DoubleBuffer rewind() Method in Java with Examples
Last Updated :
10 Sep, 2019
The rewind() method of java.nio.DoubleBuffer Class is used to rewind this buffer. This method sets the position to zero and the limit remains unaffected and if there is any position which was previously marked will be discarded.
This method should be invoked when there is any necessity of sequence of channel-write or get operations. This means that if buffer data is already written then it needs to be copied into another array. For example:
out.write(buf); // Writes remaining data
buf.rewind(); // Rewind the buffer
buf.get(array); // Copy the data into array
Syntax:
public final DoubleBuffer rewind()
Parameters: The method does not take any parameters.
Return Value: This method returns this buffer.
Below are the examples to illustrate the rewind() method:
Examples 1:
import java.nio.*;
import java.util.*;
public class GFG {
public static void main(String[] args)
{
DoubleBuffer doubleBuffer = DoubleBuffer.allocate( 4 );
doubleBuffer.put( 10.5 );
doubleBuffer.put( 20.5 );
System.out.println( "Buffer before operation: "
+ Arrays.toString(
doubleBuffer.array())
+ "\nPosition: "
+ doubleBuffer.position()
+ "\nLimit: "
+ doubleBuffer.limit());
doubleBuffer.rewind();
System.out.println( "\nBuffer after operation: "
+ Arrays.toString(
doubleBuffer.array())
+ "\nPosition: "
+ doubleBuffer.position()
+ "\nLimit: "
+ doubleBuffer.limit());
}
}
|
Output:
Buffer before operation: [10.5, 20.5, 0.0, 0.0]
Position: 2
Limit: 4
Buffer after operation: [10.5, 20.5, 0.0, 0.0]
Position: 0
Limit: 4
Examples 2:
import java.nio.*;
import java.util.*;
public class GFG {
public static void main(String[] args)
{
DoubleBuffer doubleBuffer
= DoubleBuffer.allocate( 5 );
doubleBuffer.put( 10.5 );
doubleBuffer.put( 20.5 );
doubleBuffer.put( 30.5 );
doubleBuffer.mark();
System.out.println( "Buffer before operation: "
+ Arrays.toString(
doubleBuffer.array())
+ "\nPosition: "
+ doubleBuffer.position()
+ "\nLimit: "
+ doubleBuffer.limit());
doubleBuffer.rewind();
System.out.println( "\nBuffer after operation: "
+ Arrays.toString(
doubleBuffer.array())
+ "\nPosition: "
+ doubleBuffer.position()
+ "\nLimit: "
+ doubleBuffer.limit());
}
}
|
Output:
Buffer before operation: [10.5, 20.5, 30.5, 0.0, 0.0]
Position: 3
Limit: 5
Buffer after operation: [10.5, 20.5, 30.5, 0.0, 0.0]
Position: 0
Limit: 5
Reference: https://docs.oracle.com/javase/9/docs/api/java/nio/DoubleBuffer.html#rewind–
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