Class: OrderedHash

Inherits:
Hash show all
Defined in:
lib/mongo/util/ordered_hash.rb

Overview

A hash in which the order of keys are preserved.

Under Ruby 1.9 and greater, this class has no added methods because Ruby’s Hash already keeps its keys ordered by order of insertion.

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(*a, &b) ⇒ OrderedHash

Returns a new instance of OrderedHash.



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# File 'lib/mongo/util/ordered_hash.rb', line 52

def initialize(*a, &b)
  super
  @ordered_keys = []
end

Instance Attribute Details

#ordered_keys ⇒ Object

Returns the value of attribute ordered_keys.



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# File 'lib/mongo/util/ordered_hash.rb', line 35

def ordered_keys
  @ordered_keys
end

Class Method Details

.[](*args) ⇒ Object 



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# File 'lib/mongo/util/ordered_hash.rb', line 37

def self.[] *args
  oh = OrderedHash.new
  if Hash === args[0]
    oh.merge! args[0]
  elsif (args.size % 2) != 0
    raise ArgumentError, "odd number of elements for Hash"
  else
    0.step(args.size - 1, 2) do |key|
      value = key + 1
      oh[args[key]] = args[value]
    end
  end
  oh
end

Instance Method Details

#==(other) ⇒ Object 



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# File 'lib/mongo/util/ordered_hash.rb', line 23

def ==(other)
  begin
    !other.nil? &&
      keys == other.keys &&
      values == other.values
  rescue
    false
  end
end

#[]=(key, value) ⇒ Object 



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# File 'lib/mongo/util/ordered_hash.rb', line 61

def []=(key, value)
  @ordered_keys ||= []
  @ordered_keys << key unless @ordered_keys.include?(key)
  super(key, value)
end

#clear ⇒ Object 



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# File 'lib/mongo/util/ordered_hash.rb', line 117

def clear
  super
  @ordered_keys = []
end

#delete(key, &block) ⇒ Object 



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# File 'lib/mongo/util/ordered_hash.rb', line 104

def delete(key, &block)
  @ordered_keys.delete(key) if @ordered_keys
  super
end

#delete_if(&block) ⇒ Object 



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# File 'lib/mongo/util/ordered_hash.rb', line 109

def delete_if(&block)
  self.each { |k,v|
    if yield k, v
      delete(k)
    end
  }
end

#each ⇒ Object Also known as: each_pair 



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# File 'lib/mongo/util/ordered_hash.rb', line 67

def each
  @ordered_keys ||= []
  @ordered_keys.each { |k| yield k, self[k] }
  self
end

#eql?(o) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/mongo/util/ordered_hash.rb', line 131

def eql?(o)
  if o.instance_of? OrderedHash
    self.hash == o.hash
  else
    false
  end
end

#hash ⇒ Object 



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# File 'lib/mongo/util/ordered_hash.rb', line 122

def hash
  code = 17
  each_pair do |key, value|
    code = 37 * code + key.hash
    code = 37 * code + value.hash
  end
  code & 0x7fffffff
end

#inspect ⇒ Object 



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# File 'lib/mongo/util/ordered_hash.rb', line 98

def inspect
  str = '{'
  str << (@ordered_keys || []).collect { |k| "\"#{k}\"=>#{self.[](k).inspect}" }.join(", ")
  str << '}'
end

#keys ⇒ Object 



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# File 'lib/mongo/util/ordered_hash.rb', line 57

def keys
  @ordered_keys || []
end

#merge(other) ⇒ Object 



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# File 'lib/mongo/util/ordered_hash.rb', line 83

def merge(other)
  oh = self.dup
  oh.merge!(other)
  oh
end

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



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# File 'lib/mongo/util/ordered_hash.rb', line 89

def merge!(other)
  @ordered_keys ||= []
  @ordered_keys += other.keys # unordered if not an OrderedHash
  @ordered_keys.uniq!
  super(other)
end

#to_a ⇒ Object 



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# File 'lib/mongo/util/ordered_hash.rb', line 74

def to_a
  @ordered_keys ||= []
  @ordered_keys.map { |k| [k, self[k]] }      
end

#values ⇒ Object 



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# File 'lib/mongo/util/ordered_hash.rb', line 79

def values
  collect { |k, v| v }
end