com.azure.cosmos.implementation.apachecommons.lang.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.
*/
/*
* Portions Copyright (c) Microsoft Corporation
*/
package com.azure.cosmos.implementation.apachecommons.lang;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.Objects;
public class StringUtils {
private static final int STRING_BUILDER_SIZE = 256;
// 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)
/**
* A String for a space character.
*/
public static final String SPACE = " ";
/**
* The empty String {@code ""}.
*/
public static final String EMPTY = "";
/**
* Represents a failed index search.
*/
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;
/**
* {@code StringUtils} instances should NOT be constructed in
* standard programming. Instead, the class should be used as
* {@code 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 CharSequence is empty ("") or null.
*
* @param cs the CharSequence to check, may be null
* @return {@code true} if the CharSequence is empty or null
*/
public static boolean isEmpty(final CharSequence cs) {
return cs == null || cs.length() == 0;
}
/**
* Checks if a CharSequence is not empty ("") and not null.
*
* @param cs the CharSequence to check, may be null
* @return {@code true} if the CharSequence is not empty and not null
*/
public static boolean isNotEmpty(final CharSequence cs) {
return !isEmpty(cs);
}
/**
* Removes control characters (char <= 32) from both
* ends of this String, handling {@code null} by returning
* {@code null}.
*
* @param str the String to be trimmed, may be null
* @return the trimmed string, {@code null} if null String input
*/
public static String trim(final String str) {
return str == null ? null : str.trim();
}
/**
* Removes control characters (char <= 32) from both
* ends of this String returning {@code null} if the String is
* empty ("") after the trim or if it is {@code null}.
*
* @param str the String to be trimmed, may be null
* @return the trimmed String,
* {@code null} if only chars <= 32, empty or null String input
*/
public static String trimToNull(final String str) {
final String ts = trim(str);
return isEmpty(ts) ? null : ts;
}
/**
*
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.
*
* @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} if null String input
*/
public static String strip(String str, final 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.
*
* @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} if null String input
*/
public static String stripStart(final String str, final 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.isEmpty()) {
return str;
} else {
while (start != strLen && stripChars.indexOf(str.charAt(start)) != INDEX_NOT_FOUND) {
start++;
}
}
return str.substring(start);
}
/**
* Strips any of a set of characters from the end of a String.
*
*
* @param str the String to remove characters from, may be null
* @param stripChars the set of characters to remove, null treated as whitespace
* @return the stripped String, {@code null} if null String input
*/
public static String stripEnd(final String str, final 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.isEmpty()) {
return str;
} else {
while (end != 0 && stripChars.indexOf(str.charAt(end - 1)) != INDEX_NOT_FOUND) {
end--;
}
}
return str.substring(0, end);
}
/**
* Compares two CharSequences, returning {@code true} if they represent
* equal sequences of characters.
*
*
* @see Object#equals(Object)
* @param cs1 the first CharSequence, may be {@code null}
* @param cs2 the second CharSequence, may be {@code null}
* @return {@code true} if the CharSequences are equal (case-sensitive), or both {@code null}
*/
public static boolean equals(final CharSequence cs1, final CharSequence cs2) {
if (cs1 == cs2) {
return true;
}
if (cs1 == null || cs2 == null) {
return false;
}
if (cs1.length() != cs2.length()) {
return false;
}
if (cs1 instanceof String && cs2 instanceof String) {
return cs1.equals(cs2);
}
return CharSequenceUtils.regionMatches(cs1, false, 0, cs2, 0, cs1.length());
}
/**
* Compares two CharSequences, returning {@code true} if they represent
* equal sequences of characters, ignoring case.
*
* {@code null}s are handled without exceptions. Two {@code 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 CharSequence, may be null
* @param str2 the second CharSequence, may be null
* @return {@code true} if the CharSequence are equal, case insensitive, or
* both {@code null}
*/
public static boolean equalsIgnoreCase(final CharSequence str1, final CharSequence str2) {
if (str1 == null || str2 == null) {
return str1 == str2;
} else if (str1 == str2) {
return true;
} else if (str1.length() != str2.length()) {
return false;
} else {
return CharSequenceUtils.regionMatches(str1, true, 0, str2, 0, str1.length());
}
}
/**
* Compare two Strings lexicographically, as per {@link String#compareTo(String)}, returning :
*
* - {@code int = 0}, if {@code str1} is equal to {@code str2} (or both {@code null})
* - {@code int < 0}, if {@code str1} is less than {@code str2}
* - {@code int > 0}, if {@code str1} is greater than {@code str2}
*
*
* This is a {@code null} safe version of :
* str1.compareTo(str2)
*
* {@code null} value is considered less than non-{@code null} value.
* Two {@code null} references are considered equal.
*
*
* StringUtils.compare(null, null) = 0
* StringUtils.compare(null , "a") < 0
* StringUtils.compare("a", null) > 0
* StringUtils.compare("abc", "abc") = 0
* StringUtils.compare("a", "b") < 0
* StringUtils.compare("b", "a") > 0
* StringUtils.compare("a", "B") > 0
* StringUtils.compare("ab", "abc") < 0
*
*
* @see #compare(String, String, boolean)
* @see String#compareTo(String)
* @param str1 the String to compare from
* @param str2 the String to compare to
* @return < 0, 0, > 0, if {@code str1} is respectively less, equal or greater than {@code str2}
*/
public static int compare(final String str1, final String str2) {
return compare(str1, str2, true);
}
/**
* Compare two Strings lexicographically, as per {@link String#compareTo(String)}, returning :
*
* - {@code int = 0}, if {@code str1} is equal to {@code str2} (or both {@code null})
* - {@code int < 0}, if {@code str1} is less than {@code str2}
* - {@code int > 0}, if {@code str1} is greater than {@code str2}
*
*
* This is a {@code null} safe version of :
* str1.compareTo(str2)
*
* {@code null} inputs are handled according to the {@code nullIsLess} parameter.
* Two {@code null} references are considered equal.
*
*
* StringUtils.compare(null, null, *) = 0
* StringUtils.compare(null , "a", true) < 0
* StringUtils.compare(null , "a", false) > 0
* StringUtils.compare("a", null, true) > 0
* StringUtils.compare("a", null, false) < 0
* StringUtils.compare("abc", "abc", *) = 0
* StringUtils.compare("a", "b", *) < 0
* StringUtils.compare("b", "a", *) > 0
* StringUtils.compare("a", "B", *) > 0
* StringUtils.compare("ab", "abc", *) < 0
*
*
* @see String#compareTo(String)
* @param str1 the String to compare from
* @param str2 the String to compare to
* @param nullIsLess whether consider {@code null} value less than non-{@code null} value
* @return < 0, 0, > 0, if {@code str1} is respectively less, equal ou greater than {@code str2}
*/
public static int compare(final String str1, final String str2, final boolean nullIsLess) {
if (str1 == str2) {
return 0;
}
if (str1 == null) {
return nullIsLess ? -1 : 1;
}
if (str2 == null) {
return nullIsLess ? 1 : - 1;
}
return str1.compareTo(str2);
}
/**
* Checks if CharSequence contains a search CharSequence irrespective of case,
* handling {@code null}. Case-insensitivity is defined as by
* {@link String#equalsIgnoreCase(String)}.
*
*
A {@code null} CharSequence will return {@code false}.
*
*
* StringUtils.containsIgnoreCase(null, *) = false
* StringUtils.containsIgnoreCase(*, null) = false
* StringUtils.containsIgnoreCase("", "") = true
* StringUtils.containsIgnoreCase("abc", "") = true
* StringUtils.containsIgnoreCase("abc", "a") = true
* StringUtils.containsIgnoreCase("abc", "z") = false
* StringUtils.containsIgnoreCase("abc", "A") = true
* StringUtils.containsIgnoreCase("abc", "Z") = false
*
*
* @param str the CharSequence to check, may be null
* @param searchStr the CharSequence to find, may be null
* @return true if the CharSequence contains the search CharSequence irrespective of
* case or false if not or {@code null} string input
*/
public static boolean containsIgnoreCase(final CharSequence str, final CharSequence searchStr) {
if (str == null || searchStr == null) {
return false;
}
final int len = searchStr.length();
final int max = str.length() - len;
for (int i = 0; i <= max; i++) {
if (CharSequenceUtils.regionMatches(str, true, i, searchStr, 0, len)) {
return true;
}
}
return false;
}
/**
* Checks if the CharSequence contains any character in the given
* set of characters.
*
* A {@code null} CharSequence will return {@code false}.
* A {@code null} or zero length search array will return {@code false}.
*
*
* StringUtils.containsAny(null, *) = false
* StringUtils.containsAny("", *) = false
* StringUtils.containsAny(*, null) = false
* StringUtils.containsAny(*, []) = false
* StringUtils.containsAny("zzabyycdxx",['z','a']) = true
* StringUtils.containsAny("zzabyycdxx",['b','y']) = true
* StringUtils.containsAny("zzabyycdxx",['z','y']) = true
* StringUtils.containsAny("aba", ['z']) = false
*
*
* @param cs the CharSequence to check, may be null
* @param searchChars the chars to search for, may be null
* @return the {@code true} if any of the chars are found,
* {@code false} if no match or null input
*/
public static boolean containsAny(final CharSequence cs, final char... searchChars) {
if (isEmpty(cs) || ArrayUtils.isEmpty(searchChars)) {
return false;
}
final int csLength = cs.length();
final int searchLength = searchChars.length;
final int csLast = csLength - 1;
final int searchLast = searchLength - 1;
for (int i = 0; i < csLength; i++) {
final char ch = cs.charAt(i);
for (int j = 0; j < searchLength; j++) {
if (searchChars[j] == ch) {
if (Character.isHighSurrogate(ch)) {
if (j == searchLast) {
// missing low surrogate, fine, like String.indexOf(String)
return true;
}
if (i < csLast && searchChars[j + 1] == cs.charAt(i + 1)) {
return true;
}
} else {
// ch is in the Basic Multilingual Plane
return true;
}
}
}
}
return false;
}
/**
* Checks that the CharSequence does not contain certain characters.
*
* A {@code null} CharSequence will return {@code true}.
* A {@code null} invalid character array will return {@code true}.
* An empty CharSequence (length()=0) 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 cs the CharSequence to check, may be null
* @param searchChars an array of invalid chars, may be null
* @return true if it contains none of the invalid chars, or is null
*/
public static boolean containsNone(final CharSequence cs, final char... searchChars) {
if (cs == null || searchChars == null) {
return true;
}
final int csLen = cs.length();
final int csLast = csLen - 1;
final int searchLen = searchChars.length;
final int searchLast = searchLen - 1;
for (int i = 0; i < csLen; i++) {
final char ch = cs.charAt(i);
for (int j = 0; j < searchLen; j++) {
if (searchChars[j] == ch) {
if (Character.isHighSurrogate(ch)) {
if (j == searchLast) {
// missing low surrogate, fine, like String.indexOf(String)
return false;
}
if (i < csLast && searchChars[j + 1] == cs.charAt(i + 1)) {
return false;
}
} else {
// ch is in the Basic Multilingual Plane
return false;
}
}
}
}
return true;
}
/**
* Gets a substring from the specified String avoiding exceptions.
*
* A negative start position can be used to start {@code n}
* characters from the end of the String.
*
* A {@code null} String will return {@code null}.
* An empty ("") String will return "".
*
*
* StringUtils.substring(null, *) = null
* StringUtils.substring("", *) = ""
* StringUtils.substring("abc", 0) = "abc"
* StringUtils.substring("abc", 2) = "c"
* StringUtils.substring("abc", 4) = ""
* StringUtils.substring("abc", -2) = "bc"
* StringUtils.substring("abc", -4) = "abc"
*
*
* @param str the String to get the substring from, may be null
* @param start the position to start from, negative means
* count back from the end of the String by this many characters
* @return substring from start position, {@code null} if null String input
*/
public static String substring(final String str, int start) {
if (str == null) {
return null;
}
// handle negatives, which means last n characters
if (start < 0) {
start = str.length() + start; // remember start is negative
}
if (start < 0) {
start = 0;
}
if (start > str.length()) {
return EMPTY;
}
return str.substring(start);
}
private static StringBuilder newStringBuilder(final int noOfItems) {
return new StringBuilder(noOfItems * 16);
}
/**
* Splits the provided text into an array, using whitespace as the
* separator.
* Whitespace is defined by {@link Character#isWhitespace(char)}.
*
* The separator is not included in the returned String array.
* Adjacent separators are treated as one separator.
* For more control over the split use the StrTokenizer class.
*
* A {@code null} input String returns {@code null}.
*
*
* StringUtils.split(null) = null
* StringUtils.split("") = []
* StringUtils.split("abc def") = ["abc", "def"]
* StringUtils.split("abc def") = ["abc", "def"]
* StringUtils.split(" abc ") = ["abc"]
*
*
* @param str the String to parse, may be null
* @return an array of parsed Strings, {@code null} if null String input
*/
public static String[] split(final String str) {
return split(str, null, -1);
}
/**
* Splits the provided text into an array, separator specified.
* This is an alternative to using StringTokenizer.
*
* The separator is not included in the returned String array.
* Adjacent separators are treated as one separator.
* For more control over the split use the StrTokenizer class.
*
* A {@code null} input String returns {@code null}.
*
*
* StringUtils.split(null, *) = null
* StringUtils.split("", *) = []
* StringUtils.split("a.b.c", '.') = ["a", "b", "c"]
* StringUtils.split("a..b.c", '.') = ["a", "b", "c"]
* StringUtils.split("a:b:c", '.') = ["a:b:c"]
* StringUtils.split("a b c", ' ') = ["a", "b", "c"]
*
*
* @param str the String to parse, may be null
* @param separatorChar the character used as the delimiter
* @return an array of parsed Strings, {@code null} if null String input
*/
public static String[] split(final String str, final char separatorChar) {
return splitWorker(str, separatorChar, false);
}
/**
* Splits the provided text into an array, separators specified.
* This is an alternative to using StringTokenizer.
*
* The separator is not included in the returned String array.
* Adjacent separators are treated as one separator.
* For more control over the split use the StrTokenizer class.
*
* A {@code null} input String returns {@code null}.
* A {@code null} separatorChars splits on whitespace.
*
*
* StringUtils.split(null, *) = null
* StringUtils.split("", *) = []
* StringUtils.split("abc def", null) = ["abc", "def"]
* StringUtils.split("abc def", " ") = ["abc", "def"]
* StringUtils.split("abc def", " ") = ["abc", "def"]
* StringUtils.split("ab:cd:ef", ":") = ["ab", "cd", "ef"]
*
*
* @param str the String to parse, may be null
* @param separatorChars the characters used as the delimiters,
* {@code null} splits on whitespace
* @return an array of parsed Strings, {@code null} if null String input
*/
public static String[] split(final String str, final String separatorChars) {
return splitWorker(str, separatorChars, -1, false);
}
/**
* Splits the provided text into an array with a maximum length,
* separators specified.
*
* The separator is not included in the returned String array.
* Adjacent separators are treated as one separator.
*
* A {@code null} input String returns {@code null}.
* A {@code null} separatorChars splits on whitespace.
*
* If more than {@code max} delimited substrings are found, the last
* returned string includes all characters after the first {@code max - 1}
* returned strings (including separator characters).
*
*
* StringUtils.split(null, *, *) = null
* StringUtils.split("", *, *) = []
* StringUtils.split("ab cd ef", null, 0) = ["ab", "cd", "ef"]
* StringUtils.split("ab cd ef", null, 0) = ["ab", "cd", "ef"]
* StringUtils.split("ab:cd:ef", ":", 0) = ["ab", "cd", "ef"]
* StringUtils.split("ab:cd:ef", ":", 2) = ["ab", "cd:ef"]
*
*
* @param str the String to parse, may be null
* @param separatorChars the characters used as the delimiters,
* {@code null} splits on whitespace
* @param max the maximum number of elements to include in the
* array. A zero or negative value implies no limit
* @return an array of parsed Strings, {@code null} if null String input
*/
public static String[] split(final String str, final String separatorChars, final int max) {
return splitWorker(str, separatorChars, max, false);
}
/**
* Performs the logic for the {@code split} and
* {@code splitPreserveAllTokens} methods that do not return a
* maximum array length.
*
* @param str the String to parse, may be {@code null}
* @param separatorChar the separate character
* @param preserveAllTokens if {@code true}, adjacent separators are
* treated as empty token separators; if {@code false}, adjacent
* separators are treated as one separator.
* @return an array of parsed Strings, {@code null} if null String input
*/
private static String[] splitWorker(final String str, final char separatorChar, final boolean preserveAllTokens) {
// Performance tuned for 2.0 (JDK1.4)
if (str == null) {
return null;
}
final int len = str.length();
if (len == 0) {
return ArrayUtils.EMPTY_STRING_ARRAY;
}
final List list = new ArrayList<>();
int i = 0, start = 0;
boolean match = false;
boolean lastMatch = false;
while (i < len) {
if (str.charAt(i) == separatorChar) {
if (match || preserveAllTokens) {
list.add(str.substring(start, i));
match = false;
lastMatch = true;
}
start = ++i;
continue;
}
lastMatch = false;
match = true;
i++;
}
if (match || preserveAllTokens && lastMatch) {
list.add(str.substring(start, i));
}
return list.toArray(new String[list.size()]);
}
/**
* Performs the logic for the {@code split} and
* {@code splitPreserveAllTokens} methods that return a maximum array
* length.
*
* @param str the String to parse, may be {@code null}
* @param separatorChars the separate character
* @param max the maximum number of elements to include in the
* array. A zero or negative value implies no limit.
* @param preserveAllTokens if {@code true}, adjacent separators are
* treated as empty token separators; if {@code false}, adjacent
* separators are treated as one separator.
* @return an array of parsed Strings, {@code null} if null String input
*/
private static String[] splitWorker(final String str, final String separatorChars, final int max, final boolean preserveAllTokens) {
// Performance tuned for 2.0 (JDK1.4)
// Direct code is quicker than StringTokenizer.
// Also, StringTokenizer uses isSpace() not isWhitespace()
if (str == null) {
return null;
}
final int len = str.length();
if (len == 0) {
return ArrayUtils.EMPTY_STRING_ARRAY;
}
final List list = new ArrayList<>();
int sizePlus1 = 1;
int i = 0, start = 0;
boolean match = false;
boolean lastMatch = false;
if (separatorChars == null) {
// Null separator means use whitespace
while (i < len) {
if (Character.isWhitespace(str.charAt(i))) {
if (match || preserveAllTokens) {
lastMatch = true;
if (sizePlus1++ == max) {
i = len;
lastMatch = false;
}
list.add(str.substring(start, i));
match = false;
}
start = ++i;
continue;
}
lastMatch = false;
match = true;
i++;
}
} else if (separatorChars.length() == 1) {
// Optimise 1 character case
final char sep = separatorChars.charAt(0);
while (i < len) {
if (str.charAt(i) == sep) {
if (match || preserveAllTokens) {
lastMatch = true;
if (sizePlus1++ == max) {
i = len;
lastMatch = false;
}
list.add(str.substring(start, i));
match = false;
}
start = ++i;
continue;
}
lastMatch = false;
match = true;
i++;
}
} else {
// standard case
while (i < len) {
if (separatorChars.indexOf(str.charAt(i)) >= 0) {
if (match || preserveAllTokens) {
lastMatch = true;
if (sizePlus1++ == max) {
i = len;
lastMatch = false;
}
list.add(str.substring(start, i));
match = false;
}
start = ++i;
continue;
}
lastMatch = false;
match = true;
i++;
}
}
if (match || preserveAllTokens && lastMatch) {
list.add(str.substring(start, i));
}
return list.toArray(new String[list.size()]);
}
/**
* 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 {@code 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, {@code null} if null array input
*/
public static String join(final Object[] array, final 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 {@code 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"], "--", 0, 3) = "a--b--c"
* StringUtils.join(["a", "b", "c"], "--", 1, 3) = "b--c"
* StringUtils.join(["a", "b", "c"], "--", 2, 3) = "c"
* StringUtils.join(["a", "b", "c"], "--", 2, 2) = ""
* StringUtils.join(["a", "b", "c"], null, 0, 3) = "abc"
* StringUtils.join(["a", "b", "c"], "", 0, 3) = "abc"
* StringUtils.join([null, "", "a"], ',', 0, 3) = ",,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.
* @param endIndex the index to stop joining from (exclusive).
* @return the joined String, {@code null} if null array input; or the empty string
* if {@code endIndex - startIndex <= 0}. The number of joined entries is given by
* {@code endIndex - startIndex}
* @throws ArrayIndexOutOfBoundsException ife
* {@code startIndex < 0} or
* {@code startIndex >= array.length()} or
* {@code endIndex < 0} or
* {@code endIndex > array.length()}
*/
public static String join(final Object[] array, String separator, final int startIndex, final 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)
final int noOfItems = endIndex - startIndex;
if (noOfItems <= 0) {
return EMPTY;
}
final StringBuilder buf = newStringBuilder(noOfItems);
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 {@code Iterator} into
* a single String containing the provided elements.
*
* No delimiter is added before or after the list.
* A {@code null} separator is the same as an empty String ("").
*
* See the examples here: {@link #join(Object[],String)}.
*
* @param iterator the {@code Iterator} of values to join together, may be null
* @param separator the separator character to use, null treated as ""
* @return the joined String, {@code null} if null iterator input
*/
public static String join(final Iterator iterator, final String separator) {
// handle null, zero and one elements before building a buffer
if (iterator == null) {
return null;
}
if (!iterator.hasNext()) {
return EMPTY;
}
final Object first = iterator.next();
if (!iterator.hasNext()) {
return Objects.toString(first, "");
}
// two or more elements
final StringBuilder buf = new StringBuilder(STRING_BUILDER_SIZE); // Java default is 16, probably too small
if (first != null) {
buf.append(first);
}
while (iterator.hasNext()) {
if (separator != null) {
buf.append(separator);
}
final Object obj = iterator.next();
if (obj != null) {
buf.append(obj);
}
}
return buf.toString();
}
/**
* Joins the elements of the provided {@code Iterable} into
* a single String containing the provided elements.
*
* No delimiter is added before or after the list.
* A {@code null} separator is the same as an empty String ("").
*
* See the examples here: {@link #join(Object[],String)}.
*
* @param iterable the {@code Iterable} providing the values to join together, may be null
* @param separator the separator character to use, null treated as ""
* @return the joined String, {@code null} if null iterator input
*/
public static String join(final Iterable iterable, final String separator) {
if (iterable == null) {
return null;
}
return join(iterable.iterator(), separator);
}
/**
* Removes a substring only if it is at the beginning of a source string,
* otherwise returns the source string.
*
* A {@code null} source string will return {@code null}.
* An empty ("") source string will return the empty string.
* A {@code 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,
* {@code null} if null String input
*/
public static String removeStart(final String str, final 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 {@code null} source string will return {@code null}.
* An empty ("") source string will return the empty string.
* A {@code 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,
* {@code null} if null String input
*/
public static String removeEnd(final String str, final String remove) {
if (isEmpty(str) || isEmpty(remove)) {
return str;
}
if (str.endsWith(remove)) {
return str.substring(0, str.length() - remove.length());
}
return str;
}
/**
* Replaces all occurrences of a String within another String.
*
* A {@code 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"
*
*
* @see #replace(String text, String searchString, String replacement, int max)
* @param text text to search and replace in, may be null
* @param searchString the String to search for, may be null
* @param replacement the String to replace it with, may be null
* @return the text with any replacements processed,
* {@code null} if null String input
*/
public static String replace(final String text, final String searchString, final String replacement) {
return replace(text, searchString, replacement, -1);
}
/**
* Replaces a String with another String inside a larger String,
* for the first {@code max} values of the search String.
*
* A {@code 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 searchString the String to search for, may be null
* @param replacement the String to replace it with, may be null
* @param max maximum number of values to replace, or {@code -1} if no maximum
* @return the text with any replacements processed,
* {@code null} if null String input
*/
public static String replace(final String text, final String searchString, final String replacement, final int max) {
return replace(text, searchString, replacement, max, false);
}
/**
* Replaces a String with another String inside a larger String,
* for the first {@code max} values of the search String,
* case sensitively/insensisitively based on {@code ignoreCase} value.
*
* A {@code null} reference passed to this method is a no-op.
*
*
* StringUtils.replace(null, *, *, *, false) = null
* StringUtils.replace("", *, *, *, false) = ""
* StringUtils.replace("any", null, *, *, false) = "any"
* StringUtils.replace("any", *, null, *, false) = "any"
* StringUtils.replace("any", "", *, *, false) = "any"
* StringUtils.replace("any", *, *, 0, false) = "any"
* StringUtils.replace("abaa", "a", null, -1, false) = "abaa"
* StringUtils.replace("abaa", "a", "", -1, false) = "b"
* StringUtils.replace("abaa", "a", "z", 0, false) = "abaa"
* StringUtils.replace("abaa", "A", "z", 1, false) = "abaa"
* StringUtils.replace("abaa", "A", "z", 1, true) = "zbaa"
* StringUtils.replace("abAa", "a", "z", 2, true) = "zbza"
* StringUtils.replace("abAa", "a", "z", -1, true) = "zbzz"
*
*
* @param text text to search and replace in, may be null
* @param searchString the String to search for (case insensitive), may be null
* @param replacement the String to replace it with, may be null
* @param max maximum number of values to replace, or {@code -1} if no maximum
* @param ignoreCase if true replace is case insensitive, otherwise case sensitive
* @return the text with any replacements processed,
* {@code null} if null String input
*/
private static String replace(final String text, String searchString, final String replacement, int max, final boolean ignoreCase) {
if (isEmpty(text) || isEmpty(searchString) || replacement == null || max == 0) {
return text;
}
String searchText = text;
if (ignoreCase) {
searchText = text.toLowerCase();
searchString = searchString.toLowerCase();
}
int start = 0;
int end = searchText.indexOf(searchString, start);
if (end == INDEX_NOT_FOUND) {
return text;
}
final int replLength = searchString.length();
int increase = replacement.length() - replLength;
increase = increase < 0 ? 0 : increase;
increase *= max < 0 ? 16 : max > 64 ? 64 : max;
final StringBuilder buf = new StringBuilder(text.length() + increase);
while (end != INDEX_NOT_FOUND) {
buf.append(text, start, end).append(replacement);
start = end + replLength;
if (--max == 0) {
break;
}
end = searchText.indexOf(searchString, start);
}
buf.append(text, start, text.length());
return buf.toString();
}
/**
* Repeat a String {@code repeat} times to form a
* new String.
*
*
* StringUtils.repeat(null, 2) = null
* StringUtils.repeat("", 0) = ""
* StringUtils.repeat("", 2) = ""
* StringUtils.repeat("a", 3) = "aaa"
* StringUtils.repeat("ab", 2) = "abab"
* StringUtils.repeat("a", -2) = ""
*
*
* @param str the String to repeat, may be null
* @param repeat number of times to repeat str, negative treated as zero
* @return a new String consisting of the original String repeated,
* {@code null} if null String input
*/
public static String repeat(final String str, final int repeat) {
// Performance tuned for 2.0 (JDK1.4)
if (str == null) {
return null;
}
if (repeat <= 0) {
return EMPTY;
}
final int inputLength = str.length();
if (repeat == 1 || inputLength == 0) {
return str;
}
if (inputLength == 1 && repeat <= PAD_LIMIT) {
return repeat(str.charAt(0), repeat);
}
final int outputLength = inputLength * repeat;
switch (inputLength) {
case 1 :
return repeat(str.charAt(0), repeat);
case 2 :
final char ch0 = str.charAt(0);
final char ch1 = str.charAt(1);
final char[] output2 = new char[outputLength];
for (int i = repeat * 2 - 2; i >= 0; i--, i--) {
output2[i] = ch0;
output2[i + 1] = ch1;
}
return new String(output2);
default :
final StringBuilder buf = new StringBuilder(outputLength);
for (int i = 0; i < repeat; i++) {
buf.append(str);
}
return buf.toString();
}
}
/**
* Returns padding using the specified delimiter repeated
* to a given length.
*
*
* StringUtils.repeat('e', 0) = ""
* StringUtils.repeat('e', 3) = "eee"
* StringUtils.repeat('e', -2) = ""
*
*
* Note: this method does not support padding with
* Unicode Supplementary Characters
* as they require a pair of {@code char}s to be represented.
* If you are needing to support full I18N of your applications
* consider using {@link #repeat(String, int)} instead.
*
*
* @param ch character to repeat
* @param repeat number of times to repeat char, negative treated as zero
* @return String with repeated character
* @see #repeat(String, int)
*/
public static String repeat(final char ch, final int repeat) {
if (repeat <= 0) {
return EMPTY;
}
final char[] buf = new char[repeat];
for (int i = repeat - 1; i >= 0; i--) {
buf[i] = ch;
}
return new String(buf);
}
/**
* Left pad a String with a specified character.
*
* Pad to a size of {@code size}.
*
*
* StringUtils.leftPad(null, *, *) = null
* StringUtils.leftPad("", 3, 'z') = "zzz"
* StringUtils.leftPad("bat", 3, 'z') = "bat"
* StringUtils.leftPad("bat", 5, 'z') = "zzbat"
* StringUtils.leftPad("bat", 1, 'z') = "bat"
* StringUtils.leftPad("bat", -1, 'z') = "bat"
*
*
* @param str the String to pad out, may be null
* @param size the size to pad to
* @param padChar the character to pad with
* @return left padded String or original String if no padding is necessary,
* {@code null} if null String input
*/
public static String leftPad(final String str, final int size, final char padChar) {
if (str == null) {
return null;
}
final int pads = size - str.length();
if (pads <= 0) {
return str; // returns original String when possible
}
if (pads > PAD_LIMIT) {
return leftPad(str, size, String.valueOf(padChar));
}
return repeat(padChar, pads).concat(str);
}
/**
* Left pad a String with a specified String.
*
* Pad to a size of {@code size}.
*
*
* StringUtils.leftPad(null, *, *) = null
* StringUtils.leftPad("", 3, "z") = "zzz"
* StringUtils.leftPad("bat", 3, "yz") = "bat"
* StringUtils.leftPad("bat", 5, "yz") = "yzbat"
* StringUtils.leftPad("bat", 8, "yz") = "yzyzybat"
* StringUtils.leftPad("bat", 1, "yz") = "bat"
* StringUtils.leftPad("bat", -1, "yz") = "bat"
* StringUtils.leftPad("bat", 5, null) = " bat"
* StringUtils.leftPad("bat", 5, "") = " bat"
*
*
* @param str the String to pad out, may be null
* @param size the size to pad to
* @param padStr the String to pad with, null or empty treated as single space
* @return left padded String or original String if no padding is necessary,
* {@code null} if null String input
*/
public static String leftPad(final String str, final int size, String padStr) {
if (str == null) {
return null;
}
if (isEmpty(padStr)) {
padStr = SPACE;
}
final int padLen = padStr.length();
final int strLen = str.length();
final int pads = size - strLen;
if (pads <= 0) {
return str; // returns original String when possible
}
if (padLen == 1 && pads <= PAD_LIMIT) {
return leftPad(str, size, padStr.charAt(0));
}
if (pads == padLen) {
return padStr.concat(str);
} else if (pads < padLen) {
return padStr.substring(0, pads).concat(str);
} else {
final char[] padding = new char[pads];
final char[] padChars = padStr.toCharArray();
for (int i = 0; i < pads; i++) {
padding[i] = padChars[i % padLen];
}
return new String(padding).concat(str);
}
}
/**
* Converts a String to upper case as per {@link String#toUpperCase()}.
*
* A {@code null} input String returns {@code null}.
*
* @param str the String to upper case, may be null
* @return the upper cased String, {@code null} if null String input
*/
public static String upperCase(final String str) {
if (str == null) {
return null;
}
return str.toUpperCase();
}
/**
* Checks if the CharSequence contains only Unicode digits.
* A decimal point is not a Unicode digit and returns false.
*
* {@code null} will return {@code false}.
* An empty CharSequence (length()=0) will return {@code false}.
*
* Note that the method does not allow for a leading sign, either positive or negative.
* Also, if a String passes the numeric test, it may still generate a NumberFormatException
* when parsed by Integer.parseInt or Long.parseLong, e.g. if the value is outside the range
* for int or long respectively.
*
*
* @param cs the CharSequence to check, may be null
* @return {@code true} if only contains digits, and is non-null
*/
public static boolean isNumeric(final CharSequence cs) {
if (isEmpty(cs)) {
return false;
}
final int sz = cs.length();
for (int i = 0; i < sz; i++) {
if (!Character.isDigit(cs.charAt(i))) {
return false;
}
}
return true;
}
/**
* Checks if the CharSequence contains only whitespace.
*
* @param cs the CharSequence to check, may be null
* @return {@code true} if only contains whitespace, and is non-null
*/
public static boolean isWhitespace(final CharSequence cs) {
if (cs == null) {
return false;
}
final int sz = cs.length();
for (int i = 0; i < sz; i++) {
if (!Character.isWhitespace(cs.charAt(i))) {
return false;
}
}
return true;
}
/**
* Returns either the passed in String, or if the String is
* {@code null}, the value of {@code defaultStr}.
*
*
* StringUtils.defaultString(null, "NULL") = "NULL"
* StringUtils.defaultString("", "NULL") = ""
* StringUtils.defaultString("bat", "NULL") = "bat"
*
*
* @see String#valueOf(Object)
* @param str the String to check, may be null
* @param defaultStr the default String to return
* if the input is {@code null}, may be null
* @return the passed in String, or the default if it was {@code null}
*/
public static String defaultString(final String str, final String defaultStr) {
return str == null ? defaultStr : str;
}
/**
* 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, {@code null} if null String input
*/
public static String deleteWhitespace(final String str) {
if (isEmpty(str)) {
return str;
}
final int sz = str.length();
final 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;
}
if (count == 0) {
return EMPTY;
}
return new String(chs, 0, count);
}
}