[CONF] Apache Tapestry > IoC - order

[confluence]

IoC - order Page added by Ulrich Stärk Ordering by Constraints Tapestry IoC has two specific areas where it must put some form of contribution into a specific order: Ordered Configurations, where different modules may contribute into a service's configuration Service Decorators which must be applied to services from a number of modules. In both these cases, objects (either contributions to a configuration, or decorators) are assigning qualified ids, simple ids qualified with the containing/contributing module's id. Because the contributions can come from different modules, and there isn't a specific order in which the service contribution methods are invoked, there is no natural ordering of the contributed objects. Instead, constraints are applied to each contribution. These constraints control what other objects must come before a contribution, or come after. The constraints are specified using the [Order|../apidocs/org/apache/tapestry5/ioc/annotations/Order.html] annotation (for service decorator methods), or as variable arguments at the end of the add() method for ordered configurations. Often a single contribution will have more than one constraint. Constraint Types Each constraint string begins with a prefix, "before:" or "after:", used to identify the type of constraint. The remainder of the constraint string is a comma-separated list of patterns. The contributed object will be ordered before or after the contributions identified by the patterns. Constraint Match Patterns A constraint match pattern is used to select one or more objects by their id. Match patterns support a very simple kind of wildcard matching. A "" may appear at the start, or end, or both of the pattern, and will match zero or more characters there. Thus you can have patterns such as "Data" or "Logic" or even "*User". Matching is case insensitive. Change Notification Preferences View Online