Class: Sunspot::Adapters::DataAccessor

Inherits:
Object
  • Object
show all
Defined in:
lib/sunspot/adapters.rb

Overview

Subclasses of the DataAccessor class take care of retreiving instances of the adapted class from (usually persistent) storage. Subclasses must implement the #load method, which takes an id (the value returned by InstanceAdapter#id, as a string), and returns the instance referenced by that ID. Optionally, it can also override the #load_all method, which takes an array of IDs and returns an array of instances in the order given. #load_all need only be implemented if it can be done more efficiently than simply iterating over the IDs and calling #load on each individually.

Example

class FileAccessor < Sunspot::Adapters::InstanceAdapter
  def load(id)
    @clazz.open(id)
  end
end

Sunspot::Adapters::DataAccessor.register(FileAccessor, File)

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(clazz) ⇒ DataAccessor

:nodoc:



169
170
171
 
# File 'lib/sunspot/adapters.rb', line 169

def initialize(clazz) #:nodoc:
  @clazz = clazz
end

Class Method Details

.create(clazz) ⇒ Object

Create a DataAccessor for the given class, searching registered adapters for the best match. See InstanceAdapter#adapt for discussion of inheritence.

Parameters

clazz<Class>

Class to create DataAccessor for

Returns

DataAccessor

DataAccessor implementation which provides access to given class



203
204
205
 
# File 'lib/sunspot/adapters.rb', line 203

def create(clazz) #:nodoc:
  self.for(clazz).new(clazz)
end

.for(clazz) ⇒ Object

Find the best DataAccessor implementation that adapts the given class. Starting with the class and then moving up the ancestor chain, looks for registered DataAccessor implementations.

Parameters

clazz<Class>

The class to find a DataAccessor for

Returns

Class

Implementation of DataAccessor

Raises

Sunspot::NoAdapterError

If no data accessor exists for the given class

Raises:



240
241
242
243
244
245
246
247
248
249
 
# File 'lib/sunspot/adapters.rb', line 240

def for(clazz) #:nodoc:
  original_class_name = clazz.name
  clazz.ancestors.each do |ancestor_class|
    next if ancestor_class.name.nil? || ancestor_class.name.empty?
    class_name = ancestor_class.name.to_sym
    return data_accessors[class_name] if data_accessors[class_name]
  end
  raise(Sunspot::NoAdapterError,
        "No data accessor is configured for #{original_class_name} or its superclasses. See the documentation for Sunspot::Adapters")
end

.register(data_accessor, *classes) ⇒ Object

Register data accessor for a set of classes. When searching for an accessor for a given class, Sunspot starts with the class, and then searches for registered adapters up the class’s ancestor chain.

Parameters

data_accessor<Class>

The data accessor class to register

classes…<Class>

One or more classes that this data accessor providess access to



218
219
220
221
222
 
# File 'lib/sunspot/adapters.rb', line 218

def register(data_accessor, *classes)
  classes.each do |clazz|
    data_accessors[clazz.name.to_sym] = data_accessor
  end
end

Instance Method Details

#load_all(ids) ⇒ Object

Subclasses can override this class to provide more efficient bulk loading of instances. Instances must be returned in the same order that the IDs were given.

Parameters

ids<Array>

collection of IDs

Returns

Array

collection of instances, in order of IDs given



185
186
187
 
# File 'lib/sunspot/adapters.rb', line 185

def load_all(ids)
  ids.map { |id| self.load(id) }
end