Class: Spinoza::LockManager::ReadLock

Inherits:
Object
  • Object
show all
Defined in:
lib/spinoza/system/lock-manager.rb

Overview

State of lock on one resource (e.g., a row), which may be held concurrently by any number of threads. Reentrant.

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(txn) ⇒ ReadLock

Returns a new instance of ReadLock.



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# File 'lib/spinoza/system/lock-manager.rb', line 21

def initialize txn
  @txns = Hash.new(0)
  add txn
end

Instance Attribute Details

#txns ⇒ Object (readonly)

Returns the value of attribute txns.



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# File 'lib/spinoza/system/lock-manager.rb', line 19

def txns
  @txns
end

Instance Method Details

#add(txn) ⇒ Object 



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# File 'lib/spinoza/system/lock-manager.rb', line 34

def add txn
  @txns[txn] += 1
end

#includes?(txn) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/spinoza/system/lock-manager.rb', line 30

def includes? txn
  @txns[txn] > 0
end

#remove(txn) ⇒ Object 



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# File 'lib/spinoza/system/lock-manager.rb', line 38

def remove txn
  if includes? txn
    @txns[txn] -= 1
    @txns.delete txn if @txns[txn] == 0
  else
    raise ConcurrencyError, "#{self} is not locked by #{txn}"
  end
end

#unlocked? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/spinoza/system/lock-manager.rb', line 26

def unlocked?
  @txns.all? {|t,c| c == 0}
end