Module: Protege::HookMixin::ClassMethods

Defined in:
lib/protege/extensions/hook_mixin.rb

Overview

Class-level DSL mixed into every hook class via Hook.included.

Instance Method Summary collapse

Instance Method Details

#on(*event_classes, &block) ⇒ void

This method returns an undefined value.

Declare a handler for one or more event classes.

Pure declaration: records the block in subscriptions; the event bus is wired separately by Protege::Subscribers::HookDispatcher. Each argument must be a known Protege::Event subclass. Listing several registers the same block under each. A single event may carry several handlers; they run in declaration order. Each block is invoked with the event instance via instance_exec.

Parameters:

  • event_classes (Array<Class>) —

    the event classes to handle (e.g. Protege::InferenceStartedEvent)

  • block (Proc) —

    the handler, receiving the event instance

Raises:

  • (ArgumentError) —

    when an argument is not a known event class



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# File 'lib/protege/extensions/hook_mixin.rb', line 53

def on(*event_classes, &block)
  event_classes.each do |event_class|
    unless subscriptions.key?(event_class)
      raise ArgumentError, "unknown event #{event_class.inspect} (known: #{Protege::Event.all.join(', ')})"
    end

    subscriptions[event_class] << block
  end
end

#stateful ⇒ void

This method returns an undefined value.

Declare that this hook keeps state across a single run.

A stateful hook reuses one instance per correlation_id for the lifetime of a run, so instance variables set in one handler are visible to later handlers; the instance is evicted when the run ends. Stateless hooks (the default) get a fresh instance per event.



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# File 'lib/protege/extensions/hook_mixin.rb', line 70

def stateful
  @stateful = true
end

#stateful? ⇒ Boolean

Returns true when this hook was declared stateful.

Returns:

  • (Boolean) —

    true when this hook was declared stateful



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# File 'lib/protege/extensions/hook_mixin.rb', line 75

def stateful?
  @stateful || false
end

#subscriptions ⇒ Hash{Class => Array<Proc>}

The event subscriptions, keyed by every known event class.

Pre-seeded with one entry per Protege::Event.all (each an empty array), so the map is also the set of valid on targets. Handler blocks accumulate in declaration order.

Returns:

  • (Hash{Class => Array<Proc>}) —

    each known event class mapped to its handler blocks



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# File 'lib/protege/extensions/hook_mixin.rb', line 85

def subscriptions
  @subscriptions ||= Protege::Event.all.index_with { [] }
end