org.apache.commons.lang.CharSetUtils Maven / Gradle / Ivy
/*
* 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.lang;
/**
* Operations on CharSets.
*
* This class handles null input gracefully.
* An exception will not be thrown for a null input.
* Each method documents its behaviour in more detail.
*
* @see CharSet
* @author Stephen Colebourne
* @author Phil Steitz
* @author Gary Gregory
* @since 1.0
* @version $Id: CharSetUtils.java 534588 2007-05-02 18:46:07Z bayard $
*/
public class CharSetUtils {
/**
* CharSetUtils instances should NOT be constructed in standard programming.
* Instead, the class should be used as CharSetUtils.evaluateSet(null);.
*
* This constructor is public to permit tools that require a JavaBean instance
* to operate.
*/
public CharSetUtils() {
super();
}
// Factory
//-----------------------------------------------------------------------
/**
* Creates a CharSet instance which allows a certain amount of
* set logic to be performed.
* The syntax is:
*
* - "aeio" which implies 'a','e',..
* - "^e" implies not e.
* - "ej-m" implies e,j->m. e,j,k,l,m.
*
*
*
* CharSetUtils.evaluateSet(null) = null
* CharSetUtils.evaluateSet([]) = CharSet matching nothing
* CharSetUtils.evaluateSet(["a-e"]) = CharSet matching a,b,c,d,e
*
*
* @param set the set, may be null
* @return a CharSet instance, null if null input
* @deprecated Use {@link CharSet#getInstance(String[])}.
* Method will be removed in Commons Lang 3.0.
*/
public static CharSet evaluateSet(String[] set) {
if (set == null) {
return null;
}
return new CharSet(set);
}
// 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 #evaluateSet(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 modified String, null if null string input
*/
public static String squeeze(String str, String set) {
if (StringUtils.isEmpty(str) || StringUtils.isEmpty(set)) {
return str;
}
String[] strs = new String[1];
strs[0] = set;
return squeeze(str, strs);
}
/**
* Squeezes any repetitions of a character that is mentioned in the
* supplied set.
*
* An example is:
*
* - squeeze("hello", {"el"}) => "helo"
*
*
* @see #evaluateSet(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 modified String, null if null string input
*/
public static String squeeze(String str, String[] set) {
if (StringUtils.isEmpty(str) || ArrayUtils.isEmpty(set)) {
return str;
}
CharSet chars = CharSet.getInstance(set);
StringBuffer buffer = new StringBuffer(str.length());
char[] chrs = str.toCharArray();
int sz = chrs.length;
char lastChar = ' ';
char ch = ' ';
for (int i = 0; i < sz; i++) {
ch = chrs[i];
if (chars.contains(ch)) {
if ((ch == lastChar) && (i != 0)) {
continue;
}
}
buffer.append(ch);
lastChar = ch;
}
return buffer.toString();
}
// 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 #evaluateSet(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 character count, zero if null string input
*/
public static int count(String str, String set) {
if (StringUtils.isEmpty(str) || StringUtils.isEmpty(set)) {
return 0;
}
String[] strs = new String[1];
strs[0] = set;
return count(str, strs);
}
/**
* Takes an argument in set-syntax, see evaluateSet,
* and returns the number of characters present in the specified string.
*
* An example would be:
*
* - count("hello", {"c-f", "o"}) returns 2.
*
*
* @see #evaluateSet(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 character count, zero if null string input
*/
public static int count(String str, String[] set) {
if (StringUtils.isEmpty(str) || ArrayUtils.isEmpty(set)) {
return 0;
}
CharSet chars = CharSet.getInstance(set);
int count = 0;
char[] chrs = str.toCharArray();
int sz = chrs.length;
for(int i=0; iTakes 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 #evaluateSet(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 modified String, null if null string input
* @since 2.0
*/
public static String keep(String str, String set) {
if (str == null) {
return null;
}
if (str.length() == 0 || StringUtils.isEmpty(set)) {
return "";
}
String[] strs = new String[1];
strs[0] = set;
return keep(str, strs);
}
/**
* Takes an argument in set-syntax, see evaluateSet,
* and keeps any of characters present in the specified string.
*
* An example would be:
*
* - keep("hello", {"c-f", "o"})
* returns "eo"
*
*
* @see #evaluateSet(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 modified String, null if null string input
* @since 2.0
*/
public static String keep(String str, String[] set) {
if (str == null) {
return null;
}
if (str.length() == 0 || ArrayUtils.isEmpty(set)) {
return "";
}
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 #evaluateSet(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 modified String, null if null string input
*/
public static String delete(String str, String set) {
if (StringUtils.isEmpty(str) || StringUtils.isEmpty(set)) {
return str;
}
String[] strs = new String[1];
strs[0] = set;
return delete(str, strs);
}
/**
* Takes an argument in set-syntax, see evaluateSet,
* and deletes any of characters present in the specified string.
*
* An example would be:
*
* - delete("hello", {"c-f", "o"}) returns
* "hll"
*
*
* @see #evaluateSet(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 modified String, null if null string input
*/
public static String delete(String str, String[] set) {
if (StringUtils.isEmpty(str) || ArrayUtils.isEmpty(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 modified String
*/
private static String modify(String str, String[] set, boolean expect) {
CharSet chars = CharSet.getInstance(set);
StringBuffer buffer = new StringBuffer(str.length());
char[] chrs = str.toCharArray();
int sz = chrs.length;
for(int i=0; iTranslate characters in a String.
* This is a multi character search and replace routine.
*
* An example is:
*
* - translate("hello", "ho", "jy")
* => jelly
*
*
* If the length of characters to search for is greater than the
* length of characters to replace, then the last character is
* used.
*
*
* CharSetUtils.translate(null, *, *) = null
* CharSetUtils.translate("", *, *) = ""
*
*
* @param str String to replace characters in, may be null
* @param searchChars a set of characters to search for, must not be null
* @param replaceChars a set of characters to replace, must not be null or empty ("")
* @return translated String, null if null string input
* @throws NullPointerException if searchChars or replaceChars
* is null
* @throws ArrayIndexOutOfBoundsException if replaceChars is empty ("")
* @deprecated Use {@link StringUtils#replaceChars(String, String, String)}.
* Method will be removed in Commons Lang 3.0.
* NOTE: StringUtils#replaceChars behaves differently when 'searchChars' is longer
* than 'replaceChars'. CharSetUtils#translate will use the last char of the replacement
* string whereas StringUtils#replaceChars will delete
*/
public static String translate(String str, String searchChars, String replaceChars) {
if (StringUtils.isEmpty(str)) {
return str;
}
StringBuffer buffer = new StringBuffer(str.length());
char[] chrs = str.toCharArray();
char[] withChrs = replaceChars.toCharArray();
int sz = chrs.length;
int withMax = replaceChars.length() - 1;
for(int i=0; i withMax) {
idx = withMax;
}
buffer.append(withChrs[idx]);
} else {
buffer.append(chrs[i]);
}
}
return buffer.toString();
}
}