The Distribution Definition Language - Autonomics Development: A Domain-Specific Aspect Language Approach - page 69

take in the event of an error. The DDL is designed to support any number of
protocols and recovery strategies in the same source file, thereby allowing a single
source file to be used to apply distribution to any number of class files.

4.3.1 Comments

Comments in the DDL are the same as for the Java language.
end of line
Line comments start with '//' and end at the end of the line
multi line
Multi line comments start with /* and end with */

4.3.2 Keywords

The DDL reserves the following keywords, which therefore cannot be used as
identifiers. We discuss these keywords in subsequent sections.

Keyword:
import | service | recovery | protocol | serverPlugin |

options | pointcut | nextServer | abort | continue

4.3.3 Import Statements

The import statement is used to avoid having to use fully qualified class names
when referring to Java classes in the DDL. They are therefore equivalent to the
use of Java's import statement. The import statement is defined as follows:

ImportNameList ::= SingleImport (SingleImport)*
SingleImport ::= import Imports Semi

Imports ::= Identifier (Dot | Wildcard)*

The DDL specification/program may contain any number of import state-
ments and, in common with Java's convention, import statements may only appear
at the beginning of the DDL file.
The wildcard character '*' may be used to refer to all classes in a particular
Java package.

4.3.4 Service Statement

The service statement is used to describe one or more protocols, and associated
classes, and one or more recovery statements. The name used for the service
must be the same as the name of the DDL file with the extension ddl , for example
the service named TestService must be contained in the file TestService.ddl .
The service statement is defined as:

Service ::= service Identifier LeftCurley StatementList RightCurley