Rinda::TupleEntry

A TupleEntry is a Tuple (i.e. a possible entry in some Tuplespace) together with expiry and cancellation data.

Attributes

expires[RW]

Public Class Methods

new(ary, sec=nil) click to toggle source

Creates a TupleEntry based on ary with an optional renewer or expiry time sec.

A renewer must implement the renew method which returns a Numeric, nil, or true to indicate when the tuple has expired.

 
               # File rinda/tuplespace.rb, line 25
def initialize(ary, sec=nil)
  @cancel = false
  @expires = nil
  @tuple = make_tuple(ary)
  @renewer = nil
  renew(sec)
end

Public Instance Methods

[](key) click to toggle source

Retrieves key from the tuple.

 
               # File rinda/tuplespace.rb, line 109
def [](key)
  @tuple[key]
end

alive?() click to toggle source

A TupleEntry is dead when it is canceled or expired.

 
               # File rinda/tuplespace.rb, line 43
def alive?
  !canceled? && !expired?
end

cancel() click to toggle source

Marks this TupleEntry as canceled.

 
               # File rinda/tuplespace.rb, line 36
def cancel
  @cancel = true
end

canceled?() click to toggle source

Returns the canceled status.

 
               # File rinda/tuplespace.rb, line 56
def canceled?; @cancel; end

expired?() click to toggle source

Has this tuple expired? (true/false).

A tuple has expired when its expiry timer based on the sec argument to initialize runs out.

 
               # File rinda/tuplespace.rb, line 64
def expired?
  return true unless @expires
  return false if @expires > Time.now
  return true if @renewer.nil?
  renew(@renewer)
  return true unless @expires
  return @expires < Time.now
end

fetch(key) click to toggle source

Fetches key from the tuple.

 
               # File rinda/tuplespace.rb, line 116
def fetch(key)
  @tuple.fetch(key)
end

make_expires(sec=nil) click to toggle source

Returns an expiry Time based on sec which can be one of:

Numeric: sec seconds into the future
true: the expiry time is the start of 1970 (i.e. expired)
nil: it is Tue Jan 19 03:14:07 GMT Standard Time 2038 (i.e. when UNIX clocks will die)

 
               # File rinda/tuplespace.rb, line 95
def make_expires(sec=nil)
  case sec
  when Numeric
    Time.now + sec
  when true
    Time.at(1)
  when nil
    Time.at(2**31-1)
  end
end

make_tuple(ary) click to toggle source

Creates a Rinda::Tuple for ary.

 
               # File rinda/tuplespace.rb, line 130
def make_tuple(ary)
  Rinda::Tuple.new(ary)
end

renew(sec_or_renewer) click to toggle source

Reset the expiry time according to sec_or_renewer.

nil: it is set to expire in the far future.
true: it has expired.
Numeric: it will expire in that many seconds.

Otherwise the argument refers to some kind of renewer object which will reset its expiry time.

 
               # File rinda/tuplespace.rb, line 83
def renew(sec_or_renewer)
  sec, @renewer = get_renewer(sec_or_renewer)
  @expires = make_expires(sec)
end

size() click to toggle source

The size of the tuple.

 
               # File rinda/tuplespace.rb, line 123
def size
  @tuple.size
end

value() click to toggle source

Return the object which makes up the tuple itself: the Array or Hash.

 
               # File rinda/tuplespace.rb, line 51
def value; @tuple.value; end

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Rinda::TupleEntry

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