org.apache.nifi.util

Class StringUtils

java.lang.Object

org.apache.nifi.util.StringUtils

public class StringUtils
extends Object

String Utils based on the Apache Commons Lang String Utils. These simple util methods here allow us to avoid a dependency in the core

Field Summary

Fields

Modifier and Type	Field and Description
static String	EMPTY
private static int	PAD_LIMIT The maximum size to which the padding constant(s) can expand.
static String	SPACE A String for a space character.

Constructor Summary

Constructors

Constructor and Description
StringUtils()

Method Summary

Modifier and Type	Method and Description
static boolean	isBlank(String str)
static boolean	isEmpty(String str)
static boolean	isNotBlank(String str)
static boolean	isNotEmpty(String str)
static String	join(Collection<?> collection, String delimiter)
static String	leftPad(String str, int size) Left pad a String with spaces (' ').
static String	leftPad(String str, int size, char padChar) Left pad a String with a specified character.
static String	leftPad(String str, int size, String padStr) Left pad a String with a specified String.
static String	removeEnd(String str, String remove) Removes a substring only if it is at the end of a source string, otherwise returns the source string.
static String	repeat(char ch, int repeat) Returns padding using the specified delimiter repeated to a given length.
static String	repeat(String str, int repeat) Repeat a String repeat times to form a new String.
static String	repeat(String str, String separator, int repeat) Repeat a String repeat times to form a new String, with a String separator injected each time.
static String	rightPad(String str, int size) Right pad a String with spaces (' ').
static String	rightPad(String str, int size, char padChar) Right pad a String with a specified character.
static String	rightPad(String str, int size, String padStr) Right pad a String with a specified String.
static boolean	startsWith(String str, String prefix)
static String	substringAfter(String str, String separator)
static String	toTitleCase(String input) Returns the string in "title case" (i.e.

Methods inherited from class java.lang.Object

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

Field Detail

EMPTY

public static final String EMPTY

See Also:

Constant Field Values

PAD_LIMIT

private static final int PAD_LIMIT

The maximum size to which the padding constant(s) can expand.

See Also:

Constant Field Values

SPACE

public static final String SPACE

A String for a space character.

Since:

3.2

See Also:

Constant Field Values

Constructor Detail

StringUtils

public StringUtils()

Method Detail

isBlank

public static boolean isBlank(String str)

isNotBlank

public static boolean isNotBlank(String str)

isEmpty

public static boolean isEmpty(String str)

isNotEmpty

public static boolean isNotEmpty(String str)

startsWith

public static boolean startsWith(String str,
                                 String prefix)

substringAfter

public static String substringAfter(String str,
                                    String separator)

join

public static String join(Collection<?> collection,
                          String delimiter)

leftPad

public static String leftPad(String str,
                             int size)

Left pad a String with spaces (' ').

The String is padded to the size of size.

 StringUtils.leftPad(null, *)   = null
 StringUtils.leftPad("", 3)     = "   "
 StringUtils.leftPad("bat", 3)  = "bat"
 StringUtils.leftPad("bat", 5)  = "  bat"
 StringUtils.leftPad("bat", 1)  = "bat"
 StringUtils.leftPad("bat", -1) = "bat"
 

Parameters:

str - the String to pad out, may be null

size - the size to pad to

Returns:

left padded String or original String if no padding is necessary, null if null String input

leftPad

public static String leftPad(String str,
                             int size,
                             char padChar)

Left pad a String with a specified character.

Pad to a size of size.

 StringUtils.leftPad(null, *, *)     = null
 StringUtils.leftPad("", 3, 'z')     = "zzz"
 StringUtils.leftPad("bat", 3, 'z')  = "bat"
 StringUtils.leftPad("bat", 5, 'z')  = "zzbat"
 StringUtils.leftPad("bat", 1, 'z')  = "bat"
 StringUtils.leftPad("bat", -1, 'z') = "bat"
 

Parameters:

str - the String to pad out, may be null

size - the size to pad to

padChar - the character to pad with

Returns:

left padded String or original String if no padding is necessary, null if null String input

Since:

2.0

leftPad

public static String leftPad(String str,
                             int size,
                             String padStr)

Left pad a String with a specified String.

Pad to a size of size.

 StringUtils.leftPad(null, *, *)      = null
 StringUtils.leftPad("", 3, "z")      = "zzz"
 StringUtils.leftPad("bat", 3, "yz")  = "bat"
 StringUtils.leftPad("bat", 5, "yz")  = "yzbat"
 StringUtils.leftPad("bat", 8, "yz")  = "yzyzybat"
 StringUtils.leftPad("bat", 1, "yz")  = "bat"
 StringUtils.leftPad("bat", -1, "yz") = "bat"
 StringUtils.leftPad("bat", 5, null)  = "  bat"
 StringUtils.leftPad("bat", 5, "")    = "  bat"
 

Parameters:

str - the String to pad out, may be null

size - the size to pad to

padStr - the String to pad with, null or empty treated as single space

Returns:

left padded String or original String if no padding is necessary, null if null String input

rightPad

public static String rightPad(String str,
                              int size)

Right pad a String with spaces (' ').

The String is padded to the size of size.

 StringUtils.rightPad(null, *)   = null
 StringUtils.rightPad("", 3)     = "   "
 StringUtils.rightPad("bat", 3)  = "bat"
 StringUtils.rightPad("bat", 5)  = "bat  "
 StringUtils.rightPad("bat", 1)  = "bat"
 StringUtils.rightPad("bat", -1) = "bat"
 

Parameters:

str - the String to pad out, may be null

size - the size to pad to

Returns:

right padded String or original String if no padding is necessary, null if null String input

rightPad

public static String rightPad(String str,
                              int size,
                              char padChar)

Right pad a String with a specified character.

The String is padded to the size of size.

 StringUtils.rightPad(null, *, *)     = null
 StringUtils.rightPad("", 3, 'z')     = "zzz"
 StringUtils.rightPad("bat", 3, 'z')  = "bat"
 StringUtils.rightPad("bat", 5, 'z')  = "batzz"
 StringUtils.rightPad("bat", 1, 'z')  = "bat"
 StringUtils.rightPad("bat", -1, 'z') = "bat"
 

Parameters:

str - the String to pad out, may be null

size - the size to pad to

padChar - the character to pad with

Returns:

right padded String or original String if no padding is necessary, null if null String input

Since:

2.0

rightPad

public static String rightPad(String str,
                              int size,
                              String padStr)

Right pad a String with a specified String.

The String is padded to the size of size.

 StringUtils.rightPad(null, *, *)      = null
 StringUtils.rightPad("", 3, "z")      = "zzz"
 StringUtils.rightPad("bat", 3, "yz")  = "bat"
 StringUtils.rightPad("bat", 5, "yz")  = "batyz"
 StringUtils.rightPad("bat", 8, "yz")  = "batyzyzy"
 StringUtils.rightPad("bat", 1, "yz")  = "bat"
 StringUtils.rightPad("bat", -1, "yz") = "bat"
 StringUtils.rightPad("bat", 5, null)  = "bat  "
 StringUtils.rightPad("bat", 5, "")    = "bat  "
 

Parameters:

str - the String to pad out, may be null

size - the size to pad to

padStr - the String to pad with, null or empty treated as single space

Returns:

right padded String or original String if no padding is necessary, null if null String input

repeat

public static String repeat(char ch,
                            int repeat)

Returns padding using the specified delimiter repeated to a given length.

 StringUtils.repeat('e', 0)  = ""
 StringUtils.repeat('e', 3)  = "eee"
 StringUtils.repeat('e', -2) = ""
 

Note: this method does not support padding with Unicode Supplementary Characters as they require a pair of chars to be represented. If you are needing to support full I18N of your applications consider using repeat(String, int) instead.

Parameters:

ch - character to repeat

repeat - number of times to repeat char, negative treated as zero

Returns:

String with repeated character

See Also:

repeat(String, int)

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

repeat

public static String repeat(String str,
                            String separator,
                            int repeat)

Repeat a String repeat times to form a new String, with a String separator injected each time.

 StringUtils.repeat(null, null, 2) = null
 StringUtils.repeat(null, "x", 2)  = null
 StringUtils.repeat("", null, 0)   = ""
 StringUtils.repeat("", "", 2)     = ""
 StringUtils.repeat("", "x", 3)    = "xxx"
 StringUtils.repeat("?", ", ", 3)  = "?, ?, ?"
 

Parameters:

str - the String to repeat, may be null

separator - the String to inject, 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

Since:

2.5

removeEnd

public static String removeEnd(String str,
                               String remove)

Removes a substring only if it is at the end of a source string, otherwise returns the source string.

A null source string will return null. An empty ("") source string will return the empty string. A null search string will return the source string.

 StringUtils.removeEnd(null, *)      = null
 StringUtils.removeEnd("", *)        = ""
 StringUtils.removeEnd(*, null)      = *
 StringUtils.removeEnd("www.domain.com", ".com.")  = "www.domain.com"
 StringUtils.removeEnd("www.domain.com", ".com")   = "www.domain"
 StringUtils.removeEnd("www.domain.com", "domain") = "www.domain.com"
 StringUtils.removeEnd("abc", "")    = "abc"
 

Parameters:

str - the source String to search, may be null

remove - the String to search for and remove, may be null

Returns:

the substring with the string removed if found, null if null String input

Since:

2.1

toTitleCase

public static String toTitleCase(String input)

Returns the string in "title case" (i.e. every word capitalized). If the input is null or blank, returns an empty string. Leading and trailing spaces are trimmed, and multiple internal spaces are condensed. Examples: this is a sentence -> This Is A Sentence allOneWord -> Alloneword PREVIOUSLY UPPERCASE -> Previously Uppercase multiple spaces -> Multiple Spaces

Parameters:

input - the input string

Returns:

the titlecased string