Module: ActiveModel::AttributeMethods::ClassMethods
- Defined in:
- lib/active_model/attribute_methods.rb
Defined Under Namespace
Classes: AttributeMethodMatcher
Instance Method Summary collapse
- #alias_attribute(new_name, old_name) ⇒ Object
-
#attribute_method_affix(*affixes) ⇒ Object
Declares a method available for all attributes with the given prefix and suffix.
-
#attribute_method_prefix(*prefixes) ⇒ Object
Declares a method available for all attributes with the given prefix.
-
#attribute_method_suffix(*suffixes) ⇒ Object
Declares a method available for all attributes with the given suffix.
-
#define_attr_method(name, value = nil, &block) ⇒ Object
Defines an “attribute” method (like
inheritance_column
ortable_name
). - #define_attribute_method(attr_name) ⇒ Object
-
#define_attribute_methods(attr_names) ⇒ Object
Declares the attributes that should be prefixed and suffixed by ActiveModel::AttributeMethods.
-
#generated_attribute_methods ⇒ Object
Returns true if the attribute methods defined have been generated.
-
#undefine_attribute_methods ⇒ Object
Removes all the previously dynamically defined methods from the class.
Instance Method Details
#alias_attribute(new_name, old_name) ⇒ Object
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# File 'lib/active_model/attribute_methods.rb', line 238 def alias_attribute(new_name, old_name) attribute_method_matchers.each do |matcher| matcher_new = matcher.method_name(new_name).to_s matcher_old = matcher.method_name(old_name).to_s if matcher_new =~ COMPILABLE_REGEXP && matcher_old =~ COMPILABLE_REGEXP module_eval <<-RUBY, __FILE__, __LINE__ + 1 def #{matcher_new}(*args) send(:#{matcher_old}, *args) end RUBY else define_method(matcher_new) do |*args| send(matcher_old, *args) end end end end |
#attribute_method_affix(*affixes) ⇒ Object
Declares a method available for all attributes with the given prefix and suffix. Uses method_missing
and respond_to?
to rewrite the method.
#{prefix}#{attr}#{suffix}(*args, &block)
to
#{prefix}attribute#{suffix}(#{attr}, *args, &block)
An #{prefix}attribute#{suffix}
instance method must exist and accept at least the attr
argument.
For example:
class Person
include ActiveModel::AttributeMethods
attr_accessor :name
attribute_method_affix :prefix => 'reset_', :suffix => '_to_default!'
define_attribute_methods [:name]
private
def reset_attribute_to_default!(attr)
...
end
end
person = Person.new
person.name # => 'Gem'
person.reset_name_to_default!
person.name # => 'Gemma'
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# File 'lib/active_model/attribute_methods.rb', line 233 def attribute_method_affix(*affixes) self.attribute_method_matchers += affixes.map { |affix| AttributeMethodMatcher.new :prefix => affix[:prefix], :suffix => affix[:suffix] } undefine_attribute_methods end |
#attribute_method_prefix(*prefixes) ⇒ Object
Declares a method available for all attributes with the given prefix. Uses method_missing
and respond_to?
to rewrite the method.
#{prefix}#{attr}(*args, &block)
to
#{prefix}attribute(#{attr}, *args, &block)
An instance method #{prefix}attribute
must exist and accept at least the attr
argument.
For example:
class Person
include ActiveModel::AttributeMethods
attr_accessor :name
attribute_method_prefix 'clear_'
define_attribute_methods [:name]
private
def clear_attribute(attr)
send("#{attr}=", nil)
end
end
person = Person.new
person.name = "Bob"
person.name # => "Bob"
person.clear_name
person.name # => nil
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# File 'lib/active_model/attribute_methods.rb', line 158 def attribute_method_prefix(*prefixes) self.attribute_method_matchers += prefixes.map { |prefix| AttributeMethodMatcher.new :prefix => prefix } undefine_attribute_methods end |
#attribute_method_suffix(*suffixes) ⇒ Object
Declares a method available for all attributes with the given suffix. Uses method_missing
and respond_to?
to rewrite the method.
#{attr}#{suffix}(*args, &block)
to
attribute#{suffix}(#{attr}, *args, &block)
An attribute#{suffix}
instance method must exist and accept at least the attr
argument.
For example:
class Person
include ActiveModel::AttributeMethods
attr_accessor :name
attribute_method_suffix '_short?'
define_attribute_methods [:name]
private
def attribute_short?(attr)
send(attr).length < 5
end
end
person = Person.new
person.name = "Bob"
person.name # => "Bob"
person.name_short? # => true
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# File 'lib/active_model/attribute_methods.rb', line 195 def attribute_method_suffix(*suffixes) self.attribute_method_matchers += suffixes.map { |suffix| AttributeMethodMatcher.new :suffix => suffix } undefine_attribute_methods end |
#define_attr_method(name, value = nil, &block) ⇒ Object
Defines an “attribute” method (like inheritance_column
or table_name
). A new (class) method will be created with the given name. If a value is specified, the new method will return that value (as a string). Otherwise, the given block will be used to compute the value of the method.
The original method will be aliased, with the new name being prefixed with “original_”. This allows the new method to access the original value.
Example:
class Person
include ActiveModel::AttributeMethods
cattr_accessor :primary_key
cattr_accessor :inheritance_column
define_attr_method :primary_key, "sysid"
define_attr_method( :inheritance_column ) do
original_inheritance_column + "_id"
end
end
Provides you with:
Person.primary_key
# => "sysid"
Person.inheritance_column = 'address'
Person.inheritance_column
# => 'address_id'
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# File 'lib/active_model/attribute_methods.rb', line 100 def define_attr_method(name, value=nil, &block) sing = singleton_class sing.class_eval <<-eorb, __FILE__, __LINE__ + 1 if method_defined?('original_#{name}') undef :'original_#{name}' end alias_method :'original_#{name}', :'#{name}' eorb if block_given? sing.send :define_method, name, &block else # If we can compile the method name, do it. Otherwise use define_method. # This is an important *optimization*, please don't change it. define_method # has slower dispatch and consumes more memory. if name =~ COMPILABLE_REGEXP sing.class_eval <<-RUBY, __FILE__, __LINE__ + 1 def #{name}; #{value.nil? ? 'nil' : value.to_s.inspect}; end RUBY else value = value.to_s if value sing.send(:define_method, name) { value } end end end |
#define_attribute_method(attr_name) ⇒ Object
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# File 'lib/active_model/attribute_methods.rb', line 285 def define_attribute_method(attr_name) attribute_method_matchers.each do |matcher| unless instance_method_already_implemented?(matcher.method_name(attr_name)) generate_method = "define_method_#{matcher.prefix}attribute#{matcher.suffix}" if respond_to?(generate_method) send(generate_method, attr_name) else method_name = matcher.method_name(attr_name) generated_attribute_methods.module_eval <<-RUBY, __FILE__, __LINE__ + 1 if method_defined?('#{method_name}') undef :'#{method_name}' end RUBY if method_name.to_s =~ COMPILABLE_REGEXP generated_attribute_methods.module_eval <<-RUBY, __FILE__, __LINE__ + 1 def #{method_name}(*args) send(:#{matcher.method_missing_target}, '#{attr_name}', *args) end RUBY else generated_attribute_methods.module_eval <<-RUBY, __FILE__, __LINE__ + 1 define_method('#{method_name}') do |*args| send('#{matcher.method_missing_target}', '#{attr_name}', *args) end RUBY end end end end end |
#define_attribute_methods(attr_names) ⇒ Object
Declares the attributes that should be prefixed and suffixed by ActiveModel::AttributeMethods.
To use, pass in an array of attribute names (as strings or symbols), be sure to declare define_attribute_methods
after you define any prefix, suffix or affix methods, or they will not hook in.
class Person
include ActiveModel::AttributeMethods
attr_accessor :name, :age, :address
attribute_method_prefix 'clear_'
# Call to define_attribute_methods must appear after the
# attribute_method_prefix, attribute_method_suffix or
# attribute_method_affix declares.
define_attribute_methods [:name, :age, :address]
private
def clear_attribute(attr)
...
end
end
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# File 'lib/active_model/attribute_methods.rb', line 281 def define_attribute_methods(attr_names) attr_names.each { |attr_name| define_attribute_method(attr_name) } end |
#generated_attribute_methods ⇒ Object
Returns true if the attribute methods defined have been generated.
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# File 'lib/active_model/attribute_methods.rb', line 327 def generated_attribute_methods #:nodoc: @generated_attribute_methods ||= begin mod = Module.new include mod mod end end |
#undefine_attribute_methods ⇒ Object
Removes all the previously dynamically defined methods from the class
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# File 'lib/active_model/attribute_methods.rb', line 320 def undefine_attribute_methods generated_attribute_methods.module_eval do instance_methods.each { |m| undef_method(m) } end end |