Class: Nutella::PersistedHash

Inherits:
Object
  • Object
show all
Defined in:
lib/config/persisted_hash.rb

Overview

This class behaves similarly to a regular Hash but it persists every operation to the file passed in the constructor. Not all Hash operations are supported and we added some of our own.

Instance Method Summary collapse

Constructor Details

#initialize(file) ⇒ PersistedHash

Returns a new instance of PersistedHash.



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# File 'lib/config/persisted_hash.rb', line 11

def initialize(file)
  @file=file
end

Instance Method Details

#[](key) ⇒ Object 



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# File 'lib/config/persisted_hash.rb', line 15

def []( key )
  hash = load_hash
  hash[key]
end

#[]=(key, val) ⇒ Object 



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# File 'lib/config/persisted_hash.rb', line 20

def []=( key, val )
  hash = load_hash
  hash[key]=val
  store_hash hash
end

#add_key_value?(key, val) ⇒ Boolean

Adds a <key, value> pair to the PersistedHash _only if_ there is currently no value associated with the specified key. <key, value> pair was added successfully

Returns:

  • (Boolean) —

    false if the key already exists, true if the



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# File 'lib/config/persisted_hash.rb', line 72

def add_key_value?(key, val)
  hash = load_hash
  return false if hash.key? key
  hash[key] = val
  store_hash hash
  true
end

#delete(key) ⇒ Object 



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# File 'lib/config/persisted_hash.rb', line 26

def delete( key )
  hash = load_hash
  return_value = hash.delete key
  store_hash hash
  return_value
end

#delete_key_value?(key) ⇒ Boolean

Removes a <key, value> pair from the PersistedHash _only if_ there is currently a value associated with the specified key. the specified key, true otherwise

Returns:

  • (Boolean) —

    false if there is no value associated with



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# File 'lib/config/persisted_hash.rb', line 84

def delete_key_value?( key )
  hash = load_hash
  return false if hash.delete(key).nil?
  store_hash hash
  true
end

#empty? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/config/persisted_hash.rb', line 33

def empty?
  hash = load_hash
  hash.empty?
end

#has_key?(key) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/config/persisted_hash.rb', line 38

def has_key?( key )
  hash = load_hash
  hash.has_key? key
end

#include?(key) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/config/persisted_hash.rb', line 43

def include?( key )
  has_key? key
end

#keys ⇒ Object 



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# File 'lib/config/persisted_hash.rb', line 56

def keys
  hash = load_hash
  hash.keys
end

#length ⇒ Object 



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# File 'lib/config/persisted_hash.rb', line 61

def length
  hash = load_hash
  hash.length
end

#remove_file ⇒ Object

Removes the file the hash is persisted to



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# File 'lib/config/persisted_hash.rb', line 93

def remove_file
  File.delete(@file) if File.exist?(@file)
end

#to_h ⇒ Object 



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# File 'lib/config/persisted_hash.rb', line 52

def to_h
  load_hash
end

#to_s ⇒ Object 



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# File 'lib/config/persisted_hash.rb', line 47

def to_s
  hash = load_hash
  hash.to_s
end