class PObject

Constants

VERSION

Public Class Methods

allow_missing() click to toggle source

When ‘allow_missing` is called at the inheriting class level, then all calls to any missing attribute will return `nil` and supress the normal ruby behavior of raising a `NoMethodError`.

# File lib/pobject/pobject.rb, line 8
def self.allow_missing
  send :define_method, :allow_missing? do
    true
  end
end

Public Instance Methods

[](key) click to toggle source

Allow hash-style access to any of our stored properties. This will not reload from the disk more than once.

# File lib/pobject/pobject.rb, line 39
def [](key)
  get key
end

[]=(key, value) click to toggle source

Allow hash-style assignment to new peoperties

# File lib/pobject/pobject.rb, line 44
def []=(key, value)
  set key, value
end

attributes() click to toggle source

Return attribute names, so we can print them and their values in ‘inspect`.

# File lib/pobject/pobject.rb, line 59
def attributes
  @attributes ||= attributes!
end

attributes!() click to toggle source

Return attribute names from the store. TODO: Maybe also merge with instance_variables. Pay attention to @s.

# File lib/pobject/pobject.rb, line 65
def attributes!
  result = []
  store.transaction do 
    if store_key
      result = store[store_key] || {}
      result = result.keys
    else
      result = store.roots
    end
  end
  result = result.select { |a| a.is_a? Symbol }
end

inspect() click to toggle source

Return a nice string when inspecting or printing. This will load values from the store if they were not already loaded.

# File lib/pobject/pobject.rb, line 50
def inspect
  properties = attributes.sort.map { |var| [var, get(var).to_s].join(":") }.join ', '
  properties = " #{properties}" unless properties.empty?
  "<#{self.class.name}#{properties}>"
end

Also aliased as: to_s

method_missing(method, args=nil, &_block) click to toggle source

Intercept any call to an unknown method, and try to load it from the store. If it does not exist in the store as well, then raise the usual error. This method will also be called when trying to assign to a non existing attribute. In this case, we will save it to the store.

Calls superclass method

# File lib/pobject/pobject.rb, line 19
def method_missing(method, args=nil, &_block)
  if method.to_s[-1] == "="
    set method.to_s.chomp('=').to_sym, args
  else
    content = get method
    content ? content : allow_missing? ? nil : super
  end
end

respond_to_missing?(method, include_private=false) click to toggle source

Mirror the method_missing behavior.

# File lib/pobject/pobject.rb, line 29
def respond_to_missing?(method, include_private=false)
  if method.to_s[-1] == "="
    true
  else
    allow_missing? or !!get(method.to_sym)
  end
end

to_s()

Alias for: inspect

Private Instance Methods

allow_missing?() click to toggle source

We need to have a default ‘allow_missing?` method, which may be overridden by calling `allow_missing`.

# File lib/pobject/pobject.rb, line 82
def allow_missing?
  false
end

get(key) click to toggle source

Get a value from the store, and set it as an instance variable so that subsequent calls do not access the disk.

# File lib/pobject/pobject.rb, line 88
def get(key)
  result = instance_variable_get("@#{key}")
  result.nil? ? get!(key) : result
end

get!(key) click to toggle source

Hard get value from the store.

# File lib/pobject/pobject.rb, line 94
def get!(key)
  result = store.transaction do 
    if store_key
      store[store_key] ||= {}
      store[store_key][key] 
    else
      store[key]
    end
  end
  instance_variable_set "@#{key}", result
end

set(key, value) click to toggle source

Set a key=value pair in the store, and in an instance variable so that any subsequent call to ‘get` will not have to read it from the disk. In addition, add it to the attributes list, which is used by `inspect`.

# File lib/pobject/pobject.rb, line 109
def set(key, value)
  instance_variable_set "@#{key}", value
  attributes << key unless attributes.include? key
  store.transaction do
    if store_key
      store[store_key] ||= {}
      store[store_key][key] = value
    else
      store[key] = value
    end
  end 
end

store() click to toggle source

Return the actual store object. It can either be a YAML::Store or a PStore, which behave exactly the same.

# File lib/pobject/pobject.rb, line 129
def store
  @store ||= store!
end

store!() click to toggle source

Hard get the actual store object, based on the provided file extension.

# File lib/pobject/pobject.rb, line 134
def store!
  if ['.yml', 'yaml'].include?(store_file[-4,4]) 
    YAML::Store.new(store_file) 
  else
    PStore.new(store_file)
  end
end

store_file() click to toggle source

Return the store filename.

# File lib/pobject/pobject.rb, line 143
def store_file
  @store_file ||= store_file! 
end

store_file!() click to toggle source

Hard return the store filename based on the value of ‘to_store`. If an array, the first element is the path.

# File lib/pobject/pobject.rb, line 149
def store_file!
  to_store.is_a?(Array) ? to_store[0] : to_store
end

store_key() click to toggle source

Return the key to use in case multiple objects are to be saved in the same file.

# File lib/pobject/pobject.rb, line 155
def store_key
  @store_key.nil? ? @store_key = store_key! : @store_key
end

store_key!() click to toggle source

Hard return the store key based on the ‘to_store` value. If an array, the second element represents the key.

# File lib/pobject/pobject.rb, line 161
def store_key!
  to_store.is_a?(Array) ? to_store[1] : false
end

to_store() click to toggle source

The default store location. May be overridden by the inheriting class.

# File lib/pobject/pobject.rb, line 123
def to_store
  "#{self.class.to_s.downcase}.yml"
end