CODEWITHSUNDEEP
javaarrays
Kenny
Kenny

Reputation: 1142

Add multiple bytes array

I'm adding multiple bytes array from each row, that means I need to append all of them to a variable. But this prints a empty byte array because it can't be changed. What I can do to append more bytes?

ResultSet rs = stmt.executeQuery(query);
int matchesLength = 0;

try {
      boolean b = rs.last();

      if (b) {
        matchesLength = rs.getRow();
      }
}
catch (SQLException e) {
      e.printStackTrace();
}

byte[] matches = new byte[118 * matchesLength];

while ( rs.next() ) {
  String matchId = rs.getString("id");
  String matchTitle = rs.getString("title");
  String matchDescription = rs.getString("description");
  int matchPlayers = rs.getInt("max_players");
  int matchMaxPlayers = rs.getInt("max_players");
  String matchHostId = rs.getString("host_id");

  short matchPlayersShort = (short) matchPlayers;
  byte[] matchPlayersBytes = ByteBuffer.allocate(2).putShort(matchPlayersShort).array();

  short matchMaxPlayersShort = (short) matchMaxPlayers;
  byte[] matchMaxPlayersBytes = ByteBuffer.allocate(2).putShort(matchMaxPlayersShort).array();

  byte[][] match = {
      String.format("%1$-" + 32 + "s", matchId).getBytes(),
      String.format("%1$-" + 22 + "s", matchTitle).getBytes(),
      String.format("%1$-" + 44 + "s", matchDescription).getBytes(),
      matchPlayersBytes,
      matchMaxPlayersBytes,
      String.format("%1$-" + 16 + "s", matchHostId).getBytes()
  };

  // global offset variable, for each array copy
  combineBytes(match, matches);
}

Upvotes: 1

Views: 1043

Answers (1)

Solano
Solano

Reputation: 550

Why not to create a class for encapsulate each row?

public class Match{
  private String matchId;
  private String matchTitle;
  private String matchDescription;
  etc....

  set and get for all variables;

  public byte[] getBytes(){
    here a logic to transform this attributes in a array of bytes
  }
}

Then you create a ArrayList matchList that will be filled in the rs.next() loop.

Then you will just need:

while(rs.next()){
  match = new Match();
  match.setBlabla(rs.get(value));
  ....all sets
  list.add(match);
}

when you send it through socket to your clients you just read the list and do your logic with the bytes.

Lets supose you have a list of 10 rows and you want it as bytes.

ArrayList<Match> matchList = new ArrayList<Match>();
Match m;
while(rs.next()){
  m = new Match();
  m.set // one set for each attribute getting the value from rs.get
  matchList.add(m);
}

Now for send it:

for(Match m : matchList){
  byte[] bytesToSend = m.getBytes(); //you defined this method
  send(bytesTosend) //one match send for time
}

IF you want to send all matches togheter, you have to do a loop to calculate the total bytes in the list because each Match in the list will have a diferent size in bytes (description changes, title chantes etc)

Upvotes: 1

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