Java CharArrayWriter Class | Set 2

In the Java.io.CharArrayWriter class in Java | Set 1, we have already discussed about which CharArrayWriter class and how it works. In this article, we are going to discuss some more methods of the CharArrayWriter class, which give us strong control over handling character data.

Java CharArrayWriter Methods

The image below demonstrates the methods of the CharArrayWriter class.

Now, we are going to discuss about each method one by one in detail:

1. append (char Sw): This method is used to append a specified character sequence to the Writer.

Syntax:

public CharArrayWriter append(char Sw)

• Parameter: This method takes a single parameter sw, which is the character to be appended
• Return Type: This method returns the updated CharArrayWriter object.

2. append (CharSequence char_sq): This method is used to appends a specified character sequence to the Writer.

Syntax:

public CharArrayWriter append(CharSequence char_sq)

• Parameter: This method takes a single parameter char_sq, which the character sequence to be appended.
• Return Type: This method returns the updated CharArrayWriter object.

3. append (CharSequence char_sq, int start, int end): This method is used to appends a specified part of a character sequence to the writer.

Syntax:

public CharArrayWriter append(CharSequence char_sq, int start, int end)

• Parameter: This method takes three parameters which are listed below:
  • char_sq: The character sequence to be append.
  • start: It is the starting position of the character in the CharSequence.
  • end: It is the ending position of the character in the CharSequence.

4. flush(): This method is used to flushes the writer stream

Syntax:

public void flush()

Parameter: This method does not take any parameter.

5. toCharArray(): This method is used to return a character array from the Writer Stream.

Syntax:

public char[] toCharArray()

• Parameter: This method does not take any parameter.
• Return Type: This method returns the char[] array.

6. reset(): This method is used to resets the writer buffer.

Syntax:

public void reset()

Parameter: This method does not take any parameter

Java Program to Demonstrate Key Methods of CharArrayWriter Class

Example:

// Java program illustrating the working of CharArrayWriter class methods
// append(CharSequence char_sq), append(char Sw)
// append(CharSequence char_sq, int start,int end)
// flush(), reset(), toCharArray
import java.io.*;

public class Geeks
{
	public static void main(String[] args) throws IOException
	{
		// Initializing String Witer
		CharArrayWriter geek_writer1 = new CharArrayWriter();
		CharArrayWriter geek_writer2 = new CharArrayWriter();
		CharArrayWriter geek_writer3 = new CharArrayWriter();

		char[] Sw = {'G','E','E','K','S'};

		for(char c: Sw)
		{
			// Use of append(char Sw) :
			geek_writer1 .append(c);

			System.out.println("append(char Sw) :" + geek_writer1 .toString());
		}

		// Using flush() method
		geek_writer1.flush();
		System.out.println("\nUsing flush() : "+ geek_writer1.toString());
		System.out.println("");


		// Initializing Character Sequence
		CharSequence char_sq1 = "1 Hello 1";
		CharSequence char_sq2 = " : 2 Geeks 2";

		// Use of append(CharSequence char_sq)
		geek_writer2.append(char_sq1);
		geek_writer2.append(char_sq2);

		System.out.println("append(char_sq) : " + geek_writer2.toString());

		// Use of append(CharSequence char_sq,int start,int end)
		geek_writer3.append(char_sq1, 0, 3);
		geek_writer3.append(char_sq2, 3, 6);

		System.out.println("append(char_sq,start,end) : " + geek_writer3.toString());
		System.out.println("");
		

		// Use of toCharArray()
		char[] toChar1 = geek_writer1.toCharArray();
		for (char c1 : toChar1)
		{
			System.out.println("toCharArray : "+ c1);
		}

		geek_writer1.reset();
		System.out.println("\nReset is invoked");
		

		char[] toChar2 = geek_writer1.toCharArray();
		for (char c2 : toChar2)
		{
			System.out.println("toCharArray : "+ c2);
		}


		System.out.println("\ntoCharArray not working as reset is invoked");
	}
}

Output:

append(char Sw) :G
append(char Sw) :GE
append(char Sw) :GEE
append(char Sw) :GEEK
append(char Sw) :GEEKS

Using flush() : GEEKS

append(char_sq) : 1 Hello 1 : 2 Geeks 2
append(char_sq,start,end) : 1 H2 G

toCharArray : G
toCharArray : E
toCharArray : E
toCharArray : K
toCharArray : S

Reset is invoked

toCharArray not working as reset is invoked