- Inheritance
The Forwardable module provides delegation of specified methods to a designated object, using the methods def_delegator and def_delegators.
For example, say you have a class RecordCollection which contains an array @records. You could provide the lookup method record_number(), which simply calls #[] on the @records array, like this:
class RecordCollection
extend Forwardable
def_delegator :@records, :[], :record_number
end
Further, if you wish to provide the methods size, #<<, and map, all of which delegate to @records, this is how you can do it:
class RecordCollection
# extend Forwardable, but we did that above
def_delegators :@records, :size, :<<, :map
end
Also see the example at forwardable.rb.
Attributes
| Name | Visibility | R/W | Description |
|---|---|---|---|
| debug | public | RW | force Forwardable to show up in stack backtraces of delegated methods |
Methods
Instance
| Visibility | Signature |
|---|---|
| public | def_delegator (accessor, method, ali = method) |
| public | def_delegators (accessor, *methods) |
| public | def_instance_delegator (accessor, method, ali = method) |
| public | def_instance_delegators (accessor, *methods) |
Instance Method Detail
def_delegator(accessor, method, ali = method)
Alias for def_instance_delegator
def_delegators(accessor, *methods)
Alias for def_instance_delegators
def_instance_delegator(accessor, method, ali = method)
Defines a method method which delegates to obj (i.e. it calls the method of the same name in obj). If new_name is provided, it is used as the name for the delegate method.
See the examples at Forwardable and forwardable.rb.
def_instance_delegators(accessor, *methods)
Shortcut for defining multiple delegator methods, but with no provision for using a different name. The following two code samples have the same effect:
def_delegators :@records, :size, :<<, :map def_delegator :@records, :size def_delegator :@records, :<< def_delegator :@records, :map
See the examples at Forwardable and forwardable.rb.