org.xson.web.util.StringUtils Maven / Gradle / Ivy
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package org.xson.web.util;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.Enumeration;
import java.util.List;
import java.util.Locale;
import java.util.Set;
import java.util.StringTokenizer;
import java.util.TimeZone;
import java.util.TreeSet;
public class StringUtils {
private static final String FOLDER_SEPARATOR = "/";
// private static final String WINDOWS_FOLDER_SEPARATOR = "\\";
//
// private static final String TOP_PATH = "..";
//
// private static final String CURRENT_PATH = ".";
private static final char EXTENSION_SEPARATOR = '.';
// ---------------------------------------------------------------------
// General convenience methods for working with Strings
// ---------------------------------------------------------------------
public static String trim(String str) {
if (null == str) {
return null;
}
return str.trim();
}
public static String trim(String str, String def) {
if (null == str) {
return def;
}
return str.trim();
}
/**
* Check whether the given String is empty.
*
* This method accepts any Object as an argument, comparing it to {@code null} and the empty String. As a consequence, this method will never
* return {@code true} for a non-null non-String object.
*
* The Object signature is useful for general attribute handling code that commonly deals with Strings but generally has to iterate over Objects
* since attributes may e.g. be primitive value objects as well.
*
* @param str
* the candidate String
* @since 3.2.1
*/
public static boolean isEmpty(Object str) {
return (str == null || "".equals(str));
}
/**
* Check that the given CharSequence is neither {@code null} nor of length 0. Note: Will return {@code 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 {@code null})
* @return {@code 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 String is neither {@code null} nor of length 0. Note: Will return {@code true} for a String that purely consists of
* whitespace.
*
* @param str
* the String to check (may be {@code null})
* @return {@code true} if the String is not null and has length
* @see #hasLength(CharSequence)
*/
public static boolean hasLength(String str) {
return hasLength((CharSequence) str);
}
/**
* Check whether the given CharSequence has actual text. More specifically, returns {@code true} if the string not {@code 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 {@code null})
* @return {@code true} if the CharSequence is not {@code null}, its length is greater than 0, and it does not contain whitespace only
* @see 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 {@code true} if the string not {@code null}, its length is greater
* than 0, and it contains at least one non-whitespace character.
*
* @param str
* the String to check (may be {@code null})
* @return {@code true} if the String is not {@code 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);
}
/**
* Check whether the given CharSequence contains any whitespace characters.
*
* @param str
* the CharSequence to check (may be {@code null})
* @return {@code true} if the CharSequence is not empty and contains at least 1 whitespace character
* @see Character#isWhitespace
*/
public static boolean containsWhitespace(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 contains any whitespace characters.
*
* @param str
* the String to check (may be {@code null})
* @return {@code true} if the String is not empty and contains at least 1 whitespace character
* @see #containsWhitespace(CharSequence)
*/
public static boolean containsWhitespace(String str) {
return containsWhitespace((CharSequence) str);
}
/**
* Trim leading and trailing whitespace from the given String.
*
* @param str
* the String to check
* @return the trimmed String
* @see java.lang.Character#isWhitespace
*/
public static String trimWhitespace(String str) {
if (!hasLength(str)) {
return str;
}
StringBuilder sb = new StringBuilder(str);
while (sb.length() > 0 && Character.isWhitespace(sb.charAt(0))) {
sb.deleteCharAt(0);
}
while (sb.length() > 0 && Character.isWhitespace(sb.charAt(sb.length() - 1))) {
sb.deleteCharAt(sb.length() - 1);
}
return sb.toString();
}
/**
* Trim all whitespace from the given String: leading, trailing, and in between characters.
*
* @param str
* the String to check
* @return the trimmed String
* @see java.lang.Character#isWhitespace
*/
public static String trimAllWhitespace(String str) {
if (!hasLength(str)) {
return str;
}
int len = str.length();
StringBuilder sb = new StringBuilder(str.length());
for (int i = 0; i < len; i++) {
char c = str.charAt(i);
if (!Character.isWhitespace(c)) {
sb.append(c);
}
}
return sb.toString();
}
/**
* Trim leading whitespace from the given String.
*
* @param str
* the String to check
* @return the trimmed String
* @see java.lang.Character#isWhitespace
*/
public static String trimLeadingWhitespace(String str) {
if (!hasLength(str)) {
return str;
}
StringBuilder sb = new StringBuilder(str);
while (sb.length() > 0 && Character.isWhitespace(sb.charAt(0))) {
sb.deleteCharAt(0);
}
return sb.toString();
}
/**
* Trim trailing whitespace from the given String.
*
* @param str
* the String to check
* @return the trimmed String
* @see java.lang.Character#isWhitespace
*/
public static String trimTrailingWhitespace(String str) {
if (!hasLength(str)) {
return str;
}
StringBuilder sb = new StringBuilder(str);
while (sb.length() > 0 && Character.isWhitespace(sb.charAt(sb.length() - 1))) {
sb.deleteCharAt(sb.length() - 1);
}
return sb.toString();
}
/**
* 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();
}
/**
* Trim all occurrences of the supplied trailing character from the given String.
*
* @param str
* the String to check
* @param trailingCharacter
* the trailing character to be trimmed
* @return the trimmed String
*/
public static String trimTrailingCharacter(String str, char trailingCharacter) {
if (!hasLength(str)) {
return str;
}
StringBuilder sb = new StringBuilder(str);
while (sb.length() > 0 && sb.charAt(sb.length() - 1) == trailingCharacter) {
sb.deleteCharAt(sb.length() - 1);
}
return sb.toString();
}
/**
* Test if the given String starts with the specified prefix, ignoring upper/lower case.
*
* @param str
* the String to check
* @param prefix
* the prefix to look for
* @see java.lang.String#startsWith
*/
public static boolean startsWithIgnoreCase(String str, String prefix) {
if (str == null || prefix == null) {
return false;
}
if (str.startsWith(prefix)) {
return true;
}
if (str.length() < prefix.length()) {
return false;
}
String lcStr = str.substring(0, prefix.length()).toLowerCase();
String lcPrefix = prefix.toLowerCase();
return lcStr.equals(lcPrefix);
}
/**
* Test if the given String ends with the specified suffix, ignoring upper/lower case.
*
* @param str
* the String to check
* @param suffix
* the suffix to look for
* @see java.lang.String#endsWith
*/
public static boolean endsWithIgnoreCase(String str, String suffix) {
if (str == null || suffix == null) {
return false;
}
if (str.endsWith(suffix)) {
return true;
}
if (str.length() < suffix.length()) {
return false;
}
String lcStr = str.substring(str.length() - suffix.length()).toLowerCase();
String lcSuffix = suffix.toLowerCase();
return lcStr.equals(lcSuffix);
}
/**
* 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 {@code null} if the input was {@code null}
*/
public static String quote(String str) {
return (str != null ? "'" + str + "'" : null);
}
/**
* Turn the given Object into a String with single quotes if it is a String; keeping the Object as-is else.
*
* @param obj
* the input Object (e.g. "myString")
* @return the quoted String (e.g. "'myString'"), or the input object as-is if not a String
*/
public static Object quoteIfString(Object obj) {
return (obj instanceof String ? quote((String) obj) : obj);
}
/**
* Unqualify a string qualified by a '.' dot character. For example, "this.name.is.qualified", returns "qualified".
*
* @param qualifiedName
* the qualified name
*/
public static String unqualify(String qualifiedName) {
return unqualify(qualifiedName, '.');
}
/**
* Unqualify a string qualified by a separator character. For example, "this:name:is:qualified" returns "qualified" if using a ':' separator.
*
* @param qualifiedName
* the qualified name
* @param separator
* the separator
*/
public static String unqualify(String qualifiedName, char separator) {
return qualifiedName.substring(qualifiedName.lastIndexOf(separator) + 1);
}
/**
* Capitalize a {@code String}, changing the first letter to upper case as per {@link Character#toUpperCase(char)}. No other letters are changed.
*
* @param str
* the String to capitalize, may be {@code null}
* @return the capitalized String, {@code null} if null
*/
public static String capitalize(String str) {
return changeFirstCharacterCase(str, true);
}
/**
* Uncapitalize a {@code String}, changing the first letter to lower case as per {@link Character#toLowerCase(char)} . No other letters are
* changed.
*
* @param str
* the String to uncapitalize, may be {@code null}
* @return the uncapitalized String, {@code null} if null
*/
public static String uncapitalize(String str) {
return changeFirstCharacterCase(str, false);
}
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();
}
/**
* Extract the filename from the given path, e.g. "mypath/myfile.txt" -> "myfile.txt".
*
* @param path
* the file path (may be {@code null})
* @return the extracted filename, or {@code null} if none
*/
public static String getFilename(String path) {
if (path == null) {
return null;
}
int separatorIndex = path.lastIndexOf(FOLDER_SEPARATOR);
return (separatorIndex != -1 ? path.substring(separatorIndex + 1) : path);
}
/**
* Extract the filename extension from the given path, e.g. "mypath/myfile.txt" -> "txt".
*
* @param path
* the file path (may be {@code null})
* @return the extracted filename extension, or {@code null} if none
*/
public static String getFilenameExtension(String path) {
if (path == null) {
return null;
}
int extIndex = path.lastIndexOf(EXTENSION_SEPARATOR);
if (extIndex == -1) {
return null;
}
int folderIndex = path.lastIndexOf(FOLDER_SEPARATOR);
if (folderIndex > extIndex) {
return null;
}
return path.substring(extIndex + 1);
}
/**
* Strip the filename extension from the given path, e.g. "mypath/myfile.txt" -> "mypath/myfile".
*
* @param path
* the file path (may be {@code null})
* @return the path with stripped filename extension, or {@code null} if none
*/
public static String stripFilenameExtension(String path) {
if (path == null) {
return null;
}
int extIndex = path.lastIndexOf(EXTENSION_SEPARATOR);
if (extIndex == -1) {
return path;
}
int folderIndex = path.lastIndexOf(FOLDER_SEPARATOR);
if (folderIndex > extIndex) {
return path;
}
return path.substring(0, extIndex);
}
/**
* Apply the given relative path to the given path, assuming standard Java folder separation (i.e. "/" separators).
*
* @param path
* the path to start from (usually a full file path)
* @param relativePath
* the relative path to apply (relative to the full file path above)
* @return the full file path that results from applying the relative path
*/
public static String applyRelativePath(String path, String relativePath) {
int separatorIndex = path.lastIndexOf(FOLDER_SEPARATOR);
if (separatorIndex != -1) {
String newPath = path.substring(0, separatorIndex);
if (!relativePath.startsWith(FOLDER_SEPARATOR)) {
newPath += FOLDER_SEPARATOR;
}
return newPath + relativePath;
} else {
return relativePath;
}
}
/**
* Parse the given {@code localeString} value into a {@link Locale}.
*
* This is the inverse operation of {@link Locale#toString Locale's toString}.
*
* @param localeString
* the locale String, following {@code Locale's} {@code toString()} format ("en", "en_UK", etc); also accepts spaces as separators, as
* an alternative to underscores
* @return a corresponding {@code Locale} instance
* @throws IllegalArgumentException
* in case of an invalid locale specification
*/
public static Locale parseLocaleString(String localeString) {
String[] parts = tokenizeToStringArray(localeString, "_ ", false, false);
String language = (parts.length > 0 ? parts[0] : "");
String country = (parts.length > 1 ? parts[1] : "");
validateLocalePart(language);
validateLocalePart(country);
String variant = "";
if (parts.length > 2) {
// There is definitely a variant, and it is everything after the country
// code sans the separator between the country code and the variant.
int endIndexOfCountryCode = localeString.indexOf(country, language.length()) + country.length();
// Strip off any leading '_' and whitespace, what's left is the variant.
variant = trimLeadingWhitespace(localeString.substring(endIndexOfCountryCode));
if (variant.startsWith("_")) {
variant = trimLeadingCharacter(variant, '_');
}
}
return (language.length() > 0 ? new Locale(language, country, variant) : null);
}
private static void validateLocalePart(String localePart) {
for (int i = 0; i < localePart.length(); i++) {
char ch = localePart.charAt(i);
if (ch != '_' && ch != ' ' && !Character.isLetterOrDigit(ch)) {
throw new IllegalArgumentException("Locale part \"" + localePart + "\" contains invalid characters");
}
}
}
/**
* Determine the RFC 3066 compliant language tag, as used for the HTTP "Accept-Language" header.
*
* @param locale
* the Locale to transform to a language tag
* @return the RFC 3066 compliant language tag as String
*/
public static String toLanguageTag(Locale locale) {
return locale.getLanguage() + (hasText(locale.getCountry()) ? "-" + locale.getCountry() : "");
}
/**
* Parse the given {@code timeZoneString} value into a {@link TimeZone}.
*
* @param timeZoneString
* the time zone String, following {@link TimeZone#getTimeZone(String)} but throwing {@link IllegalArgumentException} in case of an
* invalid time zone specification
* @return a corresponding {@link TimeZone} instance
* @throws IllegalArgumentException
* in case of an invalid time zone specification
*/
public static TimeZone parseTimeZoneString(String timeZoneString) {
TimeZone timeZone = TimeZone.getTimeZone(timeZoneString);
if ("GMT".equals(timeZone.getID()) && !timeZoneString.startsWith("GMT")) {
// We don't want that GMT fallback...
throw new IllegalArgumentException("Invalid time zone specification '" + timeZoneString + "'");
}
return timeZone;
}
/**
* 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 ({@code null} if the passed-in Collection was {@code null})
*/
public static String[] toStringArray(Collection collection) {
if (collection == null) {
return null;
}
return collection.toArray(new String[collection.size()]);
}
/**
* Copy the given Enumeration into a String array. The Enumeration must contain String elements only.
*
* @param enumeration
* the Enumeration to copy
* @return the String array ({@code null} if the passed-in Enumeration was {@code null})
*/
public static String[] toStringArray(Enumeration enumeration) {
if (enumeration == null) {
return null;
}
List list = Collections.list(enumeration);
return list.toArray(new String[list.size()]);
}
/**
* 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 {@code 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 {@code 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 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 {@code 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 {@code 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 ({@code null} if the input String was {@code null})
* @see java.util.StringTokenizer
* @see 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 {@code 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 {@code 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);
for (String token : tokens) {
set.add(token);
}
return set;
}
}