Class: Utils::Property

Inherits:
Object
  • Object
show all
Defined in:
lib/utils/properties.rb

Overview

Represents a single property value from a properties file.

Constant Summary collapse

REFERENCE_REGEX = 
/\$\{[^}]+}/
@@logger = 
LogEasy::Logger.get_logger(name)

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(name, value) ⇒ Property

Creates a new property.



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# File 'lib/utils/properties.rb', line 142

def initialize(name, value)
  @name = name
  @value = value
  @evaluated_value = value
  @evaluating = false
  @evaluated = false
end

Instance Attribute Details

#evaluated_value ⇒ Object

Returns the value of attribute evaluated_value.



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# File 'lib/utils/properties.rb', line 139

def evaluated_value
  @evaluated_value
end

#name ⇒ Object (readonly)

Returns the value of attribute name.



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# File 'lib/utils/properties.rb', line 137

def name
  @name
end

#value ⇒ Object (readonly)

Returns the value of attribute value.



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# File 'lib/utils/properties.rb', line 138

def value
  @value
end

Instance Method Details

#evaluate(force_evaluate = false) ⇒ Object

Each reference present in this property is passed to the given block. If no block is given the method returns immediately. The method will return immediately if this property has already been evaluated too.

If a block is given its result replaces each reference. A false may be returned to keep the original reference as is.



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# File 'lib/utils/properties.rb', line 155

def evaluate(force_evaluate = false)
  if not force_evaluate and self.evaluated
    # Property has already been evaluated. Return immediately.
    # The property has been evaluated. Do not evaluate again.
    @@logger.fine("Already evaluated '#{name}'.")
  elsif self.evaluating
    # The property is currently being evaluated and has been referenced again. Circular reference.
    raise "Circular reference detected starting at property #{name}=#{value}."
  elsif block_given?
    # This property is being evaluated. If a call to evaluate is made while evaluating is true an exception is raised.
    @@logger.fine("Evaluating '#{name}'...")
    self.evaluating = true
    self.evaluated_value = value.gsub(REFERENCE_REGEX) do |match|
      # Extract the key from the ${key} match and pass it to the block. If there is no block then do nothing.
      key = match[2..-2].to_sym
      @@logger.fine("Found reference '#{key}' in '#{name}'.")
      replacement = yield key
      # Return the original match as is if the replacement value is false.
      next match if not replacement
      # Otherwise return the replacement.
      @@logger.fine("Replacing '#{key}' in '#{name}' with '#{replacement}'.")
      next replacement
    end if value.instance_of?(String) # Only do this for Strings.
    # The property has been evaluated. Do not evaluate again.
    @@logger.debug("Final value for '#{name}' is '#{evaluated_value}'.")
    self.evaluating = false
    self.evaluated = true
  end
end