This post originated from an RSS feed registered with Ruby Buzz
by Dave Hoover.
Original Post: Ruby's Protected Access
Feed Title: Red Squirrel Reflections
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Feed Description: Dave Hoover explores the psychology of software development
Jamis posted yet another nugget of wisdom. This one was about Ruby's method visibility, which can be tricky for people coming to Ruby from Java or C#. Jamis left one aspect of the protected access level as an exercise for the rest of us, so I figured I'd write up an example that helps illustrate when you would use protected vs. private.
class Sibling
def ask(sib)
sib.tell
end
def spy_on(sib)
sib.secret # will always complain
end
protected
def tell
secret
end
private
def secret
"Charlie tooted"
end
end
rose = Sibling.new
ricky = Sibling.new
begin
puts ricky.tell
rescue
puts "Ricky will only tell another sibling"
end
begin
puts rose.spy_on(ricky)
rescue
puts "Ricky complains when Rose tries to find the secret"
end
puts rose.ask(ricky) # Ricky will tell if Rose asks nicely
One of the main differences for Java developers is that objects of the same class can't see each other's private methods.
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