Class: Ambry::Adapter

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

Overview

Adapters are responsible for persisting the database. This base adapter offers no persistence, all IO operations are just stubs. Adapters must also present the full database as a Hash to the mapper, and provide a ‘key` method that returns an array with all the keys for the specified model class.

Direct Known Subclasses

Ambry::Adapters::File

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(options = {}) ⇒ Adapter

Returns a new instance of Adapter.

Parameters:

  • options (Hash) (defaults to: {}) —

    a customizable set of options

Options Hash (options):

  • :name (String) —

    The adapter name. Defaults to Ambry::Adapter#Ambry#Ambry.default_adapter_name.



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# File 'lib/ambry/adapter.rb', line 15

def initialize(options = {})
  @name      = options[:name] || Ambry.default_adapter_name
  @read_only = false
  load_database
  Ambry.register_adapter(self)
end

Instance Attribute Details

#db ⇒ Object (readonly)

Returns the value of attribute db.



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# File 'lib/ambry/adapter.rb', line 11

def db
  @db
end

#name ⇒ Object (readonly)

Returns the value of attribute name.



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# File 'lib/ambry/adapter.rb', line 10

def name
  @name
end

#read_only ⇒ Object

Returns the value of attribute read_only.



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# File 'lib/ambry/adapter.rb', line 12

def read_only
  @read_only
end

Instance Method Details

#db_for(klass) ⇒ Object

Get a hash of all the data for the specified model class.

Parameters:

  • klass (#to_s) —

    The model class whose data to return.



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# File 'lib/ambry/adapter.rb', line 24

def db_for(klass)
  @db[klass.to_s] ||= {}
end

#export_data ⇒ Object

Inheriting adapters can overload this method to export the data to a String.



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# File 'lib/ambry/adapter.rb', line 39

def export_data
  true
end

#import_data ⇒ Object

Inheriting adapters can overload this method to load the data from some kind of storage.



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# File 'lib/ambry/adapter.rb', line 45

def import_data
  true
end

#load_database ⇒ Object

Loads the database. For this adapter, that means simply creating a new hash.



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# File 'lib/ambry/adapter.rb', line 30

def load_database
  @db = {}
end

#read_only? ⇒ Boolean

Is the adapter read only? If so, attempts to write data will raise an AmbryError.

Returns:

  • (Boolean) 


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# File 'lib/ambry/adapter.rb', line 51

def read_only?
  @read_only
end

#save_database ⇒ Object

Inheriting adapters can overload this method to persist the data to some kind of storage.

Raises:



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# File 'lib/ambry/adapter.rb', line 57

def save_database
  raise AmbryError if read_only?
  true
end