SEND [METHOD]
operand1 TO [OBJECT]
operand2
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WITH
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operand3 |
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(AD= |
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) |
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nX |
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[RETURN
operand4]
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[GIVING
operand5]
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This document covers the following topics:
For an explanation of the symbols used in the syntax diagram, see Syntax Symbols.
Related Statements: CREATE OBJECT | DEFINE CLASS | INTERFACE | METHOD | PROPERTY
Belongs to Function Group: Component Based Programming
The SEND METHOD statement is used to invoke a particular
method of an object. See the section NaturalX in the
Programming Guide for information on component-based
programming.
Operand Definition Table:
| Operand | Possible Structure | Possible Formats | Referencing Permitted | Dynamic Definition | ||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| operand1 | C | S | A | yes | no | |||||||||||||||
| operand2 | S | O | no | no | ||||||||||||||||
| operand3 | C | S | A | G | A | U | N | P | I | F | B | D | T | L | C | G | O | yes | no | |
| operand4 | S | A | A | U | N | P | I | F | B | D | T | L | C | G | O | yes | no | |||
| operand5 | S | N | I | yes | no | |||||||||||||||
The formats C and G can only be passed to methods of local classes.
Syntax Element Description:
| operand1 |
Method-Name:
operand1 is the name of a method which is supported by the object specified in operand2. Since the method names can be identical in different interfaces of a class, the method name in operand1 can also be qualified with the interface name to avoid ambiguity. In the following example, the object * Specifying only the method name. SEND 'Start' TO #O3 * Qualifying the method name with the interface name. SEND 'Iterate.Start' TO #O3 If no interface name is specified, Natural searches the method name in all the interfaces of the class. If the method name is found in more than one interface, a runtime error occurs. |
|
|---|---|---|
| operand2 |
Object Handle:
The handle of the object to which the method call is to be sent. operand2 must be defined as an object handle (HANDLE OF OBJECT). The object must already exist. To invoke a method of the current object inside a method, use the
system variable |
|
| operand3 |
Parameter(s) Specific to the Method:
As operand3 you can specify parameters specific to the method. In the following example, the object SEND 'PositionTo' TO #O3 WITH Pos Methods can have optional parameters. Optional parameters need not to be specified when the method is called. To omit an optional parameter, use the placeholder 1X. To omit n optional parameters, use the placeholder nX. In the following example, the method
* Specifying all parameters. SEND 'SetAddress' TO #O4 WITH FirstName MiddleInitial LastName Street City * Omitting one optional parameter. SEND 'SetAddress' TO #O4 WITH FirstName 1X LastName Street City * Omitting all optional parameters. SEND 'SetAddress' TO #O4 WITH FirstName 1X LastName 2X Omitting a non-optional (mandatory) parameter results in a runtime error. |
|
| AD= |
Attribute Definition: If
operand3 is a variable, you can mark it in one of
the following ways:
|
|
| AD=O | Non-modifiable, see session parameter
AD=O.
|
|
| AD=M | Modifiable, see session parameter
AD=M.
This is the default setting. |
|
| AD=A | Input only, see session parameter
AD=A.
|
|
If
operand3 is a constant, AD
cannot be explicitly specified. For constants
AD=O
always applies.
|
||
| nX |
Parameter(s) to be Skipped:
With the notation For a method implemented in Natural, a parameter that is to be
skipped must be defined with the keyword |
|
| RETURN operand4 |
RETURN Clause:
If the If the Note: |
|
| GIVING operand5 |
GIVING Clause:
If the If the |
|
The following diagram gives an overview of the programming objects that are used in this example. The corresponding source code and the program output are shown below. Links to the source code of an object are provided in the diagram.
** Example 'METH01': CREATE OBJECT and SEND METHOD
** using a class and several methods (see METH*)
************************************************************************
DEFINE DATA
LOCAL
USING METHA
LOCAL
1 L-STUDENT HANDLE OF OBJECT
1 #NAME (A20)
1 #STREET (A20)
1 #CITY (A20)
1 #SUM (I4)
1 #MULTI (I4)
END-DEFINE
*
CREATE OBJECT L-STUDENT OF CLASS 'STUDENTS' /* see METHCL for class
*
L-STUDENT.<> := 'John Smith'
*
SEND METHOD 'INIT' TO L-STUDENT /* see METHCL
WITH #VAR1 #VAR2 #VAR3 #VAR4
*
SEND METHOD 'SUMMATION' TO L-STUDENT /* see METHCL
WITH #VAR1 #VAR2 #VAR3 #VAR4
*
SEND METHOD 'MULTIPLICATION' TO L-STUDENT /* see METHCL
WITH #VAR1 #VAR2 #VAR3 #VAR4
*
#NAME := L-STUDENT.<>
#SUM := L-STUDENT.<>
#MULTI := L-STUDENT.<>
*
SEND METHOD 'ADDRESS' TO L-STUDENT /* see METHCL
*
#STREET := L-STUDENT.<>
#CITY := L-STUDENT.<>
*
*
WRITE 'Name :' #NAME
WRITE 'Street:' #STREET
WRITE 'City :' #CITY
WRITE ' '
WRITE 'The summation of ' #VAR1 #VAR2 #VAR3 #VAR4
WRITE 'is' #SUM
WRITE 'The multiplication of' #VAR1 #VAR2 #VAR3 #VAR4
WRITE 'is' #MULTI
*
END
** Example 'METHCL': DEFINE CLASS (used by METH01)
************************************************************************
* Defining class STUDENTS for METH01
*
DEFINE CLASS STUDENTS
OBJECT
USING METHO /* Object data for class STUDENTS
/*
INTERFACE STUDENT-ARITHMETICS
PROPERTY FULL-NAME
IS NAME
END-PROPERTY
PROPERTY SUM
END-PROPERTY
PROPERTY MULTI
END-PROPERTY
*
METHOD INIT
IS METH02
PARAMETER USING METHA
END-METHOD
METHOD SUMMATION
IS METH03
PARAMETER USING METHA
END-METHOD
METHOD MULTIPLICATION
IS METH04
PARAMETER USING METHA
END-METHOD
END-INTERFACE
*
INTERFACE STUDENT-ADDRESS
PROPERTY STUDENT-NAME
IS NAME
END-PROPERTY
PROPERTY STREET
END-PROPERTY
PROPERTY CITY
END-PROPERTY
*
METHOD ADDRESS
IS METH05
END-METHOD
END-INTERFACE
END-CLASS
END
Local METHO Library SYSEXSYN DBID 10 FNR 32
Command > +
I T L Name F Length Miscellaneous
All -- -------------------------------- - ---------- ------------------------->
1 NAME A 20
1 STREET A 30
1 CITY A 20
1 SUM I 4
1 MULTI I 4
Parameter METHA Library SYSEXSYN DBID 10 FNR 32
Command > +
I T L Name F Length Miscellaneous
All -- -------------------------------- - ---------- ------------------------->
1 #VAR1 I 4
1 #VAR2 I 4
1 #VAR3 I 4
1 #VAR4 I 4
** Example 'METH02': Method INIT (used by METH01) ************************************************************************ DEFINE DATA PARAMETER USING METHA OBJECT USING METHO END-DEFINE * * Method INIT of class STUDENTS * #VAR1 := 1 #VAR2 := 2 #VAR3 := 3 #VAR4 := 4 * END
** Example 'METH03': Method SUMMATION (used by METH01) ************************************************************************ DEFINE DATA PARAMETER USING METHA OBJECT USING METHO END-DEFINE * * Method SUMMATION of class STUDENTS * COMPUTE SUM = #VAR1 + #VAR2 + #VAR3 + #VAR4 END
** Example 'METH04': Method MULTIPLICATION (used by METH01) ************************************************************************ DEFINE DATA PARAMETER USING METHA OBJECT USING METHO END-DEFINE * * Method MULTIPLICATION of class STUDENTS * COMPUTE MULTI = #VAR1 * #VAR2 * #VAR3 * #VAR4 END
** Example 'METH05': Method ADDRESS (used by METH01) ************************************************************************ DEFINE DATA OBJECT USING METHO END-DEFINE * * Method ADDRESS of class STUDENTS * IF NAME = 'John Smith' STREET := 'Oxford street' CITY := 'London' END-IF END
Page 1 05-01-17 15:59:04
Name : John Smith
Street: Oxford street
City : London
The summation of 1 2 3 4
is 10
The multiplication of 1 2 3 4
is 24