Class: RDF::Util::Cache::WeakRefCache

Inherits:
RDF::Util::Cache show all
Defined in:
lib/rdf/util/cache.rb

Overview

This implementation uses the WeakRef class from Ruby's standard library, and provides adequate performance on JRuby and on Ruby 2.x.

Instance Attribute Summary

Attributes inherited from RDF::Util::Cache

#capacity

Instance Method Summary collapse

Methods inherited from RDF::Util::Cache

#capacity?, #size

Constructor Details

#initialize(capacity = nil) ⇒ WeakRefCache

Returns a new instance of WeakRefCache.

Parameters:

  • capacity (Integer) (defaults to: nil)

Since:

  • 0.2.0


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# File 'lib/rdf/util/cache.rb', line 113

def initialize(capacity = nil)
  require 'weakref' unless defined?(::WeakRef)
  super
end

Instance Method Details

#[](key) ⇒ Object

Parameters:

  • key (Object)

Returns:

  • (Object)

Since:

  • 0.2.0


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# File 'lib/rdf/util/cache.rb', line 121

def [](key)
  if (ref = @cache[key])
    if ref.weakref_alive?
      value = ref.__getobj__ rescue nil
    else
      @cache.delete(key)
      nil
    end
  end
end

#[]=(key, value) ⇒ Object

Parameters:

  • key (Object)
  • value (Object)

Returns:

  • (Object)

Since:

  • 0.2.0


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# File 'lib/rdf/util/cache.rb', line 136

def []=(key, value)
  if capacity?
    @cache[key] = WeakRef.new(value)
  end
  value
end

#delete(key) ⇒ Object

Remove cache entry for key

Parameters:

  • key (Object)

Returns:

  • (Object)

    the previously referenced object

Since:

  • 0.2.0


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# File 'lib/rdf/util/cache.rb', line 148

def delete(key)
  ref = @cache.delete(key)
  ref.__getobj__ rescue nil
end