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Apache Commons Lang, a package of Java utility classes for the
classes that are in java.lang's hierarchy, or are considered to be so
standard as to justify existence in java.lang.
The code is tested using the latest revision of the JDK for supported
LTS releases: 8, 11, 17 and 21 currently.
See https://github.com/apache/commons-lang/blob/master/.github/workflows/maven.yml
Please ensure your build environment is up-to-date and kindly report any build issues.
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.commons.lang3;
import org.apache.commons.lang3.stream.Streams;
/**
* Operations on {@link 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(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(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) {
return Streams.of(strings).allMatch(StringUtils::isEmpty);
}
/**
* 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(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(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(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() {
}
}
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