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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.
/*
* 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 {@link java.lang.CharSequence} that are
* {@code null} safe.
*
* @see java.lang.CharSequence
* @since 3.0
* @version $Id: CharSequenceUtils.java 1091471 2011-04-12 15:34:43Z scolebourne $
*/
public class CharSequenceUtils {
/**
* {@code CharSequenceUtils} instances should NOT be constructed in
* standard programming.
*
* This constructor is public to permit tools that require a JavaBean
* instance to operate.
*/
public CharSequenceUtils() {
super();
}
//-----------------------------------------------------------------------
/**
* Returns a new {@code CharSequence} that is a subsequence of this
* sequence starting with the {@code char} value at the specified index.
*
* This provides the {@code CharSequence} equivalent to {@link String#substring(int)}.
* The length (in {@code char}) of the returned sequence is {@code length() - start},
* so if {@code start == end} then an empty sequence is returned.
*
* @param cs the specified subsequence, null returns null
* @param start the start index, inclusive, valid
* @return a new subsequence, may be null
* @throws IndexOutOfBoundsException if {@code start} is negative or if
* {@code start} is greater than {@code length()}
*/
public static CharSequence subSequence(CharSequence cs, int start) {
return cs == null ? null : cs.subSequence(start, cs.length());
}
//-----------------------------------------------------------------------
/**
* Finds the first index in the {@code CharSequence} that matches the
* specified character.
*
* @param cs the {@code CharSequence} to be processed, not null
* @param searchChar the char to be searched for
* @param start the start index, negative starts at the string start
* @return the index where the search char was found, -1 if not found
*/
static int indexOf(CharSequence cs, int searchChar, int start) {
if (cs instanceof String) {
return ((String) cs).indexOf(searchChar, start);
} else {
int sz = cs.length();
if (start < 0) {
start = 0;
}
for (int i = start; i < sz; i++) {
if (cs.charAt(i) == searchChar) {
return i;
}
}
return -1;
}
}
/**
* Used by the indexOf(CharSequence methods) as a green implementation of indexOf.
*
* @param cs the {@code CharSequence} to be processed
* @param searchChar the {@code CharSequence} to be searched for
* @param start the start index
* @return the index where the search sequence was found
*/
static int indexOf(CharSequence cs, CharSequence searchChar, int start) {
return cs.toString().indexOf(searchChar.toString(), start);
// if (cs instanceof String && searchChar instanceof String) {
// // TODO: Do we assume searchChar is usually relatively small;
// // If so then calling toString() on it is better than reverting to
// // the green implementation in the else block
// return ((String) cs).indexOf((String) searchChar, start);
// } else {
// // TODO: Implement rather than convert to String
// return cs.toString().indexOf(searchChar.toString(), start);
// }
}
/**
* Finds the last index in the {@code CharSequence} that matches the
* specified character.
*
* @param cs the {@code CharSequence} to be processed
* @param searchChar the char to be searched for
* @param start the start index, negative returns -1, beyond length starts at end
* @return the index where the search char was found, -1 if not found
*/
static int lastIndexOf(CharSequence cs, int searchChar, int start) {
if (cs instanceof String) {
return ((String) cs).lastIndexOf(searchChar, start);
} else {
int sz = cs.length();
if (start < 0) {
return -1;
}
if (start >= sz) {
start = sz - 1;
}
for (int i = start; i >= 0; --i) {
if (cs.charAt(i) == searchChar) {
return i;
}
}
return -1;
}
}
/**
* Used by the lastIndexOf(CharSequence methods) as a green implementation of lastIndexOf
*
* @param cs the {@code CharSequence} to be processed
* @param searchChar the {@code CharSequence} to be searched for
* @param start the start index
* @return the index where the search sequence was found
*/
static int lastIndexOf(CharSequence cs, CharSequence searchChar, int start) {
return cs.toString().lastIndexOf(searchChar.toString(), start);
// if (cs instanceof String && searchChar instanceof String) {
// // TODO: Do we assume searchChar is usually relatively small;
// // If so then calling toString() on it is better than reverting to
// // the green implementation in the else block
// return ((String) cs).lastIndexOf((String) searchChar, start);
// } else {
// // TODO: Implement rather than convert to String
// return cs.toString().lastIndexOf(searchChar.toString(), start);
// }
}
/**
* Green implementation of toCharArray.
*
* @param cs the {@code CharSequence} to be processed
* @return the resulting char array
*/
static char[] toCharArray(CharSequence cs) {
if (cs instanceof String) {
return ((String) cs).toCharArray();
} else {
int sz = cs.length();
char[] array = new char[cs.length()];
for (int i = 0; i < sz; i++) {
array[i] = cs.charAt(i);
}
return array;
}
}
/**
* Green implementation of regionMatches.
*
* @param cs the {@code CharSequence} to be processed
* @param ignoreCase whether or not to be case insensitive
* @param thisStart the index to start on the {@code cs} CharSequence
* @param substring the {@code CharSequence} to be looked for
* @param start the index to start on the {@code substring} CharSequence
* @param length character length of the region
* @return whether the region matched
*/
static boolean regionMatches(CharSequence cs, boolean ignoreCase, int thisStart,
CharSequence substring, int start, int length) {
if (cs instanceof String && substring instanceof String) {
return ((String) cs).regionMatches(ignoreCase, thisStart, ((String) substring), start, length);
} else {
// TODO: Implement rather than convert to String
return cs.toString().regionMatches(ignoreCase, thisStart, substring.toString(), start, length);
}
}
}