Package org.zkoss.lang

Class Strings

java.lang.Object

org.zkoss.lang.Strings

public class Strings
extends java.lang.Object

String utilities and constants

Author:

tomyeh

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	Strings.Result	The result of substring(java.lang.String, int, char).

Field Summary

Fields

Modifier and Type	Field	Description
static java.lang.String	EMPTY

Constructor Summary

Constructors

Constructor	Description
Strings()

Method Summary

Modifier and Type	Method	Description
static int	anyOf(java.lang.String src, java.lang.String delimiters, int from)	Returns the index that is one of delimiters, or the length if none of delimiter is found.
static java.lang.String	defaultIfEmpty(java.lang.String value, java.lang.String defaultValue)	Returns the passed value, or the default value if it is empty.
static java.lang.String	encode(int val)	Returns an encoded string, faster and shorter than Long.toHexString.
static java.lang.String	encode(long val)	Returns an encoded string, faster and shorter than Long.toHexString.
static java.lang.StringBuffer	encode(java.lang.StringBuffer sb, int val)	Returns an encoded string buffer, faster and shorter than Integer.toHexString.
static java.lang.StringBuffer	encode(java.lang.StringBuffer sb, long val)	Returns an encoded string buffer, faster and shorter than Long.toHexString.
static java.lang.String	escape(java.lang.String src, java.lang.String specials)	Escapes (a.k.a, quote) the special characters with backslash.
static int	indexOf(java.lang.StringBuffer sb, char cc, int j)	Returns the index of the give character in the given string buffer, or -1 if not found.
static boolean	isBlank(java.lang.String s)	Returns true if the string is null or empty or pure blank.
static boolean	isEmpty(java.lang.String s)	Returns true if the string is null or empty.
static <T> java.lang.String	join(T[] array)	Joins the elements of the array into a single String separated by a comma.
static <T> java.lang.String	join(T[] array, char separator)	Joins the elements of the array into a single String separated by the given separator.
static <T> java.lang.String	join(T[] array, char separator, int startIndex, int endIndex)	Joins the elements of the array into a single String separated by the given separator from the startIndex to the endIndex.
static int	lastAnyOf(java.lang.String src, java.lang.String delimiters, int from)	The backward version of anyOf(java.lang.String, java.lang.String, int).
static int	lastIndexOf(java.lang.StringBuffer sb, char cc, int j)	Returns the last index of the give character in the given string buffer, or -1 if not found.
static int	nextSeparator(java.lang.String src, int from, char[] separators, boolean escBackslash, boolean escQuot, boolean quotAsSeparator)	Returns the next separator index in the src string.
static int	nextSeparator(java.lang.String src, int from, char[] separators, boolean escBackslash, boolean escQuot, boolean quotAsSeparator, boolean parenthesis)	Returns the next separator index in the src string.
static Strings.Result	nextToken(java.lang.String src, int from, char[] separators)	Returns the next token with unescape.
static Strings.Result	nextToken(java.lang.String src, int from, char[] separators, boolean escBackslash, boolean quotAsToken)	Returns the next token with additional options.
static Strings.Result	nextToken(java.lang.String src, int from, char[] separators, boolean escBackslash, boolean quotAsToken, boolean parenthesis)	Returns the next token with additional options.
static int	nextWhitespace(java.lang.CharSequence src, int from)	Returns the next whitespace.
static int	skipWhitespaces(java.lang.CharSequence src, int from)	Returns the next index after skipping whitespaces.
static int	skipWhitespacesBackward(java.lang.CharSequence src, int from)	The backward version of skipWhitespaces(java.lang.CharSequence, int).
static Strings.Result	substring(java.lang.String src, int from, char until)	Returns the substring from the from index up to the until character or end-of-string.
static Strings.Result	substring(java.lang.String src, int from, char until, boolean escBackslash)	Returns the substring from the from index up to the until character or end-of-string.
static java.lang.String	toString(byte[] data)	Converts the given byte[] to UTF-8 string, if possible.
static java.lang.StringBuffer	trim(java.lang.StringBuffer buf, int index)	Trims the string buffer by removing the leading and trailing whitespaces.
static java.lang.String	unescape(java.lang.String s)	Un-escape the quoted string.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

EMPTY

public static final java.lang.String EMPTY

See Also:

Constant Field Values

Constructor Detail

Strings

public Strings()

Method Detail

isEmpty

public static final boolean isEmpty(java.lang.String s)

Returns true if the string is null or empty.

isBlank

public static final boolean isBlank(java.lang.String s)

Returns true if the string is null or empty or pure blank.

trim

public static final java.lang.StringBuffer trim(java.lang.StringBuffer buf,
                                                int index)

Trims the string buffer by removing the leading and trailing whitespaces. Note: unlike String.trim(), you can specify the index of the first character to start trimming.

Like String.trim(), a whitespace is a character that has a code not great than '\u0020' (the space character)

Parameters:

buf - the string buffer to trim the leading and trailing.

index - the index of the first character to trim (i.e., consider as the leading character). If 0, it starts from the beginning.

Returns:

the same string buffer

Since:

3.0.4

encode

public static final java.lang.StringBuffer encode(java.lang.StringBuffer sb,
                                                  int val)

Returns an encoded string buffer, faster and shorter than Integer.toHexString. It uses numbers and lower-case letters only. Thus it is a valid variable name if prefix with an alphabet. At least one character is generated.

It works even in system that is case-insensitive, such as IE.

It is useful to generate a string to represent a number.

encode

public static final java.lang.StringBuffer encode(java.lang.StringBuffer sb,
                                                  long val)

Returns an encoded string buffer, faster and shorter than Long.toHexString. It uses numbers and lower-case letters only. Thus it is a valid variable name if prefix with an alphabet. At least one character is generated.

It works even in system that is case-insensitive, such as IE.

It is useful to generate a string to represent a number.

encode

public static final java.lang.String encode(int val)

Returns an encoded string, faster and shorter than Long.toHexString.

encode

public static final java.lang.String encode(long val)

Returns an encoded string, faster and shorter than Long.toHexString.

indexOf

public static final int indexOf(java.lang.StringBuffer sb,
                                char cc,
                                int j)

Returns the index of the give character in the given string buffer, or -1 if not found. It is equivalent to sb.indexOf(""+cc, j);, but faster.

Since:

5.0.3

lastIndexOf

public static final int lastIndexOf(java.lang.StringBuffer sb,
                                    char cc,
                                    int j)

Returns the last index of the give character in the given string buffer, or -1 if not found. It is equivalent to sb.lastIndexOf(""+cc, j);, but faster.

Since:

5.0.3

anyOf

public static final int anyOf(java.lang.String src,
                              java.lang.String delimiters,
                              int from)

Returns the index that is one of delimiters, or the length if none of delimiter is found.

Unlike String.indexOf(String, int), this method returns the first occurrence of any character in the delimiters.

This method is optimized to use String.indexOf(char, int) if it found the length of delimiter is 1.

Parameters:

src - the source string to search

from - the index to start the search from

delimiters - the set of characters to search for

Returns:

the index that is one of delimiters. If return >= src.length(), it means no such delimiters

See Also:

lastAnyOf(java.lang.String, java.lang.String, int)

lastAnyOf

public static final int lastAnyOf(java.lang.String src,
                                  java.lang.String delimiters,
                                  int from)

The backward version of anyOf(java.lang.String, java.lang.String, int).

This method is optimized to use String.indexOf(char, int) if it found the length of delimiter is 1.

Returns:

the previous index that is one of delimiter. If it is negative, it means no delimiter in front of from

See Also:

anyOf(java.lang.String, java.lang.String, int)

skipWhitespaces

public static final int skipWhitespaces(java.lang.CharSequence src,
                                        int from)

Returns the next index after skipping whitespaces.

skipWhitespacesBackward

public static final int skipWhitespacesBackward(java.lang.CharSequence src,
                                                int from)

The backward version of skipWhitespaces(java.lang.CharSequence, int).

Returns:

the next index that is not a whitespace. If it is negative, it means no whitespace in front of it.

nextWhitespace

public static final int nextWhitespace(java.lang.CharSequence src,
                                       int from)

Returns the next whitespace.

escape

public static final java.lang.String escape(java.lang.String src,
                                            java.lang.String specials)

Escapes (a.k.a, quote) the special characters with backslash. It prefix a backslash to any characters specified in the specials argument.

Note: specials usually contains '\\'.

For example, Maps.parse(java.util.Map<? super java.lang.String, ? super java.lang.String>, java.lang.String, char, char) will un-quote backspace. Thus, if you want to preserve backslash, you have invoke escape(s, "\\") before calling Maps.parse().

Parameters:

src - the string to process. If null, null is returned.

specials - a string of characters that shall be escaped/quoted To escape a string in JavaScript code snippet, you can use Encode.forJavaScript(String).

See Also:

unescape(java.lang.String)

unescape

public static final java.lang.String unescape(java.lang.String s)

Un-escape the quoted string.

See Also:

escape(java.lang.String, java.lang.String)

substring

public static final Strings.Result substring(java.lang.String src,
                                             int from,
                                             char until)

Returns the substring from the from index up to the until character or end-of-string. Unlike String.subsring, it converts \f, \n, \t and \r. It doesn't handle u and x yet.

Returns:

the result (never null). Result.next is the position of the until character if found, or a number larger than length() if no such character.

substring

public static final Strings.Result substring(java.lang.String src,
                                             int from,
                                             char until,
                                             boolean escBackslash)

Returns the substring from the from index up to the until character or end-of-string.

Parameters:

escBackslash - whether to treat '\\' specially (as escape char) It doesn't handle u and x yet.

Returns:

the result (never null). Result.next is the position of the until character if found, or a number larger than length() if no such character. You can tell which case it is by examining Strings.Result.separator.

nextToken

public static final Strings.Result nextToken(java.lang.String src,
                                             int from,
                                             char[] separators)
                                      throws IllegalSyntaxException

Returns the next token with unescape.

• It trims whitespaces before and after the token.
• It handles both '\'' and '"'. All characters between them are considered as a token.
• If nothing found before end-of-string, null is returned

If a separator is found, it is returned in Strings.Result.separator.

Throws:

IllegalSyntaxException - if the quoted string is unclosed.

nextToken

public static final Strings.Result nextToken(java.lang.String src,
                                             int from,
                                             char[] separators,
                                             boolean escBackslash,
                                             boolean quotAsToken)
                                      throws IllegalSyntaxException

Returns the next token with additional options. It is the same as nextToken(src, from, separators, escBackslash, quotAsToken, false); Refer to nextToken(String, int, char[], boolean, boolean, boolean) for more information.

Throws:

IllegalSyntaxException - if the quoted string is unclosed.

See Also:

nextToken(String, int, char[], boolean, boolean, boolean)

nextToken

public static final Strings.Result nextToken(java.lang.String src,
                                             int from,
                                             char[] separators,
                                             boolean escBackslash,
                                             boolean quotAsToken,
                                             boolean parenthesis)
                                      throws IllegalSyntaxException

Returns the next token with additional options.

• It trims whitespaces before and after the token.
• If quotAsToken is true, all characters between quotations ('\'' or '"') are considered as a token.
• If parenthesis is true, the separators and quotes inside a pair of parenthesis won't be treated specially. It is useful if EL expressions might be contained.
• Consider '\\' as the escape char if escBackslash is true.
• If nothing found before end-of-string, null is returned

If a separator is found, it is returned in Strings.Result.separator.

Parameters:

escBackslash - whether to treat '\\' specially (as escape char) It doesn't handle u and x yet.

quotAsToken - whether to treat characters inside '\'' or '"' as a token. Note: the quotes are excluded from the token.

parenthesis - whether to ignore separators and quotes inside a pair of parentheses. Recognized parentheses include {}, [] or ().

Throws:

IllegalSyntaxException - if the quoted string is unclosed.

Since:

3.0.6

nextSeparator

public static int nextSeparator(java.lang.String src,
                                int from,
                                char[] separators,
                                boolean escBackslash,
                                boolean escQuot,
                                boolean quotAsSeparator)

Returns the next separator index in the src string.

Parameters:

escQuot - whether to escape characters inside quotations ('\'' or '"'). In other words, ignore separators inside quotations

quotAsSeparator - whether to consider quotations as one of the separators

Since:

2.4.0

nextSeparator

public static int nextSeparator(java.lang.String src,
                                int from,
                                char[] separators,
                                boolean escBackslash,
                                boolean escQuot,
                                boolean quotAsSeparator,
                                boolean parenthesis)

Returns the next separator index in the src string.

Parameters:

escQuot - whether to escape characters inside quotations ('\'' or '"'). In other words, it specifies whether to ignore separators inside quotations

quotAsSeparator - whether to consider quotations as one of the separators. If escQuot is true, quotAsSeparator is ignored.

parenthesis - whether to ignore separators and quotes in side a pair of parentheses. Recognized parentheses include {}, [] or ().

Since:

3.0.6

join

public static final <T> java.lang.String join(T[] array)

Joins the elements of the array into a single String separated by a comma.

Parameters:

array -

Since:

8.0.0

join

public static final <T> java.lang.String join(T[] array,
                                              char separator)

Joins the elements of the array into a single String separated by the given separator.

Parameters:

array -

separator -

Since:

8.0.0

join

public static final <T> java.lang.String join(T[] array,
                                              char separator,
                                              int startIndex,
                                              int endIndex)

Joins the elements of the array into a single String separated by the given separator from the startIndex to the endIndex.

Parameters:

array -

separator -

startIndex -

endIndex -

Since:

8.0.0

toString

public static final java.lang.String toString(byte[] data)

Converts the given byte[] to UTF-8 string, if possible. Or return with the default charset.

This is a method helper for JDK 5

Since:

8.0.2

defaultIfEmpty

public static final java.lang.String defaultIfEmpty(java.lang.String value,
                                                    java.lang.String defaultValue)

Returns the passed value, or the default value if it is empty.

Parameters:

value - the value

defaultValue - the default value

Returns:

value if not empty. defaultValue if empty.

Since:

9.5.0