Component Directive
link:xsd:dpml/lang/dpml-component#1.0
Description
Definition of a part deployment strategy using the Metro component model.
Standard Attributes
| type | Set the component type classname (required unless a super-directive is declared via the uri attribute). May not be used in conjunction with the special uri attribute. |
| name | Optional overriding of the component name. If not supplied the component profile name will default to the name of the underlying component type. |
| activation | Set the auto-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 | The component lifestyle. 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. The default lifestyle policy is thread unless the component is associated with an underlying type defintion in which case the type lifestyle value will apply. |
| collection | The component garbage collection policy. 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 within a type or parent component. The key corresponds to the internal key that uniquely identifies the child component within the scope of the enclosing entity. |
| uri | Optionally set the super-profile that the definition extends. May not be used in conjunction with the type attribute. |
Attributes Interited from Part Strategy
| alias | Used in conjunction with top-level components to declare that a link uri is produced referencing an absolute artifact uri to the component definition. |
Nested Elements
| categories | The categories element may contain 0..n logging <category> directives. A category directive allows manipulation of logging channel priorities and targets. |
| context | Declaration of the component initial context state. |
| parts | Declaration of the nested components. |