Module: ODBA::Persistable

Included in:
Array, Hash, IdServer, IndexCommon
Defined in:
lib/odba/persistable.rb

Constant Summary collapse

Exact = 
meta.new
Find = 
Exact.dup
ODBA_EXCLUDE_VARS =

Classes which include Persistable may override ODBA_EXCLUDE_VARS to prevent data from being stored in the database (e.g. passwords, file descriptors). Simply redefine: ODBA_EXCLUDE_VARS = [‘@foo’]

[]
ODBA_INDEXABLE =

:nodoc:

true
ODBA_PREFETCH =

see odba_prefetch?

false
ODBA_PREDEFINE_EXCLUDE_VARS =

:nodoc:

['@odba_observers']
ODBA_PREDEFINE_SERIALIZABLE =

:nodoc:, legacy

['@odba_target_ids']
ODBA_SERIALIZABLE =

If you want to prevent Persistables from being disconnected and stored separately (Array and Hash are Persistable by default), redefine: ODBA_SERIALIZABLE = [‘@bar’]

[]
@@sanitize_ptrn = 
/[^a-z0-9_]/i
@@odba_id_name = 
RUBY_VERSION >= '1.9' ? :@odba_id : '@odba_id'

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Instance Attribute Details

#odba_id ⇒ Object

If no id had been assigned, this is now done. No attempt is made to store the Persistable in the db.



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# File 'lib/odba/persistable.rb', line 265

def odba_id
	@odba_id ||= ODBA.cache.next_id
end

#odba_name ⇒ Object

Returns the value of attribute odba_name.



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# File 'lib/odba/persistable.rb', line 166

def odba_name
  @odba_name
end

#odba_persistent ⇒ Object

Classes which include Persistable have a class-method ‘odba_index’



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# File 'lib/odba/persistable.rb', line 31

def odba_persistent
  @odba_persistent
end

#odba_prefetch ⇒ Object

Returns the value of attribute odba_prefetch.



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# File 'lib/odba/persistable.rb', line 166

def odba_prefetch
  @odba_prefetch
end

Class Method Details

.append_features(mod) ⇒ Object 



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# File 'lib/odba/persistable.rb', line 32

def Persistable.append_features(mod)
  super
  mod.module_eval {
    class << self
      def odba_index(*keys)
        require 'odba/index_definition'
        origin_klass = self
        resolve_origin = nil
        resolve_target = :none
        resolve = {}
        opts = {}
        if(keys.size > 1)
          if(keys.last.is_a?(Hash))
            opts = keys.pop
          end
          if(keys.last.is_a?(Class))
            origin_klass = keys.pop 
            resolve = keys.pop
            resolve_origin = keys.pop
          elsif(keys.last.is_a?(Symbol))
            keys.each { |key|
              resolve.store(key, {'resolve' => key})
            }
          else
            resolve = keys.pop
          end
        else
          resolve = keys.first
        end
        keys.each { |key| 
          if RUBY_VERSION >= '1.9'
            key = key.to_sym
          else
            key = key.to_s
          end
          unless(instance_methods.include?(key))
            attr_accessor key
          end
        }
        index_prefix = self.name.downcase.gsub(/::/, '_')
        index_suffix = Persistable.sanitize(keys.join('_and_'))
        index_name = sprintf("%s_%s", index_prefix, index_suffix)
        search_name = sprintf("search_by_%s", index_suffix)
        exact_name = sprintf("search_by_exact_%s", index_suffix)
        find_name = sprintf("find_by_%s", index_suffix)
        keys_name = sprintf("%s_keys", index_suffix)
        index_definition = IndexDefinition.new
        index_definition.index_name = index_name
        index_definition.origin_klass = origin_klass
        index_definition.target_klass = self
        index_definition.resolve_search_term = resolve
        index_definition.resolve_origin = resolve_origin.to_s
        index_definition.resolve_target = resolve_target
        opts.each { |key, val| index_definition.send "#{key}=", val }
        ODBA.cache.ensure_index_deferred(index_definition)
        meta_eval {
          define_method(search_name) { |*vals| 
            if(vals.size > 1) 
              args = {}
              vals.each_with_index { |val, idx|
                cond = case val
                       when Numeric, Date
                         '='
                       else
                         'like'
                       end
                args.store(keys.at(idx), 
                           { 'value' => val, 'condition' => cond })
              }
              ODBA.cache.retrieve_from_index(index_name, args)
            else
              ODBA.cache.retrieve_from_index(index_name, vals.first)
            end
          }
          define_method(exact_name) {  |*vals|
            if(vals.size > 1) 
              args = {}
              vals.each_with_index { |val, idx|
                args.store(keys.at(idx), val)
              }
              ODBA.cache.retrieve_from_index(index_name, args, 
                                             ODBA::Persistable::Exact)
            else
              ODBA.cache.retrieve_from_index(index_name, vals.first,
                                             ODBA::Persistable::Exact)
            end
          }
          define_method(find_name) {  |*vals|
            if(vals.size > 1) 
              args = {}
              vals.each_with_index { |val, idx|
                cond = case val
                       when Numeric, Date
                         '='
                       else
                         'like'
                       end
                args.store(keys.at(idx), 
                           { 'value' => val, 'condition' => cond })
              }
              ODBA.cache.retrieve_from_index(index_name, args,
                                             ODBA::Persistable::Find)
            else
              ODBA.cache.retrieve_from_index(index_name, vals.first,
                                             ODBA::Persistable::Find)
            end.first
          }
          define_method(keys_name) { |*vals|
            # TODO fix this for fulltext and condition indices
            length, = vals
            ODBA.cache.index_keys(index_name, length)
          }
        }
        index_definition
      end
      def odba_extent
        all = ODBA.cache.extent(self) 
        if(block_given?)
          all.each { |instance| yield instance }
          nil
        else
          all
        end
      end
      def odba_count
        ODBA.cache.count(self) 
      end
    end
  }
end

.sanitize(name) ⇒ Object 



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# File 'lib/odba/persistable.rb', line 163

def Persistable.sanitize(name)
  name.gsub(@@sanitize_ptrn, '_')
end

Instance Method Details

#==(other) ⇒ Object

:nodoc:



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# File 'lib/odba/persistable.rb', line 185

def ==(other) # :nodoc:
	super(other.odba_instance)
end

#dup ⇒ Object

:nodoc:



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# File 'lib/odba/persistable.rb', line 189

def dup # :nodoc:
  twin = super
  ## since twin may not be a Persistable, we need to do some magic here to 
  #  ensure that it does not have the same odba_id
  twin.instance_variable_set(@@odba_id_name, nil)
  twin
end

#eql?(other) ⇒ Boolean

:nodoc:

Returns:

  • (Boolean) 


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# File 'lib/odba/persistable.rb', line 196

def eql?(other) # :nodoc:
  (other.is_a?(Stub) && other.odba_id == @odba_id) \
    || super(other.odba_instance)
end

#odba_add_observer(obj) ⇒ Object

Add an observer for Cache#store(self), Cache#delete(self) and Cache#clean removing the object from the Cache



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# File 'lib/odba/persistable.rb', line 202

def odba_add_observer(obj)
  odba_observers.push(obj)
  obj
end

#odba_collection ⇒ Object

:nodoc:



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# File 'lib/odba/persistable.rb', line 206

def odba_collection # :nodoc:
	[]
end

#odba_cut_connection(remove_object) ⇒ Object

Removes all connections to another persistable. This method is called by the Cache server when remove_object is deleted from the database



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# File 'lib/odba/persistable.rb', line 211

def odba_cut_connection(remove_object)
	odba_potentials.each { |name|
		var = instance_variable_get(name)
		if(var.eql?(remove_object))
			instance_variable_set(name, nil)
		end
	}
end

#odba_delete ⇒ Object

Permanently deletes this Persistable from the database and remove all connections to it



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# File 'lib/odba/persistable.rb', line 221

def odba_delete
	ODBA.cache.delete(self)
end

#odba_delete_observer(observer) ⇒ Object

Delete observer as an observer on this object. It will no longer receive notifications.



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# File 'lib/odba/persistable.rb', line 226

def odba_delete_observer(observer)
  @odba_observers.delete(observer) if(@odba_observers)
end

#odba_delete_observers ⇒ Object

Delete all observers associated with this object.



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# File 'lib/odba/persistable.rb', line 230

def odba_delete_observers
  @odba_observers = nil
end

#odba_dup ⇒ Object

:nodoc:



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# File 'lib/odba/persistable.rb', line 233

def odba_dup #:nodoc:
	twin = dup
    twin.extend(Persistable)
    twin.odba_id = @odba_id
	odba_potentials.each { |name|
		var = twin.instance_variable_get(name)
		if(var.is_a?(ODBA::Stub))
			stub = var.odba_dup
			stub.odba_container = twin
			twin.instance_variable_set(name, stub)
		end
	}
	twin
end

#odba_exclude_vars ⇒ Object

:nodoc:



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# File 'lib/odba/persistable.rb', line 247

def odba_exclude_vars # :nodoc:
			exc = if(defined?(self::class::ODBA_PREDEFINE_EXCLUDE_VARS))
          self::class::ODBA_PREDEFINE_EXCLUDE_VARS
        else
          ODBA_PREDEFINE_EXCLUDE_VARS
        end
			if(defined?(self::class::ODBA_EXCLUDE_VARS))
    exc += self::class::ODBA_EXCLUDE_VARS 
  end
  if RUBY_VERSION >= '1.9'
    exc.map{|v| v.to_sym}
  else
    exc
  end
end

#odba_indexable? ⇒ Boolean

:nodoc:

Returns:

  • (Boolean) 


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# File 'lib/odba/persistable.rb', line 300

def odba_indexable? # :nodoc:
	@odba_indexable \
      || (defined?(self::class::ODBA_INDEXABLE) && self::class::ODBA_INDEXABLE)
end

#odba_isolated_dump ⇒ Object

:nodoc:



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# File 'lib/odba/persistable.rb', line 268

def odba_isolated_dump # :nodoc:
	ODBA.marshaller.dump(odba_isolated_twin)
end

#odba_isolated_store ⇒ Object

Convenience method equivalent to ODBA.cache.store(self)



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# File 'lib/odba/persistable.rb', line 272

def odba_isolated_store 
	@odba_persistent = true
	ODBA.cache.store(self)
end

#odba_isolated_stub ⇒ Object

Returns a new instance of Stub, which can be used as a stand-in replacement for this Persistable.



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# File 'lib/odba/persistable.rb', line 278

def odba_isolated_stub
	Stub.new(self.odba_id, nil, self)
end

#odba_isolated_twin ⇒ Object

Returns a duplicate of this Persistable, for which all connected Persistables have been replaced by a Stub



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# File 'lib/odba/persistable.rb', line 283

def odba_isolated_twin
	# ensure a valid odba_id
	self.odba_id
	twin = self.odba_dup
	twin.odba_replace_persistables
	twin.odba_replace_excluded!
	twin
end

#odba_notify_observers(*args) ⇒ Object

Invoke the update method in each currently associated observer in turn, passing it the given arguments



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# File 'lib/odba/persistable.rb', line 306

def odba_notify_observers(*args) 
  odba_observers.each { |obs| obs.odba_update(*args) }
end

#odba_observers ⇒ Object 



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# File 'lib/odba/persistable.rb', line 309

def odba_observers
  @odba_observers ||= []
end

#odba_potentials ⇒ Object

:nodoc:



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# File 'lib/odba/persistable.rb', line 312

def odba_potentials # :nodoc:
	instance_variables - odba_serializables - odba_exclude_vars
end

#odba_prefetch? ⇒ Boolean

A Persistable instance can be prefetchable. This means that the object can be loaded at startup by calling ODBA.cache.prefetch, and that it will never expire from the Cache. The prefetch status can be controlled per instance by setting the instance variable @odba_prefetch, and per class by overriding the module constant ODBA_PREFETCH

Returns:

  • (Boolean) 


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# File 'lib/odba/persistable.rb', line 296

def odba_prefetch?
	@odba_prefetch \
      || (defined?(self::class::ODBA_PREFETCH) && self::class::ODBA_PREFETCH)
end

#odba_replace!(obj) ⇒ Object

:nodoc:



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# File 'lib/odba/persistable.rb', line 315

def odba_replace!(obj) # :nodoc:
  instance_variables.each { |name|
    instance_variable_set(name, obj.instance_variable_get(name))
  }
end

#odba_replace_persistables ⇒ Object

:nodoc:



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# File 'lib/odba/persistable.rb', line 320

def odba_replace_persistables # :nodoc:
	odba_potentials.each { |name|
		var = instance_variable_get(name)
		if(var.is_a?(ODBA::Stub))
        var.odba_clear_receiver   # ensure we don't leak into the db
        var.odba_container = self # ensure we don't leak into memory
		elsif(var.is_a?(ODBA::Persistable))
			odba_id = var.odba_id
			stub = ODBA::Stub.new(odba_id, self, var)
			instance_variable_set(name, stub)
		end
	}
	odba_serializables.each { |name|
		var = instance_variable_get(name)
		if(var.is_a?(ODBA::Stub))
			instance_variable_set(name, var.odba_instance)
		end
	}
end

#odba_replace_stubs(odba_id, substitution) ⇒ Object

:nodoc:



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# File 'lib/odba/persistable.rb', line 339

def odba_replace_stubs(odba_id, substitution) # :nodoc:
    odba_potentials.each { |name|
      var = instance_variable_get(name)
      if(var.is_a?(Stub) && odba_id == var.odba_id)
        instance_variable_set(name, substitution)
      end
    }
end

#odba_restore(collection = []) ⇒ Object

:nodoc:



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# File 'lib/odba/persistable.rb', line 347

def odba_restore(collection=[]) # :nodoc:
end

#odba_serializables ⇒ Object

:nodoc:



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# File 'lib/odba/persistable.rb', line 349

def odba_serializables # :nodoc:
	srs = if(defined?(self::class::ODBA_PREDEFINE_SERIALIZABLE))
            self::class::ODBA_PREDEFINE_SERIALIZABLE
          else
            ODBA_PREDEFINE_SERIALIZABLE
          end
	if(defined?(self::class::ODBA_SERIALIZABLE))
      srs += self::class::ODBA_SERIALIZABLE 
    end
    if RUBY_VERSION >= '1.9'
      srs.map{|s| s.to_sym}
    else
      srs
    end
end

#odba_snapshot(snapshot_level) ⇒ Object

:nodoc:



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# File 'lib/odba/persistable.rb', line 364

def odba_snapshot(snapshot_level) # :nodoc:
	if(snapshot_level > @odba_snapshot_level.to_i)
		@odba_snapshot_level = snapshot_level
		odba_isolated_store
	end
end

#odba_store(name = nil) ⇒ Object

Stores this Persistable and recursively all connected unsaved persistables, until no more direcly connected unsaved persistables can be found. The optional parameter name can be used later to retrieve this Persistable using Cache#fetch_named



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# File 'lib/odba/persistable.rb', line 374

def odba_store(name = nil)
	begin
		unless (name.nil?)
			old_name = @odba_name
			@odba_name = name
		end
		odba_store_unsaved
      self
	rescue 
		@odba_name = old_name
		raise
	end
end

#odba_store_unsaved ⇒ Object

:nodoc:



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# File 'lib/odba/persistable.rb', line 387

def odba_store_unsaved # :nodoc:
	@odba_persistent = false
	current_level = [self]
	while(!current_level.empty?)
		next_level = []
		current_level.each { |item|
			if(item.odba_unsaved?)
				next_level += item.odba_unsaved_neighbors
				item.odba_isolated_store
			end
		}
		current_level = next_level
	end
end

#odba_stubize(obj, opts = {}) ⇒ Object

:nodoc:



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# File 'lib/odba/persistable.rb', line 401

def odba_stubize(obj, opts={}) # :nodoc:
    return false if(frozen?)
	id = obj.odba_id
	odba_potentials.each { |name|
		var = instance_variable_get(name)
		# must not be synchronized because of the following if
		# statement (if an object has already been replaced by
		# a	stub, it will have the correct id and it
		# will be ignored) 
      case var
      when Stub
        # no need to make a new stub
      when Persistable
			if(var.odba_id == id) 
          stub = ODBA::Stub.new(id, self, obj)
          instance_variable_set(name, stub) 
        end
		end
	}
    odba_notify_observers(:stubize, id, obj.object_id)
    ## allow CacheEntry to retire
    true
end

#odba_take_snapshot ⇒ Object

Recursively stores all connected Persistables.



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# File 'lib/odba/persistable.rb', line 425

def odba_take_snapshot
	@odba_snapshot_level ||= 0
	snapshot_level = @odba_snapshot_level.next
	current_level = [self]
	tree_level = 0
	while(!current_level.empty?)
		tree_level += 1
		obj_count = 0
		next_level = []
		current_level.each { |item|
			if(item.odba_unsaved?(snapshot_level))
				obj_count += 1
				next_level += item.odba_unsaved_neighbors(snapshot_level)
				item.odba_snapshot(snapshot_level)
			end
		}
		current_level = next_level #.uniq
	end
end

#odba_target_ids ⇒ Object

:nodoc:



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# File 'lib/odba/persistable.rb', line 444

def odba_target_ids # :nodoc:
	odba_potentials.collect { |name|
		var = instance_variable_get(name)
		if(var.is_a?(ODBA::Persistable))
			var.odba_id
		end
	}.compact.uniq
end

#odba_unsaved?(snapshot_level = nil) ⇒ Boolean

:nodoc:

Returns:

  • (Boolean) 


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# File 'lib/odba/persistable.rb', line 463

def odba_unsaved?(snapshot_level = nil) # :nodoc:
	if(snapshot_level.nil?)
		!@odba_persistent
		#true
	else
		@odba_snapshot_level.to_i < snapshot_level
	end
end

#odba_unsaved_neighbors(snapshot_level = nil) ⇒ Object

:nodoc:



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# File 'lib/odba/persistable.rb', line 452

def odba_unsaved_neighbors(snapshot_level = nil) # :nodoc:
	unsaved = []
	odba_potentials.each { |name|
		item = instance_variable_get(name)
			if(item.is_a?(ODBA::Persistable) \
				&& item.odba_unsaved?(snapshot_level))
				unsaved.push(item)
			end
		}
	unsaved
end