Java - ByteArrayInputStream available()

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Description

The Java ByteArrayInputStream.available() method returns the number of bytes left to be read from this input stream. It returns a value as count - pos, which is the number of bytes remaining to be read from the input buffer.

Declaration

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

public int available()

Parameters

NA

Return Value

The value returns the count of bytes to be read from the input stream.

Exception

NA

Example 1

The following example shows the usage of Java ByteArrayInputStream available() method. We've created a variable buf as byte[] and initialized with few bytes. We've created a ByteArrayInputStream reference and then initialized it with buf variable. In while loop, we're checking if stream contains any byte using available() method and then its bytes are read using read() method.

import java.io.ByteArrayInputStream;
import java.io.IOException;
public class ByteStreamTest {
   public static void main(String[] args) throws IOException {
      byte[] buf = {65, 66, 67, 68, 69};
      ByteArrayInputStream bais = null;
      
      try {
         // create new byte array input stream
         bais = new ByteArrayInputStream(buf);
         
         int count =0;
         
         // read till the end of the stream
         while((count = bais.available())>0) {
            
            // convert byte to character
            char c = (char)bais.read();
            
            // print number of bytes available
            System.out.print("available byte(s) : "+ count);
            
            // print characters read form the byte array
            System.out.println(" & byte read : "+c);
         }
         
      } catch(Exception e) {
         // if I/O error occurs
         e.printStackTrace();
      } finally {
         if(bais!=null)
            bais.close();
      }
   }
}

Output

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

available byte(s) : 5 & byte read : A
available byte(s) : 4 & byte read : B
available byte(s) : 3 & byte read : C
available byte(s) : 2 & byte read : D
available byte(s) : 1 & byte read : E

Example 2

The following example shows the usage of Java ByteArrayInputStream available() method. We've created a variable buf as byte[] and initialized with empty array. We've created a ByteArrayInputStream reference and then initialized it with buf variable. In if loop, we're checking if stream contains any byte using available() method and then its result is printed.

import java.io.ByteArrayInputStream;
import java.io.IOException;
public class ByteStreamTest {
   public static void main(String[] args) throws IOException {
      byte[] buf = {};
      ByteArrayInputStream bais = null;
      
      try {
         // create new byte array input stream
         bais = new ByteArrayInputStream(buf);
         
         if(bais.available()>0) {
            System.out.print("bytes are available");
         }else{
            System.out.print("byte stream is empty");
         } 
      } catch(Exception e) {
         // if I/O error occurs
         e.printStackTrace();
      } finally {
         if(bais!=null)
            bais.close();
      }
   }
}

Output

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

byte stream is empty