Is there an easy way to define a common interface for a group of unrelated objects?
I've got a class that serializes data. I may want to serialize this data as JSON, or perhaps YAML. Can I cleanly swap YAML for JSON objects in this case? I was hoping I could do something lik开发者_如何学JAVAe the following. Is it a pipe dream?
FORMATS = {
:json => JSON,
:yaml => YAML,
}
def serialize(data, format)
FORMATS[format].serialize(data)
end
The code you have written should work just fine, provided that classes JSON
and YAML
both have class method called serialize
. But I think the method that actually exists is #dump
.
So, you would have:
require 'json'
require 'yaml'
FORMATS = {
:json => JSON,
:yaml => YAML,
}
def serialize(data, format)
FORMATS[format].dump(data)
end
hash = {:a => 2}
puts serialize hash, :json
#=> {"a":2}
puts serialize hash, :yaml
#=> ---
#=> :a: 2
If JSON
and YAML
are classes or modules that already exist, you can write:
FORMATS = { :json => "JSON", :yaml => "YAML" }
def serialize(data, format)
Kernel.const_get(FORMATS[format]).serialize(data) # 'serialize' is a class method in this case
end
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