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Diffstat (limited to 'src/main/java/org/apache/commons/lang3/CharSetUtils.java')
| -rw-r--r-- | src/main/java/org/apache/commons/lang3/CharSetUtils.java | 243 |
1 files changed, 243 insertions, 0 deletions
diff --git a/src/main/java/org/apache/commons/lang3/CharSetUtils.java b/src/main/java/org/apache/commons/lang3/CharSetUtils.java new file mode 100644 index 000000000..b1efea59d --- /dev/null +++ b/src/main/java/org/apache/commons/lang3/CharSetUtils.java @@ -0,0 +1,243 @@ +/* + * 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. + * + * <p>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.</p> + * + * <p>#ThreadSafe#</p> + * @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. + * + * <pre> + * 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 + * </pre> + * + * @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. + * + * <pre> + * 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 + * </pre> + * + * @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. + * + * <pre> + * CharSetUtils.delete(null, *) = null + * CharSetUtils.delete("", *) = "" + * CharSetUtils.delete(*, null) = * + * CharSetUtils.delete(*, "") = * + * CharSetUtils.delete("hello", "hl") = "eo" + * CharSetUtils.delete("hello", "le") = "ho" + * </pre> + * + * @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. + * + * <pre> + * CharSetUtils.keep(null, *) = null + * CharSetUtils.keep("", *) = "" + * CharSetUtils.keep(*, null) = "" + * CharSetUtils.keep(*, "") = "" + * CharSetUtils.keep("hello", "hl") = "hll" + * CharSetUtils.keep("hello", "le") = "ell" + * </pre> + * + * @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. + * + * <pre> + * CharSetUtils.squeeze(null, *) = null + * CharSetUtils.squeeze("", *) = "" + * CharSetUtils.squeeze(*, null) = * + * CharSetUtils.squeeze(*, "") = * + * CharSetUtils.squeeze("hello", "k-p") = "helo" + * CharSetUtils.squeeze("hello", "a-e") = "hello" + * </pre> + * + * @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);}. + * + * <p>This constructor is public to permit tools that require a JavaBean instance + * to operate.</p> + */ + public CharSetUtils() { + } +} |