How to clean a buffer using clear method in java.

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How to clean a buffer using clear method in java.
Posted on: July 24, 2010 at 12:00 AM

In this tutorial you will see how to clean a buffer using clear method in java.

How to clean a buffer using clear method in java.

In this tutorial, we will discuss the use of clear() method. The Buffer class is a
container for handling primitive data type. The clear() method is available in Buffer class.
The ByteBuffer class is available in java.nio package.

In this example, the clear() method clean a buffer for further use, and after clear
method the position will be zero and limit will be capacity of buffer. The method allocate
( int capacity) creates a new byte buffer. The FileChannel class creates a channel for reading,
and writing file. The FileChannel is similar to the stream but they are few different. The channel
can read write both, but stream can either read-only or write-only. The getChannel method of
FileInputStream class returns the channel associated with this file input stream. The read()
method of FileChannel class fills byte buffer.

About ByteBuffer API:

The java.nio.ByteBuffer class extends java.nio.Buffer class. It provides the following methods:

Return type	Method	Description
static ByteBuffer	allocate( int capacity)	The allocate() method create a byte buffer of specified capacity.

code


import java.io.*;

import java.nio.*;

import java.io.FileInputStream;

import java.nio.ByteBuffer;

import java.nio.channels.FileChannel;



public class ByteBufferClear {

  public static void main(String[] args) throws IOException {

  FileInputStream aFile = new FileInputStream("bharat.txt");

 FileInputStream bFile = new FileInputStream("test.txt");

    FileChannel inChannel = aFile.getChannel();

    FileChannel inChannelb = bFile.getChannel();

    ByteBuffer buf = ByteBuffer.allocate(55);

    int bytesRead = inChannel.read(buf);

    buf.flip();

  System.out.print("\nBefore
clear method data in buffer\n");

    while (buf.hasRemaining()) {

      System.out.print((char) buf.get());

    }

    buf.clear();

    int bytesReadb = inChannelb.read(buf);

    buf.flip();

  System.out.print("\nAfter clear method data in buffer\n");

    while (buf.hasRemaining()) {

      System.out.print((char) buf.get());

    }

    aFile.close();

  }

}

Following is the output if you run the application:

C:\>java ByteBufferClear
Before clear method data in buffer
import java.nio.ByteBuffer;
import java.nio.channels.F
After clear method data in buffer
import java.io.*;

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