Java - Using the flip() and hasRemaining() Methods of a Buffer Between Relative Reads and Writes

  1. HOME
  2. Java
  3. File Input Output
  4. Buffer Writing

Description

Using the flip() and hasRemaining() Methods of a Buffer Between Relative Reads and Writes

Demo

import java.nio.ByteBuffer;

public class Main {
  public static void main(String[] args) {
    // Create a byte buffer of capacity 8
    ByteBuffer bb = ByteBuffer.allocate(8);

    // Print the buffer info
    System.out.println("After creation:");
    printBufferInfo(bb);/* w  w w  .  jav  a 2 s. c  o m*/

    // Must call flip() to reset the position to zero because
    // the printBufferInfo() method uses relative get() method,
    // which increments the position
    bb.flip();

    // Populate buffer elements from 50 to 57
    int i = 50;
    while (bb.hasRemaining()) {
      bb.put((byte) i++);
    }

    // Call flip() again to reset the position to zero,
    // because the above put() call incremented the position
    bb.flip();

    // Print the buffer info
    System.out.println("After populating data:");
    printBufferInfo(bb);
  }

  public static void printBufferInfo(ByteBuffer bb) {
    int limit = bb.limit();
    System.out.println("Position = " + bb.position() + ", Limit = " + limit);
    // We use absolute method of reading the data, so that we do
    // not affect the position of the buffer
    System.out.print("Data: ");
    while (bb.hasRemaining()) {
      System.out.print(bb.get() + " ");
    }
    System.out.println();
  }
}

Result

Related Topic