How to use org.apache.samza.storage.kv

@Override
public void put(K key, V value) {
 if (value != null) {
  instrument(metrics.numPuts, metrics.putNs, () -> kvStore.put(key, value));
 } else {
  delete(key);
 }
}

@Override
public void deleteAll(List<K> keys) {
 instrument(metrics.numDeleteAlls, metrics.deleteAllNs, () -> kvStore.deleteAll(keys));
}

@Override
public void delete(K key) {
 instrument(metrics.numDeletes, metrics.deleteNs, () -> kvStore.delete(key));
}

@Override
public V get(K key) {
 V result = instrument(metrics.numGets, metrics.getNs, () -> kvStore.get(key));
 if (result == null) {
  incCounter(metrics.numMissedLookups);
 }
 return result;
}

 @Override
 public void close() {
  wrappedIterator.close();
 }
}

@Override
public void flush() {
 kvStore.flush();
}

 @Override
 public void remove() {
  wrappedIterator.remove();
 }
}

@Override
public boolean hasNext() {
 return wrappedIterator.hasNext();
}

/**
 * Deletes the mappings for the specified {@code keys} from this key-value store (if such mappings exist).
 *
 * @param keys the keys for which the mappings are to be deleted.
 * @throws NullPointerException if the specified {@code keys} list, or any of the keys, is {@code null}.
 */
default void deleteAll(List<K> keys) {
 for (K key : keys) {
  delete(key);
 }
}

@Override
public void close() {
 wrappedIterator.close();
}

 @Override
 public TableProvider getTableProvider(String tableId) {
  return new LocalTableProvider(tableId);
 }
}

@Override
public void flush() {
 // Since the KV store will be flushed by task storage manager, only update metrics here
 instrument(metrics.numFlushes, metrics.flushNs, () -> { });
}

 @Override
 public void close() {
  wrappedIterator.close();
 }
}

 @Override
 public void remove() {
  wrappedIterator.remove();
 }
}

/**
 * Deletes the mappings for the specified {@code keys} from this key-value store (if such mappings exist).
 *
 * @param keys the keys for which the mappings are to be deleted.
 * @throws NullPointerException if the specified {@code keys} list, or any of the keys, is {@code null}.
 */
default void deleteAll(List<K> keys) {
 for (K key : keys) {
  delete(key);
 }
}

 @Override
 public void close() {
  wrappedIterator.close();
 }
}

 @Override
 public void remove() {
  wrappedIterator.remove();
 }
}

 @Override
 public void close() {
  wrappedIterator.close();
 }
}

 @Override
 public void remove() {
  wrappedIterator.remove();
 }
}

 @Override
 public void close() {
  wrappedIterator.close();
 }
}