Marcus Q# 53 I/O

[Anonymous]

Question 53)
You need to read in the lines of a large text file containing tens of megabytes of data. Which of the following would be most suitable for reading in such a file
1) new FileInputStream("file.name")
2) new InputStreamReader(new FileInputStream("file.name"))
3) new BufferedReader(new InputStreamReader(new FileInputStream("file.name")));
4) new RandomAccessFile raf=new RandomAccessFile("myfile.txt","+rw");
Question 53)
You need to read in the lines of a large text file containing tens of megabytes of data. Which of the following would be most suitable for reading in such a file
1) new FileInputStream("file.name")
2) new InputStreamReader(new FileInputStream("file.name"))
3) new BufferedReader(new InputStreamReader(new FileInputStream("file.name")));
4) new RandomAccessFile raf=new RandomAccessFile("myfile.txt","+rw");
According to the answer
) new BufferedReader(new InputStreamReader(new FileInputStream("file.name")));
The key to this question is that it asks about tens of megabytes of data, implying that performance is an issue. A Buffered Reader will optimise the performance of accessing a file. Although the objectives do not specifically mention it questions on I/O do come up on the exam.
..I thought the answer is 3..RandomAccessFile....
Can someone explain how Buffered Reader will optimise the performance ..
Thanks

[Ajith Kallambella]

BufferedReader will buffer( read ahead and store in memory for faster access )input from the specified file. Without buffering, each read call could cause bytes to be read from the file, converted into characters, and then returned, which can be very inefficient.
Similarly BufferedWriter will buffer the output and write to the physical files in large chunks in less frequent intervals( or with every call to flush ).
Hope this helps.
Ajith

[Anonymous]

Thanks Ajith I got it now...
Wali