/**
* This function replace only the first pattern matched with the replacement.
*
* @param pattern pattern string to match
* @param input input string
* @param replacement replacement string
* @return returns the processed string
* @exception throws a FrameworkException when the pattern/replacement is null.
*/
public static String replaceFirst(String pattern, String input, String replacement)
throws FrameworkException {
if ((pattern == null) || (input == null) || (replacement == null)) {
throw new FrameworkException(
"RegexUtil: replaceFirst(): pattern or input cannot be null. "
+ "pattern = "
+ pattern
+ "input = "
+ input
+ "replacement = "
+ replacement);
}
String result = null;
String perl5SubstitutionPattern = null;
Perl5Util util = new Perl5Util();
// default return value
result = input;
perl5SubstitutionPattern = makePerl5SubstitutionPattern(pattern, replacement);
pattern = makePerl5MatchPattern(pattern);
if (util.match(pattern, input)) {
result = util.substitute(perl5SubstitutionPattern, input);
}
return result;
}
/**
* This function takes a perl5 regular expression as the pattern to perform pattern matching and
* string substitution.
*
* <p>"s/pattern/replacement/[g][i][m][o][s][x]"
*
* <p>g - substitute globally (all occurence) i - case insensitive m - treat the input as
* consisting of multiple lines o - interpolate once s - treat the input as consisting of a single
* line x - enable extended expression syntax incorporating whitespace and comments
*
* <p>to perform string substitution. Unless the [g] option is specified, the dafault is to
* replace only the first occurrence.
*
* @param perl5Pattern - Perl5 regular expression
* @param input - input string
* @return result - processed string. The original input is returned when there is no match
* @exception - FrameworkException is thrown when either pattern or input is null
*/
public static String substitute(String perl5Pattern, String input) throws FrameworkException {
if ((perl5Pattern == null) || (input == null)) {
throw new FrameworkException(
"RegexUtil: replaceAll(): Either input or pattern is null."
+ "input = "
+ input
+ ", "
+ "pattern = "
+ perl5Pattern);
}
if (Debug.isLevelEnabled(Debug.MSG_STATUS)) {
Debug.log(
Debug.MSG_STATUS,
"RegexUtils: replaceAll: perl5Pattern = " + perl5Pattern + " input = " + input);
}
Perl5Util util = new Perl5Util();
String result = input;
try {
result = util.substitute(perl5Pattern, input);
} catch (RuntimeException e) {
throw new FrameworkException("RegexUtils: substitute: " + e.getMessage());
}
return result;
}
/**
* This function replace only the first pattern matched with the replacement.
*
* @param pattern pattern string to match
* @param input input string
* @param replacement replacement string
* @return returns the processed string
* @exception throws a FrameworkException when the pattern/replacement is null.
*/
public static String replaceLast(String pattern, String input, String replacement)
throws FrameworkException {
if ((pattern == null) || (input == null) || (replacement == null)) {
throw new FrameworkException(
"RegexUtil: replaceLast(): pattern or input cannot be null. "
+ "pattern = "
+ pattern
+ "input = "
+ input
+ "replacement = "
+ replacement);
}
Perl5Util util = new Perl5Util();
MatchResult matchResult = null;
String result = null;
String pre = null;
String post = null;
StringBuffer resultBuffer = new StringBuffer();
int length = input.length();
String regex = makePerl5SubstitutionPattern(pattern, replacement);
pattern = makePerl5MatchPattern(pattern);
// counts the number of match and grab the last one
while (util.match(pattern, input)) {
// getting the string before match
pre = util.preMatch();
resultBuffer.append(pre);
// get the matched string
matchResult = util.getMatch();
resultBuffer.append(matchResult.toString());
// get the post string after the match
post = util.postMatch();
// the post becomes the new input
input = post;
}
// get the last match found
matchResult = util.getMatch();
// do the string replacement on the pattern found
result = util.substitute(regex, matchResult.toString());
resultBuffer.append(result);
resultBuffer.append(post);
return resultBuffer.toString();
}
/**
* This function substitues ALL occurence of the pattern in the input with the replacement passed
* in. This function can handle such situation as when some characters in the replacement is also
* used in the pattern.
*
* <p>i.e.) pattern - & or &/[option] replacement - & or &/[option]
*
* @param pattern pattern string to match
* @param input input string
* @param replacement replacement string to be replaced with
* @return returns processed string. Default return value is the original input string.
* @exception throws FrameworkException when either pattern/input/replacement is null.
*/
public static String replaceAll(String pattern, String input, String replacement)
throws FrameworkException {
if ((pattern == null) || (replacement == null) || (input == null)) {
Debug.log(
Debug.ALL_ERRORS,
"RegexUtils.replaceAll(): pattern or replacement or input" + "is null.");
throw new FrameworkException(
"ERROR: RegexUtils: replaceAll(): pattern or replacement or input is null.");
}
Perl5Util util = new Perl5Util();
String negativeLookAheadPattern = makePerl5MatchPatternNegativeLookAhead(pattern, replacement);
String substitutionPattern =
makePerl5SubstitutionPattern(negativeLookAheadPattern, replacement);
String result = util.substitute(substitutionPattern, input);
return result;
}
