public Conversation(String name){
  this.buffer=new LinkedList<Message>();
  this.history=new LinkedList<Message>();
  this.name=name.toLowerCase();
}

public Conversation ( String name ) { this . buffer = new LinkedList < Message > ( ) ; this . history = new LinkedList < Message > ( ) ; this . name = name . toLowerCase ( ) ; }
create a new conversation with the given name
