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ByteBuffer getChar() method in Java with Examples

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source link: https://www.geeksforgeeks.org/bytebuffer-getchar-method-in-java-with-examples/
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ByteBuffer getChar() method in Java with Examples

  • Last Updated : 22 Jul, 2019
getChar()

The getChar() method of java.nio.ByteBuffer class is used to get method for reading a char value

Reads the next two bytes at this buffer’s current position, composing them into a char value according to the current byte order, and then increments the position by two.

Syntax:

public abstract char getChar()

Return Value: This method returns the char value at the buffer’s current position

Throws: This method throws BufferUnderflowException – If the buffer’s current position is not smaller than its limit, then this exception is thrown.

Below are the examples to illustrate the getChar() method:

Examples 1:

// Java program to demonstrate
// getChar() method
import java.nio.*;
import java.util.*;
public class GFG {
public static void main(String[] args)
{
// Declaring the capacity of the ByteBuffer
int capacity = 50;
// Creating the ByteBuffer
try {
// creating object of ByteBuffer
// and allocating size capacity
ByteBuffer bb = ByteBuffer.allocate(capacity);
// putting the string in the bytebuffer
bb.asCharBuffer().put("Geeks");
// rewind the Bytebuffer
bb.rewind();
// Declaring the variable
char c;
// print the ByteBuffer
System.out.println("Original ByteBuffer: ");
while ((c = bb.getChar()) != 0)
System.out.print(c + " ");
// rewind the Bytebuffer
bb.rewind();
// Reads the char at this buffer's current position
// using getChar() method
char value = bb.getChar();
// print the char value
System.out.println("\n\nByte Value: " + value);
// Reads the  char at this buffer's next position
// using getChar() method
char value1 = bb.getChar();
// print the char value
System.out.print("\nNext Byte Value: " + value1);
}
catch (IllegalArgumentException e) {
System.out.println("\nException Thrown: " + e);
}
catch (ReadOnlyBufferException e) {
System.out.println("\nException Thrown: " + e);
}
catch (BufferUnderflowException e) {
System.out.println("\nException Thrown: " + e);
}
}
}
Output:
Original ByteBuffer: 
G e e k s 

Byte Value: G

Next Byte Value: e

Examples 2:

// Java program to demonstrate
// getChar() method
import java.nio.*;
import java.util.*;
public class GFG {
public static void main(String[] args)
{
// Declaring the capacity of the ByteBuffer
int capacity = 8;
// Creating the ByteBuffer
try {
// creating object of ByteBuffer
// and allocating size capacity
ByteBuffer bb = ByteBuffer.allocate(capacity);
// putting the string in the bytebuffer
bb.asCharBuffer().put("abc");
// rewind the Bytebuffer
bb.rewind();
// Declaring the variable
char c;
// print the ByteBuffer
System.out.print("Original ByteBuffer: ");
while ((c = bb.getChar()) != 0)
System.out.print(c + " ");
// rewind the Bytebuffer
bb.rewind();
// Reads the char at this buffer's current position
// using getChar() method
char value = bb.getChar();
// print the char value
System.out.println("\n\nFirst char Value: " + value);
// Reads the  char at this buffer's next position
// using getChar() method
char value1 = bb.getChar();
// print the char value
System.out.println("\nSecond char Value: " + value1);
// Reads the  char at this buffer's next position
// using getChar() method
char value2 = bb.getChar();
// print the char value
System.out.println("\nThird char Value: " + value2);
// Reads the  char at this buffer's next position
// using getChar() method
System.out.print("\nsince the buffer current position is incremented");
System.out.print(" to greater than its limit ");
char value3 = bb.getChar();
char value4 = bb.getChar();
}
catch (BufferOverflowException e) {
System.out.println("\nException Thrown: " + e);
}
catch (ReadOnlyBufferException e) {
System.out.println("\nException Thrown: " + e);
}
catch (BufferUnderflowException e) {
System.out.println("\nException Thrown: " + e);
}
}
}
Output:
Original ByteBuffer: a b c 

First char Value: a

Second char Value: b

Third char Value: c

since the buffer current position is incremented to greater than its limit 
Exception Thrown: java.nio.BufferUnderflowException
get(int index)

The get(int index) method of ByteBuffer is used to reads two bytes at the given index, composing them into a char value according to the current byte order.

Syntax:

public abstract char getChar(int index)

Parameters: This method takes index (The index from which the Byte will be read) as a parameter.

Return Value: This method returns the char value at the given index.

Exception: This method throws IndexOutOfBoundsException. If index is negative or not smaller than the buffer’s limit this exception is thrown.

Below are the examples to illustrate the get(int index) method:

Examples 1:

// Java program to demonstrate
// getChar() method
import java.nio.*;
import java.util.*;
public class GFG {
public static void main(String[] args)
{
// Declaring the capacity of the ByteBuffer
int capacity = 50;
// Creating the ByteBuffer
try {
// creating object of ByteBuffer
// and allocating size capacity
ByteBuffer bb = ByteBuffer.allocate(capacity);
// putting the string in the bytebuffer
bb.asCharBuffer().put("abc");
// rewind the Bytebuffer
bb.rewind();
// Declaring the variable
char c;
// print the ByteBuffer
System.out.print("Original ByteBuffer: ");
while ((c = bb.getChar()) != 0)
System.out.print(c + " ");
// rewind the Bytebuffer
bb.rewind();
// Reads the char at this buffer's at index 0
// using getChar() method
char value0 = bb.getChar(0);
// print the char value
System.out.println("\n\nchar Value at index 0: "
+ value0);
// Reads the  char at this buffer's at index 2
// using getChar() method
char value1 = bb.getChar(2);
// print the char value
System.out.println("\nchar Value at index 2: "
+ value1);
// Reads the  char at this buffer's at index 4
// using getChar() method
char value2 = bb.getChar(4);
// print the char value
System.out.println("\nchar Value at index 4: "
+ value2);
}
catch (IllegalArgumentException e) {
System.out.println("\nException Thrown: " + e);
}
catch (ReadOnlyBufferException e) {
System.out.println("\nException Thrown: " + e);
}
catch (BufferUnderflowException e) {
System.out.println("\nException Thrown: " + e);
}
}
}
Output:
Original ByteBuffer: a b c 

char Value at index 0: a

char Value at index 2: b

char Value at index 4: c

Examples 2:

// Java program to demonstrate
// getChar() method
import java.nio.*;
import java.util.*;
public class GFG {
public static void main(String[] args)
{
// Declaring the capacity of the ByteBuffer
int capacity = 50;
// Creating the ByteBuffer
try {
// creating object of ByteBuffer
// and allocating size capacity
ByteBuffer bb = ByteBuffer.allocate(capacity);
// putting the string in the bytebuffer
bb.asCharBuffer().put("abc");
// rewind the Bytebuffer
bb.rewind();
// Declaring the variable
char c;
// print the ByteBuffer
System.out.print("Original ByteBuffer: ");
while ((c = bb.getChar()) != 0)
System.out.print(c + " ");
// rewind the Bytebuffer
bb.rewind();
// Reads the char at this buffer's at index 0
// using getChar() method
char value0 = bb.getChar(0);
// print the char value
System.out.println("\n\nchar Value at index 0: "
+ value0);
// Reads the  char at this buffer's at index 2
// using getChar() method
char value1 = bb.getChar(2);
// print the char value
System.out.println("\nchar Value at index 2: "
+ value1);
// Reads the  char at this buffer's at index 4
// using getChar() method
System.out.println("\nTrying to get the char"
+ " at negative index ");
char value2 = bb.getChar(-4);
}
catch (IndexOutOfBoundsException e) {
System.out.println("\nException Thrown: "
+ e);
}
catch (ReadOnlyBufferException e) {
System.out.println("\nException Thrown: "
+ e);
}
catch (BufferUnderflowException e) {
System.out.println("\nException Thrown: "
+ e);
}
}
}
Output:
Original ByteBuffer: a b c 

char Value at index 0: a

char Value at index 2: b

Trying to get the char at a negative index 

Exception Thrown: java.lang.IndexOutOfBoundsException

Reference:


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