Class: Dynamoid::TransactionWrite::UpdateFields::UpdateRequestBuilder

Inherits:
Object
  • Object
show all
Defined in:
lib/dynamoid/transaction_write/update_fields.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(model_class) ⇒ UpdateRequestBuilder

Returns a new instance of UpdateRequestBuilder.



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# File 'lib/dynamoid/transaction_write/update_fields.rb', line 130

def initialize(model_class)
  @model_class = model_class

  @attributes_to_set = {}
  @attributes_to_add = {}
  @attributes_to_delete = {}
  @attributes_to_remove = []
  @condition_expression = nil
end

Instance Attribute Details

#condition_expression=(value) ⇒ Object (writeonly)

Sets the attribute condition_expression

Parameters:

  • value —

    the value to set the attribute condition_expression to.



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# File 'lib/dynamoid/transaction_write/update_fields.rb', line 128

def condition_expression=(value)
  @condition_expression = value
end

#hash_key=(value) ⇒ Object (writeonly)

Sets the attribute hash_key

Parameters:

  • value —

    the value to set the attribute hash_key to.



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# File 'lib/dynamoid/transaction_write/update_fields.rb', line 128

def hash_key=(value)
  @hash_key = value
end

#range_key=(value) ⇒ Object (writeonly)

Sets the attribute range_key

Parameters:

  • value —

    the value to set the attribute range_key to.



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# File 'lib/dynamoid/transaction_write/update_fields.rb', line 128

def range_key=(value)
  @range_key = value
end

Instance Method Details

#add_value(name, value) ⇒ Object 



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# File 'lib/dynamoid/transaction_write/update_fields.rb', line 144

def add_value(name, value)
  @attributes_to_add[name] = value
end

#delete_value(name, value) ⇒ Object 



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# File 'lib/dynamoid/transaction_write/update_fields.rb', line 148

def delete_value(name, value)
  @attributes_to_delete[name] = value
end

#remove_attributes(names) ⇒ Object 



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# File 'lib/dynamoid/transaction_write/update_fields.rb', line 152

def remove_attributes(names)
  @attributes_to_remove.concat(names)
end

#request ⇒ Object 



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# File 'lib/dynamoid/transaction_write/update_fields.rb', line 156

def request
  key = { @model_class.hash_key => @hash_key }
  key[@model_class.range_key] = @range_key if @model_class.range_key?

  # Build UpdateExpression and keep names and values placeholders mapping
  # in ExpressionAttributeNames and ExpressionAttributeValues.
  update_expression_statements = []
  expression_attribute_names = {}
  expression_attribute_values = {}
  name_placeholder = '#_n0'
  value_placeholder = ':_v0'

  unless @attributes_to_set.empty?
    statements = []

    @attributes_to_set.each do |name, value|
      statements << "#{name_placeholder} = #{value_placeholder}"

      expression_attribute_names[name_placeholder] = name
      expression_attribute_values[value_placeholder] = value

      name_placeholder = name_placeholder.succ
      value_placeholder = value_placeholder.succ
    end

    update_expression_statements << "SET #{statements.join(', ')}"
  end

  unless @attributes_to_add.empty?
    statements = []

    @attributes_to_add.each do |name, value|
      statements << "#{name_placeholder} #{value_placeholder}"

      expression_attribute_names[name_placeholder] = name
      expression_attribute_values[value_placeholder] = value

      name_placeholder = name_placeholder.succ
      value_placeholder = value_placeholder.succ
    end

    update_expression_statements << "ADD #{statements.join(', ')}"
  end

  unless @attributes_to_delete.empty?
    statements = []

    @attributes_to_delete.each do |name, value|
      statements << "#{name_placeholder} #{value_placeholder}"

      expression_attribute_names[name_placeholder] = name
      expression_attribute_values[value_placeholder] = value

      name_placeholder = name_placeholder.succ
      value_placeholder = value_placeholder.succ
    end

    update_expression_statements << "DELETE #{statements.join(', ')}"
  end

  unless @attributes_to_remove.empty?
    name_placeholders = []

    @attributes_to_remove.each do |name|
      name_placeholders << name_placeholder

      expression_attribute_names[name_placeholder] = name

      name_placeholder = name_placeholder.succ
      value_placeholder = value_placeholder.succ
    end

    update_expression_statements << "REMOVE #{name_placeholders.join(', ')}"
  end

  update_expression = update_expression_statements.join(' ')

  {
    update: {
      key: key,
      table_name: @model_class.table_name,
      update_expression: update_expression,
      expression_attribute_names: expression_attribute_names,
      expression_attribute_values: expression_attribute_values,
      condition_expression: @condition_expression
    }
  }
end

#set_attributes(attributes) ⇒ Object

rubocop:disable Naming/AccessorMethodName



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# File 'lib/dynamoid/transaction_write/update_fields.rb', line 140

def set_attributes(attributes) # rubocop:disable Naming/AccessorMethodName
  @attributes_to_set.merge!(attributes)
end