org.unix4j.util

Class StringUtil

java.lang.Object

org.unix4j.util.StringUtil

public class StringUtil
extends Object

Utility class with static methods for strings.

Method Summary

Modifier and Type	Method and Description
static boolean	containsIgnoreCase(String source, String target) Returns true if and only if the string s contains the specified target string performing case insensitive string comparison.
static boolean	equalsIgnoreCase(char ch1, char ch2) Returns true if the two characters are equal if case is ignored.
static int	findEndTrimNewlineChars(CharSequence s) Finds and returns the end of the given character sequence after trimming new line characters from the right.
static int	findEndTrimWhitespace(CharSequence s) Finds and returns the end of the given character sequence after trimming white space characters from the right.
static int	findStartTrimNewlineChars(CharSequence s) Finds and returns the start of the given sequence after trimming newline characters from the left.
static int	findStartTrimNewlineChars(CharSequence s, int start) Finds and returns the start of the given sequence after trimming newline characters from the left, starting at the given start index.
static int	findStartTrimWhitespace(CharSequence s) Finds and returns the start of the given sequence after trimming whitespace characters from the left.
static int	findStartTrimWhitespace(CharSequence s, int start) Finds and returns the start of the given sequence after trimming whitespace characters from the left, starting at the given start index.
static int	findWhitespace(CharSequence s) Finds and returns the first whitespace character in the given sequence, or the length of the string if no whitespace is found.
static int	findWhitespace(CharSequence s, int start) Finds and returns the first whitespace character in the given sequence at or after start.
static String	fixSizeString(int size, boolean alignLeft, char filler, long value) Returns the given value as a string of fixed length size padding or truncating the value if necessary.
static String	fixSizeString(int size, boolean alignLeft, char filler, String s) Returns the given string s into a string of fixed length size padding or truncating the string if necessary.
static String	fixSizeString(int size, boolean alignLeft, String s) Returns the given string s into a string of fixed length size padding or truncating the string with spaces if necessary.
static int	indexOfIgnoreCase(String source, String target) Returns the index within the source string of the first occurrence of the specified target substring performing case insensitive string comparison.
static List<Line>	splitLines(String s) Splits the given string into lines and returns each line as a separate string in the result list.
static boolean	startsWithIgnoreCase(String s, String prefix) Tests if this string s starts with the specified prefix performing case insensitive string comparison.

Methods inherited from class java.lang.Object

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

Method Detail

fixSizeString

public static String fixSizeString(int size,
                                   boolean alignLeft,
                                   char filler,
                                   long value)

Returns the given value as a string of fixed length size padding or truncating the value if necessary.

If left==true, the given value is left-aligned appending the given filler character to make up the fixed length. If the given value turns out to be longer than size when transformed into a string, it is truncated from the right.

If left==false, the given value is right-aligned and filler characters are added from the left if necessary. If value is longer than size it is truncated from the left.

Examples with size=3:

• left=true, filler=' ', value=89 --> "89 "
• left=true, filler=' ', value=1234 --> "123"
• left=false, filler=' ', value=89 --> " 89"
• left=false, filler='0', value=89 --> "089"
• left=false, filler=' ', value=1234 --> "234"

Parameters:

size - the fixed size of the returned string

alignLeft - true if value should be left-aligned

filler - the filler character if value is shorter than size

value - the value to format

Returns:

the value as a fixed size string, padded or truncated if necessary

fixSizeString

public static String fixSizeString(int size,
                                   boolean alignLeft,
                                   String s)

Returns the given string s into a string of fixed length size padding or truncating the string with spaces if necessary.

If left==true, the given string s is left-aligned appending spaces to make up the fixed length. If s turns out to be longer than size it is truncated from the right.

If left==false, the given string s is right-aligned and space characters are added from the left if necessary. If s is longer than size it is truncated from the left.

Examples with size=3:

• left=true, s="XY" --> "XY "
• left=true, s="Abcd" --> "Abc"
• left=false, s="XY" --> " XY"
• left=false, s="Abcd" --> "bcd"

Parameters:

size - the fixed size of the returned string

alignLeft - true if value should be left-aligned

s - the string to format

Returns:

the string s as a fixed size string, padded or truncated if necessary

fixSizeString

public static String fixSizeString(int size,
                                   boolean alignLeft,
                                   char filler,
                                   String s)

Returns the given string s into a string of fixed length size padding or truncating the string if necessary.

If left==true, the given string s is left-aligned appending the given filler character to make up the fixed length. If s turns out to be longer than size it is truncated from the right.

If left==false, the given string s is right-aligned and filler characters are added from the left if necessary. If s is longer than size it is truncated from the left.

Examples with size=3:

• left=true, filler=' ', s="XY" --> "XY "
• left=true, filler=' ', s="Abcd" --> "Abc"
• left=false, filler=' ', s="XY" --> " XY"
• left=false, filler='0', s="12" --> "012"
• left=false, filler=' ', s="Abcd" --> "bcd"

Parameters:

size - the fixed size of the returned string

alignLeft - true if value should be left-aligned

filler - the filler character if s is shorter than size

s - the string to format

Returns:

the string s as a fixed size string, padded or truncated if necessary

splitLines

public static List<Line> splitLines(String s)

Splits the given string into lines and returns each line as a separate string in the result list. The result list will contain at least one entry unless the string is empty.

A trailing newline after the last line is ignored, meaning that no empty string is appended as separate line if the string ends with a newline. However multiple trailing newlines will still lead to empty line strings at the end of the list.

Note that all line ending characters are accepted to split lines, no matter what operating system this code is hosted on. More precisely, the LF and CR characters are recognized as line ending characters, either as single character or as a pair CR+LF or LF+CR.

Parameters:

s - the string to split

Returns:

a list with the lines found in s

findStartTrimWhitespace

public static int findStartTrimWhitespace(CharSequence s)

Finds and returns the start of the given sequence after trimming whitespace characters from the left.

Parameters:

s - the character sequence

Returns:

the index containing the first non-whitespace character, or the length of the character sequence if all characters are blank

findStartTrimWhitespace

public static int findStartTrimWhitespace(CharSequence s,
                                          int start)

Finds and returns the start of the given sequence after trimming whitespace characters from the left, starting at the given start index.

Parameters:

s - the character sequence

start - the first index to consider in the char sequence

Returns:

the index containing the first non-whitespace character, or the length of the character sequence if all characters are blank

findEndTrimWhitespace

public static int findEndTrimWhitespace(CharSequence s)

Finds and returns the end of the given character sequence after trimming white space characters from the right. Whitespace characters are defined by Character.isWhitespace(char). .

Parameters:

s - the character sequence

Returns:

the index after the last non-whitespace character, or zero if all characters are blank

findStartTrimNewlineChars

public static int findStartTrimNewlineChars(CharSequence s)

Finds and returns the start of the given sequence after trimming newline characters from the left. The following character sequences are treated as newline characters: "\n", "\r\n".

Parameters:

s - the character sequence

Returns:

the index containing the first character that is not part of a newline sequence, or the length of the character sequence if all characters are newline chars

findStartTrimNewlineChars

public static int findStartTrimNewlineChars(CharSequence s,
                                            int start)

Finds and returns the start of the given sequence after trimming newline characters from the left, starting at the given start index. . The following character sequences are treated as newline characters: "\n", "\r\n".

Parameters:

s - the character sequence

start - the first index to consider in the char sequence

Returns:

the index containing the first character that is not part of a newline sequence, or the length of the character sequence if all characters are newline chars

findEndTrimNewlineChars

public static int findEndTrimNewlineChars(CharSequence s)

Finds and returns the end of the given character sequence after trimming new line characters from the right. The following character sequences are treated as newline characters: "\n", "\r\n".

Parameters:

s - the character sequence

Returns:

the index after the last character that is not part of a newline sequence, or zero if all characters are newline chars

findWhitespace

public static int findWhitespace(CharSequence s)

Finds and returns the first whitespace character in the given sequence, or the length of the string if no whitespace is found.

Parameters:

s - the character sequence

Returns:

the index containing the first whitespace character, or the length of the character sequence if all characters are blank

findWhitespace

public static int findWhitespace(CharSequence s,
                                 int start)

Finds and returns the first whitespace character in the given sequence at or after start. Returns the length of the string if no whitespace is found.

Parameters:

s - the character sequence

start - the first index to consider in the char sequence

Returns:

the index containing the first whitespace character at or after start, or the length of the character sequence if all characters are blank

containsIgnoreCase

public static boolean containsIgnoreCase(String source,
                                         String target)

Returns true if and only if the string s contains the specified target string performing case insensitive string comparison.

Parameters:

source - the characters being searched.

target - the characters being searched for.

Returns:

true if this string contains s, false otherwise

Throws:

NullPointerException - if s is null

startsWithIgnoreCase

public static boolean startsWithIgnoreCase(String s,
                                           String prefix)

Tests if this string s starts with the specified prefix performing case insensitive string comparison.

Parameters:

s - the string to search

prefix - the prefix.

Returns:

true if the character sequence represented by the argument is a prefix of the character sequence represented by the string s; false otherwise. Note also that true will be returned if the argument is an empty string or is equal to this String object as determined by the Object.equals(Object) method.

indexOfIgnoreCase

public static int indexOfIgnoreCase(String source,
                                    String target)

Returns the index within the source string of the first occurrence of the specified target substring performing case insensitive string comparison.

The returned index is the smallest value k for which:

 startsWithIgnoreCase(source.substring(k), target)
 

If no such value of k exists, then -1 is returned.

Copied from String.indexOf(..) modified to do case-insensitive search. The source is the character array being searched, and the target is the string being searched for.

Parameters:

source - the characters being searched.

target - the characters being searched for.

Returns:

the index of the first occurrence of the specified substring (ignoring the case), or -1 if there is no such occurrence.

equalsIgnoreCase

public static boolean equalsIgnoreCase(char ch1,
                                       char ch2)

Returns true if the two characters are equal if case is ignored.

Parameters:

ch1 - the first character

ch2 - the second character

Returns:

true if both characters are the same according to case-insensitive comparison