public void getKeysWithRegEx(String regex, boolean allowTombstones, SetCollector collector)
      throws IOException {
    _getKeysWithInterest(InterestType.REGULAR_EXPRESSION, regex, allowTombstones, collector);
  }
finds all the keys matching the given regular expression (or all keys if regex is ".*")

@param regex the regular expression
@param allowTombstones whether to include destroyed entries
@param collector object that will receive the keys as they arrive
geode-core/src/main/java/org/apache/geode/internal/cache/PartitionedRegion.java