com.yy.androidlib.util.apache.StringUtils 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 com.yy.androidlib.util.apache;
/**
* Operations on {@link java.lang.String} that are
* null safe.
*
*
* - IsEmpty/IsBlank
* - checks if a String contains text
* - Trim/Strip
* - removes leading and trailing whitespace
* - Equals
* - compares two strings null-safe
* - IndexOf/LastIndexOf/Contains
* - null-safe index-of checks
*
- IndexOfAny/LastIndexOfAny/IndexOfAnyBut/LastIndexOfAnyBut
* - index-of any of a set of Strings
* - ContainsOnly/ContainsNone
* - does String contains only/none of these characters
* - Substring/Left/Right/Mid
* - null-safe substring extractions
* - SubstringBefore/SubstringAfter/SubstringBetween
* - substring extraction relative to other strings
* - Split/Join
* - splits a String into an array of substrings and vice versa
* - Remove/Delete
* - removes part of a String
* - Replace/Overlay
* - Searches a String and replaces one String with another
* - Chomp/Chop
* - removes the last part of a String
* - LeftPad/RightPad/Center/Repeat
* - pads a String
* - UpperCase/LowerCase/SwapCase/Capitalize/Uncapitalize
* - changes the case of a String
* - CountMatches
* - counts the number of occurrences of one String in another
* - IsAlpha/IsNumeric/IsWhitespace/IsAsciiPrintable
* - checks the characters in a String
* - DefaultString
* - protects against a null input String
* - Reverse/ReverseDelimited
* - reverses a String
* - Abbreviate
* - abbreviates a string using ellipsis
* - Difference
* - compares two Strings and reports on their differences
* - LevensteinDistance
* - the number of changes needed to change one String into another
*
*
* The StringUtils class defines certain words related to
* String handling.
*
*
* - null -
null
* - empty - a zero-length string (
"")
* - space - the space character (
' ', char 32)
* - whitespace - the characters defined by {@link Character#isWhitespace(char)}
* - trim - the characters <= 32 as in {@link String#trim()}
*
*
* StringUtils handles null input Strings quietly.
* That is to say that a null input will return null.
* Where a boolean or int is being returned
* details vary by method.
*
* A side effect of the null handling is that a
* NullPointerException should be considered a bug in
* StringUtils (except for deprecated methods).
*
* Methods in this class give sample code to explain their operation.
* The symbol * is used to indicate any input including null.
*
* @author Apache Jakarta Turbine
* @author Jon S. Stevens
* @author Daniel Rall
* @author Greg Coladonato
* @author Ed Korthof
* @author Rand McNeely
* @author Stephen Colebourne
* @author Fredrik Westermarck
* @author Holger Krauth
* @author Alexander Day Chaffee
* @author Henning P. Schmiedehausen
* @author Arun Mammen Thomas
* @author Gary Gregory
* @author Phil Steitz
* @author Al Chou
* @author Michael Davey
* @author Reuben Sivan
* @author Chris Hyzer
* @version $Id: StringUtils.java 492377 2007-01-04 01:20:30Z scolebourne $
* @see java.lang.String
* @since 1.0
*/
public class StringUtils {
// Performance testing notes (JDK 1.4, Jul03, scolebourne)
// Whitespace:
// Character.isWhitespace() is faster than WHITESPACE.indexOf()
// where WHITESPACE is a string of all whitespace characters
//
// Character access:
// String.charAt(n) versus toCharArray(), then array[n]
// String.charAt(n) is about 15% worse for a 10K string
// They are about equal for a length 50 string
// String.charAt(n) is about 4 times better for a length 3 string
// String.charAt(n) is best bet overall
//
// Append:
// String.concat about twice as fast as StringBuffer.append
// (not sure who tested this)
/**
* The empty String "".
*
* @since 2.0
*/
public static final String EMPTY = "";
/**
* Represents a failed index search.
*
* @since 2.1
*/
public static final int INDEX_NOT_FOUND = -1;
/**
* The maximum size to which the padding constant(s) can expand.
*/
private static final int PAD_LIMIT = 8192;
/**
* StringUtils instances should NOT be constructed in
* standard programming. Instead, the class should be used as
* StringUtils.trim(" foo ");.
*
* This constructor is public to permit tools that require a JavaBean
* instance to operate.
*/
public StringUtils() {
super();
}
// Empty checks
//-----------------------------------------------------------------------
/**
* Checks if a String is empty ("") or null.
*
*
* StringUtils.isEmpty(null) = true
* StringUtils.isEmpty("") = true
* StringUtils.isEmpty(" ") = false
* StringUtils.isEmpty("bob") = false
* StringUtils.isEmpty(" bob ") = false
*
*
* NOTE: This method changed in Lang version 2.0.
* It no longer trims the String.
* That functionality is available in isBlank().
*
* @param str the String to check, may be null
* @return true if the String is empty or null
*/
public static boolean isEmpty(String str) {
return str == null || str.length() == 0;
}
/**
* Checks if a String is not empty ("") and not null.
*
*
* StringUtils.isNotEmpty(null) = false
* StringUtils.isNotEmpty("") = false
* StringUtils.isNotEmpty(" ") = true
* StringUtils.isNotEmpty("bob") = true
* StringUtils.isNotEmpty(" bob ") = true
*
*
* @param str the String to check, may be null
* @return true if the String is not empty and not null
*/
public static boolean isNotEmpty(String str) {
return !StringUtils.isEmpty(str);
}
/**
* Checks if a String is whitespace, empty ("") or null.
*
*
* StringUtils.isBlank(null) = true
* StringUtils.isBlank("") = true
* StringUtils.isBlank(" ") = true
* StringUtils.isBlank("bob") = false
* StringUtils.isBlank(" bob ") = false
*
*
* @param str the String to check, may be null
* @return true if the String is null, empty or whitespace
* @since 2.0
*/
public static boolean isBlank(String str) {
int strLen;
if (str == null || (strLen = str.length()) == 0) {
return true;
}
for (int i = 0; i < strLen; i++) {
if (!(Character.isWhitespace(str.charAt(i)))) {
return false;
}
}
return true;
}
/**
* Checks if a String is not empty (""), not null and not whitespace only.
*
*
* StringUtils.isNotBlank(null) = false
* StringUtils.isNotBlank("") = false
* StringUtils.isNotBlank(" ") = false
* StringUtils.isNotBlank("bob") = true
* StringUtils.isNotBlank(" bob ") = true
*
*
* @param str the String to check, may be null
* @return true if the String is
* not empty and not null and not whitespace
* @since 2.0
*/
public static boolean isNotBlank(String str) {
return !StringUtils.isBlank(str);
}
// Trim
//-----------------------------------------------------------------------
/**
* Removes control characters (char <= 32) from both
* ends of this String, handling null by returning
* an empty String ("").
*
*
* StringUtils.clean(null) = ""
* StringUtils.clean("") = ""
* StringUtils.clean("abc") = "abc"
* StringUtils.clean(" abc ") = "abc"
* StringUtils.clean(" ") = ""
*
*
* @param str the String to clean, may be null
* @return the trimmed text, never null
* @see java.lang.String#trim()
* @deprecated Use the clearer named {@link #trimToEmpty(String)}.
* Method will be removed in Commons Lang 3.0.
*/
public static String clean(String str) {
return str == null ? EMPTY : str.trim();
}
/**
* Removes control characters (char <= 32) from both
* ends of this String, handling null by returning
* null.
*
* The String is trimmed using {@link String#trim()}.
* Trim removes start and end characters <= 32.
* To strip whitespace use {@link #strip(String)}.
*
* To trim your choice of characters, use the
* {@link #strip(String, String)} methods.
*
*
* StringUtils.trim(null) = null
* StringUtils.trim("") = ""
* StringUtils.trim(" ") = ""
* StringUtils.trim("abc") = "abc"
* StringUtils.trim(" abc ") = "abc"
*
*
* @param str the String to be trimmed, may be null
* @return the trimmed string, null if null String input
*/
public static String trim(String str) {
return str == null ? null : str.trim();
}
/**
* Removes control characters (char <= 32) from both
* ends of this String returning null if the String is
* empty ("") after the trim or if it is null.
*
* The String is trimmed using {@link String#trim()}.
* Trim removes start and end characters <= 32.
* To strip whitespace use {@link #stripToNull(String)}.
*
*
* StringUtils.trimToNull(null) = null
* StringUtils.trimToNull("") = null
* StringUtils.trimToNull(" ") = null
* StringUtils.trimToNull("abc") = "abc"
* StringUtils.trimToNull(" abc ") = "abc"
*
*
* @param str the String to be trimmed, may be null
* @return the trimmed String,
* null if only chars <= 32, empty or null String input
* @since 2.0
*/
public static String trimToNull(String str) {
String ts = trim(str);
return isEmpty(ts) ? null : ts;
}
/**
* Removes control characters (char <= 32) from both
* ends of this String returning an empty String ("") if the String
* is empty ("") after the trim or if it is null.
*
* The String is trimmed using {@link String#trim()}.
* Trim removes start and end characters <= 32.
* To strip whitespace use {@link #stripToEmpty(String)}.
*
*
* StringUtils.trimToEmpty(null) = ""
* StringUtils.trimToEmpty("") = ""
* StringUtils.trimToEmpty(" ") = ""
* StringUtils.trimToEmpty("abc") = "abc"
* StringUtils.trimToEmpty(" abc ") = "abc"
*
*
* @param str the String to be trimmed, may be null
* @return the trimmed String, or an empty String if null input
* @since 2.0
*/
public static String trimToEmpty(String str) {
return str == null ? EMPTY : str.trim();
}
// Stripping
//-----------------------------------------------------------------------
/**
* Strips whitespace from the start and end of a String.
*
* This is similar to {@link #trim(String)} but removes whitespace.
* Whitespace is defined by {@link Character#isWhitespace(char)}.
*
* A null input String returns null.
*
*
* StringUtils.strip(null) = null
* StringUtils.strip("") = ""
* StringUtils.strip(" ") = ""
* StringUtils.strip("abc") = "abc"
* StringUtils.strip(" abc") = "abc"
* StringUtils.strip("abc ") = "abc"
* StringUtils.strip(" abc ") = "abc"
* StringUtils.strip(" ab c ") = "ab c"
*
*
* @param str the String to remove whitespace from, may be null
* @return the stripped String, null if null String input
*/
public static String strip(String str) {
return strip(str, null);
}
/**
* Strips whitespace from the start and end of a String returning
* null if the String is empty ("") after the strip.
*
* This is similar to {@link #trimToNull(String)} but removes whitespace.
* Whitespace is defined by {@link Character#isWhitespace(char)}.
*
*
* StringUtils.stripToNull(null) = null
* StringUtils.stripToNull("") = null
* StringUtils.stripToNull(" ") = null
* StringUtils.stripToNull("abc") = "abc"
* StringUtils.stripToNull(" abc") = "abc"
* StringUtils.stripToNull("abc ") = "abc"
* StringUtils.stripToNull(" abc ") = "abc"
* StringUtils.stripToNull(" ab c ") = "ab c"
*
*
* @param str the String to be stripped, may be null
* @return the stripped String,
* null if whitespace, empty or null String input
* @since 2.0
*/
public static String stripToNull(String str) {
if (str == null) {
return null;
}
str = strip(str, null);
return str.length() == 0 ? null : str;
}
/**
* Strips whitespace from the start and end of a String returning
* an empty String if null input.
*
* This is similar to {@link #trimToEmpty(String)} but removes whitespace.
* Whitespace is defined by {@link Character#isWhitespace(char)}.
*
*
* StringUtils.stripToEmpty(null) = ""
* StringUtils.stripToEmpty("") = ""
* StringUtils.stripToEmpty(" ") = ""
* StringUtils.stripToEmpty("abc") = "abc"
* StringUtils.stripToEmpty(" abc") = "abc"
* StringUtils.stripToEmpty("abc ") = "abc"
* StringUtils.stripToEmpty(" abc ") = "abc"
* StringUtils.stripToEmpty(" ab c ") = "ab c"
*
*
* @param str the String to be stripped, may be null
* @return the trimmed String, or an empty String if null input
* @since 2.0
*/
public static String stripToEmpty(String str) {
return str == null ? EMPTY : strip(str, null);
}
/**
* 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.
*
* A null input String returns null.
* An empty string ("") input returns the empty string.
*
* If the stripChars String is null, whitespace is
* stripped as defined by {@link Character#isWhitespace(char)}.
* Alternatively use {@link #strip(String)}.
*
*
* 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"
*
*
* @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, null 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);
}
/**
* Strips any of a set of characters from the start of a String.
*
* A null input String returns null.
* An empty string ("") input returns the empty string.
*
* If the stripChars String is null, whitespace is
* stripped as defined by {@link Character#isWhitespace(char)}.
*
*
* 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 "
*
*
* @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, null 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);
}
/**
* Strips any of a set of characters from the end of a String.
*
* A null input String returns null.
* An empty string ("") input returns the empty string.
*
* If the stripChars String is null, whitespace is
* stripped as defined by {@link Character#isWhitespace(char)}.
*
*
* 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"
*
*
* @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, null 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);
}
// StripAll
//-----------------------------------------------------------------------
/**
* Strips whitespace from the start and end of every String in an array.
* Whitespace is defined by {@link Character#isWhitespace(char)}.
*
* A new array is returned each time, except for length zero.
* A null array will return null.
* An empty array will return itself.
* A null array entry will be ignored.
*
*
* StringUtils.stripAll(null) = null
* StringUtils.stripAll([]) = []
* StringUtils.stripAll(["abc", " abc"]) = ["abc", "abc"]
* StringUtils.stripAll(["abc ", null]) = ["abc", null]
*
*
* @param strs the array to remove whitespace from, may be null
* @return the stripped Strings, null if null array input
*/
public static String[] stripAll(String[] strs) {
return stripAll(strs, null);
}
/**
* Strips any of a set of characters from the start and end of every
* String in an array.
* Whitespace is defined by {@link Character#isWhitespace(char)}.
*
* A new array is returned each time, except for length zero.
* A null array will return null.
* An empty array will return itself.
* A null array entry will be ignored.
* A null stripChars will strip whitespace as defined by
* {@link Character#isWhitespace(char)}.
*
*
* 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]
*
*
* @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, null 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;
}
// Equals
//-----------------------------------------------------------------------
/**
* Compares two Strings, returning true if they are equal.
*
* nulls are handled without exceptions. Two null
* references are considered to be equal. The comparison is case sensitive.
*
*
* StringUtils.equals(null, null) = true
* StringUtils.equals(null, "abc") = false
* StringUtils.equals("abc", null) = false
* StringUtils.equals("abc", "abc") = true
* StringUtils.equals("abc", "ABC") = false
*
*
* @param str1 the first String, may be null
* @param str2 the second String, may be null
* @return true if the Strings are equal, case sensitive, or
* both null
* @see java.lang.String#equals(Object)
*/
public static boolean equals(String str1, String str2) {
return str1 == null ? str2 == null : str1.equals(str2);
}
/**
* Compares two Strings, returning true if they are equal ignoring
* the case.
*
* nulls are handled without exceptions. Two null
* references are considered equal. Comparison is case insensitive.
*
*
* StringUtils.equalsIgnoreCase(null, null) = true
* StringUtils.equalsIgnoreCase(null, "abc") = false
* StringUtils.equalsIgnoreCase("abc", null) = false
* StringUtils.equalsIgnoreCase("abc", "abc") = true
* StringUtils.equalsIgnoreCase("abc", "ABC") = true
*
*
* @param str1 the first String, may be null
* @param str2 the second String, may be null
* @return true if the Strings are equal, case insensitive, or
* both null
* @see java.lang.String#equalsIgnoreCase(String)
*/
public static boolean equalsIgnoreCase(String str1, String str2) {
return str1 == null ? str2 == null : str1.equalsIgnoreCase(str2);
}
// IndexOf
//-----------------------------------------------------------------------
/**
* Finds the first index within a String, handling null.
* This method uses {@link String#indexOf(int)}.
*
* A null or empty ("") String will return -1.
*
*
* StringUtils.indexOf(null, *) = -1
* StringUtils.indexOf("", *) = -1
* StringUtils.indexOf("aabaabaa", 'a') = 0
* StringUtils.indexOf("aabaabaa", 'b') = 2
*
*
* @param str the String to check, may be null
* @param searchChar the character to find
* @return the first index of the search character,
* -1 if no match or null string input
* @since 2.0
*/
public static int indexOf(String str, char searchChar) {
if (isEmpty(str)) {
return -1;
}
return str.indexOf(searchChar);
}
/**
* Finds the first index within a String from a start position,
* handling null.
* This method uses {@link String#indexOf(int, int)}.
*
* A null or empty ("") String will return -1.
* A negative start position is treated as zero.
* A start position greater than the string length returns -1.
*
*
* StringUtils.indexOf(null, *, *) = -1
* StringUtils.indexOf("", *, *) = -1
* StringUtils.indexOf("aabaabaa", 'b', 0) = 2
* StringUtils.indexOf("aabaabaa", 'b', 3) = 5
* StringUtils.indexOf("aabaabaa", 'b', 9) = -1
* StringUtils.indexOf("aabaabaa", 'b', -1) = 2
*
*
* @param str the String to check, may be null
* @param searchChar the character to find
* @param startPos the start position, negative treated as zero
* @return the first index of the search character,
* -1 if no match or null string input
* @since 2.0
*/
public static int indexOf(String str, char searchChar, int startPos) {
if (isEmpty(str)) {
return -1;
}
return str.indexOf(searchChar, startPos);
}
/**
* Finds the first index within a String, handling null.
* This method uses {@link String#indexOf(String)}.
*
* A null String will return -1.
*
*
* StringUtils.indexOf(null, *) = -1
* StringUtils.indexOf(*, null) = -1
* StringUtils.indexOf("", "") = 0
* StringUtils.indexOf("aabaabaa", "a") = 0
* StringUtils.indexOf("aabaabaa", "b") = 2
* StringUtils.indexOf("aabaabaa", "ab") = 1
* StringUtils.indexOf("aabaabaa", "") = 0
*
*
* @param str the String to check, may be null
* @param searchStr the String to find, may be null
* @return the first index of the search String,
* -1 if no match or null string input
* @since 2.0
*/
public static int indexOf(String str, String searchStr) {
if (str == null || searchStr == null) {
return -1;
}
return str.indexOf(searchStr);
}
/**
* Finds the n-th index within a String, handling null.
* This method uses {@link String#indexOf(String)}.
*
* A null String will return -1.
*
*
* StringUtils.ordinalIndexOf(null, *, *) = -1
* StringUtils.ordinalIndexOf(*, null, *) = -1
* StringUtils.ordinalIndexOf("", "", *) = 0
* StringUtils.ordinalIndexOf("aabaabaa", "a", 1) = 0
* StringUtils.ordinalIndexOf("aabaabaa", "a", 2) = 1
* StringUtils.ordinalIndexOf("aabaabaa", "b", 1) = 2
* StringUtils.ordinalIndexOf("aabaabaa", "b", 2) = 5
* StringUtils.ordinalIndexOf("aabaabaa", "ab", 1) = 1
* StringUtils.ordinalIndexOf("aabaabaa", "ab", 2) = 4
* StringUtils.ordinalIndexOf("aabaabaa", "", 1) = 0
* StringUtils.ordinalIndexOf("aabaabaa", "", 2) = 0
*
*
* @param str the String to check, may be null
* @param searchStr the String to find, may be null
* @param ordinal the n-th searchStr to find
* @return the n-th index of the search String,
* -1 (INDEX_NOT_FOUND) if no match or null string input
* @since 2.1
*/
public static int ordinalIndexOf(String str, String searchStr, int ordinal) {
if (str == null || searchStr == null || ordinal <= 0) {
return INDEX_NOT_FOUND;
}
if (searchStr.length() == 0) {
return 0;
}
int found = 0;
int index = INDEX_NOT_FOUND;
do {
index = str.indexOf(searchStr, index + 1);
if (index < 0) {
return index;
}
found++;
} while (found < ordinal);
return index;
}
/**
* Finds the first index within a String, handling null.
* This method uses {@link String#indexOf(String, int)}.
*
* A null String will return -1.
* A negative start position is treated as zero.
* An empty ("") search String always matches.
* A start position greater than the string length only matches
* an empty search String.
*
*
* StringUtils.indexOf(null, *, *) = -1
* StringUtils.indexOf(*, null, *) = -1
* StringUtils.indexOf("", "", 0) = 0
* StringUtils.indexOf("aabaabaa", "a", 0) = 0
* StringUtils.indexOf("aabaabaa", "b", 0) = 2
* StringUtils.indexOf("aabaabaa", "ab", 0) = 1
* StringUtils.indexOf("aabaabaa", "b", 3) = 5
* StringUtils.indexOf("aabaabaa", "b", 9) = -1
* StringUtils.indexOf("aabaabaa", "b", -1) = 2
* StringUtils.indexOf("aabaabaa", "", 2) = 2
* StringUtils.indexOf("abc", "", 9) = 3
*
*
* @param str the String to check, may be null
* @param searchStr the String to find, may be null
* @param startPos the start position, negative treated as zero
* @return the first index of the search String,
* -1 if no match or null string input
* @since 2.0
*/
public static int indexOf(String str, String searchStr, int startPos) {
if (str == null || searchStr == null) {
return -1;
}
// JDK1.2/JDK1.3 have a bug, when startPos > str.length for "", hence
if (searchStr.length() == 0 && startPos >= str.length()) {
return str.length();
}
return str.indexOf(searchStr, startPos);
}
// LastIndexOf
//-----------------------------------------------------------------------
/**
* Finds the last index within a String, handling null.
* This method uses {@link String#lastIndexOf(int)}.
*
* A null or empty ("") String will return -1.
*
*
* StringUtils.lastIndexOf(null, *) = -1
* StringUtils.lastIndexOf("", *) = -1
* StringUtils.lastIndexOf("aabaabaa", 'a') = 7
* StringUtils.lastIndexOf("aabaabaa", 'b') = 5
*
*
* @param str the String to check, may be null
* @param searchChar the character to find
* @return the last index of the search character,
* -1 if no match or null string input
* @since 2.0
*/
public static int lastIndexOf(String str, char searchChar) {
if (isEmpty(str)) {
return -1;
}
return str.lastIndexOf(searchChar);
}
/**
* Finds the last index within a String from a start position,
* handling null.
* This method uses {@link String#lastIndexOf(int, int)}.
*
* A null or empty ("") String will return -1.
* A negative start position returns -1.
* A start position greater than the string length searches the whole string.
*
*
* StringUtils.lastIndexOf(null, *, *) = -1
* StringUtils.lastIndexOf("", *, *) = -1
* StringUtils.lastIndexOf("aabaabaa", 'b', 8) = 5
* StringUtils.lastIndexOf("aabaabaa", 'b', 4) = 2
* StringUtils.lastIndexOf("aabaabaa", 'b', 0) = -1
* StringUtils.lastIndexOf("aabaabaa", 'b', 9) = 5
* StringUtils.lastIndexOf("aabaabaa", 'b', -1) = -1
* StringUtils.lastIndexOf("aabaabaa", 'a', 0) = 0
*
*
* @param str the String to check, may be null
* @param searchChar the character to find
* @param startPos the start position
* @return the last index of the search character,
* -1 if no match or null string input
* @since 2.0
*/
public static int lastIndexOf(String str, char searchChar, int startPos) {
if (isEmpty(str)) {
return -1;
}
return str.lastIndexOf(searchChar, startPos);
}
/**
* Finds the last index within a String, handling null.
* This method uses {@link String#lastIndexOf(String)}.
*
* A null String will return -1.
*
*
* StringUtils.lastIndexOf(null, *) = -1
* StringUtils.lastIndexOf(*, null) = -1
* StringUtils.lastIndexOf("", "") = 0
* StringUtils.lastIndexOf("aabaabaa", "a") = 0
* StringUtils.lastIndexOf("aabaabaa", "b") = 2
* StringUtils.lastIndexOf("aabaabaa", "ab") = 1
* StringUtils.lastIndexOf("aabaabaa", "") = 8
*
*
* @param str the String to check, may be null
* @param searchStr the String to find, may be null
* @return the last index of the search String,
* -1 if no match or null string input
* @since 2.0
*/
public static int lastIndexOf(String str, String searchStr) {
if (str == null || searchStr == null) {
return -1;
}
return str.lastIndexOf(searchStr);
}
/**
* Finds the first index within a String, handling null.
* This method uses {@link String#lastIndexOf(String, int)}.
*
* A null String will return -1.
* A negative start position returns -1.
* An empty ("") search String always matches unless the start position is negative.
* A start position greater than the string length searches the whole string.
*
*
* StringUtils.lastIndexOf(null, *, *) = -1
* StringUtils.lastIndexOf(*, null, *) = -1
* StringUtils.lastIndexOf("aabaabaa", "a", 8) = 7
* StringUtils.lastIndexOf("aabaabaa", "b", 8) = 5
* StringUtils.lastIndexOf("aabaabaa", "ab", 8) = 4
* StringUtils.lastIndexOf("aabaabaa", "b", 9) = 5
* StringUtils.lastIndexOf("aabaabaa", "b", -1) = -1
* StringUtils.lastIndexOf("aabaabaa", "a", 0) = 0
* StringUtils.lastIndexOf("aabaabaa", "b", 0) = -1
*
*
* @param str the String to check, may be null
* @param searchStr the String to find, may be null
* @param startPos the start position, negative treated as zero
* @return the first index of the search String,
* -1 if no match or null string input
* @since 2.0
*/
public static int lastIndexOf(String str, String searchStr, int startPos) {
if (str == null || searchStr == null) {
return -1;
}
return str.lastIndexOf(searchStr, startPos);
}
// Contains
//-----------------------------------------------------------------------
/**
* Checks if String contains a search character, handling null.
* This method uses {@link String#indexOf(int)}.
*
* A null or empty ("") String will return false.
*
*
* StringUtils.contains(null, *) = false
* StringUtils.contains("", *) = false
* StringUtils.contains("abc", 'a') = true
* StringUtils.contains("abc", 'z') = false
*
*
* @param str the String to check, may be null
* @param searchChar the character to find
* @return true if the String contains the search character,
* false if not or null string input
* @since 2.0
*/
public static boolean contains(String str, char searchChar) {
if (isEmpty(str)) {
return false;
}
return str.indexOf(searchChar) >= 0;
}
/**
* Checks if String contains a search String, handling null.
* This method uses {@link String#indexOf(String)}.
*
* A null String will return false.
*
*
* StringUtils.contains(null, *) = false
* StringUtils.contains(*, null) = false
* StringUtils.contains("", "") = true
* StringUtils.contains("abc", "") = true
* StringUtils.contains("abc", "a") = true
* StringUtils.contains("abc", "z") = false
*
*
* @param str the String to check, may be null
* @param searchStr the String to find, may be null
* @return true if the String contains the search String,
* false if not or null string input
* @since 2.0
*/
public static boolean contains(String str, String searchStr) {
if (str == null || searchStr == null) {
return false;
}
return str.indexOf(searchStr) >= 0;
}
/**
* Checks if String contains a search String irrespective of case,
* handling null. This method uses
* {@link #contains(String, String)}.
*
* A null String will return false.
*
*
* StringUtils.contains(null, *) = false
* StringUtils.contains(*, null) = false
* StringUtils.contains("", "") = true
* StringUtils.contains("abc", "") = true
* StringUtils.contains("abc", "a") = true
* StringUtils.contains("abc", "z") = false
* StringUtils.contains("abc", "A") = true
* StringUtils.contains("abc", "Z") = false
*
*
* @param str the String to check, may be null
* @param searchStr the String to find, may be null
* @return true if the String contains the search String irrespective of
* case or false if not or null string input
*/
public static boolean containsIgnoreCase(String str, String searchStr) {
if (str == null || searchStr == null) {
return false;
}
return contains(str.toUpperCase(), searchStr.toUpperCase());
}
/**
* Search a String to find the first index of any
* character not in the given set of characters.
*
* A null String will return -1.
* A null search string will return -1.
*
*
* StringUtils.indexOfAnyBut(null, *) = -1
* StringUtils.indexOfAnyBut("", *) = -1
* StringUtils.indexOfAnyBut(*, null) = -1
* StringUtils.indexOfAnyBut(*, "") = -1
* StringUtils.indexOfAnyBut("zzabyycdxx", "za") = 3
* StringUtils.indexOfAnyBut("zzabyycdxx", "") = 0
* StringUtils.indexOfAnyBut("aba","ab") = -1
*
*
* @param str the String to check, may be null
* @param searchChars the chars to search for, may be null
* @return the index of any of the chars, -1 if no match or null input
* @since 2.0
*/
public static int indexOfAnyBut(String str, String searchChars) {
if (isEmpty(str) || isEmpty(searchChars)) {
return -1;
}
for (int i = 0; i < str.length(); i++) {
if (searchChars.indexOf(str.charAt(i)) < 0) {
return i;
}
}
return -1;
}
// ContainsNone
//-----------------------------------------------------------------------
/**
* Checks that the String does not contain certain characters.
*
* A null String will return true.
* A null invalid character array will return true.
* An empty String ("") always returns true.
*
*
* StringUtils.containsNone(null, *) = true
* StringUtils.containsNone(*, null) = true
* StringUtils.containsNone("", *) = true
* StringUtils.containsNone("ab", '') = true
* StringUtils.containsNone("abab", 'xyz') = true
* StringUtils.containsNone("ab1", 'xyz') = true
* StringUtils.containsNone("abz", 'xyz') = false
*
*
* @param str the String to check, may be null
* @param invalidChars an array of invalid chars, may be null
* @return true if it contains none of the invalid chars, or is null
* @since 2.0
*/
public static boolean containsNone(String str, char[] invalidChars) {
if (str == null || invalidChars == null) {
return true;
}
int strSize = str.length();
int validSize = invalidChars.length;
for (int i = 0; i < strSize; i++) {
char ch = str.charAt(i);
for (int j = 0; j < validSize; j++) {
if (invalidChars[j] == ch) {
return false;
}
}
}
return true;
}
/**
* Checks that the String does not contain certain characters.
*
* A null String will return true.
* A null invalid character array will return true.
* An empty String ("") always returns true.
*
*
* StringUtils.containsNone(null, *) = true
* StringUtils.containsNone(*, null) = true
* StringUtils.containsNone("", *) = true
* StringUtils.containsNone("ab", "") = true
* StringUtils.containsNone("abab", "xyz") = true
* StringUtils.containsNone("ab1", "xyz") = true
* StringUtils.containsNone("abz", "xyz") = false
*
*
* @param str the String to check, may be null
* @param invalidChars a String of invalid chars, may be null
* @return true if it contains none of the invalid chars, or is null
* @since 2.0
*/
public static boolean containsNone(String str, String invalidChars) {
if (str == null || invalidChars == null) {
return true;
}
return containsNone(str, invalidChars.toCharArray());
}
// SubStringAfter/SubStringBefore
//-----------------------------------------------------------------------
/**
* Gets the substring before the first occurrence of a separator.
* The separator is not returned.
*
* A null string input will return null.
* An empty ("") string input will return the empty string.
* A null separator will return the input string.
*
*
* StringUtils.substringBefore(null, *) = null
* StringUtils.substringBefore("", *) = ""
* StringUtils.substringBefore("abc", "a") = ""
* StringUtils.substringBefore("abcba", "b") = "a"
* StringUtils.substringBefore("abc", "c") = "ab"
* StringUtils.substringBefore("abc", "d") = "abc"
* StringUtils.substringBefore("abc", "") = ""
* StringUtils.substringBefore("abc", null) = "abc"
*
*
* @param str the String to get a substring from, may be null
* @param separator the String to search for, may be null
* @return the substring before the first occurrence of the separator,
* null if null String input
* @since 2.0
*/
public static String substringBefore(String str, String separator) {
if (isEmpty(str) || separator == null) {
return str;
}
if (separator.length() == 0) {
return EMPTY;
}
int pos = str.indexOf(separator);
if (pos == -1) {
return str;
}
return str.substring(0, pos);
}
/**
* Gets the substring after the first occurrence of a separator.
* The separator is not returned.
*
* A null string input will return null.
* An empty ("") string input will return the empty string.
* A null separator will return the empty string if the
* input string is not null.
*
*
* StringUtils.substringAfter(null, *) = null
* StringUtils.substringAfter("", *) = ""
* StringUtils.substringAfter(*, null) = ""
* StringUtils.substringAfter("abc", "a") = "bc"
* StringUtils.substringAfter("abcba", "b") = "cba"
* StringUtils.substringAfter("abc", "c") = ""
* StringUtils.substringAfter("abc", "d") = ""
* StringUtils.substringAfter("abc", "") = "abc"
*
*
* @param str the String to get a substring from, may be null
* @param separator the String to search for, may be null
* @return the substring after the first occurrence of the separator,
* null if null String input
* @since 2.0
*/
public static String substringAfter(String str, String separator) {
if (isEmpty(str)) {
return str;
}
if (separator == null) {
return EMPTY;
}
int pos = str.indexOf(separator);
if (pos == -1) {
return EMPTY;
}
return str.substring(pos + separator.length());
}
/**
* Gets the substring before the last occurrence of a separator.
* The separator is not returned.
*
* A null string input will return null.
* An empty ("") string input will return the empty string.
* An empty or null separator will return the input string.
*
*
* StringUtils.substringBeforeLast(null, *) = null
* StringUtils.substringBeforeLast("", *) = ""
* StringUtils.substringBeforeLast("abcba", "b") = "abc"
* StringUtils.substringBeforeLast("abc", "c") = "ab"
* StringUtils.substringBeforeLast("a", "a") = ""
* StringUtils.substringBeforeLast("a", "z") = "a"
* StringUtils.substringBeforeLast("a", null) = "a"
* StringUtils.substringBeforeLast("a", "") = "a"
*
*
* @param str the String to get a substring from, may be null
* @param separator the String to search for, may be null
* @return the substring before the last occurrence of the separator,
* null if null String input
* @since 2.0
*/
public static String substringBeforeLast(String str, String separator) {
if (isEmpty(str) || isEmpty(separator)) {
return str;
}
int pos = str.lastIndexOf(separator);
if (pos == -1) {
return str;
}
return str.substring(0, pos);
}
/**
* Gets the substring after the last occurrence of a separator.
* The separator is not returned.
*
* A null string input will return null.
* An empty ("") string input will return the empty string.
* An empty or null separator will return the empty string if
* the input string is not null.
*
*
* StringUtils.substringAfterLast(null, *) = null
* StringUtils.substringAfterLast("", *) = ""
* StringUtils.substringAfterLast(*, "") = ""
* StringUtils.substringAfterLast(*, null) = ""
* StringUtils.substringAfterLast("abc", "a") = "bc"
* StringUtils.substringAfterLast("abcba", "b") = "a"
* StringUtils.substringAfterLast("abc", "c") = ""
* StringUtils.substringAfterLast("a", "a") = ""
* StringUtils.substringAfterLast("a", "z") = ""
*
*
* @param str the String to get a substring from, may be null
* @param separator the String to search for, may be null
* @return the substring after the last occurrence of the separator,
* null if null String input
* @since 2.0
*/
public static String substringAfterLast(String str, String separator) {
if (isEmpty(str)) {
return str;
}
if (isEmpty(separator)) {
return EMPTY;
}
int pos = str.lastIndexOf(separator);
if (pos == -1 || pos == (str.length() - separator.length())) {
return EMPTY;
}
return str.substring(pos + separator.length());
}
// Substring between
//-----------------------------------------------------------------------
/**
* Gets the String that is nested in between two instances of the
* same String.
*
* A null input String returns null.
* A null tag returns null.
*
*
* StringUtils.substringBetween(null, *) = null
* StringUtils.substringBetween("", "") = ""
* StringUtils.substringBetween("", "tag") = null
* StringUtils.substringBetween("tagabctag", null) = null
* StringUtils.substringBetween("tagabctag", "") = ""
* StringUtils.substringBetween("tagabctag", "tag") = "abc"
*
*
* @param str the String containing the substring, may be null
* @param tag the String before and after the substring, may be null
* @return the substring, null if no match
* @since 2.0
*/
public static String substringBetween(String str, String tag) {
return substringBetween(str, tag, tag);
}
/**
* Gets the String that is nested in between two Strings.
* Only the first match is returned.
*
* A null input String returns null.
* A null open/close returns null (no match).
* An empty ("") open and close returns an empty string.
*
*
* StringUtils.substringBetween("wx[b]yz", "[", "]") = "b"
* StringUtils.substringBetween(null, *, *) = null
* StringUtils.substringBetween(*, null, *) = null
* StringUtils.substringBetween(*, *, null) = null
* StringUtils.substringBetween("", "", "") = ""
* StringUtils.substringBetween("", "", "]") = null
* StringUtils.substringBetween("", "[", "]") = null
* StringUtils.substringBetween("yabcz", "", "") = ""
* StringUtils.substringBetween("yabcz", "y", "z") = "abc"
* StringUtils.substringBetween("yabczyabcz", "y", "z") = "abc"
*
*
* @param str the String containing the substring, may be null
* @param open the String before the substring, may be null
* @param close the String after the substring, may be null
* @return the substring, null if no match
* @since 2.0
*/
public static String substringBetween(String str, String open, String close) {
if (str == null || open == null || close == null) {
return null;
}
int start = str.indexOf(open);
if (start != -1) {
int end = str.indexOf(close, start + open.length());
if (end != -1) {
return str.substring(start + open.length(), end);
}
}
return null;
}
// Joining
//-----------------------------------------------------------------------
/**
* Concatenates elements of an array into a single String.
* Null objects or empty strings within the array are represented by
* empty strings.
*
*
* StringUtils.concatenate(null) = null
* StringUtils.concatenate([]) = ""
* StringUtils.concatenate([null]) = ""
* StringUtils.concatenate(["a", "b", "c"]) = "abc"
* StringUtils.concatenate([null, "", "a"]) = "a"
*
*
* @param array the array of values to concatenate, may be null
* @return the concatenated String, null if null array input
* @deprecated Use the better named {@link #join(Object[])} instead.
* Method will be removed in Commons Lang 3.0.
*/
public static String concatenate(Object[] array) {
return join(array, null);
}
/**
* Joins the elements of the provided array into a single String
* containing the provided list of elements.
*
* No separator is added to the joined String.
* Null objects or empty strings within the array are represented by
* empty strings.
*
*
* StringUtils.join(null) = null
* StringUtils.join([]) = ""
* StringUtils.join([null]) = ""
* StringUtils.join(["a", "b", "c"]) = "abc"
* StringUtils.join([null, "", "a"]) = "a"
*
*
* @param array the array of values to join together, may be null
* @return the joined String, null if null array input
* @since 2.0
*/
public static String join(Object[] array) {
return join(array, null);
}
/**
* Joins the elements of the provided array into a single String
* containing the provided list of elements.
*
* No delimiter is added before or after the list.
* Null objects or empty strings within the array are represented by
* empty strings.
*
*
* StringUtils.join(null, *) = null
* StringUtils.join([], *) = ""
* StringUtils.join([null], *) = ""
* StringUtils.join(["a", "b", "c"], ';') = "a;b;c"
* StringUtils.join(["a", "b", "c"], null) = "abc"
* StringUtils.join([null, "", "a"], ';') = ";;a"
*
*
* @param array the array of values to join together, may be null
* @param separator the separator character to use
* @return the joined String, null if null array input
* @since 2.0
*/
public static String join(Object[] array, char separator) {
if (array == null) {
return null;
}
return join(array, separator, 0, array.length);
}
/**
* Joins the elements of the provided array into a single String
* containing the provided list of elements.
*
* No delimiter is added before or after the list.
* Null objects or empty strings within the array are represented by
* empty strings.
*
*
* StringUtils.join(null, *) = null
* StringUtils.join([], *) = ""
* StringUtils.join([null], *) = ""
* StringUtils.join(["a", "b", "c"], ';') = "a;b;c"
* StringUtils.join(["a", "b", "c"], null) = "abc"
* StringUtils.join([null, "", "a"], ';') = ";;a"
*
*
* @param array the array of values to join together, may be null
* @param separator the separator character to use
* @param startIndex the first index to start joining from. It is
* an error to pass in an end index past the end of the array
* @param endIndex the index to stop joining from (exclusive). It is
* an error to pass in an end index past the end of the array
* @return the joined String, null if null array input
* @since 2.0
*/
public static String join(Object[] array, char separator, int startIndex, int endIndex) {
if (array == null) {
return null;
}
int bufSize = (endIndex - startIndex);
if (bufSize <= 0) {
return EMPTY;
}
bufSize *= ((array[startIndex] == null ? 16 : array[startIndex].toString().length()) + 1);
StringBuffer buf = new StringBuffer(bufSize);
for (int i = startIndex; i < endIndex; i++) {
if (i > startIndex) {
buf.append(separator);
}
if (array[i] != null) {
buf.append(array[i]);
}
}
return buf.toString();
}
/**
* Joins the elements of the provided array into a single String
* containing the provided list of elements.
*
* No delimiter is added before or after the list.
* A null separator is the same as an empty String ("").
* Null objects or empty strings within the array are represented by
* empty strings.
*
*
* StringUtils.join(null, *) = null
* StringUtils.join([], *) = ""
* StringUtils.join([null], *) = ""
* StringUtils.join(["a", "b", "c"], "--") = "a--b--c"
* StringUtils.join(["a", "b", "c"], null) = "abc"
* StringUtils.join(["a", "b", "c"], "") = "abc"
* StringUtils.join([null, "", "a"], ',') = ",,a"
*
*
* @param array the array of values to join together, may be null
* @param separator the separator character to use, null treated as ""
* @return the joined String, null if null array input
*/
public static String join(Object[] array, String separator) {
if (array == null) {
return null;
}
return join(array, separator, 0, array.length);
}
/**
* Joins the elements of the provided array into a single String
* containing the provided list of elements.
*
* No delimiter is added before or after the list.
* A null separator is the same as an empty String ("").
* Null objects or empty strings within the array are represented by
* empty strings.
*
*
* StringUtils.join(null, *) = null
* StringUtils.join([], *) = ""
* StringUtils.join([null], *) = ""
* StringUtils.join(["a", "b", "c"], "--") = "a--b--c"
* StringUtils.join(["a", "b", "c"], null) = "abc"
* StringUtils.join(["a", "b", "c"], "") = "abc"
* StringUtils.join([null, "", "a"], ',') = ",,a"
*
*
* @param array the array of values to join together, may be null
* @param separator the separator character to use, null treated as ""
* @param startIndex the first index to start joining from. It is
* an error to pass in an end index past the end of the array
* @param endIndex the index to stop joining from (exclusive). It is
* an error to pass in an end index past the end of the array
* @return the joined String, null if null array input
*/
public static String join(Object[] array, String separator, int startIndex, int endIndex) {
if (array == null) {
return null;
}
if (separator == null) {
separator = EMPTY;
}
// endIndex - startIndex > 0: Len = NofStrings *(len(firstString) + len(separator))
// (Assuming that all Strings are roughly equally long)
int bufSize = (endIndex - startIndex);
if (bufSize <= 0) {
return EMPTY;
}
bufSize *= ((array[startIndex] == null ? 16 : array[startIndex].toString().length()) + separator.length());
StringBuffer buf = new StringBuffer(bufSize);
for (int i = startIndex; i < endIndex; i++) {
if (i > startIndex) {
buf.append(separator);
}
if (array[i] != null) {
buf.append(array[i]);
}
}
return buf.toString();
}
/**
* Deletes all whitespaces from a String as defined by
* {@link Character#isWhitespace(char)}.
*
*
* StringUtils.deleteWhitespace(null) = null
* StringUtils.deleteWhitespace("") = ""
* StringUtils.deleteWhitespace("abc") = "abc"
* StringUtils.deleteWhitespace(" ab c ") = "abc"
*
*
* @param str the String to delete whitespace from, may be null
* @return the String without whitespaces, null if null String input
*/
public static String deleteWhitespace(String str) {
if (isEmpty(str)) {
return str;
}
int sz = str.length();
char[] chs = new char[sz];
int count = 0;
for (int i = 0; i < sz; i++) {
if (!Character.isWhitespace(str.charAt(i))) {
chs[count++] = str.charAt(i);
}
}
if (count == sz) {
return str;
}
return new String(chs, 0, count);
}
// Remove
//-----------------------------------------------------------------------
/**
* Removes a substring only if it is at the begining of a source string,
* otherwise returns the source string.
*
* A null source string will return null.
* An empty ("") source string will return the empty string.
* A null search string will return the source string.
*
*
* StringUtils.removeStart(null, *) = null
* StringUtils.removeStart("", *) = ""
* StringUtils.removeStart(*, null) = *
* StringUtils.removeStart("www.domain.com", "www.") = "domain.com"
* StringUtils.removeStart("domain.com", "www.") = "domain.com"
* StringUtils.removeStart("www.domain.com", "domain") = "www.domain.com"
* StringUtils.removeStart("abc", "") = "abc"
*
*
* @param str the source String to search, may be null
* @param remove the String to search for and remove, may be null
* @return the substring with the string removed if found,
* null if null String input
* @since 2.1
*/
public static String removeStart(String str, String remove) {
if (isEmpty(str) || isEmpty(remove)) {
return str;
}
if (str.startsWith(remove)) {
return str.substring(remove.length());
}
return str;
}
/**
* Removes a substring only if it is at the end of a source string,
* otherwise returns the source string.
*
* A null source string will return null.
* An empty ("") source string will return the empty string.
* A null search string will return the source string.
*
*
* StringUtils.removeEnd(null, *) = null
* StringUtils.removeEnd("", *) = ""
* StringUtils.removeEnd(*, null) = *
* StringUtils.removeEnd("www.domain.com", ".com.") = "www.domain.com."
* StringUtils.removeEnd("www.domain.com", ".com") = "www.domain"
* StringUtils.removeEnd("www.domain.com", "domain") = "www.domain.com"
* StringUtils.removeEnd("abc", "") = "abc"
*
*
* @param str the source String to search, may be null
* @param remove the String to search for and remove, may be null
* @return the substring with the string removed if found,
* null if null String input
* @since 2.1
*/
public static String removeEnd(String str, String remove) {
if (isEmpty(str) || isEmpty(remove)) {
return str;
}
if (str.endsWith(remove)) {
return str.substring(0, str.length() - remove.length());
}
return str;
}
/**
* Removes all occurances of a substring from within the source string.
*
* A null source string will return null.
* An empty ("") source string will return the empty string.
* A null remove string will return the source string.
* An empty ("") remove string will return the source string.
*
*
* StringUtils.remove(null, *) = null
* StringUtils.remove("", *) = ""
* StringUtils.remove(*, null) = *
* StringUtils.remove(*, "") = *
* StringUtils.remove("queued", "ue") = "qd"
* StringUtils.remove("queued", "zz") = "queued"
*
*
* @param str the source String to search, may be null
* @param remove the String to search for and remove, may be null
* @return the substring with the string removed if found,
* null if null String input
* @since 2.1
*/
public static String remove(String str, String remove) {
if (isEmpty(str) || isEmpty(remove)) {
return str;
}
return replace(str, remove, "", -1);
}
/**
* Removes all occurances of a character from within the source string.
*
* A null source string will return null.
* An empty ("") source string will return the empty string.
*
*
* StringUtils.remove(null, *) = null
* StringUtils.remove("", *) = ""
* StringUtils.remove("queued", 'u') = "qeed"
* StringUtils.remove("queued", 'z') = "queued"
*
*
* @param str the source String to search, may be null
* @param remove the char to search for and remove, may be null
* @return the substring with the char removed if found,
* null if null String input
* @since 2.1
*/
public static String remove(String str, char remove) {
if (isEmpty(str) || str.indexOf(remove) == -1) {
return str;
}
char[] chars = str.toCharArray();
int pos = 0;
for (int i = 0; i < chars.length; i++) {
if (chars[i] != remove) {
chars[pos++] = chars[i];
}
}
return new String(chars, 0, pos);
}
// Replacing
//-----------------------------------------------------------------------
/**
* Replaces a String with another String inside a larger String, once.
*
* A null reference passed to this method is a no-op.
*
*
* StringUtils.replaceOnce(null, *, *) = null
* StringUtils.replaceOnce("", *, *) = ""
* StringUtils.replaceOnce("any", null, *) = "any"
* StringUtils.replaceOnce("any", *, null) = "any"
* StringUtils.replaceOnce("any", "", *) = "any"
* StringUtils.replaceOnce("aba", "a", null) = "aba"
* StringUtils.replaceOnce("aba", "a", "") = "ba"
* StringUtils.replaceOnce("aba", "a", "z") = "zba"
*
*
* @param text text to search and replace in, may be null
* @param repl the String to search for, may be null
* @param with the String to replace with, may be null
* @return the text with any replacements processed,
* null if null String input
* @see #replace(String text, String repl, String with, int max)
*/
public static String replaceOnce(String text, String repl, String with) {
return replace(text, repl, with, 1);
}
/**
* Replaces all occurrences of a String within another String.
*
* A null reference passed to this method is a no-op.
*
*
* StringUtils.replace(null, *, *) = null
* StringUtils.replace("", *, *) = ""
* StringUtils.replace("any", null, *) = "any"
* StringUtils.replace("any", *, null) = "any"
* StringUtils.replace("any", "", *) = "any"
* StringUtils.replace("aba", "a", null) = "aba"
* StringUtils.replace("aba", "a", "") = "b"
* StringUtils.replace("aba", "a", "z") = "zbz"
*
*
* @param text text to search and replace in, may be null
* @param repl the String to search for, may be null
* @param with the String to replace with, may be null
* @return the text with any replacements processed,
* null if null String input
* @see #replace(String text, String repl, String with, int max)
*/
public static String replace(String text, String repl, String with) {
return replace(text, repl, with, -1);
}
/**
* Replaces a String with another String inside a larger String,
* for the first max values of the search String.
*
* A null reference passed to this method is a no-op.
*
*
* StringUtils.replace(null, *, *, *) = null
* StringUtils.replace("", *, *, *) = ""
* StringUtils.replace("any", null, *, *) = "any"
* StringUtils.replace("any", *, null, *) = "any"
* StringUtils.replace("any", "", *, *) = "any"
* StringUtils.replace("any", *, *, 0) = "any"
* StringUtils.replace("abaa", "a", null, -1) = "abaa"
* StringUtils.replace("abaa", "a", "", -1) = "b"
* StringUtils.replace("abaa", "a", "z", 0) = "abaa"
* StringUtils.replace("abaa", "a", "z", 1) = "zbaa"
* StringUtils.replace("abaa", "a", "z", 2) = "zbza"
* StringUtils.replace("abaa", "a", "z", -1) = "zbzz"
*
*
* @param text text to search and replace in, may be null
* @param repl the String to search for, may be null
* @param with the String to replace with, may be null
* @param max maximum number of values to replace, or -1 if no maximum
* @return the text with any replacements processed,
* null if null String input
*/
public static String replace(String text, String repl, String with, int max) {
if (isEmpty(text) || isEmpty(repl) || with == null || max == 0) {
return text;
}
int start = 0;
int end = text.indexOf(repl, start);
if (end == -1) {
return text;
}
int replLength = repl.length();
int increase = with.length() - replLength;
increase = (increase < 0 ? 0 : increase);
increase *= (max < 0 ? 16 : (max > 64 ? 64 : max));
StringBuffer buf = new StringBuffer(text.length() + increase);
while (end != -1) {
buf.append(text.substring(start, end)).append(with);
start = end + replLength;
if (--max == 0) {
break;
}
end = text.indexOf(repl, start);
}
buf.append(text.substring(start));
return buf.toString();
}
// Replace, character based
//-----------------------------------------------------------------------
/**
* Replaces all occurrences of a character in a String with another.
* This is a null-safe version of {@link String#replace(char, char)}.
*
* A null string input returns null.
* An empty ("") string input returns an empty string.
*
*
* StringUtils.replaceChars(null, *, *) = null
* StringUtils.replaceChars("", *, *) = ""
* StringUtils.replaceChars("abcba", 'b', 'y') = "aycya"
* StringUtils.replaceChars("abcba", 'z', 'y') = "abcba"
*
*
* @param str String to replace characters in, may be null
* @param searchChar the character to search for, may be null
* @param replaceChar the character to replace, may be null
* @return modified String, null if null string input
* @since 2.0
*/
public static String replaceChars(String str, char searchChar, char replaceChar) {
if (str == null) {
return null;
}
return str.replace(searchChar, replaceChar);
}
/**
* Replaces multiple characters in a String in one go.
* This method can also be used to delete characters.
*
* For example:
* replaceChars("hello", "ho", "jy") = jelly.
*
* A null string input returns null.
* An empty ("") string input returns an empty string.
* A null or empty set of search characters returns the input string.
*
* The length of the search characters should normally equal the length
* of the replace characters.
* If the search characters is longer, then the extra search characters
* are deleted.
* If the search characters is shorter, then the extra replace characters
* are ignored.
*
*
* StringUtils.replaceChars(null, *, *) = null
* StringUtils.replaceChars("", *, *) = ""
* StringUtils.replaceChars("abc", null, *) = "abc"
* StringUtils.replaceChars("abc", "", *) = "abc"
* StringUtils.replaceChars("abc", "b", null) = "ac"
* StringUtils.replaceChars("abc", "b", "") = "ac"
* StringUtils.replaceChars("abcba", "bc", "yz") = "ayzya"
* StringUtils.replaceChars("abcba", "bc", "y") = "ayya"
* StringUtils.replaceChars("abcba", "bc", "yzx") = "ayzya"
*
*
* @param str String to replace characters in, may be null
* @param searchChars a set of characters to search for, may be null
* @param replaceChars a set of characters to replace, may be null
* @return modified String, null if null string input
* @since 2.0
*/
public static String replaceChars(String str, String searchChars, String replaceChars) {
if (isEmpty(str) || isEmpty(searchChars)) {
return str;
}
if (replaceChars == null) {
replaceChars = "";
}
boolean modified = false;
int replaceCharsLength = replaceChars.length();
int strLength = str.length();
StringBuffer buf = new StringBuffer(strLength);
for (int i = 0; i < strLength; i++) {
char ch = str.charAt(i);
int index = searchChars.indexOf(ch);
if (index >= 0) {
modified = true;
if (index < replaceCharsLength) {
buf.append(replaceChars.charAt(index));
}
} else {
buf.append(ch);
}
}
if (modified) {
return buf.toString();
} else {
return str;
}
}
// Overlay
//-----------------------------------------------------------------------
/**
* Overlays part of a String with another String.
*
*
* StringUtils.overlayString(null, *, *, *) = NullPointerException
* StringUtils.overlayString(*, null, *, *) = NullPointerException
* StringUtils.overlayString("", "abc", 0, 0) = "abc"
* StringUtils.overlayString("abcdef", null, 2, 4) = "abef"
* StringUtils.overlayString("abcdef", "", 2, 4) = "abef"
* StringUtils.overlayString("abcdef", "zzzz", 2, 4) = "abzzzzef"
* StringUtils.overlayString("abcdef", "zzzz", 4, 2) = "abcdzzzzcdef"
* StringUtils.overlayString("abcdef", "zzzz", -1, 4) = IndexOutOfBoundsException
* StringUtils.overlayString("abcdef", "zzzz", 2, 8) = IndexOutOfBoundsException
*
*
* @param text the String to do overlaying in, may be null
* @param overlay the String to overlay, may be null
* @param start the position to start overlaying at, must be valid
* @param end the position to stop overlaying before, must be valid
* @return overlayed String, null if null String input
* @throws NullPointerException if text or overlay is null
* @throws IndexOutOfBoundsException if either position is invalid
* @deprecated Use better named {@link #overlay(String, String, int, int)} instead.
* Method will be removed in Commons Lang 3.0.
*/
public static String overlayString(String text, String overlay, int start, int end) {
return new StringBuffer(start + overlay.length() + text.length() - end + 1).append(text.substring(0, start)).append(overlay).append(text.substring(end)).toString();
}
/**
* Overlays part of a String with another String.
*
* A null string input returns null.
* A negative index is treated as zero.
* An index greater than the string length is treated as the string length.
* The start index is always the smaller of the two indices.
*
*
* StringUtils.overlay(null, *, *, *) = null
* StringUtils.overlay("", "abc", 0, 0) = "abc"
* StringUtils.overlay("abcdef", null, 2, 4) = "abef"
* StringUtils.overlay("abcdef", "", 2, 4) = "abef"
* StringUtils.overlay("abcdef", "", 4, 2) = "abef"
* StringUtils.overlay("abcdef", "zzzz", 2, 4) = "abzzzzef"
* StringUtils.overlay("abcdef", "zzzz", 4, 2) = "abzzzzef"
* StringUtils.overlay("abcdef", "zzzz", -1, 4) = "zzzzef"
* StringUtils.overlay("abcdef", "zzzz", 2, 8) = "abzzzz"
* StringUtils.overlay("abcdef", "zzzz", -2, -3) = "zzzzabcdef"
* StringUtils.overlay("abcdef", "zzzz", 8, 10) = "abcdefzzzz"
*
*
* @param str the String to do overlaying in, may be null
* @param overlay the String to overlay, may be null
* @param start the position to start overlaying at
* @param end the position to stop overlaying before
* @return overlayed String, null if null String input
* @since 2.0
*/
public static String overlay(String str, String overlay, int start, int end) {
if (str == null) {
return null;
}
if (overlay == null) {
overlay = EMPTY;
}
int len = str.length();
if (start < 0) {
start = 0;
}
if (start > len) {
start = len;
}
if (end < 0) {
end = 0;
}
if (end > len) {
end = len;
}
if (start > end) {
int temp = start;
start = end;
end = temp;
}
return new StringBuffer(len + start - end + overlay.length() + 1).append(str.substring(0, start)).append(overlay).append(str.substring(end)).toString();
}
}