Java.io.InputStreamReader.ready() Method

Description

The java.io.InputStreamReader.ready() method tells whether this stream is ready to be read.

Declaration

Following is the declaration for java.io.InputStreamReader.ready() method:

public boolean ready()

Parameters

• NA

Return Value

The method returns true if the next read is guaranteed not to block for input, else false.

Exception

• IOException -- If an I/O error occurs

Example

The following example shows the usage of java.io.InputStreamReader.ready() method.

package com.tutorialspoint;

import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStreamReader;

public class InputStreamReaderDemo {
   public static void main(String[] args) throws IOException {
      
      FileInputStream fis = null;
      InputStreamReader isr =null;
      boolean bool = false;
      int i;
      char c;
      
      try {
         // new input stream reader is created 
         fis = new FileInputStream("C:/test.txt");
         isr = new InputStreamReader(fis);
         
         // reads into the char buffer
         while((i=isr.read())!=-1)
         {
            // converts int to char
            c=(char)i;
            
            // prints the character
            System.out.println("Character read: "+c);
            
            // true if the next read is guaranteed
            bool = isr.ready();
            
            // prints
            System.out.println("Ready to read: "+bool);
         }
      } catch (Exception e) {
      
         // print error
         e.printStackTrace();
      } finally {
         
         // closes the stream and releases resources associated
         if(fis!=null)
            fis.close();
         if(isr!=null)
            isr.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:

ABCDE

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

Character read: A
Ready to read: true
Character read: B
Ready to read: true
Character read: C
Ready to read: true
Character read: D
Ready to read: true
Character read: E
Ready to read: false