Dividing a Text File into Sub Files

Question

Hello Guys,
Thanks for being here to help people with their programming problems. I am trying to create a programs that divides the Romeo and Juliet play into different Acts. The play has 5 Acts, subdivided into several Scenes.
I am trying to ignore everything before ACT 1 Starts. The idea I am trying to use is the follow.
Create a function which get a BufferReader as input.
Create and StringBuilder to build the ACTs.
Create a loop to go thru the play line by line.
Store the line in a String variable.
Append the line to the StringBuilder.
If the string matches to "ACT 1" delete everything in the StringBuilder.
Keep looping. If the string matches to ACT 2, create a New file called Act 1 with the content of the builder.
I have 2 problems. The first is a NullPointerException. The second is that I got the program to create the file before, however, everything was in a single line, as opposed to multiple line like the play I am using. The other problems is that the "word" ACT 2 wasn't check and the program overlooked it. Everthing until the end of the file was written in the file act1.txt
Here is the file with the play I am using (Romeo_Juliet.txt)
[https://docs.google.com/leaf?id=0BxusGNRkVpmsODFkOWZjNmUtMWY2MS00ZTk2LWIzN2YtYzk0YWNkYWQ4MDYw&hl=en]
Please Help!!!
I will really appreciate it!
Here is my code
import java.io.*;
import java.lang.*;
public class DivideActs {
     static void divideIntoActs(BufferedReader br){
          FileOutputStream out; // declare a file output object
          PrintStream p; // declare a print stream object
          String line = new String();
          StringBuilder builder = new StringBuilder();
          String st = new String();
          int count = 0;
          try {
               while (br.readLine() != null) {
                    line = br.readLine();
                    if (line.toString().matches("ACT 1")) {
                         line = "";
                         count = builder.length();
                         builder.delete(0, count);
                    // line = br.readLine().toString();
                    builder.append(line);
                    if (line.matches("ACT 2")) {
                         out = new FileOutputStream("act1.txt");
                         p = new PrintStream(out);
                         st = builder.toString();
                         p.println(st);
                         System.out.println("File Written Succesfully");
                         p.close();
          } catch (FileNotFoundException e) {
               System.out.println("Could not load file!");
          } catch (IOException e) {
               e.printStackTrace();
     public static void main(String[] args) throws IOException {
          FileReader reader = new FileReader("Romeo_Juliet.txt");
          BufferedReader buffReader = new BufferedReader(reader);
          divideIntoActs(buffReader);
          buffReader.close();
}Edited by: locorecto on Apr 25, 2010 10:54 AM

Answer 1

locorecto wrote:
I have 2 problems. The first is a NullPointerException.The stack trace produced by the NPE should tell you what line is throwing the exception.
The second is that I got the program to create the file before, however, everything was in a single line, as opposed to multiple line like the play I am using. readLine() doesn't preserve the newline at the end of the line. You'll have to add it back in.
The other problems is that the "word" ACT 2 wasn't check and the program overlooked it. Everthing until the end of the file was written in the file act1.txtMaybe the line wasn't exactly "ACT 2". You're probably better off using regular expressions. Or at least something like String.indexOf.
There are more problems.
import java.lang.*;You don't have to import the java.lang package. It's automatically imported.
          FileOutputStream out; // declare a file output object
          PrintStream p; // declare a print stream object
To be pedantic: you're not declaring objects here. You're declaring reference variables that will refer to objects of the given type.
          String line = new String();
You need to declare line, but assigning an empty string to it is pointless.
          String st = new String();
Same here. Also, you can declare this in the block where you use it.
               while (br.readLine() != null) {
                    line = br.readLine();Do you see what you're doing here? You're throwing away every alternate line. You read a line to see if it's null, throw it away, then read the next line.
This is probably why it's not finding "ACT 2" (it's on an even-numbered line where you're looking for odd, or vice-versa). But even if it found the "ACT 2" line, your output would be missing half the lines.
                    if (line.toString().matches("ACT 1")) {That toString() there is unnecessary. line is already a String.
                         line = "";If you just do a continue; at the end of this block, you don't need to bother with this.
                         count = builder.length();
                         builder.delete(0, count);I think you could just do builder.setLength(0). Or just instantiate a new StringBuilder. For that matter you don't need to create a StringBuilder at all until you find Act I.
If you make a change like this, you no longer need the count variable.
You know, Perl is made for tasks like this.