libneedle-ruby1.8 1.3.0-1 / usr / share / doc / libneedle-ruby1.8 / doc / manual / parts / 02_creating.txt

Creating a registry is as simple as calling @Needle::Registry.new@. This will give you a new registry object, bootstrapped to contain a few general services.

{{{lang=ruby,number=true,caption=Creating a registry
require 'needle'

registry = Needle::Registry.new
}}}

Once you have the reference to the registry, you can register services with it, create new namespaces in it, and so forth.

Alternatively, you can pass a block to @#new@:

{{{lang=ruby,number=true,caption=Creating a registry with a block
registry = Needle::Registry.new do |r|
  ...
end
}}}

The parameter to the block will be a reference to the registry. This allows you to register services with the registry as soon as it is created.

Another convenience method is @#define!@:

{{{lang=ruby,number=true,caption=Creating a registry with #define!
registry = Needle::Registry.define! do
  ...
end
}}}

This block accepts no parameters, and evaluates the block as if it were passed to @Registry#define!@ (see below).

There can be problems with using @define!@, however, since it uses @instance_eval@ to evaluate the block within the context of another object. If you find yourself running into scoping issues, you might want to consider using @#define@:

{{{lang=ruby,number=true,caption=Creating a registry with #define
registry = Needle::Registry.define do |b|
  ...
end
}}}

This block accepts a single parameter--a "builder" object to aid in registering services--and evaluates the block as if it were passed to @Registry#define@ (see below).