Component Directive
Description
Definition of a part deployment strategy using the Metro component model.
Standard Attributes
| class | Declares the component classname (required). |
| name | Sets the component name. |
| activation | Set the activation policy (optional). The default value is SYSTEM. Possible values include STARTUP (triggers activation on startup), DEMAND (activation trigger on demand) and SYSTEM (activation decesions are delagated to the container). |
| lifestyle | Set the lifestyle policy (optional). Allowable values include singleton, thread, and transient. A component declaring the singleton lifestyle may be shared across all consumers within the JVM (i.e. the potential for concurrent access will exist). A component declaring the thread lifestyle policy may have a set of instances corresponding to the number of threads requesting access. A component declaring the transient lifestyle will instantiated for each access request. |
| collection | Sets the garbage collection policy (optional). Allowable values include weak, soft and hard. A component type declaring a weak collection policy will be garbage collected at the discretion of the JVM. A component declaring a soft collection policy will be garbage collected in the event of memory contention. A component declaring the hard collection policy will remain in memory for the lifetime of the JVM unless explicitly removed via a management system or controlling application. |
Special Attributes
| key | Required only when declaring a nested component as a child within a <parts> directive. The key uniquely identifies the child component within the scope of the enclosing entity. |