Volatile Sets Dictionary

This project aims to extend python's native dictionary class, in order to add volatile sets. Volatile sets are a combination of key and value that expires after a period of time. This time is decided by the user.

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Instalatiton

You can install it using pip with the following command.

pip install volatile_dictionary

To install it by cloning its github repository, use the following commands. The "-e" flag install it in the path you clone it to, so, changes in the code will be instantly valid for the package users.

git clone https://github.com/pedrogyrao/volatile_dictionary
cd volatile_dictionary
pip install -e .

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Using the VolatileDictionary Class

First import it in your project:

from volatile_dictionary import VolatileDictionary

Then instantiate it:

volatile_dict = VolatileDictionary()

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VolatileDictionary works as a normal dictionary

volatile_dict['key'] = 'value'
print(volatile_dict['key'])

saves internally the set "{'key', 'value'}" and outputs:

value

This set added above is nonvolatile. To add a volatile the key must be a length 2 tuple and with the second element being the set's duration time in seconds.

volatile_dict['volatile_key', 2] = 'volatile_value'

for the 2 seconds after the above line is ran, this code

print(volatile_dict['volatile_key'])

will output:

volatile_value

after 2 seconds the set "{'volatile_key': 'volatile_value'}" will be deleted.

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To manipulate this volatile sets three methods were created:

• is_set_volatile(key): returns "True" if the set is volatile and "False" if the set is nonvolatile.
• get_set_lifetime(key): returns the remaining lifetime of the specified key. If the key doesn't represent a volatile set, the method raises "NonvolatileTypeError".
• cancel_volatily(key): cancel the volatility of a volatile set. If the key doesn't represent a volatile set, the method raises "NonvolatileTypeError".

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In order to work with this differentiation between volatile and nonvolatile sets, the basic dict methods "keys", "values" and "items" were implemented too:

• volatile_keys and nonvolatile_keys;
• volatile_values and nonvolatile_values;
• volatile_items and nonvolatile_items.