聊聊claudb的hash command

@Command("hset")
@ParamLength(3)
@ParamType(DataType.HASH)
public class HashSetCommand implements DBCommand {
​
  @Override
  public RedisToken execute(Database db, Request request) {
    DatabaseValue value = hash(entry(request.getParam(1), request.getParam(2)));
​
    DatabaseValue resultValue = db.merge(safeKey(request.getParam(0)), value,
        (oldValue, newValue) -> {
          Map<SafeString, SafeString> merge = new HashMap<>();
          merge.putAll(oldValue.getHash().toMap());
          merge.putAll(newValue.getHash().toMap());
          return hash(ImmutableMap.from(merge));
        });
​
    ImmutableMap<SafeString, SafeString> resultMap = resultValue.getHash();
​
    return integer(resultMap.get(request.getParam(1)) == null);
  }
}

@ReadOnly
@Command("hget")
@ParamLength(2)
@ParamType(DataType.HASH)
public class HashGetCommand implements DBCommand {
​
  @Override
  public RedisToken execute(Database db, Request request) {
    ImmutableMap<SafeString, SafeString> map = db.getHash(request.getParam(0));
    return map.get(request.getParam(1))
        .map(RedisToken::string)
        .getOrElse(RedisToken::nullString);
  }
}

@ReadOnly
@Command("hgetall")
@ParamLength(1)
@ParamType(DataType.HASH)
public class HashGetAllCommand implements DBCommand {
​
  @Override
  public RedisToken execute(Database db, Request request) {
    DatabaseValue value = db.get(safeKey(request.getParam(0)));
    if (value != null) {
      return convert(value);
    } else {
      return array();
    }
  }
}

@ReadOnly
@Command("hexists")
@ParamLength(2)
@ParamType(DataType.HASH)
public class HashExistsCommand implements DBCommand {
​
  @Override
  public RedisToken execute(Database db, Request request) {
    ImmutableMap<SafeString, SafeString> map = db.getHash(request.getParam(0));
    return integer(map.containsKey(request.getParam(1)));
  }
}

@Command("hdel")
@ParamLength(2)
@ParamType(DataType.HASH)
public class HashDeleteCommand implements DBCommand {
​
  @Override
  public RedisToken execute(Database db, Request request) {
    ImmutableList<SafeString> keys = request.getParams().asList().tail();
​
    List<SafeString> removedKeys = new LinkedList<>();
    db.merge(safeKey(request.getParam(0)), DatabaseValue.EMPTY_HASH, (oldValue, newValue) -> {
      ImmutableMap<SafeString, SafeString> merge = oldValue.getHash();
      for (SafeString key : keys) {
        merge.get(key).stream().forEach(removedKeys::add);
        merge = merge.remove(key);
      }
      return hash(merge);
    });
​
    return integer(!removedKeys.isEmpty());
  }
}

@ReadOnly
@Command("hkeys")
@ParamLength(1)
@ParamType(DataType.HASH)
public class HashKeysCommand implements DBCommand {
​
  @Override
  public RedisToken execute(Database db, Request request) {
    ImmutableMap<SafeString, SafeString> map = db.getHash(request.getParam(0));
    return convert(map.keys());
  }
}

@ReadOnly
@Command("hlen")
@ParamLength(1)
@ParamType(DataType.HASH)
public class HashLengthCommand implements DBCommand {
​
  @Override
  public RedisToken execute(Database db, Request request) {
    ImmutableMap<SafeString, SafeString> hash = db.getHash(request.getParam(0));
    return integer(hash.size());
  }
}

@ReadOnly
@Command("hmget")
@ParamLength(2)
@ParamType(DataType.HASH)
public class HashMultiGetCommand implements DBCommand {
​
  @Override
  public RedisToken execute(Database db, Request request) {
​
    ImmutableMap<SafeString, SafeString> map = db.getHash(request.getParam(0));
​
    List<RedisToken> rtList = new ArrayList<>();
​
    for (int paramNumber = 1; paramNumber < request.getParams().size(); paramNumber++) {
      Option<SafeString> oss = map.get(request.getParam(paramNumber));
      rtList.add(oss.map(RedisToken::string).getOrElse(RedisToken::nullString));
    }
​
    return convert(rtList);
  }
​
}

@Command("hmset")
@ParamLength(3)
@ParamType(DataType.HASH)
public class HashMultiSetCommand implements DBCommand {
​
  @Override
  public RedisToken execute(Database db, Request request) {
​
    for (int paramNumber = 1; paramNumber < request.getParams().size(); paramNumber += 2) {
​
      SafeString mapKey = request.getParam(paramNumber);
      SafeString mapVal = request.getParam(paramNumber + 1);
​
      DatabaseValue value = hash(entry(mapKey, mapVal));
​
      db.merge(safeKey(request.getParam(0)), value,
          (oldValue, newValue) -> {
            Map<SafeString, SafeString> merge = new HashMap<>();
            merge.putAll(oldValue.getHash().toMap());
            merge.putAll(newValue.getHash().toMap());
            return hash(ImmutableMap.from(merge));
          }
      );
​
    }
​
    return responseOk();
  }
}

@ReadOnly
@Command("hvals")
@ParamLength(1)
@ParamType(DataType.HASH)
public class HashValuesCommand implements DBCommand {
​
  @Override
  public RedisToken execute(Database db, Request request) {
    ImmutableMap<SafeString, SafeString> map = db.getHash(request.getParam(0));
    return convert(map.values());
  }
}