### Question:
ShipTypeAndSizeStatisticData implements StatisticData, ThreeKeyMap { int extractStatisticId(short key) { return 0; } protected  ShipTypeAndSizeStatisticData(int maxKey1, int maxKey2, int maxNumKey3); static ShipTypeAndSizeStatisticData create(); @Override @SuppressWarnings("unused") String getMeaningOfKey1(); @Override @SuppressWarnings("unused") String getMeaningOfKey2(); @Override @SuppressWarnings("unused") String getMeaningOfKey3(); @Override String getStatisticName(); @Override String getStatisticDataType(); @Override TreeMap<Integer, TreeMap<Integer, HashMap<String, Integer>>> getData(); @Override void incrementValue(int key1, int key2, String key3); @Override void setValue(int key1, int key2, String key3, int value); @Override Integer getValue(int key1, int key2, String key3); @Override int getSumFor(String key3); static final String STAT_SHIP_COUNT; }### Answer:
@Test public void extractStatisticsId() { assertEquals(0, statistics.extractStatisticId((short) 0)); assertEquals(0, statistics.extractStatisticId((short) 9)); assertEquals(0, statistics.extractStatisticId((short) 11)); assertEquals(0, statistics.extractStatisticId((short) 55)); }