The rewind() method of java.nio.ByteBuffer Class is used to rewind this buffer. The position is set to zero and the mark is discarded. Invoke this method before a sequence of channel-write or get operations, assuming that the limit has already been set appropriately. Invoking this method neither changes nor discards the mark’s value.
Syntax:
public ByteBuffer rewind()
Return Value: This method returns this buffer.
Below are the examples to illustrate the rewind() method:
Examples 1:
// Java program to demonstrate // rewind() method import java.nio.*;
import java.util.*;
public class GFG {
public static void main(String[] args)
{
// defining and allocating ByteBuffer
// using allocate() method
ByteBuffer byteBuffer = ByteBuffer.allocate( 4 );
// put byte value in byteBuffer
// using put() method
byteBuffer.put(( byte ) 20 );
byteBuffer.put(( byte ) 'a' );
// print the byte buffer
System.out.println( "Buffer before operation: "
+ Arrays.toString(byteBuffer.array())
+ "\nPosition: " + byteBuffer.position()
+ "\nLimit: " + byteBuffer.limit());
// rewind the Buffer
// using rewind() method
byteBuffer.rewind();
// print the bytebuffer
System.out.println( "\nBuffer after operation: "
+ Arrays.toString(byteBuffer.array())
+ "\nPosition: " + byteBuffer.position()
+ "\nLimit: " + byteBuffer.limit());
}
} |
Output:
Buffer before operation: [20, 97, 0, 0] Position: 2 Limit: 4 Buffer after operation: [20, 97, 0, 0] Position: 0 Limit: 4
Examples 2:
// Java program to demonstrate // rewind() method import java.nio.*;
import java.util.*;
public class GFG {
public static void main(String[] args)
{
// defining and allocating ByteBuffer
// using allocate() method
ByteBuffer byteBuffer = ByteBuffer.allocate( 5 );
// put byte value in byteBuffer
// using put() method
byteBuffer.put(( byte ) 20 );
byteBuffer.put(( byte ) 30 );
byteBuffer.put(( byte ) 40 );
// mark will be going to discarded by rewind()
byteBuffer.mark();
// print the buffer
System.out.println( "Buffer before operation: "
+ Arrays.toString(byteBuffer.array())
+ "\nPosition: " + byteBuffer.position()
+ "\nLimit: " + byteBuffer.limit());
// Rewind the Buffer
// using rewind() method
byteBuffer.rewind();
// print the buffer
System.out.println( "\nBuffer after operation: "
+ Arrays.toString(byteBuffer.array())
+ "\nPosition: " + byteBuffer.position()
+ "\nLimit: " + byteBuffer.limit());
}
} |
Output:
Buffer before operation: [20, 30, 40, 0, 0] Position: 3 Limit: 5 Buffer after operation: [20, 30, 40, 0, 0] Position: 0 Limit: 5
Reference: https://docs.oracle.com/javase/9/docs/api/java/nio/ByteBuffer.html#rewind–