----
 Ordering by Constraints
 ----
 
Ordering by Constraints

  Tapestry IoC has two specific areas where it must put some form of contribution into
  a specific order:
  
  * {{{configuration.html#Ordered List}Ordered Configurations}}, where different modules
    may contribute into a service's configuration
    
  * {{{decorator.html}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
  {{{../apidocs/org/apache/tapestry5/ioc/annotations/Order.html}Order}} 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.