Class: Aspire::Enumerator::JSONEnumerator

Inherits:
Object
  • Object
show all
Defined in:
lib/aspire/enumerator/json_enumerator.rb

Overview

Enumerates over the properties of a JSON data structure

Direct Known Subclasses

LinkedDataURIEnumerator

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(yielder = nil, **hooks) ⇒ void

Initialises a new JSONEnumerator instance

Parameters:

  • yielder (Enumerator::Yielder) (defaults to: nil) —

    the yielder from an Enumerator

  • hooks (Hash) —

    a hash of executable callback hooks: {

    after_array: proc { |key,value,index| }
after_hash: proc { |key,value,index| }
after_yield: proc { |key,value,index| }
before_array: proc { |key,value,index| }
before_hash: proc { |key,value,index| }
before_yield: proc { |key,value,index| }

    }

    Each callback is a Proc accepting a property key (name), value, and optionally the numeric index of the property in its parent array (this is nil if the property is not an array member).

    Value is an array for after/before_array, a hash for after/before_hash and any type for after/before_yield.

    All before hooks must return a truthy value to allow processing of the value, or a falsey value to prevent processing of the value.

    Filters should be implemented in before hooks

    Before hooks can also be used to process arrays and hashes as a whole. They should return false if property-level processing is not required.



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# File 'lib/aspire/enumerator/json_enumerator.rb', line 42

def initialize(yielder = nil, **hooks)
  self.hooks = hooks
  self.yielder = yielder
end

Instance Attribute Details

#hooks ⇒ Hash

Returns the callback hooks.

Returns:

  • (Hash) —

    the callback hooks



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# File 'lib/aspire/enumerator/json_enumerator.rb', line 8

def hooks
  @hooks
end

#yielder ⇒ Enumerator::Yielder

Returns the yielder instance from an Enumerator.

Returns:

  • (Enumerator::Yielder) —

    the yielder instance from an Enumerator



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# File 'lib/aspire/enumerator/json_enumerator.rb', line 13

def yielder
  @yielder
end

Instance Method Details

#[](hook, *args, **kwargs) ⇒ Object 



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# File 'lib/aspire/enumerator/json_enumerator.rb', line 47

def [](hook, *args, **kwargs)
  h = hooks[hook]
  return true unless h && h.respond_to?(:call)
  h.call(*args, **kwargs) ? true : false
end

#[]=(hook, proc) ⇒ Object 



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# File 'lib/aspire/enumerator/json_enumerator.rb', line 53

def []=(hook, proc)
  unless proc.is_a?(Proc) || proc.is_a?(Method)
    raise ArgumentError, 'Proc or Method expected'
  end
  hooks[hook] = proc
end

#array(key, array, index) ⇒ void

This method returns an undefined value.

Enumerates an array of JSON data structures

Parameters:

  • key (String) —

    the property name

  • array (Object) —

    the property value

  • index (Integer) —

    the index of the property in its parent array, or nil if not part of an array



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# File 'lib/aspire/enumerator/json_enumerator.rb', line 66

def array(key, array, index)
  return unless self[:before_array, key, array, index]
  i = 0
  array.each do |value|
    enumerate(key, value, i)
    i += 1
  end
  self[:after_array, key, array, index]
end

#enumerate(key, value, index = nil) ⇒ void

This method returns an undefined value.

Enumerates the property/value pairs of a JSON data structure

Parameters:

  • key (String) —

    the property name

  • value (Object) —

    the property value

  • index (Integer) (defaults to: nil) —

    the index of the property in its parent array, or nil if not part of an array



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# File 'lib/aspire/enumerator/json_enumerator.rb', line 82

def enumerate(key, value, index = nil)
  if value.is_a?(Array)
    array(key, value, index)
  elsif value.is_a?(Hash)
    hash(key, value, index)
  else
    property(key, value, index)
  end
end

#enumerator(key, value) ⇒ Enumerator

Returns an enumerator enumerating property/value pairs of JSON data

Parameters:

  • key (String) —

    the initial key of the data

  • value (Object) —

    the initial value of the data

Returns:



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# File 'lib/aspire/enumerator/json_enumerator.rb', line 96

def enumerator(key, value)
  ::Enumerator.new do |yielder|
    self.yielder = yielder
    enumerate(key, value)
  end
end

#hash(key, hash, index = nil) ⇒ void

This method returns an undefined value.

Enumerates the property/value pairs of a JSON hash

Parameters:

  • key (String) —

    the property name

  • hash (Hash) —

    the hash to enumerate

  • index (Integer) (defaults to: nil) —

    the index of the property in its parent array, or nil if not part of an array



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# File 'lib/aspire/enumerator/json_enumerator.rb', line 109

def hash(key, hash, index = nil)
  return unless self[:before_hash, key, hash, index]
  hash.each do |k, v|
    v.is_a?(Array) || v.is_a?(Hash) ? enumerate(k, v) : property(k, v)
  end
  self[:after_hash, key, hash, index]
end

#property(key, value, index = nil) ⇒ void

This method returns an undefined value.

Yields a property/value pair

Parameters:

  • key (String) —

    the property name

  • value (Object) —

    the property value

  • index (Integer) (defaults to: nil) —

    the index of the property in its parent array, or nil if not part of an array



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# File 'lib/aspire/enumerator/json_enumerator.rb', line 123

def property(key, value, index = nil)
  return unless self[:before_yield, key, value, index]
  yielder << [key, value, index]
  self[:after_yield, hooks, key, value, index]
end