|
/**
* 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.
*/
/**
* <p>Operations on {@link java.lang.String} that are
* <code>null</code> safe.</p>
*
* @see java.lang.String
* @author <a href="http://jakarta.apache.org/turbine/">Apache Jakarta Turbine</a>
* @author <a href="mailto:jon@latchkey.com">Jon S. Stevens</a>
* @author Daniel L. Rall
* @author <a href="mailto:gcoladonato@yahoo.com">Greg Coladonato</a>
* @author <a href="mailto:ed@apache.org">Ed Korthof</a>
* @author <a href="mailto:rand_mcneely@yahoo.com">Rand McNeely</a>
* @author Stephen Colebourne
* @author <a href="mailto:fredrik@westermarck.com">Fredrik Westermarck</a>
* @author Holger Krauth
* @author <a href="mailto:alex@purpletech.com">Alexander Day Chaffee</a>
* @author <a href="mailto:hps@intermeta.de">Henning P. Schmiedehausen</a>
* @author Arun Mammen Thomas
* @author Gary Gregory
* @author Phil Steitz
* @author Al Chou
* @author Michael Davey
* @author Reuben Sivan
* @author Chris Hyzer
* @author Scott Johnson
* @since 1.0
* @version $Id: StringUtils.java 635447 2008-03-10 06:27:09Z bayard $
*/
public class Main {
// StripAll
//-----------------------------------------------------------------------
/**
* <p>Strips whitespace from the start and end of every String in an array.
* Whitespace is defined by {@link Character#isWhitespace(char)}.</p>
*
* <p>A new array is returned each time, except for length zero.
* A <code>null</code> array will return <code>null</code>.
* An empty array will return itself.
* A <code>null</code> array entry will be ignored.</p>
*
* <pre>
* StringUtils.stripAll(null) = null
* StringUtils.stripAll([]) = []
* StringUtils.stripAll(["abc", " abc"]) = ["abc", "abc"]
* StringUtils.stripAll(["abc ", null]) = ["abc", null]
* </pre>
*
* @param strs the array to remove whitespace from, may be null
* @return the stripped Strings, <code>null</code> if null array input
*/
public static String[] stripAll(String[] strs) {
return stripAll(strs, null);
}
/**
* <p>Strips any of a set of characters from the start and end of every
* String in an array.</p>
* Whitespace is defined by {@link Character#isWhitespace(char)}.</p>
*
* <p>A new array is returned each time, except for length zero.
* A <code>null</code> array will return <code>null</code>.
* An empty array will return itself.
* A <code>null</code> array entry will be ignored.
* A <code>null</code> stripChars will strip whitespace as defined by
* {@link Character#isWhitespace(char)}.</p>
*
* <pre>
* StringUtils.stripAll(null, *) = null
* StringUtils.stripAll([], *) = []
* StringUtils.stripAll(["abc", " abc"], null) = ["abc", "abc"]
* StringUtils.stripAll(["abc ", null], null) = ["abc", null]
* StringUtils.stripAll(["abc ", null], "yz") = ["abc ", null]
* StringUtils.stripAll(["yabcz", null], "yz") = ["abc", null]
* </pre>
*
* @param strs the array to remove characters from, may be null
* @param stripChars the characters to remove, null treated as whitespace
* @return the stripped Strings, <code>null</code> if null array input
*/
public static String[] stripAll(String[] strs, String stripChars) {
int strsLen;
if (strs == null || (strsLen = strs.length) == 0) {
return strs;
}
String[] newArr = new String[strsLen];
for (int i = 0; i < strsLen; i++) {
newArr[i] = strip(strs[i], stripChars);
}
return newArr;
}
/**
* <p>Strips any of a set of characters from the start and end of a String.
* This is similar to {@link String#trim()} but allows the characters
* to be stripped to be controlled.</p>
*
* <p>A <code>null</code> input String returns <code>null</code>.
* An empty string ("") input returns the empty string.</p>
*
* <p>If the stripChars String is <code>null</code>, whitespace is
* stripped as defined by {@link Character#isWhitespace(char)}.
* Alternatively use {@link #strip(String)}.</p>
*
* <pre>
* StringUtils.strip(null, *) = null
* StringUtils.strip("", *) = ""
* StringUtils.strip("abc", null) = "abc"
* StringUtils.strip(" abc", null) = "abc"
* StringUtils.strip("abc ", null) = "abc"
* StringUtils.strip(" abc ", null) = "abc"
* StringUtils.strip(" abcyx", "xyz") = " abc"
* </pre>
*
* @param str the String to remove characters from, may be null
* @param stripChars the characters to remove, null treated as whitespace
* @return the stripped String, <code>null</code> if null String input
*/
public static String strip(String str, String stripChars) {
if (isEmpty(str)) {
return str;
}
str = stripStart(str, stripChars);
return stripEnd(str, stripChars);
}
/**
* <p>Strips any of a set of characters from the start of a String.</p>
*
* <p>A <code>null</code> input String returns <code>null</code>.
* An empty string ("") input returns the empty string.</p>
*
* <p>If the stripChars String is <code>null</code>, whitespace is
* stripped as defined by {@link Character#isWhitespace(char)}.</p>
*
* <pre>
* StringUtils.stripStart(null, *) = null
* StringUtils.stripStart("", *) = ""
* StringUtils.stripStart("abc", "") = "abc"
* StringUtils.stripStart("abc", null) = "abc"
* StringUtils.stripStart(" abc", null) = "abc"
* StringUtils.stripStart("abc ", null) = "abc "
* StringUtils.stripStart(" abc ", null) = "abc "
* StringUtils.stripStart("yxabc ", "xyz") = "abc "
* </pre>
*
* @param str the String to remove characters from, may be null
* @param stripChars the characters to remove, null treated as whitespace
* @return the stripped String, <code>null</code> if null String input
*/
public static String stripStart(String str, String stripChars) {
int strLen;
if (str == null || (strLen = str.length()) == 0) {
return str;
}
int start = 0;
if (stripChars == null) {
while ((start != strLen) && Character.isWhitespace(str.charAt(start))) {
start++;
}
} else if (stripChars.length() == 0) {
return str;
} else {
while ((start != strLen) && (stripChars.indexOf(str.charAt(start)) != -1)) {
start++;
}
}
return str.substring(start);
}
/**
* <p>Strips any of a set of characters from the end of a String.</p>
*
* <p>A <code>null</code> input String returns <code>null</code>.
* An empty string ("") input returns the empty string.</p>
*
* <p>If the stripChars String is <code>null</code>, whitespace is
* stripped as defined by {@link Character#isWhitespace(char)}.</p>
*
* <pre>
* StringUtils.stripEnd(null, *) = null
* StringUtils.stripEnd("", *) = ""
* StringUtils.stripEnd("abc", "") = "abc"
* StringUtils.stripEnd("abc", null) = "abc"
* StringUtils.stripEnd(" abc", null) = " abc"
* StringUtils.stripEnd("abc ", null) = "abc"
* StringUtils.stripEnd(" abc ", null) = " abc"
* StringUtils.stripEnd(" abcyx", "xyz") = " abc"
* </pre>
*
* @param str the String to remove characters from, may be null
* @param stripChars the characters to remove, null treated as whitespace
* @return the stripped String, <code>null</code> if null String input
*/
public static String stripEnd(String str, String stripChars) {
int end;
if (str == null || (end = str.length()) == 0) {
return str;
}
if (stripChars == null) {
while ((end != 0) && Character.isWhitespace(str.charAt(end - 1))) {
end--;
}
} else if (stripChars.length() == 0) {
return str;
} else {
while ((end != 0) && (stripChars.indexOf(str.charAt(end - 1)) != -1)) {
end--;
}
}
return str.substring(0, end);
}
// Empty checks
//-----------------------------------------------------------------------
/**
* <p>Checks if a String is empty ("") or null.</p>
*
* <pre>
* StringUtils.isEmpty(null) = true
* StringUtils.isEmpty("") = true
* StringUtils.isEmpty(" ") = false
* StringUtils.isEmpty("bob") = false
* StringUtils.isEmpty(" bob ") = false
* </pre>
*
* <p>NOTE: This method changed in Lang version 2.0.
* It no longer trims the String.
* That functionality is available in isBlank().</p>
*
* @param str the String to check, may be null
* @return <code>true</code> if the String is empty or null
*/
public static boolean isEmpty(String str) {
return str == null || str.length() == 0;
}
}
|