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/*
 * 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;

/**
 * 

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 behaviour in more detail.

* *

#ThreadSafe#

* @see CharSet * @since 1.0 */ public class CharSetUtils { /** *

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() { super(); } // Squeeze //----------------------------------------------------------------------- /** *

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(); } // ContainsAny //----------------------------------------------------------------------- /** *

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; } // Count //----------------------------------------------------------------------- /** *

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; } // Keep //----------------------------------------------------------------------- /** *

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); } // Delete //----------------------------------------------------------------------- /** *

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); } //----------------------------------------------------------------------- /** * 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(); } /** * 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; } }




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