org.codelibs.elasticsearch.common.Strings Maven / Gradle / Ivy
/*
* Licensed to Elasticsearch under one or more contributor
* license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright
* ownership. Elasticsearch licenses this file to you under
* the Apache License, Version 2.0 (the "License"); you may
* not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
package org.codelibs.elasticsearch.common;
import org.apache.lucene.util.BytesRefBuilder;
import org.codelibs.elasticsearch.ExceptionsHelper;
import org.codelibs.elasticsearch.common.bytes.BytesReference;
import org.codelibs.elasticsearch.common.io.FastStringReader;
import org.codelibs.elasticsearch.common.util.CollectionUtils;
import org.codelibs.elasticsearch.common.xcontent.ToXContent;
import org.codelibs.elasticsearch.common.xcontent.XContentBuilder;
import org.codelibs.elasticsearch.common.xcontent.json.JsonXContent;
import java.io.BufferedReader;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.HashSet;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import java.util.Set;
import java.util.StringTokenizer;
import java.util.TreeSet;
import static java.util.Collections.unmodifiableSet;
import static org.codelibs.elasticsearch.common.util.set.Sets.newHashSet;
/**
*
*/
public class Strings {
public static final String[] EMPTY_ARRAY = new String[0];
private static final String FOLDER_SEPARATOR = "/";
private static final String WINDOWS_FOLDER_SEPARATOR = "\\";
private static final String TOP_PATH = "src/test";
private static final String CURRENT_PATH = ".";
public static void spaceify(int spaces, String from, StringBuilder to) throws Exception {
try (BufferedReader reader = new BufferedReader(new FastStringReader(from))) {
String line;
while ((line = reader.readLine()) != null) {
for (int i = 0; i < spaces; i++) {
to.append(' ');
}
to.append(line).append('\n');
}
}
}
/**
* Splits a backslash escaped string on the separator.
*
* Current backslash escaping supported:
*
\n \t \r \b \f are escaped the same as a Java String
*
Other characters following a backslash are produced verbatim (\c => c)
*
* @param s the string to split
* @param separator the separator to split on
* @param decode decode backslash escaping
*/
public static List splitSmart(String s, String separator, boolean decode) {
ArrayList lst = new ArrayList<>(2);
StringBuilder sb = new StringBuilder();
int pos = 0, end = s.length();
while (pos < end) {
if (s.startsWith(separator, pos)) {
if (sb.length() > 0) {
lst.add(sb.toString());
sb = new StringBuilder();
}
pos += separator.length();
continue;
}
char ch = s.charAt(pos++);
if (ch == '\\') {
if (!decode) {
sb.append(ch);
}
if (pos >= end)
{
break; // ERROR, or let it go?
}
ch = s.charAt(pos++);
if (decode) {
switch (ch) {
case 'n':
ch = '\n';
break;
case 't':
ch = '\t';
break;
case 'r':
ch = '\r';
break;
case 'b':
ch = '\b';
break;
case 'f':
ch = '\f';
break;
}
}
}
sb.append(ch);
}
if (sb.length() > 0) {
lst.add(sb.toString());
}
return lst;
}
//---------------------------------------------------------------------
// General convenience methods for working with Strings
//---------------------------------------------------------------------
/**
* Check that the given CharSequence is neither null nor of length 0.
* Note: Will return true for a CharSequence that purely consists of whitespace.
*
* StringUtils.hasLength(null) = false
* StringUtils.hasLength("") = false
* StringUtils.hasLength(" ") = true
* StringUtils.hasLength("Hello") = true
*
*
* @param str the CharSequence to check (may be null)
* @return true if the CharSequence is not null and has length
* @see #hasText(String)
*/
public static boolean hasLength(CharSequence str) {
return (str != null && str.length() > 0);
}
/**
* Check that the given BytesReference is neither null nor of length 0
* Note: Will return true for a BytesReference that purely consists of whitespace.
*
* @param bytesReference the BytesReference to check (may be null)
* @return true if the BytesReference is not null and has length
* @see #hasLength(CharSequence)
*/
public static boolean hasLength(BytesReference bytesReference) {
return (bytesReference != null && bytesReference.length() > 0);
}
/**
* Check that the given String is neither null nor of length 0.
* Note: Will return true for a String that purely consists of whitespace.
*
* @param str the String to check (may be null)
* @return true if the String is not null and has length
* @see #hasLength(CharSequence)
*/
public static boolean hasLength(String str) {
return hasLength((CharSequence) str);
}
/**
* Check that the given CharSequence is either null or of length 0.
* Note: Will return false for a CharSequence that purely consists of whitespace.
*
* StringUtils.isEmpty(null) = true
* StringUtils.isEmpty("") = true
* StringUtils.isEmpty(" ") = false
* StringUtils.isEmpty("Hello") = false
*
*
* @param str the CharSequence to check (may be null)
* @return true if the CharSequence is either null or has a zero length
*/
public static boolean isEmpty(CharSequence str) {
return !hasLength(str);
}
/**
* Check whether the given CharSequence has actual text.
* More specifically, returns true if the string not null,
* its length is greater than 0, and it contains at least one non-whitespace character.
*
* StringUtils.hasText(null) = false
* StringUtils.hasText("") = false
* StringUtils.hasText(" ") = false
* StringUtils.hasText("12345") = true
* StringUtils.hasText(" 12345 ") = true
*
*
* @param str the CharSequence to check (may be null)
* @return true if the CharSequence is not null,
* its length is greater than 0, and it does not contain whitespace only
* @see java.lang.Character#isWhitespace
*/
public static boolean hasText(CharSequence str) {
if (!hasLength(str)) {
return false;
}
int strLen = str.length();
for (int i = 0; i < strLen; i++) {
if (!Character.isWhitespace(str.charAt(i))) {
return true;
}
}
return false;
}
/**
* Check whether the given String has actual text.
* More specifically, returns true if the string not null,
* its length is greater than 0, and it contains at least one non-whitespace character.
*
* @param str the String to check (may be null)
* @return true if the String is not null, its length is
* greater than 0, and it does not contain whitespace only
* @see #hasText(CharSequence)
*/
public static boolean hasText(String str) {
return hasText((CharSequence) str);
}
/**
* Trim all occurrences of the supplied leading character from the given String.
*
* @param str the String to check
* @param leadingCharacter the leading character to be trimmed
* @return the trimmed String
*/
public static String trimLeadingCharacter(String str, char leadingCharacter) {
if (!hasLength(str)) {
return str;
}
StringBuilder sb = new StringBuilder(str);
while (sb.length() > 0 && sb.charAt(0) == leadingCharacter) {
sb.deleteCharAt(0);
}
return sb.toString();
}
/**
* Test whether the given string matches the given substring
* at the given index.
*
* @param str the original string (or StringBuilder)
* @param index the index in the original string to start matching against
* @param substring the substring to match at the given index
*/
public static boolean substringMatch(CharSequence str, int index, CharSequence substring) {
for (int j = 0; j < substring.length(); j++) {
int i = index + j;
if (i >= str.length() || str.charAt(i) != substring.charAt(j)) {
return false;
}
}
return true;
}
/**
* Count the occurrences of the substring in string s.
*
* @param str string to search in. Return 0 if this is null.
* @param sub string to search for. Return 0 if this is null.
*/
public static int countOccurrencesOf(String str, String sub) {
if (str == null || sub == null || str.length() == 0 || sub.length() == 0) {
return 0;
}
int count = 0;
int pos = 0;
int idx;
while ((idx = str.indexOf(sub, pos)) != -1) {
++count;
pos = idx + sub.length();
}
return count;
}
/**
* Replace all occurrences of a substring within a string with
* another string.
*
* @param inString String to examine
* @param oldPattern String to replace
* @param newPattern String to insert
* @return a String with the replacements
*/
public static String replace(String inString, String oldPattern, String newPattern) {
if (!hasLength(inString) || !hasLength(oldPattern) || newPattern == null) {
return inString;
}
StringBuilder sb = new StringBuilder();
int pos = 0; // our position in the old string
int index = inString.indexOf(oldPattern);
// the index of an occurrence we've found, or -1
int patLen = oldPattern.length();
while (index >= 0) {
sb.append(inString.substring(pos, index));
sb.append(newPattern);
pos = index + patLen;
index = inString.indexOf(oldPattern, pos);
}
sb.append(inString.substring(pos));
// remember to append any characters to the right of a match
return sb.toString();
}
/**
* Delete all occurrences of the given substring.
*
* @param inString the original String
* @param pattern the pattern to delete all occurrences of
* @return the resulting String
*/
public static String delete(String inString, String pattern) {
return replace(inString, pattern, "");
}
/**
* Delete any character in a given String.
*
* @param inString the original String
* @param charsToDelete a set of characters to delete.
* E.g. "az\n" will delete 'a's, 'z's and new lines.
* @return the resulting String
*/
public static String deleteAny(String inString, String charsToDelete) {
if (!hasLength(inString) || !hasLength(charsToDelete)) {
return inString;
}
StringBuilder sb = new StringBuilder();
for (int i = 0; i < inString.length(); i++) {
char c = inString.charAt(i);
if (charsToDelete.indexOf(c) == -1) {
sb.append(c);
}
}
return sb.toString();
}
//---------------------------------------------------------------------
// Convenience methods for working with formatted Strings
//---------------------------------------------------------------------
/**
* Quote the given String with single quotes.
*
* @param str the input String (e.g. "myString")
* @return the quoted String (e.g. "'myString'"),
* or null if the input was null
*/
public static String quote(String str) {
return (str != null ? "'" + str + "'" : null);
}
/**
* Capitalize a String, changing the first letter to
* upper case as per {Character#toUpperCase(char)}.
* No other letters are changed.
*
* @param str the String to capitalize, may be null
* @return the capitalized String, null if null
*/
public static String capitalize(String str) {
return changeFirstCharacterCase(str, true);
}
private static String changeFirstCharacterCase(String str, boolean capitalize) {
if (str == null || str.length() == 0) {
return str;
}
StringBuilder sb = new StringBuilder(str.length());
if (capitalize) {
sb.append(Character.toUpperCase(str.charAt(0)));
} else {
sb.append(Character.toLowerCase(str.charAt(0)));
}
sb.append(str.substring(1));
return sb.toString();
}
public static final Set INVALID_FILENAME_CHARS = unmodifiableSet(
newHashSet('\\', '/', '*', '?', '"', '<', '>', '|', ' ', ','));
public static boolean validFileName(String fileName) {
for (int i = 0; i < fileName.length(); i++) {
char c = fileName.charAt(i);
if (INVALID_FILENAME_CHARS.contains(c)) {
return false;
}
}
return true;
}
public static boolean validFileNameExcludingAstrix(String fileName) {
for (int i = 0; i < fileName.length(); i++) {
char c = fileName.charAt(i);
if (c != '*' && INVALID_FILENAME_CHARS.contains(c)) {
return false;
}
}
return true;
}
/**
* Normalize the path by suppressing sequences like "path/.." and
* inner simple dots.
* The result is convenient for path comparison. For other uses,
* notice that Windows separators ("\") are replaced by simple slashes.
*
* @param path the original path
* @return the normalized path
*/
public static String cleanPath(String path) {
if (path == null) {
return null;
}
String pathToUse = replace(path, WINDOWS_FOLDER_SEPARATOR, FOLDER_SEPARATOR);
// Strip prefix from path to analyze, to not treat it as part of the
// first path element. This is necessary to correctly parse paths like
// "file:core/../core/io/Resource.class", where the ".." should just
// strip the first "core" directory while keeping the "file:" prefix.
int prefixIndex = pathToUse.indexOf(":");
String prefix = "";
if (prefixIndex != -1) {
prefix = pathToUse.substring(0, prefixIndex + 1);
pathToUse = pathToUse.substring(prefixIndex + 1);
}
if (pathToUse.startsWith(FOLDER_SEPARATOR)) {
prefix = prefix + FOLDER_SEPARATOR;
pathToUse = pathToUse.substring(1);
}
String[] pathArray = delimitedListToStringArray(pathToUse, FOLDER_SEPARATOR);
List pathElements = new LinkedList<>();
int tops = 0;
for (int i = pathArray.length - 1; i >= 0; i--) {
String element = pathArray[i];
if (CURRENT_PATH.equals(element)) {
// Points to current directory - drop it.
} else if (TOP_PATH.equals(element)) {
// Registering top path found.
tops++;
} else {
if (tops > 0) {
// Merging path element with element corresponding to top path.
tops--;
} else {
// Normal path element found.
pathElements.add(0, element);
}
}
}
// Remaining top paths need to be retained.
for (int i = 0; i < tops; i++) {
pathElements.add(0, TOP_PATH);
}
return prefix + collectionToDelimitedString(pathElements, FOLDER_SEPARATOR);
}
/**
* Copy the given Collection into a String array.
* The Collection must contain String elements only.
*
* @param collection the Collection to copy
* @return the String array (null if the passed-in
* Collection was null)
*/
public static String[] toStringArray(Collection collection) {
if (collection == null) {
return null;
}
return collection.toArray(new String[collection.size()]);
}
public static Set splitStringByCommaToSet(final String s) {
return splitStringToSet(s, ',');
}
public static String[] splitStringByCommaToArray(final String s) {
if (s == null || s.isEmpty()) {
return Strings.EMPTY_ARRAY;
} else {
return s.split(",");
}
}
/**
* A convenience method for splitting a delimited string into
* a set and trimming leading and trailing whitespace from all
* split strings.
*
* @param s the string to split
* @param c the delimiter to split on
* @return the set of split strings
*/
public static Set splitStringToSet(final String s, final char c) {
if (s == null || s.isEmpty()) {
return Collections.emptySet();
}
final char[] chars = s.toCharArray();
int count = 1;
for (final char x : chars) {
if (x == c) {
count++;
}
}
final Set result = new HashSet<>(count);
final int len = chars.length;
int start = 0; // starting index in chars of the current substring.
int pos = 0; // current index in chars.
int end = 0; // the position of the end of the current token
for (; pos < len; pos++) {
if (chars[pos] == c) {
int size = end - start;
if (size > 0) { // only add non empty strings
result.add(new String(chars, start, size));
}
start = pos + 1;
end = start;
} else if (Character.isWhitespace(chars[pos])) {
if (start == pos) {
// skip over preceding whitespace
start++;
}
} else {
end = pos + 1;
}
}
int size = end - start;
if (size > 0) {
result.add(new String(chars, start, size));
}
return result;
}
/**
* Split a String at the first occurrence of the delimiter.
* Does not include the delimiter in the result.
*
* @param toSplit the string to split
* @param delimiter to split the string up with
* @return a two element array with index 0 being before the delimiter, and
* index 1 being after the delimiter (neither element includes the delimiter);
* or null if the delimiter wasn't found in the given input String
*/
public static String[] split(String toSplit, String delimiter) {
if (!hasLength(toSplit) || !hasLength(delimiter)) {
return null;
}
int offset = toSplit.indexOf(delimiter);
if (offset < 0) {
return null;
}
String beforeDelimiter = toSplit.substring(0, offset);
String afterDelimiter = toSplit.substring(offset + delimiter.length());
return new String[]{beforeDelimiter, afterDelimiter};
}
/**
* Tokenize the given String into a String array via a StringTokenizer.
* Trims tokens and omits empty tokens.
* The given delimiters string is supposed to consist of any number of
* delimiter characters. Each of those characters can be used to separate
* tokens. A delimiter is always a single character; for multi-character
* delimiters, consider using delimitedListToStringArray
*
* @param str the String to tokenize
* @param delimiters the delimiter characters, assembled as String
* (each of those characters is individually considered as delimiter).
* @return an array of the tokens
* @see java.util.StringTokenizer
* @see java.lang.String#trim()
* @see #delimitedListToStringArray
*/
public static String[] tokenizeToStringArray(String str, String delimiters) {
return tokenizeToStringArray(str, delimiters, true, true);
}
/**
* Tokenize the given String into a String array via a StringTokenizer.
*
The given delimiters string is supposed to consist of any number of
* delimiter characters. Each of those characters can be used to separate
* tokens. A delimiter is always a single character; for multi-character
* delimiters, consider using delimitedListToStringArray
*
* @param str the String to tokenize
* @param delimiters the delimiter characters, assembled as String
* (each of those characters is individually considered as delimiter)
* @param trimTokens trim the tokens via String's trim
* @param ignoreEmptyTokens omit empty tokens from the result array
* (only applies to tokens that are empty after trimming; StringTokenizer
* will not consider subsequent delimiters as token in the first place).
* @return an array of the tokens (null if the input String
* was null)
* @see java.util.StringTokenizer
* @see java.lang.String#trim()
* @see #delimitedListToStringArray
*/
public static String[] tokenizeToStringArray(
String str, String delimiters, boolean trimTokens, boolean ignoreEmptyTokens) {
if (str == null) {
return null;
}
StringTokenizer st = new StringTokenizer(str, delimiters);
List tokens = new ArrayList<>();
while (st.hasMoreTokens()) {
String token = st.nextToken();
if (trimTokens) {
token = token.trim();
}
if (!ignoreEmptyTokens || token.length() > 0) {
tokens.add(token);
}
}
return toStringArray(tokens);
}
/**
* Take a String which is a delimited list and convert it to a String array.
* A single delimiter can consists of more than one character: It will still
* be considered as single delimiter string, rather than as bunch of potential
* delimiter characters - in contrast to tokenizeToStringArray.
*
* @param str the input String
* @param delimiter the delimiter between elements (this is a single delimiter,
* rather than a bunch individual delimiter characters)
* @return an array of the tokens in the list
* @see #tokenizeToStringArray
*/
public static String[] delimitedListToStringArray(String str, String delimiter) {
return delimitedListToStringArray(str, delimiter, null);
}
/**
* Take a String which is a delimited list and convert it to a String array.
*
A single delimiter can consists of more than one character: It will still
* be considered as single delimiter string, rather than as bunch of potential
* delimiter characters - in contrast to tokenizeToStringArray.
*
* @param str the input String
* @param delimiter the delimiter between elements (this is a single delimiter,
* rather than a bunch individual delimiter characters)
* @param charsToDelete a set of characters to delete. Useful for deleting unwanted
* line breaks: e.g. "\r\n\f" will delete all new lines and line feeds in a String.
* @return an array of the tokens in the list
* @see #tokenizeToStringArray
*/
public static String[] delimitedListToStringArray(String str, String delimiter, String charsToDelete) {
if (str == null) {
return new String[0];
}
if (delimiter == null) {
return new String[]{str};
}
List result = new ArrayList<>();
if ("".equals(delimiter)) {
for (int i = 0; i < str.length(); i++) {
result.add(deleteAny(str.substring(i, i + 1), charsToDelete));
}
} else {
int pos = 0;
int delPos;
while ((delPos = str.indexOf(delimiter, pos)) != -1) {
result.add(deleteAny(str.substring(pos, delPos), charsToDelete));
pos = delPos + delimiter.length();
}
if (str.length() > 0 && pos <= str.length()) {
// Add rest of String, but not in case of empty input.
result.add(deleteAny(str.substring(pos), charsToDelete));
}
}
return toStringArray(result);
}
/**
* Convert a CSV list into an array of Strings.
*
* @param str the input String
* @return an array of Strings, or the empty array in case of empty input
*/
public static String[] commaDelimitedListToStringArray(String str) {
return delimitedListToStringArray(str, ",");
}
/**
* Convenience method to convert a CSV string list to a set.
* Note that this will suppress duplicates.
*
* @param str the input String
* @return a Set of String entries in the list
*/
public static Set commaDelimitedListToSet(String str) {
Set set = new TreeSet<>();
String[] tokens = commaDelimitedListToStringArray(str);
set.addAll(Arrays.asList(tokens));
return set;
}
/**
* Convenience method to return a Collection as a delimited (e.g. CSV)
* String. E.g. useful for toString() implementations.
*
* @param coll the Collection to display
* @param delim the delimiter to use (probably a ",")
* @param prefix the String to start each element with
* @param suffix the String to end each element with
* @return the delimited String
*/
public static String collectionToDelimitedString(Iterable coll, String delim, String prefix, String suffix) {
return collectionToDelimitedString(coll, delim, prefix, suffix, new StringBuilder());
}
public static String collectionToDelimitedString(Iterable coll, String delim, String prefix, String suffix, StringBuilder sb) {
Iterator it = coll.iterator();
while (it.hasNext()) {
sb.append(prefix).append(it.next()).append(suffix);
if (it.hasNext()) {
sb.append(delim);
}
}
return sb.toString();
}
/**
* Convenience method to return a Collection as a delimited (e.g. CSV)
* String. E.g. useful for toString() implementations.
*
* @param coll the Collection to display
* @param delim the delimiter to use (probably a ",")
* @return the delimited String
*/
public static String collectionToDelimitedString(Iterable coll, String delim) {
return collectionToDelimitedString(coll, delim, "", "");
}
/**
* Convenience method to return a Collection as a CSV String.
* E.g. useful for toString() implementations.
*
* @param coll the Collection to display
* @return the delimited String
*/
public static String collectionToCommaDelimitedString(Iterable coll) {
return collectionToDelimitedString(coll, ",");
}
/**
* Convenience method to return a String array as a delimited (e.g. CSV)
* String. E.g. useful for toString() implementations.
*
* @param arr the array to display
* @param delim the delimiter to use (probably a ",")
* @return the delimited String
*/
public static String arrayToDelimitedString(Object[] arr, String delim) {
return arrayToDelimitedString(arr, delim, new StringBuilder());
}
public static String arrayToDelimitedString(Object[] arr, String delim, StringBuilder sb) {
if (isEmpty(arr)) {
return "";
}
for (int i = 0; i < arr.length; i++) {
if (i > 0) {
sb.append(delim);
}
sb.append(arr[i]);
}
return sb.toString();
}
/**
* Convenience method to return a String array as a CSV String.
* E.g. useful for toString() implementations.
*
* @param arr the array to display
* @return the delimited String
*/
public static String arrayToCommaDelimitedString(Object[] arr) {
return arrayToDelimitedString(arr, ",");
}
/**
* Format the double value with a single decimal points, trimming trailing '.0'.
*/
public static String format1Decimals(double value, String suffix) {
String p = String.valueOf(value);
int ix = p.indexOf('.') + 1;
int ex = p.indexOf('E');
char fraction = p.charAt(ix);
if (fraction == '0') {
if (ex != -1) {
return p.substring(0, ix - 1) + p.substring(ex) + suffix;
} else {
return p.substring(0, ix - 1) + suffix;
}
} else {
if (ex != -1) {
return p.substring(0, ix) + fraction + p.substring(ex) + suffix;
} else {
return p.substring(0, ix) + fraction + suffix;
}
}
}
/**
* Determine whether the given array is empty:
* i.e. null or of zero length.
*
* @param array the array to check
*/
private static boolean isEmpty(Object[] array) {
return (array == null || array.length == 0);
}
private Strings() {
}
public static byte[] toUTF8Bytes(CharSequence charSequence) {
return toUTF8Bytes(charSequence, new BytesRefBuilder());
}
public static byte[] toUTF8Bytes(CharSequence charSequence, BytesRefBuilder spare) {
spare.copyChars(charSequence);
return Arrays.copyOf(spare.bytes(), spare.length());
}
/**
* Return substring(beginIndex, endIndex) that is impervious to string length.
*/
public static String substring(String s, int beginIndex, int endIndex) {
if (s == null) {
return s;
}
int realEndIndex = s.length() > 0 ? s.length() - 1 : 0;
if (endIndex > realEndIndex) {
return s.substring(beginIndex);
} else {
return s.substring(beginIndex, endIndex);
}
}
/**
* If an array only consists of zero or one element, which is "*" or "_all" return an empty array
* which is usually used as everything
*/
public static boolean isAllOrWildcard(String[] data) {
return CollectionUtils.isEmpty(data) ||
data.length == 1 && ("_all".equals(data[0]) || "*".equals(data[0]));
}
/**
* Return a {String} that is the json representation of the provided
* {ToXContent}.
*/
public static String toString(ToXContent toXContent) {
return toString(toXContent, false);
}
/**
* Return a {String} that is the json representation of the provided
* {ToXContent}.
* @param wrapInObject set this to true if the ToXContent instance expects to be inside an object
*/
public static String toString(ToXContent toXContent, boolean wrapInObject) {
try {
XContentBuilder builder = JsonXContent.contentBuilder();
if (wrapInObject) {
builder.startObject();
}
toXContent.toXContent(builder, ToXContent.EMPTY_PARAMS);
if (wrapInObject) {
builder.endObject();
}
return builder.string();
} catch (IOException e) {
return "Error building toString out of XContent: " + ExceptionsHelper.stackTrace(e);
}
}
/**
* Truncates string to a length less than length. Backtracks to throw out
* high surrogates.
*/
public static String cleanTruncate(String s, int length) {
if (s == null) {
return s;
}
/*
* Its pretty silly for you to truncate to 0 length but just in case
* someone does this shouldn't break.
*/
if (length == 0) {
return "";
}
if (length >= s.length()) {
return s;
}
if (Character.isHighSurrogate(s.charAt(length - 1))) {
length--;
}
return s.substring(0, length);
}
public static boolean isNullOrEmpty(@Nullable String s) {
return s == null || s.isEmpty();
}
public static String coalesceToEmpty(@Nullable String s) {
return s == null ? "" : s;
}
public static String padStart(String s, int minimumLength, char c) {
if (s == null) {
throw new NullPointerException("s");
}
if (s.length() >= minimumLength) {
return s;
} else {
StringBuilder sb = new StringBuilder(minimumLength);
for (int i = s.length(); i < minimumLength; i++) {
sb.append(c);
}
sb.append(s);
return sb.toString();
}
}
}