User-Defined Functions
Use
If the standard functions for a target-field mapping do not fulfill your requirements, or if the graphical representation becomes unclear due to the complexity of the mapping, you have the option of creating your own user-defined functions. You can use this function to create Java source code. The function is included in the Java coding that is generated for the message mapping as a Java method.
Java programs must not be stateful. For example, you are not permitted to write data to a database table. The PCK cannot track these side effects. As a result, when it attempts to resend a message that has not yet been received by a receiver, data may inadvertently be written to the database twice.
Also note that you are not permitted to call java.lang.System.exit()or java.lang.System.setProperties().
A user-defined function is only visible in the message mapping in which you created it. You can insert the function in the data-flow editor by using the function category User-Defined, just like a standard function.
Integration
You can use your Java programs from imported archives in user-defined functions if the Java programs are located in the same, or an underlying software component version as the message mapping.
Prerequisites
You have created a message mapping and have loaded an XML structure for both the source and the target structure.
Features
You can use the following user-defined functions:
● Simple Functions (Cache = Value)
This function type can process individual field input values for each function call. Therefore, simple functions expect strings as input values and return a string.
● Advanced Functions (Cache = Context or Cache = Queue)
This function type can process multiple field input values for each function call. Before you call the function, you can either import all the field values of a context or the whole queue for the field in an array. For more information, see Advanced User-Defined Functions.
Note that when dealing with large messages, saving the entire queue in the cache requires a lot of memory at runtime. In such cases, it is therefore better to work with contexts.
○ For both function types you can use the following objects in the source code:
Objects in Simple and Advanced Functions
Object |
Use |
This object enables you to cache the values that you want to read again when you next call the same user-defined function. |
|
This object enables you to cache the values that you want to read again when you next call any user-defined function that is in the same message mapping. |
Activities
1.
To create a new
user-defined function, in the data-flow editor, choose Create New
Function (
), which is
located on the lower left-hand side of the screen. In the menu, choose
Simple Function or Advanced Function.
2. In the window that appears, specify the attributes of the new function:
Name
Technical name of the function. The name is displayed in the function chooser
and on the data-flow object.
Description
Description of how the function is used.
Cache
Function type (see
above)
Argument Count
In this table, you specify the number of input values the function can
process, and name them. All functions are of type String.
3. In the window that appears, you can create Java source code:
...
a. You can import Java packages to your methods from the Imports input field, by specifying them separated by a comma or semi-colon:
You do not need to import the packages java.lang.*, java.util.*, java.io.*, and java.lang.reflect.* since all message mappings require these packages and therefore import them. You should be able to access standard JDK and J2EE packages of the SAP Web Application Server by simply specifying the package under Import. In other words, you do not have to import it as an archive into the Integration Repository. You can also access classes of the SAP XML Toolkit, the SAP Java Connector, and the SAP Logging Service (see also: Runtime Environment (Java-Mappings)).
In addition to the standard packages, you can also specify Java packages that you have imported as archives and that are located in the same, or in an underlying software component version as the message mapping.
b. Create your Java source text in the editor window or copy source text from another editor.
4. Confirm with Save and Close.
5. User-defined functions are limited to the message mapping in which you created the function. To save the new function, save the message mapping.
6. To test the function, use the test environment.
The new function is now visible in the User-Defined function category. When you select this category, a corresponding button is displayed in the function chooser pushbutton bar. To edit, delete, or add the function to the data-flow editor, choose the arrow next to the button and select from the list box displayed.