Using ABAP Exception classes with Message classes (Part 1 of 2)

We’ve talked about Exception Classes, and we’ve talked about Message Classes. Now let’s see how we can combine these two together.

Let’s take a scenario, in which you have an exception that is thrown whenever a database error occurs in your program. Let’s call this exception class CX_DB_ERROR. We want our exception to display various messages that can also be translated later on to different languages. For example, “Error when writing to database” or “Error when reading from database”. So let’s combine ABAP Exception and Message classes.

1. First, create a message class through SE91. For this example’s sake, let’s call it CM_DATABASE_MESSAGES

2. Add a few messages to the message class. For our example, let’s add the message: “An error occurred when writing to table &1”. &1 indicates that a parameter would be inserted to the message. This parameter would be the name of the table that caused the error. We’ll get back to this in a few minutes.

3. Now open SE80 and create the exception class CX_DB_ERROR .

4. Remember that our message from step 2 states which table caused the error? Now’s the time to add this parameter. So click on the “Attributes” tab, and add an attribute for the table name. Let’s call it TABLE_NAME, and give it the type STRING.

5. Next, click on the “Texts” tab.

6. Enter a key to the message you would like to display on your exception class. In our example, let’s add the key WRITE_ERROR, indicating an error occurred when writing to the database.

7. Click on the “Message Text” button.

8. A new dialog opens, titled “Assign Attributes of an Exception Class to a Message”.

9. In the field “Message Class”, insert the name of the Message Class associated with your exception class. Let’s insert the class CM_DATABASE_MESSAGES, which we created earlier.

10. Now we need to choose the message number. Click on the choice button and choose the message “An error occurred when writing to table &1”. The number of the message should now appear in the field (as we created only one message in our example, it should be 000).

11. Now, you have to choose attributes that would be associated with the parameter &1. Click on the drop down list button, and choose the TABLE_NAME attribute we created earlier.

12. Save everything and activate.

You’ve just finished creating an exception class that uses a message class. In the next post, I’ll show you how to use the exception class with the message.