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Recursive command parser that solves a repeat statement

I am building a parser that recognizes simple commands such as "DOWN.", "UP." and "REP 3.". It must be able to parse the commands rather freely. It should be legal to write
"DOWN % asdf asdf asdf
."
Where % represents a comment and the fullstop signifying end-of-command. This fullstop can be on the next line.
This is all good and well so far, however I'm struggling with the Rep part (represents Repeat.)
I should be able to issue a command as follows:
DOWN .DOWN. REP 3 " DOWN. DOWN.
DOWN . % hello this is a comment
REP 2 " DOWN. ""
This should give me 17 DOWNS. The semantics is as follows for repeat: REP x " commands " where x is the amount of times it shall repeat the commands listed inside the quotation marks. Note that REP can be nested inside of REP. The following code is for handling the DOWN command. The incoming text is read from System.in or a text file.
public void repeat(String workingString) {
if (workingString.matches(tokens)) {
if (workingString.matches("REP")) {
repada();
} else
if (workingString.matches("(DOWN).*")) {
String job = workingString.substring(4);
job = job.trim();
if (job.equals("")) {
String temp= sc.next();
temp= temp.trim();
// Word after DOWN.
if (temp.matches("\\.")) {
leo.down()
// If word after DOWN is a comment %
} else if (temp.matches("%.*")) {
boolean t = comment();
} else {
throw SyntaxError();
}
} else if (job.matches("\\..*")) {
workingString += job;
System.out.println("Confirm DOWN with .");
}
} else if (workingString.matches("\\.")) {
instructions += workingString;
System.out.println("Fullstop");
} else if (workingString.matches("%.*")) {
comment();
} else {
// work = sc.next();
work = work.trim().toUpperCase();
System.out.println(work);
}
} else {
System.out.println("No such token: " + workingString);
}
}
I got a working start on the repeat function:
public String repada(){
String times = sc.next();
times.trim();
if (times.matches("%.*")) {
comment();
times = sc.next();
}
String quote = sc.next();
quote.trim();
if(quote.matches("%.*")){
comment();
quote = sc.next();
}
String repeater = "";
System.out.println("REP " + times + " "+quote);}
However I'm thinking my whole system of doing things might need a rework. Any advice on how I could more easily solve this issue would be greatly appreciated!

Manipulating Strings in a File Scanner ~ Java

I was given a file that has list of names phone numbers, calls in and out ect... Like this
Adams#Marilyn#8233331109#0#0#01012014#C
Anderson#John#5025559980#20#15#12152013#M
Baker-Brown#Angelica#9021329944#0#3#02112014#C
The # are delimiters between data items and each line has the call status as the last item.
I need to know how I can display each persons information on the screen in a format such as:
Name Phone Calls Out Calls In Last Call
Marilyn Adams (823) 333-1109 0 0 01-01-2104
John Anderson (502) 555-9980 20 15 12-15-2013
Angelica Baker-Brown (859) 254-1109 11 5 02-11-2014
I have to use substring method to extract the phone number and add parentheses/dashes ect...
So Far my code looks like this
Also I am in a beginners Java coding class....
import java.util.Scanner;
import java.io.*;
public class phonedata2_1 {
public static void main(String[] args) throws IOException {
String Phonefile, FirstName, LastName;
Scanner PhoneScan, fileScan;
System.out.println(" Name Phone Calls Out Calls In Last Call Status");
fileScan = new Scanner(new File("phonedata.txt"));
while (fileScan.hasNext()) {
Phonefile = fileScan.nextLine();
PhoneScan = new Scanner(Phonefile);
PhoneScan.useDelimiter("#");
System.out.println(PhoneScan.next() + " "
+ PhoneScan.next() + "\t"
+ PhoneScan.next() + "\t"
+ PhoneScan.next() + "\t"
+ PhoneScan.next() + "\t"
+ PhoneScan.next() + "\t"
+ PhoneScan.next());
}
System.out.println("\nTotal outgoing calls for the period: " + "\nTotal incoming calls for the period: \n");
}
}

Finds every "data-segment" by using regex, then splits it with # as delimiter and prints it:
File blub = new File("blub.txt");
Scanner scanner = null;
try
{
scanner = new Scanner(blub);
}
catch (FileNotFoundException e){}
while(scanner.hasNext("((\\S*)#){6}(\\w)"))
{
String buffer = scanner.next("((\\S*)#){6}(\\w)");
for(String value : buffer.split("#"))
System.out.print(value + " ");
System.out.println();
}
Output:
Adams Marilyn 8233331109 0 0 01012014 C
Anderson John 5025559980 20 15 12152013 M
Baker-Brown Angelica 9021329944 0 3 02112014 C
Note:
You can use any whitespace character to separate each data-segment in the input file, so even spaces are okay or tabs(or crazy mix with empty lines and so on).
For farther use of data:
you could add your data in an arraylist since buffer.split("#") gives you an array of the data-segment, so you can output it easier with your desired changes to each value.(or in a different order)

You can use the .split(String regex) to split the line you are reading by throwing in the # as a delimeter. This will yield an array which you can traverse and print the contents accordingly. Also, it would seem that besides the initial line, all call data starts with a , so you could use split twice to parse your text file:
EDIT: Seeing your comment, I also realized that afterwards, however, since the .split() method takes a regex as parameter, it means that this problem can be walked around without much hassle. My example is as follows:
String str = "Adams#Marilyn#8233331109#0#0#01012014#C Anderson#John#5025559980#20#15#12152013#M Baker-Brown#Angelica#9021329944#0#3#02112014#C";
String[] lines = str.split(" ");
System.out.println("Name\tPhone\tCalls\tOut\tCalls In\tLast Call");
for(String line : lines)
{
String[] lineInfo = line.split("#");
for(String info : lineInfo)
{
System.out.print(info + "\t");
}
System.out.println();
}
I had to add some extra tabs manually, but this is the output:
Name Phone Calls Out Calls In Last Call
Adams Marilyn 8233331109 0 0 01012014 C
Anderson John 5025559980 20 15 12152013 M
Baker-Brown Angelica 9021329944 0 3 02112014 C

Something like this should work. You still need to do all the manipulation of the phone number yourself, but all the data will be in the call info so you should be able to work from that!
while (fileScan.hasNext())
{
//Get a single record
Phonefile = fileScan.nextLine();
//Seperate the elements of the record
String[] callInfo = Phonefile.split("#");
for(String infoPart: callInfo)
{
System.out.print(infoPart+ "\t");
}
System.out.println()
}

Error reading data from textfile

I have an application that suppose to read data from the text file with student details (student.txt), such that I have a studentNo, StudentName, Marks etc. . .
Here is a sample of the data that's in the textfile :
20405587 "ZULU,B M" 65 67
20407388 "JUGGERNATH,N" 66 63
20408427 "KHATHI,P X" 60 60
20409821 "SINGH,T" 62 59
20410422 "NKOMO,N N" 58 60
I'm using a scanner to read from the file, here is my code so far. . .it gives me an error
try
{
BufferedReader br = new BufferedReader(new FileReader("student.txt"));
String line = br.readLine();
while (line!=null)
{
Scanner scan = new Scanner(line);
scan.useDelimiter(" ");
String dummystudent=scan.next();
int studentNo= Integer.parseInt(dummystudent);
String dummyname1 = scan.next();
String dummyname2 = scan.next();
String studentName = dummyname1+dummyname2;
String dummytest1 = scan.next();
int test1= Integer.parseInt(dummytest1);
String dummytest2 = scan.next();
int test2= Integer.parseInt(dummytest2);
tad1.setText(tad1.getText()+"Student Number: " + studentNo + '\n' + "Student Name :" + studentName );
line = br.readLine();
}
br.close();
}
catch(Exception b)
{
JOptionPane.showMessageDialog(null,b.getMessage());
}

You set the delimiter to a single space. This is the problem. next will return an empty string a few times because those lines of yours has more than one consecutive spaces.
Instead you want to say one or more spaces:
sc.useDelimiter(" +");
It's still not 100% since "ZULU,B M" has a space in the middle and "JUGGERNATH,N" doesn't, but I'll leave that to you to figure out. Maybe:
sc.useDelimiter("\"");
somewhere in the middle there.
The + has to do with regular expressions, see this for more in general and this for more Java-specific.

Your parsing seems to be overkill.
Consider using Scanner to read the line and use StringUtils.split() to parse the line.
Here is some code:
public static void main(String[] args)
{
int index = 1; // Just for printing.
for (String current : input)
{
String[] split1; // result: number, name, numbers
String[] split2;
String studentName1;
String studentName2;
String studentNumber;
String testScore1;
String testScore2;
split1 = StringUtils.split(current, '"');
studentNumber = StringUtils.trim(split1[0]);
split2 = StringUtils.split(split1[1], ',');
studentName1 = StringUtils.trim(split2[0]);
studentName2 = StringUtils.trim(split2[1]);
split2 = StringUtils.split(split1[2]); // default seperator is whitespace.
testScore1 = StringUtils.trim(split2[0]);
testScore2 = StringUtils.trim(split2[1]);
System.out.println(
index + ":" +
" Number: " + ">" + studentNumber + "" + studentName1 + "" + studentName2 + "" + testScore1 + "" + testScore2 + "
Note: StringUtils is from Apache Commons Lang

Easiest way to end would to be go line by line.
Pattern filePatten = Pattern.compile("\\s*(\\d+)\\s+(\"[^\"]+\")\\s+(\\d+)\\s+(\\d+)\\s*");
while (scanner.hasNextLine()) {
String line = scanner.nextLine();
Matcher matcher = filePattern.matcher(line);
if (matcher.matches()) {
String id = matcher.group(1);
String name = matcher.group(2);
//etc
} else {
//Warn : Fragile Regex
}
}
Each group in the regex captures a part of the line. The second group captures the name with quotes. You might want to remove it.

You should be using the delimiter "? +"?, the delimiter is a regex, and your string has multiple spaces to separate fields, you also need to take into account quotes around string fields. I'm yet to workout how to solve string fields with spaces.
http://docs.oracle.com/javase/1.5.0/docs/api/java/util/Scanner.html#useDelimiter(java.lang.String)
Using Regex you should be able to do it using the below regex string, and select the subgroups 1-4, through a Matcher
([0-9]{8}) +"([A-Z, ]+)" +([0-9]{2}) +([0-9]{2})

Finding errors in LaTeX document, java

So I have a bunch of LaTeX styled documents, one looks like this...
\documentclass{article}
\usepackage{amsmath, amssymb, amsthm}
\begin{document}
{\Large \begin{center} Homework Problems \end{center}}\begin{itemize}\item\end{itemize}
\begin{enumerate}
\item Prove: For all sets $A$ and $B$, $(A - B) \cup
(A \cap B) = A$.
\begin{proof}
\begin{align}
& (A - B) \cup (A \cap B) && \\
& = (A \cap B^c) \cup (A \cap B) && \text{by
Alternate Definition of Set Difference} \\
& = A \cap (B^c \cup B) && \text{by Distributive Law} \\
& = A \cap (B \cup B^c) && \text{by Commutative Law} \\
& = A \cap U && \text{by Union with the Complement Law} \\
& = A && \text{by Intersection with $U$ Law}
\end{align}
\end{proof}
\item If $n = 4k + 3$, does 8 divide $n^2 - 1$?
\begin{proof}
Let $n = 4k + 3$ for some integer $k$. Then
\begin{align}
n^2 - 1 & = (4k + 3)^2 - 1 \\
& = 16k^2 + 24k + 9 - 1 \\
& = 16k^2 + 24k + 8 \\
& = 8(2k^2 + 3k + 1) \text{,}
\end{align}
which is certainly divisible by 8.
\end{proof}
\end{enumerate}
\end{document}
Now first I had to read through each document and line and find all of the "\begin{BLOCK}" and "\end{BLOCK}" commands and add the BLOCK string to a Stack and when I found the matching "\end" I would call the pop() command on my Stack. I pretty much got all that done, it's just not well organized, or at least I think there is a better way to go about it than all my "if" statements. So that is my first question, is there something better than the way I did it?
Next is I want to find errors and report them. For example, if I removed the line "\begin{document}" from the text above, I want the program to run through, do everything it is suppose to, but when It reaches the line "\end{document}" it reports the missing "\begin" command. I got my code to handle other examples, such as removing the "\begin" commands for enumerate or itemize, but I can't get that case to work.
Finally I want to be able to handle missing "\end" commands. I have made an attempt at it but I can't quite get the conditioning right. Let's say I have this document...
\begin{argument}
\begin{Palin}No it can't. An argument is a connected series of statements intended to establish a proposition.\end{Palin}
\begin{Cleese}No it isn't.\end{Cleese}
\begin{Palin}\expression{exclamation}Yes it is! It's not just contradiction.\end{Palin}
\begin{Cleese}Look, if I argue with you, I must take up a contrary position.\end{Cleese}
\begin{Palin}Yes, but that's not just saying \begin{quotation}'No it isn't.'\end{Palin}
\begin{Cleese}\expression{exclamation}Yes it is!\end{Cleese}
\begin{Palin}\expression{exclamation}No it isn't!\end{Palin}
\begin{Cleese}\expression{exclamation}Yes it is!\end{Cleese}
\begin{Palin}Argument is an intellectual process. Contradiction is just the automatic gainsaying of any statement the other person makes.\end{Palin}
\end{argument}
You'll notice on line 6 there is a "\begin{quotation}" command without an "\end". My code when going through this particular document gives me this as output...
PARSE ERROR Line 6: Missing command \begin{Palin}.
PARSING TERMINATED!
This is obviously not true, but I don't know how to restructure my error handling to get these cases to work. Can anyone provide any help? Especially in the way of organizing this code to better suite it for finding these issues.
-------------------------------------------CODE-------------------------------------------
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.util.Scanner;
import java.util.Stack;
import java.util.StringTokenizer;
public class LaTeXParser{
public static void main(String args[]) throws FileNotFoundException{
Scanner scan = new Scanner(System.in);
Stack s = new Stack();
int lineCount = 0;
String line;
String nextData = null;
String title = null;
String fname;
System.out.print("Enter the name of the file (no extension): ");
fname = scan.next();
fname = fname + ".txt";
FileInputStream fstream = new FileInputStream(fname);
Scanner fscan = new Scanner(fstream);
System.out.println();
while(fscan.hasNextLine()){
lineCount++;
line = fscan.nextLine();
StringTokenizer tok = new StringTokenizer(line);
while(tok.hasMoreElements()){
nextData = tok.nextToken();
System.out.println("The line: "+nextData);
if(nextData.contains("\\begin") && !nextData.contains("\\end")){
if(nextData.charAt(1) == 'b'){
title = nextData.substring(nextData.indexOf("{") + 1, nextData.indexOf("}"));
s.push(title);
}
}//end of BEGIN if
if(nextData.contains("\\end") && !nextData.contains("\\begin")){
String[] theLine = nextData.split("[{}]");
for(int i = 0 ; i < theLine.length ; i++){
if(theLine[i].contains("\\end") && !s.isEmpty() && theLine[i+1].equals(s.peek())){
s.pop();
i++;
}
if(theLine[i].contains("\\end") && !theLine[i+1].equals(s.peek())){
System.out.println("PARSE ERROR Line " + lineCount + ": Missing command \\begin{" + theLine[i+1] + "}.");
System.out.println("PARSING TERMINATED!");
System.exit(0);
}
}
}//end of END if
if(nextData.contains("\\begin") && nextData.contains("\\end")){
String[] theLine = nextData.split("[{}]");
for(int i = 0 ; i < theLine.length ; i++){
if(theLine[i].contains("\\end") && theLine[i+1].equals(s.peek())){
s.pop();
}
if(theLine[i].equals("\\begin")){
title = theLine[i+1];
s.push(title);
}
}
}//end of BEGIN AND END if
}
}//end of whiles
fscan.close();
if(s.isEmpty()){
System.out.println();
System.out.println(fname + " LaTeX file is valid!");
System.exit(0);
}
while(!s.isEmpty()){
}
}
}

Having trouble reading files in java

I have some trouble reading file in Java.
What a file looks like:
Answer 1:
1. This is an apple
2. Something
Answer 2:
1. This is a cool website
2. I love banana
3. This is a table
4. Programming is fun
Answer 3.
1. Hello World
....
What I want to do is separate them into two items:
One is the Answer number; The other one is list of answers.
So assuming I have a object class called Answer:
String of answer number
List of answers.
This is what I have done so far to debug my code before I put it into object class. But I'm not able to get the correct result
public void reader(String file) throws FileNotFoundException, IOException {
FileReader fR = new FileReader(file);
BufferedReader bR = new BufferedReader(fR);
String line = null;
int count = 0 ;
String blockNum = "";
String printState = "" ;
while ((line = bR.readLine()) != null) {
if(line.contains("Answer")){
//System.out.println("Contain Answer statement: " + line);
count++;
blockNum = line;
printState = "";
}
else{
//System.out.println("No Answer Statement: " + line);
printState += line + " / " ;
}
System.out.println( count + " " + blockNum + " " + printState );
}
// Close the input stream
bR.close();
fR.close();
}
I'm pretty sure I did something stupid while I'm coding. I'm not too sure how to read it so that it will have separate it.
Right now the output looks like this:
1 Answer 1:
1 Answer 1: 1. This is an apple /
1 Answer 1: 1. This is an apple / 2. Something /
2 Answer 2:
2 Answer 2: 1. This is a cool website /
2 Answer 2: 1. This is a cool website / 2. I love banana /
2 Answer 2: 1. This is a cool website / 2. I love banana / 3. This is a table /
2 Answer 2: 1. This is a cool website / 2. I love banana / 3. This is a table / 4. Programming is fun /
3 Answer 3.
3 Answer 3. 1. Hello World /
But I want the output to be something like this:
1 Answer 1: 1. This is an apple / 2. Something /
2 Answer 2: 1. This is a cool website / 2. I love banana / 3. This is a table / 4. Programming is fun /
3 Answer 3. 1. Hello World /

You are printing a line of output for each line of input you read. Try moving the println inside the part of the loop that checks for answer to make sure you print each answer/answer value set only once. E.g.:
if(line.contains("Answer")) {
if (printState != "") {
System.out.println(count + " " + blockNum + " " + printState);
}
...
}
EDIT: You will also need to print when you exit the while loop to make sure you print the last answer/answer value set.

One solution use a flag for printTime as a boolean.
boolean printTime = false;
...
if(line.contains("Answer")) {
if (printTime!= false) {
System.out.println( count + " " + blockNum + " " + printState );
printTime=false;
}
...
}else{
//System.out.println("No Answer Statement: " + line);
printState += line + " / " ;
printTime=true; // you have one answer
}
...
add a little extra print at the end of the while for last answer
that way you can have several printState for one answer in one line.
But correct "java" way of handle this is to create your objects:
List<Answer> listOfAnswer = new LinkedList<Answer>();
Answer answer;
...
if(line.contains("Answer")){
//System.out.println("Contain Answer statement: " + line);
count++;
answer = new Answer(line);
listOfAnswer.add(answer)
}
else{
answer.add(new Answer(line));
}
}
...
and only after print them out :)
System.out.println(listOfAnswer.toString());
Simpler solution is to use a
Map<Integer, LinkedList<String>> answers = new LinkedHashMap<Integer, LinkedList<String>();

The main output issue is that you are printing inside the line-iterating loop (while).
To solve it, you can follow what #Albion answered and change where the print is done inside the while, but as the EDIT on his answer states, there is a flaw and you will have to print an extra time after the loop, in order to get the correct result.
There is an alternative tough, that is to not print it inside the loop at all, which i consider to be the correct approach in your case. To do it, you need little more than using StringBuilder instead of String!
I have also spotted some needless variables, and there is also a flaw in using the if(line.contains("Answer")) method, that is that if "Answer" string appears inside one of the options texts, it will get a true and mess your results, for example:
Answer 1:
1. This is an apple
2. Capitalizing Is The Answer!
3. Something
Will output:
1 Answer 1: 1. This is an apple /
2 2. Capitalizing Is The Answer! 3. Something
In most cases, the best approach to finding a dynamic pattern (as yours is, for it changes the number and, in the last Answer, the ':' with a '.' too) is to use a (pattern) Matcher! I used this: if(line.matches("Answer \\d[\\:\\.]")), and if you are not yet used to it, see the Pattern Docs, as String.matches() is something you will probably use a lot when processing text.
Explaining every single change is a little troublesome, and the code is simple enough for you master after you analyse it, so i'll simply post what my approach would be:
public static void StackAnswer(String file) throws FileNotFoundException, IOException{
BufferedReader br = new BufferedReader(new FileReader(file));
StringBuilder output = new StringBuilder();
int count = 0;
while(br.ready()){
String line = br.readLine().trim();
if(line.matches("Answer \\d[\\:\\.]")){
count++;
output.append(System.lineSeparator()).append(count).append(' ').append(line);
} else {
output.append(" / ").append(line);
}
}
System.out.println(output.toString().trim());
br.close();
}
Good luck!

See working example:
public void reader(String file) throws FileNotFoundException,
IOException {
BufferedReader reader = new BufferedReader(new FileReader(file));
String line = "";
while (reader.ready()) {
line = reader.readLine();
if (!line.contains("Answer")) {
System.out.print(line + " / ");
} else {
System.out.println();
System.out.print(line + " ");
}
}
}