What is CharUtils.isAsciiControl in Java?
isAsciiControl is a static method of the CharUtils class that is used to check if the input character is an ASCII control character or not.
What are ASCII control characters?
ASCII control characters are characters whose ASCII value is in the range of 0 to 31. The table below lists the ASCII control characters.
| ASCII Value | Symbol | Description |
|---|---|---|
| 0 | NUL | Null |
| 1 | SOH | Start of heading |
| 2 | STX | Start of text |
| 3 | ETX | End of text |
| 4 | EOT | End of transmission |
| 5 | ENQ | Enquiry |
| 6 | ACK | Acknowledge |
| 7 | BEL | Bell (audible or attention signal) |
| 8 | BS | Backspace |
| 9 | TAB | Horizontal tabulation |
| 10 | LF | Line feed |
| 11 | VT | Vertical tabulation |
| 12 | FF | Form feed |
| 13 | CR | Carriage return |
| 14 | SO | Shift out |
| 15 | SI | Shift in |
| 16 | DLE | Data link rscape |
| 17 | DC1 | Device control 1 |
| 18 | DC2 | Device control 2 |
| 19 | DC3 | Device control 3 |
| 20 | DC4 | Device control 4 |
| 21 | NAK | Negative acknowledge |
| 22 | SYN | Synchronous idle |
| 23 | ETB | End of transmission block |
| 24 | CAN | Cancel |
| 25 | EM | End of medium |
| 26 | SUB | Substitute |
| 27 | ESC | Escape |
| 28 | FS | File separator |
| 29 | GS | Group separator |
| 30 | RS | Record separator |
| 31 | US | Unit separator |
How to import CharUtils
CharUtils is defined in the Apache Commons Lang package. Apache Commons Lang can be added to the Maven project by adding the following dependency to the pom.xml file.
<dependency>
<groupId>org.apache.commons</groupId>
<artifactId>commons-lang3</artifactId>
<version>3.12.0</version>
</dependency>
For other versions of the commons-lang package, refer to the Maven Repository.
We can import the CharUtils class as follows.
import org.apache.commons.lang3.CharUtils;
Syntax
public static boolean isAsciiControl(final char ch)
Parameters
final char ch: the character to check.
Return value
The function returns true if the character is an ASCII control character; otherwise, it returns false.
Code
import org.apache.commons.lang3.CharUtils;
public class Main {
public static void main(String[] args) {
char c1 = 'F';
System.out.printf("The output of CharUtils.isAsciiControl() for the character '%s' is %s", c1, CharUtils.isAsciiControl(c1));
System.out.println();
c1 = '\n';
System.out.printf("The output of CharUtils.isAsciiControl() for the character '%s' is %s", c1, CharUtils.isAsciiControl(c1));
System.out.println();
c1 = '\r';
System.out.printf("The output of CharUtils.isAsciiControl() for the character '%s' is %s", c1, CharUtils.isAsciiControl(c1));
System.out.println();
c1 = 'È';
System.out.printf("The output of CharUtils.isAsciiControl() for the character '%s' is %s", c1, CharUtils.isAsciiControl(c1));
System.out.println();
}
}Explanation
-
character -
FThe method returns
false, as the character is not an ASCII control character and the numerical value of the character is not in the range of 0 to 31. -
character -
\nThe method returns
true, as the character is an ASCII control character and the numerical value of the character is in the range of 0 to 31. -
character -
\rThe method returns
true, as the character is an ASCII control character and the numerical value of the character is in the range of 0 to 31. -
character -
ÈThe method returns
false, as the character is not an ASCII control character and the numerical value of the character is not in the range of 0 to 31.
Expected output
The output of CharUtils.isAsciiControl() for the character 'F' is false
The output of CharUtils.isAsciiControl() for the character '
' is true
The output of CharUtils.isAsciiControl() for the character '
' is true
The output of CharUtils.isAsciiControl() for the character 'È' is false
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