Java String Reader

StreamReaderClass:

This class is present in the java.io package. It is a character stream in which string act as a source.This method provides to read characters from a string.

Character Stream:

• This class is provided by java.io. package.
• This class is used to overcome the limitations of the byte stream.
• The main purpose is to read characters and write the characters.
• This stream is divided into types of classes. They are:
• Reader class
• Writer class.

Reader class:

• It is used to read characters from the input stream.
• It throws an IO Exception while reading the input.

Writer class:

• It is used to write characters to the output stream.
• Methods present in class throw IO Exception.

Declaration of StringReader class:

  public class StringReader extends Reader;

Methods in StringReader class:

• read()
• close()
• read(char[] c, int start, int length)
• skip(long s)
• ready()
• mark()
• reset()
• mark supported()

read():

• It is used to read single characters from the stream.
• It returns -1 if it reaches the end of the file or end of input.
• It represents whether the next character is present or not.
• Return type of read() method is int(Integer).

Syntax:

public int read()

Program:

import java.io.*;
 class Example1 {
   public static void main(String[] s) throws IOException {
      String s1 = "JAVA";
      StringReader s2=new StringReader(s1);
      for(int i=0;i<s1.length();i++)
      {
      char c=(char) s2.read();
      System . out . println(c);
      }
      s2.close();
   }
}

Output:

J
A
V
A

• It is used to close the character stream.
• Return type of close() method is void.
• If the stream has been closed then performing methods like read() and other methods throw an IOException.

Syntax:

  public void close()

Program:

Import java.io.*;
class Example15
{
public static void main(String s[]) throws IOException
{
String string1 = “JavaProgramming”;
StringReader String2=new StringReader(string1);
System.out.print(String2.read());
String2.close();
}
}

Output:

J

read(char[] c, int start, int length):

• It stores the reading characters in the array form.
• It returns the count of characters.
• Integer is the return type.

Syntax:

public int read(char[] c, int start, int length)

c -It is the Destination buffer

start – at which index it starts writing characters.

length -.Several characters.

Program:

import java.io.*;
class Example2 {
public static void main(String[] s) throws IOException {
String s2 = "JAVA";
StringReader s2=new StringReader(s1);
char c[]=new char[10];
try{
s2.read(c,0,5);
System . out .  println(c);
c.close();
}
catch (IOException E){
System. out. println(E);
}
}

    Output:

     Java

skip (long s):

• It returns the number of skipped characters from the stream.
• Long is the return type.

Syntax:

   public long skip(long s)

Program:

import java.io.*;
class Example14
{
  public static void main(String s[]) throws IOException
 {
   String s=”JavaProgramming”;
   StringReader s1= new StringReader(s);
   for (int i = 0; i < 4; i++) {  
            char c = (char) s1.read();
            s1.skip(3);  
  System . out . print(c);
         }  
            s1.close();  
   }  
}

Output:

JPri

ready():

• It checks whether the character stream is ready to be read or not.
• Return type of ready() method is boolean.

Syntax:

public boolean ready();

Program:

import java.io.*;
    class Example18
    {
      public static void main ( String s[]) throws IOException
     {
        String string1=”Java”;
        StringReader string2=new StringReader(string1);
        System . out . println(“Print true if it is ready otherwise false:”+string2.ready());
}
}

Output:

Print true if it is ready otherwise false: true

mark(int Limit):

• This method is used to represent the present position in the stream.
• Void is the return type.

Syntax:

public void mark(int Limit)

Program:

import java.io.*;  
class Example17{  
  public static void main(String[] s) throws IOException{  
    StringReader string1= new StringReader("Apple");  
    string1 . mark(1);  
    System . out . println(string1.read());
     string1 . close();  
    
  }  
} 

  Output:

65

reset ():

• It is used to reset the stream with the most recent mark.
• Return type of reset(0 method is void.

Syntax:

public void reset () throws IOException.

Program:

import java.io.*;  
 class Example10 
{  
  public static void main(String[] s) throws IOException
{  
    StringReader string1 = new StringReader("Coding");  
    string1.mark(1);  
    System . out . println(string1 . read());
     string1 . reset();
     string1 . close();  
    
  }  
}

Output:

67

mark supported ():

• It is used to check whether it supports the mark() method or not.
• void is the return type.

Syntax:

 public void markSupported()

Program:

import java.io.*;
class Example7
 {
    public static void main(String[] s) throws IOException
    {
        try {
  String s1 = “JavaProgramming”;
StringReader s2= new StringReader(s1);
   System . out . println(“Print True if it supports otherwise False:"
                               + s2.markSupported());
  
            s2.close();
        }
 
    }
}

Output :

Print True if it supports otherwise False: true