Class: Unit::ComposedUnit

Inherits:
BaseUnit show all
Includes:
Comparable
Defined in:
lib/unitmanager/unit_composition.rb

Overview

Implementation of what is called ‘composed unit of measure’. This is a result of performing multiplication or division of quantities with simple units. Example: 1 lb per in or 70 mi per hour

Instance Attribute Summary collapse

Instance Method Summary collapse

Methods included from Comparable

#compatible?, #contains?

Methods inherited from BaseUnit

#[], once

Constructor Details

#initialize(params) ⇒ ComposedUnit

Returns a new instance of ComposedUnit.



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# File 'lib/unitmanager/unit_composition.rb', line 28

def initialize(params)
  params = Optimizer.process(params)

  @coefficient = params[:coefficient] || 1
  @dividends = params[:dividends] || []
  @divisors = params[:divisors] || [] 
end

Instance Attribute Details

#coefficient ⇒ Object (readonly)

Returns the value of attribute coefficient.



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# File 'lib/unitmanager/unit_composition.rb', line 26

def coefficient
  @coefficient
end

#dividends ⇒ Object (readonly)

Returns the value of attribute dividends.



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# File 'lib/unitmanager/unit_composition.rb', line 26

def dividends
  @dividends
end

#divisors ⇒ Object (readonly)

Returns the value of attribute divisors.



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# File 'lib/unitmanager/unit_composition.rb', line 26

def divisors
  @divisors
end

Instance Method Details

#==(other) ⇒ Object

Two composed units are equal if their coefficients are the same and units contain same set of dividends and divisors.



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# File 'lib/unitmanager/unit_composition.rb', line 70

def ==(other)
  return false if other == nil
  return false unless other.kind_of?(self.class)
  
  result = (coefficient == other.coefficient) &&
   dividends.same?(other.dividends) &&
   divisors.same?(other.divisors)
  
  return result
end

#dividend ⇒ Object 



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# File 'lib/unitmanager/unit_composition.rb', line 52

def dividend
  ComposedUnit.new({:dividends => @dividends})
end

#divisor ⇒ Object 



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# File 'lib/unitmanager/unit_composition.rb', line 56

def divisor
  ComposedUnit.new({:divisors => @divisors})
end

#eql?(other) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/unitmanager/unit_composition.rb', line 81

def eql?(other)
  self == other
end

#from_base(value) ⇒ Object 



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# File 'lib/unitmanager/unit_composition.rb', line 40

def from_base(value)
  value * from_base_coef
end

#h_base ⇒ Object

Returns unit representing hierarchy base for the given unit. The Hierarchy is the “based on” chain.



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# File 'lib/unitmanager/unit_composition.rb', line 46

def h_base
  ComposedUnit.new({ :coefficient => 1.0,
        :dividends => Optimizer.base(@dividends),
        :divisors => Optimizer.base(@divisors) })
end

#reverse ⇒ Object 



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# File 'lib/unitmanager/unit_composition.rb', line 60

def reverse
  ComposedUnit.new({
    :coefficient => 1.0 / coefficient,
    :dividends => @divisors.collect{|unit| unit },
    :divisors => @dividends.collect{|unit| unit }
  })
end

#to_base(value) ⇒ Object 



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# File 'lib/unitmanager/unit_composition.rb', line 36

def to_base(value)
  value * to_base_coef
end