Java Character isISOControl() Method

The Character.isISOControl() method in Java is used to determine if a specified character is an ISO control character.

Table of Contents

1. Introduction
2. isISOControl() Method Syntax
3. Examples
   • Checking Control Characters
   • Handling Non-Control Characters
4. Real-World Use Case
5. Conclusion

Introduction

The Character.isISOControl() method is a static method in the Character class in Java. It checks whether a given character is an ISO control character, which includes characters in the range \u0000 through \u001F and \u007F through \u009F. These characters are typically non-printable and are used to control the flow of text.

isISOControl()() Method Syntax

The syntax for the isISOControl() method is as follows:

public static boolean isISOControl(char ch)

• ch: The character to be tested.

The method returns:

• true if the character is an ISO control character.
• false otherwise.

Examples

Checking Control Characters

The isISOControl() method can be used to check if a character is an ISO control character.

Example

public class IsISOControlExample {
    public static void main(String[] args) {
        char controlChar1 = '\u0000'; // Null character
        char controlChar2 = '\u007F'; // Delete character

        boolean isControl1 = Character.isISOControl(controlChar1);
        boolean isControl2 = Character.isISOControl(controlChar2);

        System.out.println("Is '\\u0000' an ISO control character? " + isControl1);
        System.out.println("Is '\\u007F' an ISO control character? " + isControl2);
    }
}

Output:

Is '\u0000' an ISO control character? true
Is '\u007F' an ISO control character? true

In this example, both characters are ISO control characters.

Handling Non-Control Characters

The isISOControl() method returns false for characters that are not ISO control characters.

Example

public class NonControlCharacterExample {
    public static void main(String[] args) {
        char nonControlChar = 'A';

        boolean isControl = Character.isISOControl(nonControlChar);

        System.out.println("Is 'A' an ISO control character? " + isControl);
    }
}

Output:

Is 'A' an ISO control character? false

In this example, the method returns false because the character 'A' is not an ISO control character.

Checking Multiple Characters

You can check multiple characters to determine which ones are ISO control characters.

Example

public class MultipleCharactersExample {
    public static void main(String[] args) {
        char[] chars = { '\u0000', '\u001F', '\u0020', '\u007F', '\u009F', 'A' };

        for (char ch : chars) {
            boolean isControl = Character.isISOControl(ch);
            System.out.printf("Is '\\u%04X' an ISO control character? %b%n", (int) ch, isControl);
        }
    }
}

Output:

Is '\u0000' an ISO control character? true
Is '\u001F' an ISO control character? true
Is '\u0020' an ISO control character? false
Is '\u007F' an ISO control character? true
Is '\u009F' an ISO control character? true
Is '\u0041' an ISO control character? false

In this example, the code checks each character and prints whether it is an ISO control character.

Real-World Use Case

Filtering Out Control Characters

In a real-world application, you might need to filter out ISO control characters from a text string.

Example

public class FilterControlCharactersExample {
    public static void main(String[] args) {
        String text = "Hello\u0000World\u007F!";
        StringBuilder filteredText = new StringBuilder();

        for (char ch : text.toCharArray()) {
            if (!Character.isISOControl(ch)) {
                filteredText.append(ch);
            }
        }

        System.out.println("Filtered text: " + filteredText.toString());
    }
}

Output:

Filtered text: HelloWorld!

In this example, the code removes the ISO control characters from the string.

Conclusion

The Character.isISOControl() method in Java is a simple and effective way to check if a character is an ISO control character. By understanding how to use this method, you can efficiently handle text processing tasks that involve control characters in your Java applications. Whether you are checking individual characters, handling non-control characters, or filtering out control characters from text, the isISOControl() method provides a reliable solution for these tasks.