/*
* 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;
/**
* <p>Operations on {@code CharSet} instances.</p>
*
* <p>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.</p>
*
* <p>#ThreadSafe#</p>
* @see CharSet
* @since 1.0
*/
public class
CharSetUtils {
/**
* <p>CharSetUtils instances should NOT be constructed in standard programming.
* Instead, the class should be used as {@code CharSetUtils.evaluateSet(null);}.</p>
*
* <p>This constructor is public to permit tools that require a JavaBean instance
* to operate.</p>
*/
public
CharSetUtils() {
super();
}
// Squeeze
//-----------------------------------------------------------------------
/**
* <p>Squeezes any repetitions of a character that is mentioned in the
* supplied set.</p>
*
* <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(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;
} else {
if (
notInChars == null ||
ch !=
notInChars) {
if (
chars.
contains(
ch)) {
inChars =
ch;
continue;
} else {
notInChars =
ch;
}
}
}
}
buffer.
append(
ch);
lastChar =
ch;
}
return
buffer.
toString();
}
// ContainsAny
//-----------------------------------------------------------------------
/**
* <p>Takes an argument in set-syntax, see evaluateSet,
* and identifies whether any of the characters are present in the specified string.</p>
*
* <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(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
//-----------------------------------------------------------------------
/**
* <p>Takes an argument in set-syntax, see evaluateSet,
* and returns the number of characters present in the specified string.</p>
*
* <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(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
//-----------------------------------------------------------------------
/**
* <p>Takes an argument in set-syntax, see evaluateSet,
* and keeps any of characters present in the specified string.</p>
*
* <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(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
//-----------------------------------------------------------------------
/**
* <p>Takes an argument in set-syntax, see evaluateSet,
* and deletes any of characters present in the specified string.</p>
*
* <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(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();
final int
sz =
chrs.length;
for(int
i=0;
i<
sz;
i++) {
if(
chars.
contains(
chrs[
i]) ==
expect) {
buffer.
append(
chrs[
i]);
}
}
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;
}
}