Read lines from a file

Question

With "ApartmentFileHandler" I can write Apartment-objects to a file and read them from a file.
To write I loop through each room in the apartment and write its size
and type. I put 1 Room per line.
To read I read each line of the file and recreate the room stored
there. When there are no lines left in the file I pass the Rooms from
the file to the Apartment constructor and return the new Apartment.
Only one Apartment is stored in each file. (Apartment doesn?t implement
Serializable, so I cant write straight Apartment-objects to a file.)
So in the file, there are stored one "Room" per line: String type,
double size
QUESTION: How am I able to read all lines: first line first -> make a new room of
it, and store to a roomArray? Then second -> do same as I did to the
first.
Now my read()-method doesn't read all lines. How to change it to read next line?
Thanks in advance.
public class Room extends Space
public Room(String type, double area)
public String getType()
public double getSize()
public class Apartment extends Space
public static final String KITCHEN
public Apartment(Room[] rooms)
public String getType()
public double getSize()
public Room[] getRooms()
public class ApartmentFileHandler extends Object {
     private FileOutputStream ostream;
     private ObjectOutputStream op;
     private FileInputStream istream;
     private ObjectInputStream ip;
     private String filepath;
public ApartmentFileHandler (String filepath) {
                          this.filepath = filepath;      
public Apartment read()
                                  throws InvalidApartmentFile,
                                             IOException {
      istream = new FileInputStream(filepath);
      ip = new ObjectInputStream(istream);
                              // count how many rows in the file ie. rooms
                       String lineThatIsRead = ip.readLine();
                       int count =0;                                             
                       while (lineThatIsRead != null) {
                                count =count +1;
                                lineThatIsRead =ip.readLine();
     Room room;
     Room roomArray[ ] = new Room[count];
      for(int i =0; i<count; i++) {
                              String type  =ip.readUTF();
          double size =ip.readDouble();
                               room =new Room(type, size);
          roomArray[ i ] =room;
                            Apartment apartment = new Apartment(roomArray);
                            return apartment;
        public void write(Apartment apartment)
              throws IOException {
                ostream = new FileOutputStream(filepath);
                op = new ObjectOutputStream(ostream);
                int numberOfRooms =apartment.getRooms().length;
                Room[] allRooms =apartment.getRooms();
                for (int i=0; i< numberOfRooms; i++) {
                     op.writeUTF( allRooms[ i ].getType() );
                     op.writeDouble( allRooms[ i ].getSize() );
                     op.writeChars("\n");

Answer 1

Hi,
I recommend using java.io.BufferedReader in conjunction with java.io.FileReader:
BufferedReader reader=new BufferedReader(new FileReader(filepath));
java.io.BufferedReader provides the method public java.lang.String readLine() throws java.io.IOException which lets you read a complete line from the underlying java.io.Reader object. Furthermore, BufferedReader will - as the name implies - buffer your IO-operations which will help you improve the program's performance. In order to read all the lines contained in a text file you might want to apply a loop:
String line;
while((line=reader.readLine())!=null && line.length()!=0){
//process data in string line (parse into string and double)
Of course, everything must be contained within a try-catch-block in order to be able to handle upcoming IOException objects.
Regards,
Michael