class Transaction::Simple::Group

A transaction group is an object wrapper that manages a group of objects as if they were a single object for the purpose of transaction management. All transactions for this group of objects should be performed against the transaction group object, not against individual objects in the group.

Transaction Group Usage

require 'transaction/simple/group'

x = "Hello, you."
y = "And you, too."

g = Transaction::Simple::Group.new(x, y)
g.start_transaction(:first)     # -> [ x, y ]
g.transaction_open?(:first)     # -> true
x.transaction_open?(:first)     # -> true
y.transaction_open?(:first)     # -> true

x.gsub!(/you/, "world")         # -> "Hello, world."
y.gsub!(/you/, "me")            # -> "And me, too."

g.start_transaction(:second)    # -> [ x, y ]
x.gsub!(/world/, "HAL")         # -> "Hello, HAL."
y.gsub!(/me/, "Dave")           # -> "And Dave, too."
g.rewind_transaction(:second)   # -> [ x, y ]
x                               # -> "Hello, world."
y                               # -> "And me, too."

x.gsub!(/world/, "HAL")         # -> "Hello, HAL."
y.gsub!(/me/, "Dave")           # -> "And Dave, too."

g.commit_transaction(:second)   # -> [ x, y ]
x                               # -> "Hello, HAL."
y                               # -> "And Dave, too."

g.abort_transaction(:first)     # -> [ x, y ]
x                               = -> "Hello, you."
y                               = -> "And you, too."

Attributes

objects[R]

Returns the objects that are covered by this transaction group.

Public Class Methods

new(*objects) { |self| ... } click to toggle source

Creates a transaction group for the provided objects. If a block is provided, the transaction group object is yielded to the block; when the block is finished, the transaction group object will be cleared with clear.

# File lib/transaction/simple/group.rb, line 46
def initialize(*objects)
  @objects = objects || []
  @objects.freeze
  @objects.each { |obj| obj.extend(Transaction::Simple) }

  if block_given?
    begin
      yield self
    ensure
      self.clear
    end
  end
end

Public Instance Methods

abort_transaction(name = nil) click to toggle source

Aborts the transaction. Resets the object state to what it was before the transaction was started and closes the transaction. If name is specified, then the intervening transactions and the named transaction will be aborted. Otherwise, only the current transaction is aborted.

If the current or named transaction has been started by a block (Transaction::Simple.start), then the execution of the block will be halted with break self.

# File lib/transaction/simple/group.rb, line 107
def abort_transaction(name = nil)
  @objects.each { |obj| obj.abort_transaction(name) }
end
clear() click to toggle source

Clears the object group. Removes references to the objects so that they can be garbage collected.

# File lib/transaction/simple/group.rb, line 65
def clear
  @objects = @objects.dup.clear
end
commit_transaction(name = nil) click to toggle source

If name is nil (default), the current transaction level is closed out and the changes are committed.

If name is specified and name is in the list of named transactions, then all transactions are closed and committed until the named transaction is reached.

# File lib/transaction/simple/group.rb, line 117
def commit_transaction(name = nil)
  @objects.each { |obj| obj.commit_transaction(name) }
end
rewind_transaction(name = nil) click to toggle source

Rewinds the transaction. If name is specified, then the intervening transactions will be aborted and the named transaction will be rewound. Otherwise, only the current transaction is rewound.

# File lib/transaction/simple/group.rb, line 95
def rewind_transaction(name = nil)
  @objects.each { |obj| obj.rewind_transaction(name) }
end
start_transaction(name = nil) click to toggle source

Starts a transaction for the group. Stores the current object state. If a transaction name is specified, the transaction will be named. Transaction names must be unique. Transaction names of nil will be treated as unnamed transactions.

# File lib/transaction/simple/group.rb, line 88
def start_transaction(name = nil)
  @objects.each { |obj| obj.start_transaction(name) }
end
transaction(action = nil, name = nil) click to toggle source

Alternative method for calling the transaction methods. An optional name can be specified for named transaction support.

transaction(:start)

start_transaction

transaction(:rewind)

rewind_transaction

transaction(:abort)

abort_transaction

transaction(:commit)

commit_transaction

transaction(:name)

transaction_name

transaction

transaction_open?

# File lib/transaction/simple/group.rb, line 130
def transaction(action = nil, name = nil)
  @objects.each { |obj| obj.transaction(action, name) }
end
transaction_name() click to toggle source

Returns the current name of the transaction for the group. Transactions not explicitly named are named nil.

# File lib/transaction/simple/group.rb, line 80
def transaction_name
  @objects[0].transaction_name
end
transaction_open?(name = nil) click to toggle source

Tests to see if all of the objects in the group have an open transaction. See Transaction::Simple#transaction_open? for more information.

# File lib/transaction/simple/group.rb, line 72
def transaction_open?(name = nil)
  @objects.inject(true) do |val, obj|
    val = val and obj.transaction_open?(name)
  end
end