Java.io.FilterInputStream.available() Method

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Description

The java.io.FilterInputStream.available() returns an estimate of the number of bytes that can be read from this input stream without blocking by the next invoker of a method for this input stream.

Declaration

Following is the declaration for java.io.FilterInputStream.available() method −

public int available()

Parameters

NA

Return Value

The method returns an estimate of the number of bytes that can be read.

Exception

IOException − If an I/O error occurs.

Example

The following example shows the usage of java.io.FilterInputStream.available() method.

package com.tutorialspoint;

import java.io.BufferedInputStream;
import java.io.FileInputStream;
import java.io.FilterInputStream;
import java.io.IOException;
import java.io.InputStream;

public class FilterInputStreamDemo {
   public static void main(String[] args) throws IOException {
      InputStream is = null; 
      FilterInputStream fis = null; 
      int i = 0, j = 0;
      char c;
      
      try {
         // create input streams
         is = new FileInputStream("C://test.txt");
         fis = new BufferedInputStream(is);
         
         // read till the end of the file
         while((i = fis.read())!=-1) {
         
            // converts integer to character
            c = (char)i;
            
            // prints
            System.out.print("Read: "+c);
            
            // number of bytes available
            j = fis.available();
            
            // prints
            System.out.println("; Available bytes: "+j);
         }
         
      } catch(Exception e) {
         // if any error occurs
         e.printStackTrace();
      } finally {
         // releases any system resources associated with the stream
         if(is!=null)
            is.close();
         if(fis!=null)
            fis.close();
      }
   }
}

Assuming we have a text file c:/test.txt, which has the following content. This file will be used as an input for our example program −

ABCDEF

Let us compile and run the above program, this will produce the following result −

Read: A; Available bytes: 5
Read: B; Available bytes: 4
Read: C; Available bytes: 3
Read: D; Available bytes: 2
Read: E; Available bytes: 1
Read: F; Available bytes: 0