CDL
Each component used in the solution must be described in the CDL language, in a separate <component name>.cdl file.
The name of a CDL file must match the name of the component that it describes.
A CDL file includes the following sections:
- The name of the component. The reserved word
componentis placed before the component name.The component name must begin with an uppercase letter and must not contain an underscore (_).
- Security interface within this component. This section is optional. It must be added only if the component contains a security interface. It is declared with the reserved word
security, which should be followed by the full name of the interface. - A list of interface implementations included in this component. Interfaces are declared in the
interfacessection in which each interface implementation is specified with a separate string in the following format:interfaces {
<interface implementation name>:<interface name>
}
A component can contain several implementations of one interface. All implemented interfaces must be described in the IDL language in IDL files.
The interface implementation name must not contain an underscore (_).
- The list of instances of components embedded in this component. This section is optional. It should be added if the component contains embedded components. Components are declared in the
componentssection in which each component instance is specified with a separate string in the following format:components {
<component instance name>:<component name>
}
For each specified component, a separate file named
<component name>.cdlneeds to be created, containing a description of the component in the CDL language. Multiple instances of the same component can be added to a component, and each instance can have a separate state.The component instance name must not contain an underscore (_).
CDL supports single-line comments and multi-line C++-style comments.
Examples of CDL files
At its simplest, the component contains a single interface implementation similar to the ping component from the echo example.
Ping.cdl
/* Component name: Ping */
component Ping
/* The component contains a named implementation of the IPing interface. Implementation name: pingimpl.*/
components {
pingimpl: IPing
}
In the following example, the CoFoo component contains implementations of two interfaces declared in two different packages named Foo and Baz (i.e. in the Foo.idl and Bar.idl files):
CoFoo.cdl
/* Component name: CoFoo */
component CoFoo
interfaces {
/* The component contains an implementation of the Foo interface. Implementation name: foo.*/
foo: Foo
/* The component contains three different implementations of the Bar interface. Names of the implementations: bar1, bar2 and bar3.*/
bar1: Bar
bar2: Bar
bar3: Bar
}
In the following example, the CoFoo component contains a single interface implementation and an embedded component.
CoFoo.cdl
/* Component name: CoFoo */
component CoFoo
interfaces {
/* The component contains an implementation of the Foo interface. Implementation name: foo.*/
foo: Foo
}
components {
/* The component contains an instance of the CoBar component. Instance name: bar.*/
bar: CoBar
}