Class: ActiveRecord::Migration::CommandRecorder
- Inherits:
-
Object
- Object
- ActiveRecord::Migration::CommandRecorder
- Defined in:
- lib/active_record/migration/command_recorder.rb
Overview
ActiveRecord::Migration::CommandRecorder records commands done during a migration and knows how to reverse those commands. The CommandRecorder knows how to invert the following commands:
-
add_column
-
add_index
-
add_timestamp
-
create_table
-
remove_timestamps
-
rename_column
-
rename_index
-
rename_table
Instance Attribute Summary collapse
-
#commands ⇒ Object
Returns the value of attribute commands.
-
#delegate ⇒ Object
Returns the value of attribute delegate.
Instance Method Summary collapse
-
#initialize(delegate = nil) ⇒ CommandRecorder
constructor
A new instance of CommandRecorder.
-
#inverse ⇒ Object
Returns a list that represents commands that are the inverse of the commands stored in
commands
. -
#record(*command) ⇒ Object
record
command
. -
#respond_to?(*args) ⇒ Boolean
:nodoc:.
Constructor Details
#initialize(delegate = nil) ⇒ CommandRecorder
Returns a new instance of CommandRecorder.
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# File 'lib/active_record/migration/command_recorder.rb', line 18 def initialize(delegate = nil) @commands = [] @delegate = delegate end |
Dynamic Method Handling
This class handles dynamic methods through the method_missing method
#method_missing(method, *args, &block) ⇒ Object (private)
Forwards any missing method call to the target.
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# File 'lib/active_record/migration/command_recorder.rb', line 97 def method_missing(method, *args, &block) @delegate.send(method, *args, &block) rescue NoMethodError => e raise e, e..sub(/ for #<.*$/, " via proxy for #{@delegate}") end |
Instance Attribute Details
#commands ⇒ Object
Returns the value of attribute commands.
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# File 'lib/active_record/migration/command_recorder.rb', line 16 def commands @commands end |
#delegate ⇒ Object
Returns the value of attribute delegate.
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# File 'lib/active_record/migration/command_recorder.rb', line 16 def delegate @delegate end |
Instance Method Details
#inverse ⇒ Object
Returns a list that represents commands that are the inverse of the commands stored in commands
. For example:
recorder.record(:rename_table, [:old, :new])
recorder.inverse # => [:rename_table, [:new, :old]]
This method will raise an IrreversibleMigration exception if it cannot invert the commands
.
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# File 'lib/active_record/migration/command_recorder.rb', line 39 def inverse @commands.reverse.map { |name, args| method = :"invert_#{name}" raise IrreversibleMigration unless respond_to?(method, true) send(method, args) } end |
#record(*command) ⇒ Object
record command
. command
should be a method name and arguments. For example:
recorder.record(:method_name, [:arg1, arg2])
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# File 'lib/active_record/migration/command_recorder.rb', line 27 def record(*command) @commands << command end |
#respond_to?(*args) ⇒ Boolean
:nodoc:
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# File 'lib/active_record/migration/command_recorder.rb', line 47 def respond_to?(*args) # :nodoc: super || delegate.respond_to?(*args) end |