Class: Methodist::Observer

Inherits:
Pattern
  • Object
show all
Defined in:
lib/methodist/observer.rb

Overview

Methodist::Observer

Base class for Methodist observers

Defined Under Namespace

Classes: ExecuteBlockWasNotDefined

Class Attribute Summary collapse

Class Method Summary collapse

Methods inherited from Pattern

#methodistic?

Class Attribute Details

.execution_block ⇒ Object (readonly)

Returns the value of attribute execution_block.



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# File 'lib/methodist/observer.rb', line 8

def execution_block
  @execution_block
end

Class Method Details

.execute(&block) ⇒ Object

Method for passing execution block for execution after observed method



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# File 'lib/methodist/observer.rb', line 110

def execute(&block)
  @execution_block = block
end

.observe(klass, method_name, skip_if: nil, instance_method: true, &main_block) ⇒ Object

Subscribe to the instance method of the klass to observe

Parameters

  • klass [Class] - The owner of the method for observation

  • method_name [String/Symbol] - Observation method name

Options

  • skip_if [Proc] - Skip triggered execution if condition is true (default nil)

  • instance_method [Boolean] - True if observer klass instance method, false if observer klass method (default true)

Yield

main_block - execution block. If this block was passed, ‘#execute` block will be ignored



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# File 'lib/methodist/observer.rb', line 26

def observe(klass, method_name, skip_if: nil, instance_method: true, &main_block)
  method_names = generate_method_names(method_name)

  # Make dump original method.
  if instance_method
    alias_instance_method(klass, method_names[:dump], method_names[:name])
  else
    alias_class_method(klass, method_names[:dump], method_names[:name])
  end

  observe_method!(klass, method_names, skip_if: skip_if, instance_method: instance_method, &main_block)
end

.observe_class_method(klass, method_name, skip_if: nil, &main_block) ⇒ Object

Subscribe to the class method of the klass to observe

Parameters

  • klass [Class] - The owner of the method for observation

  • method_name [String/Symbol] - Observation method name

Options

  • skip_if [Proc] - Skip triggered execution if condition is true

Yield

main_block - execution block. If this block was passed, ‘#execute` block will be ignored



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# File 'lib/methodist/observer.rb', line 54

def observe_class_method(klass, method_name, skip_if: nil, &main_block)
  observe(klass, method_name, skip_if: skip_if, instance_method: false, &main_block)
end

.observed_methods ⇒ Object 



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# File 'lib/methodist/observer.rb', line 114

def observed_methods
  @observed_method ||= []
end

.stop_observe(klass, method_name, instance_method: true) ⇒ Object

Stop observation instance method of klass for observe

Parameters

  • klass [Class] - Klass owner of the observed method

  • method_name [String/Symbol] - Name of the observed method



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# File 'lib/methodist/observer.rb', line 65

def stop_observe(klass, method_name, instance_method: true)
  method_names = generate_method_names(method_name)

  if instance_method
    unless method_defined?(klass, method_names[:observed]) && method_defined?(klass, method_names[:dump])
      return false
    end

    klass.send(:alias_method, method_names[:name], method_names[:dump]) # restore dumped instance method
    klass.send(:remove_method, method_names[:observed]) # remove observed instance method
    klass.send(:remove_method, method_names[:dump]) # remove dump instance method
  else
    unless klass_method_defined?(klass, method_names[:observed]) && klass_method_defined?(klass, method_names[:dump])
      return false
    end

    klass.singleton_class.send(:alias_method, method_names[:name], method_names[:dump]) # restore dumped class method
    klass.singleton_class.send(:remove_method, method_names[:observed]) # remove observed class method
    klass.singleton_class.send(:remove_method, method_names[:dump]) # remove dump class method
  end

  remove_from_observed(klass, method_names[:name], instance_method: instance_method)
  true
end

.trigger!(klass, method_name, result, *args) ⇒ Object

The executable block is passed to #execute Parameters klass and method_name are passed to block call

Parameters

  • klass [Class] - Klass owner of the observed method

  • method [Class] - Name of the observed method

Raise

ExecuteBlockWasNotDefined - when no block was passed to the execute method in the observer class

Raises:



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# File 'lib/methodist/observer.rb', line 101

def trigger!(klass, method_name, result, *args)
  block = execution_block rescue nil
  raise ExecuteBlockWasNotDefined, "You must define execute block in your #{self.name}" unless block
  block.call(klass, method_name, result, *args)
end