Class: ActiveModel::Type::Value

Inherits:
Object
  • Object
show all
Defined in:
activemodel/lib/active_model/type/value.rb

Overview

The base class for all attribute types. This class also serves as the default type for attributes that do not specify a type.

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(precision: nil, limit: nil, scale: nil) ⇒ Value

Initializes a type with three basic configuration settings: precision, limit, and scale. The Value base class does not define behavior for these settings. It uses them for equality comparison and hash key generation only.


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# File 'activemodel/lib/active_model/type/value.rb', line 14

def initialize(precision: nil, limit: nil, scale: nil)
  @precision = precision
  @scale = scale
  @limit = limit
end

Instance Attribute Details

#limitObject (readonly)

Returns the value of attribute limit.


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# File 'activemodel/lib/active_model/type/value.rb', line 8

def limit
  @limit
end

#precisionObject (readonly)

Returns the value of attribute precision.


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# File 'activemodel/lib/active_model/type/value.rb', line 8

def precision
  @precision
end

#scaleObject (readonly)

Returns the value of attribute scale.


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# File 'activemodel/lib/active_model/type/value.rb', line 8

def scale
  @scale
end

Instance Method Details

#==(other) ⇒ Object Also known as: eql?


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# File 'activemodel/lib/active_model/type/value.rb', line 117

def ==(other)
  self.class == other.class &&
    precision == other.precision &&
    scale == other.scale &&
    limit == other.limit
end

#assert_valid_value(_) ⇒ Object


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# File 'activemodel/lib/active_model/type/value.rb', line 129

def assert_valid_value(_)
end

#binary?Boolean

These predicates are not documented, as I need to look further into their use, and see if they can be removed entirely.

Returns:


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# File 'activemodel/lib/active_model/type/value.rb', line 73

def binary? # :nodoc:
  false
end

#cast(value) ⇒ Object

Type casts a value from user input (e.g. from a setter). This value may be a string from the form builder, or a ruby object passed to a setter. There is currently no way to differentiate between which source it came from.

The return value of this method will be returned from ActiveRecord::AttributeMethods::Read#read_attribute. See also: Value#cast_value.

value The raw input, as provided to the attribute setter.


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# File 'activemodel/lib/active_model/type/value.rb', line 53

def cast(value)
  cast_value(value) unless value.nil?
end

#changed?(old_value, new_value, _new_value_before_type_cast) ⇒ Boolean

Determines whether a value has changed for dirty checking. old_value and new_value will always be type-cast. Types should not need to override this method.

Returns:


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# File 'activemodel/lib/active_model/type/value.rb', line 80

def changed?(old_value, new_value, _new_value_before_type_cast)
  old_value != new_value
end

#changed_in_place?(raw_old_value, new_value) ⇒ Boolean

Determines whether the mutable value has been modified since it was read. Returns false by default. If your type returns an object which could be mutated, you should override this method. You will need to either:

  • pass new_value to Value#serialize and compare it to raw_old_value

or

  • pass raw_old_value to Value#deserialize and compare it to new_value

raw_old_value The original value, before being passed to deserialize.

new_value The current value, after type casting.

Returns:


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# File 'activemodel/lib/active_model/type/value.rb', line 101

def changed_in_place?(raw_old_value, new_value)
  false
end

#deserialize(value) ⇒ Object

Converts a value from database input to the appropriate ruby type. The return value of this method will be returned from ActiveRecord::AttributeMethods::Read#read_attribute. The default implementation just calls Value#cast.

value The raw input, as provided from the database.


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# File 'activemodel/lib/active_model/type/value.rb', line 39

def deserialize(value)
  cast(value)
end

#force_equality?(_value) ⇒ Boolean

:nodoc:

Returns:


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# File 'activemodel/lib/active_model/type/value.rb', line 109

def force_equality?(_value) # :nodoc:
  false
end

#hashObject


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# File 'activemodel/lib/active_model/type/value.rb', line 125

def hash
  [self.class, precision, scale, limit].hash
end

#map(value) {|value| ... } ⇒ Object

:nodoc:

Yields:

  • (value)

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# File 'activemodel/lib/active_model/type/value.rb', line 113

def map(value) # :nodoc:
  yield value
end

#serializable?(value) ⇒ Boolean

Returns true if this type can convert value to a type that is usable by the database. For example a boolean type can return true if the value parameter is a Ruby boolean, but may return false if the value parameter is some other object.

Returns:


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# File 'activemodel/lib/active_model/type/value.rb', line 24

def serializable?(value)
  true
end

#serialize(value) ⇒ Object

Casts a value from the ruby type to a type that the database knows how to understand. The returned value from this method should be a String, Numeric, Date, Time, Symbol, true, false, or nil.


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# File 'activemodel/lib/active_model/type/value.rb', line 61

def serialize(value)
  value
end

#typeObject

Returns the unique type name as a Symbol. Subclasses should override this method.


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# File 'activemodel/lib/active_model/type/value.rb', line 30

def type
end

#type_cast_for_schema(value) ⇒ Object

Type casts a value for schema dumping. This method is private, as we are hoping to remove it entirely.


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# File 'activemodel/lib/active_model/type/value.rb', line 67

def type_cast_for_schema(value) # :nodoc:
  value.inspect
end

#value_constructed_by_mass_assignment?(_value) ⇒ Boolean

:nodoc:

Returns:


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# File 'activemodel/lib/active_model/type/value.rb', line 105

def value_constructed_by_mass_assignment?(_value) # :nodoc:
  false
end