@Override
public boolean isActive(FeatureState state, FeatureUser user) {
if (user != null && Strings.isNotBlank(user.getName())) {
String percentageAsString = state.getParameter(PARAM_PERCENTAGE);
try {
int percentage = Integer.valueOf(percentageAsString);
if (percentage > 0) {
int hashCode = Math.abs(calculateHashCode(user, state.getFeature()));
return (hashCode % 100) < percentage;
}
} catch (NumberFormatException e) {
log.error(
"Invalid gradual rollout percentage for feature "
+ state.getFeature().name()
+ ": "
+ percentageAsString);
}
}
return false;
}
protected int calculateHashCode(FeatureUser user, Feature feature) {
Validate.notNull(user, "user is required");
return new StringBuilder()
.append(user.getName().toLowerCase(Locale.ENGLISH).trim())
.append(":")
.append(feature != null ? feature.name() : "")
.toString()
.hashCode();
}