org.codehaus.plexus.util.xml.StringUtils Maven / Gradle / Ivy
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*
* This software consists of voluntary contributions made by many
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*
* Common String manipulation routines, extracted from Plexus Utils and trimmed down for Plexus Xml.
*
*
* Originally from Turbine and the GenerationJavaCore library.
*
*
* @author Jon S. Stevens
* @author Daniel Rall
* @author Greg Coladonato
* @author Henri Yandell
* @author Ed Korthof
* @author Rand McNeely
* @author Stephen Colebourne
* @author Fredrik Westermarck
* @author Holger Krauth
* @author Alexander Day Chaffee
* @author Vincent Siveton
* @since 1.0
*
*/
class StringUtils {
/**
*
* StringUtils instances should NOT be constructed in standard programming. Instead, the class should
* be used as StringUtils.trim(" foo ");.
*
*
* This constructor is public to permit tools that require a JavaBean manager to operate.
*
*/
private StringUtils() {}
/**
* Checks if a String is null or empty.
*
* Note: In releases prior 3.5.0, this method trimmed the input string such that it worked
* the same as {@link #isBlank(String)}. Since release 3.5.0 it no longer returns {@code true} for strings
* containing only whitespace characters.
*
* @param str the String to check
* @return true if the String is null, or length zero
*/
public static boolean isEmpty(String str) {
return ((str == null) || (str.isEmpty()));
}
// Splitting
// --------------------------------------------------------------------------
/**
* @param text The string to parse.
* @param separator Characters used as the delimiters. If null, splits on whitespace.
* @return an array of parsed Strings
*/
public static String[] split(String text, String separator) {
return split(text, separator, -1);
}
/**
*
* Splits the provided text into a array, based on a given separator.
*
*
* The separator is not included in the returned String array. The maximum number of splits to perform can be
* controlled. A null separator will cause parsing to be on whitespace.
*
*
* This is useful for quickly splitting a String directly into an array of tokens, instead of an enumeration of
* tokens (as StringTokenizer does).
*
*
* @param str The string to parse.
* @param separator Characters used as the delimiters. If null, splits on whitespace.
* @param max The maximum number of elements to include in the array. A zero or negative value implies no limit.
* @return an array of parsed Strings
*/
private static String[] split(String str, String separator, int max) {
StringTokenizer tok;
if (separator == null) {
// Null separator means we're using StringTokenizer's default
// delimiter, which comprises all whitespace characters.
tok = new StringTokenizer(str);
} else {
tok = new StringTokenizer(str, separator);
}
int listSize = tok.countTokens();
if ((max > 0) && (listSize > max)) {
listSize = max;
}
String[] list = new String[listSize];
int i = 0;
int lastTokenBegin;
int lastTokenEnd = 0;
while (tok.hasMoreTokens()) {
if ((max > 0) && (i == listSize - 1)) {
// In the situation where we hit the max yet have
// tokens left over in our input, the last list
// element gets all remaining text.
String endToken = tok.nextToken();
lastTokenBegin = str.indexOf(endToken, lastTokenEnd);
list[i] = str.substring(lastTokenBegin);
break;
} else {
list[i] = tok.nextToken();
lastTokenBegin = str.indexOf(list[i], lastTokenEnd);
lastTokenEnd = lastTokenBegin + list[i].length();
}
i++;
}
return list;
}
/**
*
* Repeat a String n times to form a new string.
*
*
* @param str String to repeat
* @param repeat number of times to repeat str
* @return String with repeated String
* @throws NegativeArraySizeException if repeat < 0
* @throws NullPointerException if str is null
*/
public static String repeat(String str, int repeat) {
StringBuilder buffer = new StringBuilder(repeat * str.length());
for (int i = 0; i < repeat; i++) {
buffer.append(str);
}
return buffer.toString();
}
/**
* Remove all duplicate whitespace characters and line terminators are replaced with a single space.
*
* @param s a not null String
* @return a string with unique whitespace.
* @since 1.5.7
*/
public static String removeDuplicateWhitespace(String s) {
StringBuilder result = new StringBuilder();
int length = s.length();
boolean isPreviousWhiteSpace = false;
for (int i = 0; i < length; i++) {
char c = s.charAt(i);
boolean thisCharWhiteSpace = Character.isWhitespace(c);
if (!(isPreviousWhiteSpace && thisCharWhiteSpace)) {
result.append(c);
}
isPreviousWhiteSpace = thisCharWhiteSpace;
}
return result.toString();
}
/**
* Parses the given String and replaces all occurrences of '\n', '\r' and '\r\n' with the system line separator.
*
* @param s a not null String
* @param ls the wanted line separator ("\n" on UNIX), if null using the System line separator.
* @return a String that contains only System line separators.
* @throws IllegalArgumentException if ls is not '\n', '\r' and '\r\n' characters.
* @since 1.5.7
*/
public static String unifyLineSeparators(String s, String ls) {
if (s == null) {
return null;
}
if (ls == null) {
ls = System.getProperty("line.separator");
}
if (!(ls.equals("\n") || ls.equals("\r") || ls.equals("\r\n"))) {
throw new IllegalArgumentException("Requested line separator is invalid.");
}
int length = s.length();
StringBuilder buffer = new StringBuilder(length);
for (int i = 0; i < length; i++) {
if (s.charAt(i) == '\r') {
if ((i + 1) < length && s.charAt(i + 1) == '\n') {
i++;
}
buffer.append(ls);
} else if (s.charAt(i) == '\n') {
buffer.append(ls);
} else {
buffer.append(s.charAt(i));
}
}
return buffer.toString();
}
}