Class: PayPal::SDK::Core::Util::OrderedHash

Inherits:
Hash
  • Object
show all
Defined in:
lib/paypal-sdk/core/util/ordered_hash.rb

Overview

:nodoc:

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(*args, &block) ⇒ OrderedHash

In MRI the Hash class is core and written in C. In particular, methods are programmed with explicit C function calls and polymorphism is not honored.

For example, []= is crucial in this implementation to maintain the @keys array but hash.c invokes rb_hash_aset() originally. This prevents method reuse through inheritance and forces us to reimplement stuff.

For instance, we cannot use the inherited #merge! because albeit the algorithm itself would work, our []= is not being called at all by the C code.



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# File 'lib/paypal-sdk/core/util/ordered_hash.rb', line 22

def initialize(*args, &block)
  super
  @keys = []
end

Class Method Details

.[](*args) ⇒ Object 



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# File 'lib/paypal-sdk/core/util/ordered_hash.rb', line 27

def self.[](*args)
  ordered_hash = new

  if (args.length == 1 && args.first.is_a?(Array))
    args.first.each do |key_value_pair|
      next unless (key_value_pair.is_a?(Array))
      ordered_hash[key_value_pair[0]] = key_value_pair[1]
    end

    return ordered_hash
  end

  unless (args.size % 2 == 0)
    raise ArgumentError.new("odd number of arguments for Hash")
  end

  args.each_with_index do |val, ind|
    next if (ind % 2 != 0)
    ordered_hash[val] = args[ind + 1]
  end

  ordered_hash
end

Instance Method Details

#[]=(key, value) ⇒ Object 



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# File 'lib/paypal-sdk/core/util/ordered_hash.rb', line 57

def []=(key, value)
  @keys << key if !has_key?(key)
  super
end

#clear ⇒ Object 



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# File 'lib/paypal-sdk/core/util/ordered_hash.rb', line 116

def clear
  super
  @keys.clear
  self
end

#delete(key) ⇒ Object 



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# File 'lib/paypal-sdk/core/util/ordered_hash.rb', line 62

def delete(key)
  if has_key? key
    index = @keys.index(key)
    @keys.delete_at index
  end
  super
end

#delete_if ⇒ Object 



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# File 'lib/paypal-sdk/core/util/ordered_hash.rb', line 70

def delete_if
  super
  sync_keys!
  self
end

#each ⇒ Object Also known as: each_pair 



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# File 'lib/paypal-sdk/core/util/ordered_hash.rb', line 110

def each
  @keys.each {|key| yield [key, self[key]]}
end

#each_key ⇒ Object 



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# File 'lib/paypal-sdk/core/util/ordered_hash.rb', line 102

def each_key
  @keys.each { |key| yield key }
end

#each_value ⇒ Object 



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# File 'lib/paypal-sdk/core/util/ordered_hash.rb', line 106

def each_value
  @keys.each { |key| yield self[key]}
end

#initialize_copy(other) ⇒ Object 



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# File 'lib/paypal-sdk/core/util/ordered_hash.rb', line 51

def initialize_copy(other)
  super
  # make a deep copy of keys
  @keys = other.keys
end

#inspect ⇒ Object 



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# File 'lib/paypal-sdk/core/util/ordered_hash.rb', line 154

def inspect
  "#<OrderedHash #{super}>"
end

#invert ⇒ Object 



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# File 'lib/paypal-sdk/core/util/ordered_hash.rb', line 150

def invert
  OrderedHash[self.to_a.map!{|key_value_pair| key_value_pair.reverse}]
end

#keys ⇒ Object 



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# File 'lib/paypal-sdk/core/util/ordered_hash.rb', line 86

def keys
  @keys.dup
end

#merge(other_hash, &block) ⇒ Object 



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# File 'lib/paypal-sdk/core/util/ordered_hash.rb', line 139

def merge(other_hash, &block)
  dup.merge!(other_hash, &block)
end

#merge!(other_hash) ⇒ Object Also known as: update 



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# File 'lib/paypal-sdk/core/util/ordered_hash.rb', line 128

def merge!(other_hash)
  if block_given?
    other_hash.each { |k, v| self[k] = key?(k) ? yield(k, self[k], v) : v }
  else
    other_hash.each { |k, v| self[k] = v }
  end
  self
end

#reject(&block) ⇒ Object 



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# File 'lib/paypal-sdk/core/util/ordered_hash.rb', line 82

def reject(&block)
  dup.reject!(&block)
end

#reject! ⇒ Object 



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# File 'lib/paypal-sdk/core/util/ordered_hash.rb', line 76

def reject!
  super
  sync_keys!
  self
end

#replace(other) ⇒ Object

When replacing with another hash, the initial order of our keys must come from the other hash -ordered or not.



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# File 'lib/paypal-sdk/core/util/ordered_hash.rb', line 144

def replace(other)
  super
  @keys = other.keys
  self
end

#shift ⇒ Object 



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# File 'lib/paypal-sdk/core/util/ordered_hash.rb', line 122

def shift
  k = @keys.first
  v = delete(k)
  [k, v]
end

#to_a ⇒ Object 



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# File 'lib/paypal-sdk/core/util/ordered_hash.rb', line 98

def to_a
  @keys.map { |key| [ key, self[key] ] }
end

#to_hash ⇒ Object 



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# File 'lib/paypal-sdk/core/util/ordered_hash.rb', line 94

def to_hash
  self
end

#to_yaml_type ⇒ Object 



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# File 'lib/paypal-sdk/core/util/ordered_hash.rb', line 5

def to_yaml_type
  "!tag:yaml.org,2002:map"
end

#values ⇒ Object 



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# File 'lib/paypal-sdk/core/util/ordered_hash.rb', line 90

def values
  @keys.collect { |key| self[key] }
end