public void addIdentityPosition(int position,Set<Identity> participants){
  for (  Identity participant : participants) {
    Set<Integer> positions=identityPositions.get(participant.getId());
    if (positions == null) {
      positions=new HashSet<>();
      identityPositions.put(participant.getId(),positions);
    }
    positions.add(position);
  }
}

public void addIdentityPosition ( int position , Set < Identity > participants ) { for ( Identity participant : participants ) { Set < Integer > positions = identityPositions . get ( participant . getId ( ) ) ; if ( positions == null ) { positions = new HashSet < > ( ) ; identityPositions . put ( participant . getId ( ) , positions ) ; } positions . add ( position ) ; } }
set identities associated with the position in the adapter .
