final ArrayPatternConverter[] converterArray = new ArrayPatternConverter[converters.size()];
patternConverters = converters.toArray(converterArray);
for (final ArrayPatternConverter converter : patternConverters) {
if (converter instanceof DatePatternConverter) {
final DatePatternConverter dateConverter = (DatePatternConverter) converter;
frequency = calculateFrequency(dateConverter.getPattern());
}
}
}