Regular Expression Fails for Large Inputs

Question

I've got a problem on mu RegEx
This is happenning for only when I input large files to it.
My code is shown brlow...
public static boolean isComment(String line) {
Pattern pattern = Pattern.compile("((?:/\\*(?:--^*|(?:\\*+--*/--^--))*\\*+/)|(?:--.*))", Pattern.CASE_INSENSITIVE);
Matcher matcher = pattern.matcher(line);
return matcher.find();
public static boolean isNewLine(String line) {
Pattern pattern = Pattern.compile("^[\\s\n]+$", Pattern.CASE_INSENSITIVE);
Matcher matcher = pattern.matcher(line);
return matcher.find();
public static boolean isKeyWord(String line) {
Pattern pattern = Pattern.compile("^[ \t\n]*(DECLARE|PACKAGE|TRIGGER|PROCEDURE|TYPE|CREATE|ALTER)", Pattern.CASE_INSENSITIVE);^
^Matcher matcher = pattern.matcher(line);^
^return matcher.find();^
^}^
^public static String isCTExists(String regEx, String line) {^
^Pattern pattern = Pattern.compile(regEx, Pattern.CASE_INSENSITIVE);^
^Matcher matcher = pattern.matcher(line);^
^String s = line;^
^while (matcher.find()) {^
^s = matcher.replaceAll(replaceCTStr(matcher.group()));^
^}^
^if (s.equals(""))^
^return line;^
^else^
^return s;^
^}^
^public static String replaceCTStr(String line) {^
^Pattern pattern = Pattern.compile("\\)", Pattern.CASE_INSENSITIVE);^
^Matcher matcher = pattern.matcher(line);^
^return matcher.replaceFirst("\\)\n/");^
^}^
^public static String isExists(String regEx, String line) {^
^Pattern pattern = Pattern.compile(regEx, Pattern.CASE_INSENSITIVE);^
^Matcher matcher = pattern.matcher(line);^
^String s = line;^
^while (matcher.find()) {^
^s = matcher.replaceAll(replaceStr(matcher.group()));^
^}^
^if (s.equals(""))^
^return line;^
^else^
^return s;^
^}^
^public static String replaceStr(String line) {^
^Pattern pattern = Pattern.compile("END[ \t]*;", Pattern.CASE_INSENSITIVE);^
^Matcher matcher = pattern.matcher(line);^
^return matcher.replaceFirst("END;\n/");^
^}^
^public static boolean isHaveEnding(String line) {^
^Pattern pattern = Pattern.compile("(END[ \t\"A-Za-z_]*;[ \t\n]*)$|([\\)]{1}[ \t\n]*)$", Pattern.CASE_INSENSITIVE);^
^Matcher matcher = pattern.matcher(line);^
^return matcher.find();^
^}^
^public static String checkCTMid(String regEx, String line) {^
^Pattern pattern = Pattern.compile(regEx, Pattern.CASE_INSENSITIVE);^
^Matcher matcher = pattern.matcher(line);^
^boolean notEnded = false;^
^String s = "";^
^String temp = "";^
^while (matcher.find()) {^
^if (matcher.group() != null) {^
^if (isComment(matcher.group())) {^
^s += matcher.group();^
^} else if (isNewLine(matcher.group())) // all the new line characters handled here...^
^{^
^s += matcher.group();^
^continue;^
^}^
^}^
^if (matcher.group(1) != null && !matcher.group(1).equals("")) {^
^if (notEnded && isKeyWord(matcher.group(1))) {^
^s += "\n/";^
^notEnded = false;^
^} else^
^notEnded = false;^
^temp = isCTExists("(\\)[ \n\t\r]*--;--^(?:DECLARE|PACKAGE|TRIGGER|PROCEDURE|TYPE|CREATE|ALTER))", matcher.group(1));
temp = isExists("(END;[ \n\t\r]*[^/](?:DECLARE|PACKAGE|TRIGGER|PROCEDURE|TYPE|CREATE|ALTER))", temp);
s += temp;+
+if (isHaveEnding(matcher.group(1))) {+
+notEnded = true;+
+}+
+}+
+}+
+return s;+
+}+
+public static void main(String[] args) {+
+String str = readFile("test.txt");+
+System.out.println("Read Compleate");+
+String strWithoutComments = checkCTMid( "(?:/\\*(?:--^*--|(?:\\*+--^/*--))*\\*+/)|(?:--.*)|((?:--^/-++|/(?!\\*)|-(?!-))*+)" , str ); //ok^--
--^String strWithoutbSlashMiddleEndForCT = isCTExists( "(\\)[ \t\n\r]*--;/--^--$)" , strWithoutComments);
String strWithoutbSlashMiddleEnd = isExists( "(END;[ \t\n\r]*--^/--$)" , strWithoutbSlashMiddleEndForCT);
System.out.println(strWithoutbSlashMiddleEnd);
{code}
This code is currently parse SQL statements and add '/' characters finding the missed places.
When i give this 'test.txt' as a long file (with 10000 LOC) gives belov error.
*Exception in thread "main" java.lang.StackOverflowError*
* at java.lang.Character.codePointAt(Character.java:2335)*
* at java.util.regex.Pattern$BitClass.match(Pattern.java:2873)*
* at java.util.regex.Pattern$Branch.match(Pattern.java:4530)*
* at java.util.regex.Pattern$GroupHead.match(Pattern.java:4570)*
* at java.util.regex.Pattern$Loop.match(Pattern.java:4697)*
* at java.util.regex.Pattern$GroupTail.match(Pattern.java:4629)*
* at java.util.regex.Pattern$BitClass.match(Pattern.java:2876)*
* at java.util.regex.Pattern$Branch.match(Pattern.java:4530)*
* at java.util.regex.Pattern$GroupHead.match(Pattern.java:4570)*
* at java.util.regex.Pattern$Loop.match(Pattern.java:4697)*
* at java.util.regex.Pattern$GroupTail.match(Pattern.java:4629)*
* at java.util.regex.Pattern$BitClass.match(Pattern.java:2876)*
* at java.util.regex.Pattern$Branch.match(Pattern.java:4530)*
* at java.util.regex.Pattern$GroupHead.match(Pattern.java:4570)*
* at java.util.regex.Pattern$Loop.match(Pattern.java:4697)*
* at java.util.regex.Pattern$GroupTail.match(Pattern.java:4629)*
* at java.util.regex.Pattern$BitClass.match(Pattern.java:2876)*
* at java.util.regex.Pattern$Branch.match(Pattern.java:4530)*
* at java.util.regex.Pattern$GroupHead.match(Pattern.java:4570)*
* at java.util.regex.Pattern$Loop.match(Pattern.java:4697)*
* at java.util.regex.Pattern$GroupTail.match(Pattern.java:4629)*
* at java.util.regex.Pattern$BitClass.match(Pattern.java:2876)*
* at java.util.regex.Pattern$Branch.match(Pattern.java:4530)*
* at java.util.regex.Pattern$GroupHead.match(Pattern.java:4570)*
* at java.util.regex.Pattern$Loop.match(Pattern.java:4697)*
* at java.util.regex.Pattern$GroupTail.match(Pattern.java:4629)*
* at java.util.regex.Pattern$BitClass.match(Pattern.java:2876)*
* at java.util.regex.Pattern$Branch.match(Pattern.java:4530)*
* at java.util.regex.Pattern$GroupHead.match(Pattern.java:4570)*
* at java.util.regex.Pattern$Loop.match(Pattern.java:4697)*
* at java.util.regex.Pattern$GroupTail.match(Pattern.java:4629)*
* at java.util.regex.Pattern$BitClass.match(Pattern.java:2876)*
This is not hapenning for small files.
Can anyone help!                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       

Answer 1

Let's see if I can get this to display as intended: {noformat}(?:/\*(?:[^*]|(?:\*+[^/*]))*\*+/)|(?:--.*)|((?:[^/-]++|/(?!\*)|-(?!-))*+){noformat} Okay, when I try that regex (in EditPad Pro, against the source code of this web page), I see this result: The second alternative, {noformat}(?:--.*){noformat} matches anything from a double hyphen to the end of that line, and the third alternative: {noformat}((?:[^/-]++|/(?!\*)|-(?!-))*+){noformat} matches everything else (up to the next double hyphen, that is). These pages happen to contain a lot of SGML comments, so there are plenty of double hyphens to match. In a large document with only a few double hyphens, it would be easy to blow the stack trying to find the next stopping point.
What exactly is the isComment() method supposed to do? Are you trying to match a line that consists entirely of a comment, or just a line that contains a comment? And how exactly do you define a comment?