples of Natural subprograms and the interface objects generated from them.
The parameter definitions indicated below are extracted from example subprograms, which are supplied in the Natural system library SYSRPC.
The following DEFINE DATA PARAMETER
area (example
subprogram TESTS5) shows four modifiable parameters and the corresponding
parameter definitions on the
Interface Object Generation screen:
DEFINE DATA PARAMETER 01 #IDENTIFIER (A10) 01 #N-OF-ID (I4) 01 #FREQ (P5.2) 01 #A100 (A100/5,4)
Interface Object Generation | ||||||||
---|---|---|---|---|---|---|---|---|
Level | Attr | Type | Length | Prec | Dimension 1 | Dimension 2 | Dimension 3 | |
1 | 01 | M | A | 10 | ||||
2 | 01 | M | I | 4 | ||||
3 | 01 | M | P | 5 | 2 | |||
4 | 01 | M | A | 100 | 5 | 4 |
The following DEFINE DATA PARAMETER
area (example
subprogram TESTS6) shows a nested group structure and the corresponding
parameter definitions on the
Interface Object Generation screen:
DEFINE DATA PARAMETER 01 GROUP-1(10) 02 A (A20) 02 B (A20) 02 GROUP-2(20) 03 C (A10/5) 03 D (A10) 01 LINE (A) DYNAMIC
Interface Object Generation | ||||||||
---|---|---|---|---|---|---|---|---|
Level | Attr | Type | Length | Prec | Dimension 1 | Dimension 2 | Dimension 3 | |
1 | 01 | M | G | 10 | ||||
2 | 02 | M | A | 20 | ||||
3 | 02 | M | A | 20 | ||||
4 | 02 | M | G | 20 | ||||
5 | 03 | M | A | 10 | 5 | |||
6 | 03 | M | A | 10 | ||||
7 | 01 | M | A | DYNAMIC |
The following DEFINE DATA PARAMETER
area (example
subprogram TESTS7) shows a nested group structure with extensible dimensions
and the corresponding parameter definitions on the Interface Object Generation
screen.
DEFINE DATA PARAMETER 01 GROUP-1(10) 02 A (A20) 02 B (A20) 02 GROUP-2(0:*) 03 C (A10/5) 03 D (A10) 01 LINE (A) DYNAMIC
Interface Object Generation | ||||||||
---|---|---|---|---|---|---|---|---|
Level | Attr | Type | Length | Prec | Dimension 1 | Dimension 2 | Dimension 3 | |
1 | 01 | M | G | 10 | ||||
2 | 02 | M | A | 20 | ||||
3 | 02 | M | A | 20 | ||||
4 | 02 | M | G | * | ||||
5 | 03 | M | A | 10 | 5 | |||
6 | 03 | M | A | 10 | ||||
7 | 01 | M | A | DYNAMIC |