Class: SmartInject

Inherits:
Object
  • Object
show all
Defined in:
lib/smart_inject.rb

Overview

SmartInject - Made DI deadly simple

SmartInject is a minimalist, flexible and efficient dependency injection for Ruby.

Here, no DSL, no complex machinery, no dynamic change on the object model. This is just a lightweight class that bring you DI using constructor, one of the most used method for DI. You can use it without constraint on your design.

SmartInject can be used in isolation within your Gem just by applying standard ruby code: extend a class from SmartInject, and this is your new DI container.

Feel free to see the code of SmartInject (very short), get the gem or copy-past the SmartInject class file into your project… There is no external dependency.

SmartInject is intented to be under your control. No magic here.

Defined Under Namespace

Classes: ContainerError, InjectionError, SmartInjectError

Class Method Summary collapse

Class Method Details

.[](klass) ⇒ Object 



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# File 'lib/smart_inject.rb', line 34

def [](klass)
  klass_name = klass.to_s

  if @share_injections
    service = running[klass_name]
    return service if service
  end

  service = services.fetch(klass_name) { raise InjectionError, "service #{klass_name} unknown. Try to add #{name}.add(self) at the begining of #{klass_name} class." }
  try_instanciate(service).tap do |instance|
    running[klass_name] = instance if @share_injections
  end
end

.add(klass, &block) ⇒ Object 



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# File 'lib/smart_inject.rb', line 57

def add(klass, &block)
  (raise ContainerError, "the #{name} container is already started. No add allowed") if frozen?
  (raise ContainerError, "first argument must be a class. Found: #{klass}") unless klass.instance_of?(Class)

  services[klass.name] = block || klass
  running.delete(klass.name)
  self
end

.remap(looked_klass, injected_klass) ⇒ Object 



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# File 'lib/smart_inject.rb', line 48

def remap(looked_klass, injected_klass)
  (raise ContainerError, "the #{name} container is already started. No remap allowed") if frozen?
  (raise ContainerError, "first argument must be a class. Found: #{looked_klass}") unless looked_klass.instance_of?(Class)
  (raise ContainerError, "second argument must be a class. Found: #{injected_klass}") unless injected_klass.instance_of?(Class)

  services[looked_klass.name] = injected_klass
  self
end

.services ⇒ Object 



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# File 'lib/smart_inject.rb', line 30

def services
  @services ||= {}
end

.share_injections ⇒ Object 



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# File 'lib/smart_inject.rb', line 78

def share_injections
  (raise ContainerError, "the #{name} container is already started. No share_injections allowed") if frozen?

  @share_injections = true
  self
end

.share_injections? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/smart_inject.rb', line 85

def share_injections?
  !!(@share_injections)
end

.start_container! ⇒ Object 



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# File 'lib/smart_inject.rb', line 66

def start_container!
  return self if frozen?
  return freeze if @share_injections

  services.each do |(klass_name, service)|
    next if running[klass_name]

    try_instanciate(service).tap { |instance| running[klass_name] = instance }
  end
  freeze
end