Class: ODBA::CacheEntry

Inherits:
Object show all
Defined in:
lib/odba/cache_entry.rb

Overview

:nodoc: all

Constant Summary collapse

@@id_table = 
{}
@@finalizer = 
proc { |object_id|
  if(odba_id = @@id_table.delete(object_id))
    ODBA.cache.invalidate odba_id
  end
}

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(obj) ⇒ CacheEntry

Returns a new instance of CacheEntry.



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# File 'lib/odba/cache_entry.rb', line 16

def initialize(obj)
  @odba_id = obj.odba_id
  update obj
  @accessed_by = {}
  @odba_observers = obj.odba_observers
  @cache_entry_mutex = Mutex.new
end

Instance Attribute Details

#accessed_by ⇒ Object (readonly)

Returns the value of attribute accessed_by.



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# File 'lib/odba/cache_entry.rb', line 15

def accessed_by
  @accessed_by
end

#last_access ⇒ Object

Returns the value of attribute last_access.



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# File 'lib/odba/cache_entry.rb', line 14

def last_access
  @last_access
end

#odba_id ⇒ Object (readonly)

Returns the value of attribute odba_id.



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# File 'lib/odba/cache_entry.rb', line 15

def odba_id
  @odba_id
end

#odba_object_id ⇒ Object (readonly)

Returns the value of attribute odba_object_id.



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# File 'lib/odba/cache_entry.rb', line 15

def odba_object_id
  @odba_object_id
end

Instance Method Details

#_odba_object ⇒ Object 



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# File 'lib/odba/cache_entry.rb', line 72

def _odba_object
    @odba_object || object_id2ref(@odba_object_id, @odba_id)
end

#object_id2ref(object_id, odba_id) ⇒ Object 



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# File 'lib/odba/cache_entry.rb', line 35

def object_id2ref(object_id, odba_id)
  if (obj = ObjectSpace._id2ref(object_id)) \
    && obj.is_a?(Persistable) && !obj.odba_unsaved? \
    && obj.odba_id == odba_id
    obj
  end
rescue RangeError, NoMethodError => e
  nil
end

#odba_add_reference(object) ⇒ Object 



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# File 'lib/odba/cache_entry.rb', line 47

def odba_add_reference(object)
    return unless object.respond_to?(:odba_id)
    @cache_entry_mutex.synchronize do
      @accessed_by.store(object.object_id, object.odba_id)
    end
	object
end

#odba_cut_connections! ⇒ Object 



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# File 'lib/odba/cache_entry.rb', line 54

def odba_cut_connections!
    @cache_entry_mutex.synchronize do
      @accessed_by.each { |object_id, odba_id|
        if((item = odba_id2ref(odba_id) || object_id2ref(object_id, odba_id)) \
          && item.respond_to?(:odba_cut_connection))
          item.odba_cut_connection(_odba_object)
        end
      }
    end
end

#odba_id2ref(odba_id) ⇒ Object 



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# File 'lib/odba/cache_entry.rb', line 44

def odba_id2ref(odba_id)
  odba_id && ODBA.cache.include?(odba_id) && ODBA.cache.fetch(odba_id)
end

#odba_notify_observers(*args) ⇒ Object 



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# File 'lib/odba/cache_entry.rb', line 64

def odba_notify_observers(*args)
  @odba_observers.each { |obs| obs.odba_update(*args) }
end

#odba_object ⇒ Object 



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# File 'lib/odba/cache_entry.rb', line 67

def odba_object
			@last_access  = Time.now
  @odba_object = _odba_object
  @odba_object || ODBA.cache.fetch(@odba_id)
end

#odba_old?(retire_horizon = Time.now - ODBA.cache.retire_age) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/odba/cache_entry.rb', line 75

def odba_old?(retire_horizon = Time.now - ODBA.cache.retire_age)
    !_odba_object.odba_unsaved? \
      && (retire_horizon > @last_access)
end

#odba_replace!(obj) ⇒ Object 



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# File 'lib/odba/cache_entry.rb', line 120

def odba_replace!(obj)
    oldhash = _odba_object.hash
	_odba_object.odba_replace!(obj)
    if(_odba_object.hash != oldhash)
      @cache_entry_mutex.synchronize do
        @accessed_by.each { |object_id, odba_id|
          if(item = odba_id2ref(odba_id) || object_id2ref(object_id, odba_id))
            item.rehash if(item.respond_to? :rehash)
          end
        }
      end
    end
end

#odba_retire(opts = {}) ⇒ Object 



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# File 'lib/odba/cache_entry.rb', line 79

def odba_retire opts={}
	# replace with stubs in accessed_by
    instance = _odba_object
    if opts[:force]
      @cache_entry_mutex.synchronize do
        @accessed_by.each do |object_id, odba_id|
          if item = odba_id2ref(odba_id)
            item.odba_stubize instance, opts
          elsif(item = object_id2ref(object_id, odba_id))
            if item.is_a?(Persistable) && !item.is_a?(Stub)
              item.odba_stubize instance, opts
            end
          end
        end
      end
      @accessed_by.clear
      @odba_object = nil
    else
      @accessed_by.delete_if { |object_id, odba_id|
        if(item = odba_id2ref(odba_id))
          item.odba_stubize instance
        elsif(item = object_id2ref(object_id, odba_id))
          case item
          when Stub
            true
          when Array, Hash
            false
          when Persistable
            item.odba_stubize instance
          else
            true
          end
        else
          true
        end
      }
      if @accessed_by.empty?
        @odba_object = nil
      end
    end
end

#update(obj) ⇒ Object 



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# File 'lib/odba/cache_entry.rb', line 23

def update obj
  @last_access = Time.now
  @odba_object = obj
  @odba_class = obj.class
  @odba_id = obj.odba_id
  unless @odba_object_id == obj.object_id
    @@id_table.delete @odba_object_id
    @odba_object_id = obj.object_id
    @@id_table.store @odba_object_id, @odba_id
    ObjectSpace.define_finalizer obj, @@finalizer
  end
end