Class: Palsy::Generic

Inherits:
Object
  • Object
show all
Defined in:
lib/palsy/basic/generic.rb

Overview

Palsy::Generic is the base type for Palsy types. It implements the basic things needed for Palsy to work.

Creating your own type is just a function of subclassing this and overriding the method Palsy::Generic#create_table, and adding methods you expect users to use to operate against the type. For example, this is what Palsy::Object#create_table looks like:

class Palsy::Object < Palsy::Generic
  def create_table
    @db.execute %Q[
      create table if not exists #{@table_name} (
        id integer not null primary key autoincrement,
        key varchar(255) not null,
        value text not null,
        UNIQUE(key)
      )
    ]
  end
end

Direct Known Subclasses

Collection, Object

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(table_name, object_name = nil) ⇒ Generic

This is the base constructor for all Palsy types and should always be run in subclasses before any action is taken by the class’s initializer.



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# File 'lib/palsy/basic/generic.rb', line 39

def initialize(table_name, object_name=nil)
  raise "a table_name must be provided!" unless table_name

  @table_name   = table_name
  @object_name  = object_name
  post_marshal_init
  create_table
end

Instance Attribute Details

#db ⇒ Object

The instance of Palsy. Overwriting this is probably not a good idea.



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# File 'lib/palsy/basic/generic.rb', line 28

def db
  @db
end

#object_name ⇒ Object (readonly)

The name of the object this object is bound to inside the table. May be nil for certain types.



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# File 'lib/palsy/basic/generic.rb', line 33

def object_name
  @object_name
end

#table_name ⇒ Object (readonly)

The name of the table this object is bound to.



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# File 'lib/palsy/basic/generic.rb', line 30

def table_name
  @table_name
end

Class Method Details

._load(value) ⇒ Object

Marshal helper to load objects.



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# File 'lib/palsy/basic/generic.rb', line 51

def self._load(value)
  obj = self.new(*Marshal.load(value))
  return obj
end

Instance Method Details

#==(other) ⇒ Object

Equality method for comparing Palsy objects.



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# File 'lib/palsy/basic/generic.rb', line 85

def ==(other)
  [:db, :table_name, :object_name].all? { |x| self.send(x) == other.send(x) }
end

#_dump(level) ⇒ Object

Marshal helper to dump objects. Only the table and object names are preserved.



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# File 'lib/palsy/basic/generic.rb', line 60

def _dump(level)
  self.db = nil
  res = Marshal.dump([@table_name, @object_name])
  post_marshal_init
  return res
end

#create_table ⇒ Object

Virtual method to define the create_table interface. Just raises, intended to be overridden.



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# File 'lib/palsy/basic/generic.rb', line 78

def create_table
  raise "Do not use the Generic type directly!"
end

#post_marshal_init ⇒ Object

Helper to manage the database instance for Marshal operations.



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# File 'lib/palsy/basic/generic.rb', line 70

def post_marshal_init
  @db = Palsy.instance
end