StringUtils (tablesaw-core 0.37.0 API)

java.lang.Object
- tech.tablesaw.util.StringUtils

```
public class StringUtils
extends Object
```
Operations on String that are null safe.
StringUtils handles null input Strings quietly. That is to say that a null input will return null. Where a boolean or int is being returned details vary by method.
A side effect of the null handling is that a NullPointerException should be considered a bug in StringUtils.
Methods in this class give sample code to explain their operation. The symbol * is used to indicate any input including null.
#ThreadSafe#

Since:

1.0

See Also:

String

Method Summary

All Methods Static Methods Concrete Methods
Modifier and Type	Method and Description
`static String`	`abbreviate(String str, String abbrevMarker, int maxWidth)` Abbreviates a String using ellipses.
`static String`	`capitalize(String str)` Capitalizes a String changing the first character to title case as per `Character.toTitleCase(int)`.
`static boolean`	`isAllLowerCase(String cs)` Checks if the CharSequence contains only lowercase characters.
`static boolean`	`isAllUpperCase(String cs)` Checks if the CharSequence contains only uppercase characters.
`static boolean`	`isAlpha(String cs)` Checks if the CharSequence contains only Unicode letters.
`static boolean`	`isAlphanumeric(String cs)` Checks if the CharSequence contains only Unicode letters or digits.
`static boolean`	`isNumeric(String cs)` Checks if the CharSequence contains only Unicode digits.
`static String`	`join(Object[] array, char separator)` Joins the elements of the provided array into a single String containing the provided list of elements.
`static int`	`length(CharSequence cs)` Gets a CharSequence length or `0` if the CharSequence is `null`.
`static String`	`repeat(String str, int repeat)` Repeat a String `repeat` times to form a new String.
`static String[]`	`splitByCharacterTypeCamelCase(String str)` Splits a String by Character type as returned by `java.lang.Character.getType(char)`.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Method Detail
  - splitByCharacterTypeCamelCase
```
public static String[] splitByCharacterTypeCamelCase(String str)
```
    Splits a String by Character type as returned by java.lang.Character.getType(char). Groups of contiguous characters of the same type are returned as complete tokens, with the following exception: if camelCase is true, the character of type Character.UPPERCASE_LETTER, if any, immediately preceding a token of type Character.LOWERCASE_LETTER will belong to the following token rather than to the preceding, if any, Character.UPPERCASE_LETTER token.
    
    Parameters:
    
    str - the String to split, may be null
    
    Returns:
    
    an array of parsed Strings, null if null String input
    
    Since:
    
    2.4
  - join
```
public static String join(Object[] array,
                          char separator)
```
    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. 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([null, "", "a"], ';')  = ";;a"
 
```
    Parameters:
    
    array - the array of values to join together, may be null
    
    separator - the separator character to use
    
    Returns:
    
    the joined String, null if null array input
    
    Since:
    
    2.0
  - repeat
```
public static String repeat(String str,
                            int repeat)
```
    Repeat a String 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) = ""
 
```
    Parameters:
    
    str - the String to repeat, may be null
    
    repeat - number of times to repeat str, negative treated as zero
    
    Returns:
    
    a new String consisting of the original String repeated, null if null String input
  - length
```
public static int length(CharSequence cs)
```
    Gets a CharSequence length or 0 if the CharSequence is null.
    
    Parameters:
    
    cs - a CharSequence or null
    
    Returns:
    
    CharSequence length or 0 if the CharSequence is null.
    
    Since:
    
    2.4, 3.0 Changed signature from length(String) to length(CharSequence)
  - capitalize
```
public static String capitalize(String str)
```
    Capitalizes a String changing the first character to title case as per Character.toTitleCase(int). No other characters are changed.
    A null input String returns null.
```
 StringUtils.capitalize(null)  = null
 StringUtils.capitalize("")    = ""
 StringUtils.capitalize("cat") = "Cat"
 StringUtils.capitalize("cAt") = "CAt"
 StringUtils.capitalize("'cat'") = "'cat'"
 
```
    Parameters:
    
    str - the String to capitalize, may be null
    
    Returns:
    
    the capitalized String, null if null String input
    
    Since:
    
    2.0
  - isAlpha
```
public static boolean isAlpha(String cs)
```
    Checks if the CharSequence contains only Unicode letters.
    null will return false. An empty CharSequence (length()=0) will return false.
```
 StringUtils.isAlpha(null)   = false
 StringUtils.isAlpha("")     = false
 StringUtils.isAlpha("  ")   = false
 StringUtils.isAlpha("abc")  = true
 StringUtils.isAlpha("ab2c") = false
 StringUtils.isAlpha("ab-c") = false
 
```
    Parameters:
    
    cs - the CharSequence to check, may be null
    
    Returns:
    
    true if only contains letters, and is non-null
    
    Since:
    
    3.0 Changed signature from isAlpha(String) to isAlpha(CharSequence), 3.0 Changed "" to return false and not true
  - isAlphanumeric
```
public static boolean isAlphanumeric(String cs)
```
    Checks if the CharSequence contains only Unicode letters or digits.
    null will return false. An empty CharSequence (length()=0) will return false.
```
 StringUtils.isAlphanumeric(null)   = false
 StringUtils.isAlphanumeric("")     = false
 StringUtils.isAlphanumeric("  ")   = false
 StringUtils.isAlphanumeric("abc")  = true
 StringUtils.isAlphanumeric("ab c") = false
 StringUtils.isAlphanumeric("ab2c") = true
 StringUtils.isAlphanumeric("ab-c") = false
 
```
    Parameters:
    
    cs - the CharSequence to check, may be null
    
    Returns:
    
    true if only contains letters or digits, and is non-null
    
    Since:
    
    3.0 Changed signature from isAlphanumeric(String) to isAlphanumeric(CharSequence), 3.0 Changed "" to return false and not true
  - isNumeric
```
public static boolean isNumeric(String cs)
```
    Checks if the CharSequence contains only Unicode digits. A decimal point is not a Unicode digit and returns false.
    null will return false. An empty CharSequence (length()=0) will return 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.
```
 StringUtils.isNumeric(null)   = false
 StringUtils.isNumeric("")     = false
 StringUtils.isNumeric("  ")   = false
 StringUtils.isNumeric("123")  = true
 StringUtils.isNumeric("१२३")  = true
 StringUtils.isNumeric("12 3") = false
 StringUtils.isNumeric("ab2c") = false
 StringUtils.isNumeric("12-3") = false
 StringUtils.isNumeric("12.3") = false
 StringUtils.isNumeric("-123") = false
 StringUtils.isNumeric("+123") = false
 
```
    Parameters:
    
    cs - the CharSequence to check, may be null
    
    Returns:
    
    true if only contains digits, and is non-null
    
    Since:
    
    3.0 Changed signature from isNumeric(String) to isNumeric(CharSequence), 3.0 Changed "" to return false and not true
  - isAllLowerCase
```
public static boolean isAllLowerCase(String cs)
```
    Checks if the CharSequence contains only lowercase characters.
    null will return false. An empty CharSequence (length()=0) will return false.
```
 StringUtils.isAllLowerCase(null)   = false
 StringUtils.isAllLowerCase("")     = false
 StringUtils.isAllLowerCase("  ")   = false
 StringUtils.isAllLowerCase("abc")  = true
 StringUtils.isAllLowerCase("abC")  = false
 StringUtils.isAllLowerCase("ab c") = false
 StringUtils.isAllLowerCase("ab1c") = false
 StringUtils.isAllLowerCase("ab/c") = false
 
```
    Parameters:
    
    cs - the CharSequence to check, may be null
    
    Returns:
    
    true if only contains lowercase characters, and is non-null
    
    Since:
    
    2.5, 3.0 Changed signature from isAllLowerCase(String) to isAllLowerCase(CharSequence)
  - isAllUpperCase
```
public static boolean isAllUpperCase(String cs)
```
    Checks if the CharSequence contains only uppercase characters.
    null will return false. An empty String (length()=0) will return false.
```
 StringUtils.isAllUpperCase(null)   = false
 StringUtils.isAllUpperCase("")     = false
 StringUtils.isAllUpperCase("  ")   = false
 StringUtils.isAllUpperCase("ABC")  = true
 StringUtils.isAllUpperCase("aBC")  = false
 StringUtils.isAllUpperCase("A C")  = false
 StringUtils.isAllUpperCase("A1C")  = false
 StringUtils.isAllUpperCase("A/C")  = false
 
```
    Parameters:
    
    cs - the CharSequence to check, may be null
    
    Returns:
    
    true if only contains uppercase characters, and is non-null
    
    Since:
    
    2.5, 3.0 Changed signature from isAllUpperCase(String) to isAllUpperCase(CharSequence)
  - abbreviate
```
public static String abbreviate(String str,
                                String abbrevMarker,
                                int maxWidth)
```
    Abbreviates a String using ellipses. This will turn "Now is the time for all good men" into "Now is the time for..."
    Specifically:
    - If the number of characters in str is less than or equal to maxWidth, return str.
    - Else abbreviate it to (substring(str, 0, max-3) + "...").
    - If maxWidth is less than 4, throw an IllegalArgumentException.
    - In no case will it return a String of length greater than maxWidth.
```
 StringUtils.abbreviate(null, *)      = null
 StringUtils.abbreviate("", 4)        = ""
 StringUtils.abbreviate("abcdefg", 6) = "abc..."
 StringUtils.abbreviate("abcdefg", 7) = "abcdefg"
 StringUtils.abbreviate("abcdefg", 8) = "abcdefg"
 StringUtils.abbreviate("abcdefg", 4) = "a..."
 StringUtils.abbreviate("abcdefg", 3) = IllegalArgumentException
 
```
    Parameters:
    
    str - the String to check, may be null
    
    abbrevMarker - the String indicate abbreviation
    
    maxWidth - maximum length of result String, must be at least 4
    
    Returns:
    
    abbreviated String, null if null String input
    
    Throws:
    
    IllegalArgumentException - if the width is too small
    
    Since:
    
    2.0

Class StringUtils

Method Summary

Methods inherited from class java.lang.Object

Method Detail

splitByCharacterTypeCamelCase

join

repeat

length

capitalize

isAlpha

isAlphanumeric

isNumeric

isAllLowerCase

isAllUpperCase

abbreviate