What is the best way to initialize the following instance in my class?

Consider the following class where I am overwriting the OutputStream

  public class MyOutputStream extends java.io.OutputStream {

  public String clientId = null;
  public String fileId = null;
  public String filelocation = null;
  public DBClient clientobj = null;
  public OuputStream out = null;

  public MyOuputStream(String clientid, String fileid, String filelocation) {
        this.clientid = clientid;
            this.fileid = fileid;
            this.filelocation = filelocation;
        }

  public void write(byte[] bytes) throws IOException {
    out.write(bytes);
  }

  private DBClient getInstance(String clientid, String fileid) throws DBClientException {
         return this.clientobj = DBClient.getInstance(clientid, fileid); 
  }

  private OutputStream getOuputStream(DFSClient clientobj) throws Exception {
       return this.out = clientobj.getOutputStream();
  }

}

In the above code to write using MyOuputStream the DBClient object and OuputStream has to be initialized before write operation

Someone, please suggest me an appropriate design pattern to solve this.