contractAPI module

abcFinance specifies a contract API. This allows the user to use the full python language to specify contracts.

Both / all contract parties get a copy of the contract.

class contractAPI.Action(action, more_info=None)

Bases: object

An action has to properties. The action to be executed and further information. This could be for example whether the action is obligatory or not.

Example:

Action(('pay', 50, 'UBS'), 'compulsory')

The action property and more_info, can have any content the tuple (‘pay’, 50, ‘UBV’) is just and example.

action = None

self.action, action to be executed,

more_info = None

self.more_info, further information

class contractAPI.Contract(issuing_party, *_, **__)

Bases: object

A contract is a tree or sequence of Action`s. A contract must implement :method:`get_action, which gives the next action given the current time and relevant state. Further it must implement :method:`action_executed`, which is lets the contract know that an action has been is executed.

Optionally is_terminanted should return whether the contract is terminated.

In order to use a contract with a book keeping system :method:`valuation` needs to return the valuation

action_executed(obligation)

Let the contract know that a particular obligation has been executed. This is used by the agent that execute the obligation on his copy and by the receiving agent on his copy of the contract.

Example:

self.num_excecuted_payments += 1

get_actions(party, time, *_, **__)

Returns a list of actions that have to or could be executed now arguments are the current time and any state informations that are necessary to decide which actions have to could be taken.

Example:

if self.issuing_party == party:
    if self.num_excecuted_payments < self.number_of_payments_required:
        return [Action(('pay', self.amount), 'at_least_3_times')]
else:
    return []

is_terminanted()

Whether the contract is terminated.

Example:

if.num_excecuted_payments >= self.number_of_payments_required:
    return True
else:
    return False

last_valuation()

sign(party)

Signs the contract and sets the self.counter_party property

valuation(party, time, *_, **__)

returns a valuation of the contract. Arguments:

party, the party for whom the valuation is made time, current time other state variables necessary for the valuation