post-e-voting/source-code/online-voting-channel/ov-commons/ov-commons-errormanagement

sVote error management module

The error management module helps manage errors produced during the execution of discrete parts of the code. An error management policy defines the behaviour of a function when it does not end successfully. The usual case for this situation will be to periodically retry the action until successful.

As an example, the following snippet illustrates a function that will be called a few times before considering it has failed. This might help in an environment with faulty network connections.

final retries = 10;
PersistentErrorManagementPolicy policy = new PersistentErrorManagementPolicy(retries);
try {
    policy.manage(() -> quoteService.getQuote());
} catch (HttpException e) {
    System.out.printf('The quote could not be retrieved even after %d attempts', retries);
}

An implementation can also define a number of exceptions that should not be managed, letting the function fail immediately instead.

TimedErrorManagementPolicy policy = new TimedErrorManagementPolicy(5, ChronoUnit.MINUTES, HttpException.class);
try {
    policy.manage(() -> quoteService.getQuote());
} catch (HttpException e) {
    System.out.printf('The HTTP service is not available. No retries will be attempted');
} catch (OtherException other) {
// [...]

Fallible function

The function to run should be encapsulated as FallibleFunction, a functional interface that throws Exception. Users of the module are encouraged to subclass both ExecutionPolicy and FallibleFunction so that it throws a more concrete exception.