* Operations on {@code CharSet} instances. *
* ** This class handles {@code null} input gracefully. An exception will not be * thrown for a {@code null} input. Each method documents its behavior in more * detail. *
* ** #ThreadSafe# *
* * @see CharSet * @since 1.0 */ public class CharSetUtils { /** ** Takes an argument in set-syntax, see evaluateSet, and identifies whether any * of the characters are present in the specified string. *
* *
* CharSetUtils.containsAny(null, *) = false
* CharSetUtils.containsAny("", *) = false
* CharSetUtils.containsAny(*, null) = false
* CharSetUtils.containsAny(*, "") = false
* CharSetUtils.containsAny("hello", "k-p") = true
* CharSetUtils.containsAny("hello", "a-d") = false
*
*
* @see CharSet#getInstance(java.lang.String...) for set-syntax.
* @param str String to look for characters in, may be null
* @param set String[] set of characters to identify, may be null
* @return whether or not the characters in the set are in the primary string
* @since 3.2
*/
public static boolean containsAny(final String str, final String... set) {
if (StringUtils.isEmpty(str) || deepEmpty(set)) {
return false;
}
final CharSet chars = CharSet.getInstance(set);
for (final char c : str.toCharArray()) {
if (chars.contains(c)) {
return true;
}
}
return false;
}
/**
* * Takes an argument in set-syntax, see evaluateSet, and returns the number of * characters present in the specified string. *
* *
* CharSetUtils.count(null, *) = 0
* CharSetUtils.count("", *) = 0
* CharSetUtils.count(*, null) = 0
* CharSetUtils.count(*, "") = 0
* CharSetUtils.count("hello", "k-p") = 3
* CharSetUtils.count("hello", "a-e") = 1
*
*
* @see CharSet#getInstance(java.lang.String...) for set-syntax.
* @param str String to count characters in, may be null
* @param set String[] set of characters to count, may be null
* @return the character count, zero if null string input
*/
public static int count(final String str, final String... set) {
if (StringUtils.isEmpty(str) || deepEmpty(set)) {
return 0;
}
final CharSet chars = CharSet.getInstance(set);
int count = 0;
for (final char c : str.toCharArray()) {
if (chars.contains(c)) {
count++;
}
}
return count;
}
/**
* Determines whether or not all the Strings in an array are empty or not.
*
* @param strings String[] whose elements are being checked for emptiness
* @return whether or not the String is empty
*/
private static boolean deepEmpty(final String[] strings) {
if (strings != null) {
for (final String s : strings) {
if (StringUtils.isNotEmpty(s)) {
return false;
}
}
}
return true;
}
/**
* * Takes an argument in set-syntax, see evaluateSet, and deletes any of * characters present in the specified string. *
* *
* CharSetUtils.delete(null, *) = null
* CharSetUtils.delete("", *) = ""
* CharSetUtils.delete(*, null) = *
* CharSetUtils.delete(*, "") = *
* CharSetUtils.delete("hello", "hl") = "eo"
* CharSetUtils.delete("hello", "le") = "ho"
*
*
* @see CharSet#getInstance(java.lang.String...) for set-syntax.
* @param str String to delete characters from, may be null
* @param set String[] set of characters to delete, may be null
* @return the modified String, {@code null} if null string input
*/
public static String delete(final String str, final String... set) {
if (StringUtils.isEmpty(str) || deepEmpty(set)) {
return str;
}
return modify(str, set, false);
}
/**
* * Takes an argument in set-syntax, see evaluateSet, and keeps any of characters * present in the specified string. *
* *
* CharSetUtils.keep(null, *) = null
* CharSetUtils.keep("", *) = ""
* CharSetUtils.keep(*, null) = ""
* CharSetUtils.keep(*, "") = ""
* CharSetUtils.keep("hello", "hl") = "hll"
* CharSetUtils.keep("hello", "le") = "ell"
*
*
* @see CharSet#getInstance(java.lang.String...) for set-syntax.
* @param str String to keep characters from, may be null
* @param set String[] set of characters to keep, may be null
* @return the modified String, {@code null} if null string input
* @since 2.0
*/
public static String keep(final String str, final String... set) {
if (str == null) {
return null;
}
if (str.isEmpty() || deepEmpty(set)) {
return StringUtils.EMPTY;
}
return modify(str, set, true);
}
/**
* Implementation of delete and keep
*
* @param str String to modify characters within
* @param set String[] set of characters to modify
* @param expect whether to evaluate on match, or non-match
* @return the modified String, not null
*/
private static String modify(final String str, final String[] set, final boolean expect) {
final CharSet chars = CharSet.getInstance(set);
final StringBuilder buffer = new StringBuilder(str.length());
final char[] chrs = str.toCharArray();
for (final char chr : chrs) {
if (chars.contains(chr) == expect) {
buffer.append(chr);
}
}
return buffer.toString();
}
/**
* * Squeezes any repetitions of a character that is mentioned in the supplied * set. *
* *
* CharSetUtils.squeeze(null, *) = null
* CharSetUtils.squeeze("", *) = ""
* CharSetUtils.squeeze(*, null) = *
* CharSetUtils.squeeze(*, "") = *
* CharSetUtils.squeeze("hello", "k-p") = "helo"
* CharSetUtils.squeeze("hello", "a-e") = "hello"
*
*
* @see CharSet#getInstance(java.lang.String...) for set-syntax.
* @param str the string to squeeze, may be null
* @param set the character set to use for manipulation, may be null
* @return the modified String, {@code null} if null string input
*/
public static String squeeze(final String str, final String... set) {
if (StringUtils.isEmpty(str) || deepEmpty(set)) {
return str;
}
final CharSet chars = CharSet.getInstance(set);
final StringBuilder buffer = new StringBuilder(str.length());
final char[] chrs = str.toCharArray();
final int sz = chrs.length;
char lastChar = chrs[0];
char ch = ' ';
Character inChars = null;
Character notInChars = null;
buffer.append(lastChar);
for (int i = 1; i < sz; i++) {
ch = chrs[i];
if (ch == lastChar) {
if (inChars != null && ch == inChars) {
continue;
}
if (notInChars == null || ch != notInChars) {
if (chars.contains(ch)) {
inChars = ch;
continue;
}
notInChars = ch;
}
}
buffer.append(ch);
lastChar = ch;
}
return buffer.toString();
}
/**
* * CharSetUtils instances should NOT be constructed in standard programming. * Instead, the class should be used as {@code CharSetUtils.evaluateSet(null);}. *
* ** This constructor is public to permit tools that require a JavaBean instance * to operate. *
*/ public CharSetUtils() { } }