Class: KerbalDyn::Data

Inherits:
Object
  • Object
show all
Defined in:
lib/kerbaldyn/data.rb

Overview

:nodoc: all

A class for doing the work of getting and maintaining singletons of data resources.

NOTE: There is NO reason a client to the library shoudl be in here; indeed, this is likely to drastically change, so using this class directly will result in trouble later.

Constant Summary collapse

FILE_MAP =

Files added here are automatically recognized by the fetch method. Files must be in the data directory.

{
  :planet_data => 'planet_data.json'
}

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(key, data_file_name) ⇒ Data

Initialize with the given key and data file name (in the data directory). This does NOT auto-add to the registry. Fetch will do so for entries in FILE_MAP.

Raises:

  • (ArgumentError) 


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# File 'lib/kerbaldyn/data.rb', line 35

def initialize(key, data_file_name)
  # Get a handle on the file.
  data_file = Pathname.new(__FILE__).dirname + 'data' + data_file_name.to_s
  raise ArgumentError, "No such file #{data_file.to_s}" unless data_file.exist?

  # Parse
  @data = case data_file.extname
          when '.json'
            JSON.parse( data_file.read, :symbolize_names => true )
          else
            raise ArgumentError "Cannot parse files of type #{data_file.extname}"
          end

  # Set key and freeze
  @key = key.freeze
  @data.freeze
end

Instance Attribute Details

#data ⇒ Object (readonly)

Returns the value of attribute data.



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# File 'lib/kerbaldyn/data.rb', line 53

def data
  @data
end

#key ⇒ Object (readonly)

Returns the value of attribute key.



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# File 'lib/kerbaldyn/data.rb', line 53

def key
  @key
end

Class Method Details

.fetch(key) ⇒ Object

Fetch a data singleton by the stored key.

If the key is unknown, then it attempts to fetch the data from disk.



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# File 'lib/kerbaldyn/data.rb', line 21

def self.fetch(key)
  registry = self.registry
  data_obj = registry.include?(key) ? registry[key] : registry[key]=self.new(key, FILE_MAP[key])
  return data_obj.data
end

.registry ⇒ Object

A method for directly getting the registry; this shoudl typically be treated as private.



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# File 'lib/kerbaldyn/data.rb', line 28

def self.registry
  return @registry ||= {}
end