de.mklinger.micro.strings

Class Strings

java.lang.Object

de.mklinger.micro.strings.Strings

public class Strings
extends Object

Utility class for Strings, checking for emptiness and text.

Author:

Marc Klinger - mklinger[at]mklinger[dot]de

Method Summary

Modifier and Type	Method and Description
static <T extends CharSequence> boolean	hasText(T str) Check whether the given CharSequence has actual text.
static <T extends CharSequence> boolean	isEmpty(T str) Check whether the given CharSequence is empty.
static <T extends CharSequence> T	requireNonEmpty(T str) Checks that the specified string is not empty.
static <T extends CharSequence> T	requireNonEmpty(T str, String msg) Checks that the specified string is not empty and throws a customized IllegalArgumentException if it is.
static <T extends CharSequence> T	requireText(T str) Checks that the specified string contains non-whitespace text.
static <T extends CharSequence> T	requireText(T str, String msg) Checks that the specified string contains non-whitespace text and throws a customized IllegalArgumentException if it does not.

Methods inherited from class java.lang.Object

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

Method Detail

requireText

public static <T extends CharSequence> T requireText(T str)

Checks that the specified string contains non-whitespace text. This method is designed primarily for doing parameter validation in methods and constructors, as demonstrated below:

 public Foo(String bar) {
        this.bar = Strings.requireText(bar);
 }
 

Type Parameters:

T - the type of the char sequence

Parameters:

str - the char sequence to check for text

Returns:

str if it contains non-whitespace text

Throws:

IllegalArgumentException - if str is null or empty or consists of whitespace text only

requireText

public static <T extends CharSequence> T requireText(T str,
                                                     String msg)

Checks that the specified string contains non-whitespace text and throws a customized IllegalArgumentException if it does not. This method is designed primarily for doing parameter validation in methods and constructors, as demonstrated below:

 public Foo(String bar) {
        this.bar = Strings.requireText(bar, "bar must contain text");
 }
 

Type Parameters:

T - the type of the char sequence

Parameters:

str - the char sequence to check for text

Returns:

str if it contains non-whitespace text

Throws:

IllegalArgumentException - if str is null or empty or consists of whitespace text only

hasText

public static <T extends CharSequence> boolean hasText(T str)

Check whether the given CharSequence has actual text. More specifically, returns true if the string is not null, its length is greater than 0, and it contains at least one non-whitespace character.

 Strings.hasText(null) = false
 Strings.hasText("") = false
 Strings.hasText(" ") = false
 Strings.hasText("12345") = true
 Strings.hasText(" 12345 ") = true
 

Type Parameters:

T - the type of the char sequence

Parameters:

str - the CharSequence to check (may be null)

Returns:

true if the CharSequence is not null, its length is greater than 0, and it does not contain whitespace only

See Also:

Character.isWhitespace(char)

requireNonEmpty

public static <T extends CharSequence> T requireNonEmpty(T str)

Checks that the specified string is not empty. This method is designed primarily for doing parameter validation in methods and constructors, as demonstrated below:

 public Foo(String bar) {
        this.bar = Strings.requireNonEmpty(bar);
 }
 

Type Parameters:

T - the type of the char sequence

Parameters:

str - the char sequence to check

Returns:

str if it is not empty

Throws:

IllegalArgumentException - if str is null or empty

requireNonEmpty

public static <T extends CharSequence> T requireNonEmpty(T str,
                                                         String msg)

Checks that the specified string is not empty and throws a customized IllegalArgumentException if it is. This method is designed primarily for doing parameter validation in methods and constructors, as demonstrated below:

 public Foo(String bar) {
        this.bar = Strings.requireNonEmpty(bar, "bar must not be empty");
 }
 

Type Parameters:

T - the type of the char sequence

Parameters:

str - the char sequence to check

Returns:

str if it is not empty

Throws:

IllegalArgumentException - if str is null or empty

isEmpty

public static <T extends CharSequence> boolean isEmpty(T str)

Check whether the given CharSequence is empty. More specifically, returns true if the string is not null and its length is greater than 0.

 Strings.isEmpty(null) = true
 Strings.isEmpty("") = true
 Strings.isEmpty(" ") = false
 Strings.isEmpty("12345") = false
 

Type Parameters:

T - the type of the char sequence

Parameters:

str - the CharSequence to check (may be null)

Returns:

true if the CharSequence is not null and its length is greater than 0