Java.io.StreamTokenizer Class in Java | Set 2

Last Updated : 09 Jan, 2017

Methods:

parseNumbers() : java.io.StreamTokenizer.parseNumbers() specifies that the number in StreamTokenizer is parsed, so that each character – ” 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 ” has a numeric attribute.
When the parser encounters a word token that has the format of a double precision floating-point number, it treats the token as a number rather than a word, by setting the ttype field to the value TT_NUMBER and putting the numeric value of the token into the nval field.
Syntax :

  public void parseNumbers()  Parameters :  -----------  Return :  void

Implementation :

   // Java Program  illustrating use of parseNumbers() method 
  
import java.io.*; 
public class NewClass 
{ 
    public static void main(String[] args) throws InterruptedException, 
    FileNotFoundException, IOException 
    { 
        FileReader reader = new FileReader("ABC.txt"); 
        BufferedReader bufferread = new BufferedReader(reader); 
        StreamTokenizer token = new StreamTokenizer(bufferread); 
  
        // Use of parseNumbers() method 
        // specifies that the number in StreamTokenizer is parsed 
         token.parseNumbers(); 
  
        int t; 
        while ((t = token.nextToken()) != StreamTokenizer.TT_EOF) 
        { 
            switch (t) 
            { 
            case StreamTokenizer.TT_NUMBER: 
                System.out.println("Number : " + token.nval); 
                break; 
            case StreamTokenizer.TT_WORD: 
                System.out.println("Word : " + token.sval); 
                break; 
  
            } 
        } 
    } 
} 
 
  

Note :
This program won’t run here as no ‘ABC’ file exists. You can check this code on Java compiler on your system.
To check this code, create a file ‘ABC’ on your system.
‘ABC’ file contains :

Hello Geeks 1
This 2
3is
about 4
parseNumbers()

Output :

  Word : Hello  Word : Geeks  Number : 1.0  Word : This  Number : 2.0  Number : 3.0  Word : is  Word : about  Number : 4.0  Word : parseNumbers

quoteChar() : java.io.StreamTokenizer.quoteChar(int arg) specifies that it delimits the matching character as string constant in StreamTokenizer.
When the nextToken method encounters a string constant, the ttype field is set to the string delimiter and the sval field is set to the body of the string.
Syntax :

  public void quoteChar(int arg)  Parameters :  arg : the character to be dilimit   Return :  void

Implementation :

   // Java Program  illustrating use of quoteChar() method 
  
import java.io.*; 
public class NewClass 
{ 
    public static void main(String[] args) throws InterruptedException, 
                                             FileNotFoundException, IOException 
    { 
        FileReader reader = new FileReader("ABC.txt"); 
        BufferedReader bufferread = new BufferedReader(reader); 
        StreamTokenizer token = new StreamTokenizer(bufferread); 
  
        // specify o as a quote char 
        token.quoteChar('o'); 
  
        int t; 
        while ((t = token.nextToken()) != StreamTokenizer.TT_EOF) 
        { 
            switch (t) 
            { 
            case StreamTokenizer.TT_WORD: 
                System.out.println("Word : " + token.sval); 
                break; 
            case StreamTokenizer.TT_NUMBER: 
                System.out.println("Number : " + token.nval); 
                break; 
            default: 
                System.out.println((char) t + " encountered."); 
  
            } 
        } 
    } 
} 
 
  

Hello
Geeks
This
is
about
quoteChar()

Output :

  Word : Hell  o encountered.  Word : Geeks  Word : This  Word : is  Word : ab  o encountered.  Word : qu  o encountered.

resetSyntax() : java.io.StreamTokenizer.resetSynatx() resets Syntax when a number is met, so that all characters are set as ‘Ordinary’ in StreamTokenizer.
Syntax :

  public void resetSyntax()  Parameters :  ---------  Return :  void

Implementation :

   // Java Program  illustrating use of resetSyntax() method 
  
import java.io.*; 
public class NewClass 
{ 
    public static void main(String[] args) throws InterruptedException, 
                                             FileNotFoundException, IOException 
    { 
        FileReader reader = new FileReader("ABC.txt"); 
        BufferedReader bufferread = new BufferedReader(reader); 
        StreamTokenizer token = new StreamTokenizer(bufferread); 
  
         
        int t; 
        while ((t = token.nextToken()) != StreamTokenizer.TT_EOF) 
        { 
            switch (t) 
            { 
            case StreamTokenizer.TT_WORD: 
                System.out.println("Word : " + token.sval); 
                break; 
            case StreamTokenizer.TT_NUMBER: 
                  
                 // Use of resetSyntax()  
                 token.resetSyntax(); 
  
                System.out.println("Number : " + token.nval); 
                break; 
            default: 
                System.out.println((char) t + " encountered."); 
  
            } 
        } 
    } 
} 
 
  

Hello
This
is
resetSyntax()
1 xmpl
2 🙂
3
Output :

  Word : Hello  Word : This  Word : is  Word : resetSyntax  ( encountered.  ) encountered.  Number : 1.0    encountered.  x encountered.  m encountered.  p encountered.  l encountered.   encountered.     encountered.  2 encountered.    encountered.  : encountered.  ) encountered.   encountered.     encountered.  3 encountered.

slashSlashComments() : java.io.StreamTokenizer.slashSlashComments(boolean arg) specifies whether to consider C++ – style comments by tokenizer or not. If ‘arg’ is set true, then the StreamTokenizer recognises and ignores C++ – style comments. ‘//’ is considered as starting of a comment.
If the flag argument is false, then C++- style comments are not treated specially.
Syntax :

  public void slashSlashComments(boolean arg)  Parameters :  arg : tells whether to recognise and ignore C++ - style comments or not.  Return :  void

Implementation :

   // Java Program  illustrating use of slashSlashComments() method 
  
import java.io.*; 
public class NewClass 
{ 
    public static void main(String[] args) throws InterruptedException, 
                                               FileNotFoundException, IOException 
    { 
        FileReader reader = new FileReader("ABC.txt"); 
        BufferedReader bufferread = new BufferedReader(reader); 
        StreamTokenizer token = new StreamTokenizer(bufferread); 
  
        // Use of slashSlashComments() 
        // Here 'arg' is set to true i.e. to recognise and ignore C++style Comments 
        boolean arg = true; 
        token.slashSlashComments(arg); 
  
        int t; 
        while ((t = token.nextToken()) != StreamTokenizer.TT_EOF) 
        { 
            switch (t) 
            { 
            case StreamTokenizer.TT_WORD: 
                System.out.println("Word : " + token.sval); 
                break; 
            case StreamTokenizer.TT_NUMBER: 
                System.out.println("Number : " + token.nval); 
                break; 
            } 
        } 
    } 
} 
 
  

This program is about slashSlashComments // method

This method considers ‘method’ in ABC.txt file as an comment and thus ignores it.
Output :

  Word : This  Word : program  Word : is  Word : about  Word : slashSlashComments

slashStarComments() : java.io.StreamTokenizer.slashStarComments(boolean arg) specifies whether to consider C – style comments by tokenizer or not. If ‘arg’ is set true, then the StreamTokenizer recognises and ignores C – style comments. ‘/*……*/’ is considered as a comment.
Syntax :

  public void slashStarComments(boolean arg)  Parameters :  arg : tells whether to recognise and ignore C - style comments or not.  Return :  void

Implementation :

   // Java Program illustrating use of slashStarComments() method 
  
import java.io.*; 
public class NewClass 
{ 
    public static void main(String[] args) throws InterruptedException, 
                                              FileNotFoundException, IOException 
    { 
        FileReader reader = new FileReader("ABC.txt"); 
        BufferedReader bufferread = new BufferedReader(reader); 
        StreamTokenizer token = new StreamTokenizer(bufferread); 
  
        // Use of slashStarComments() 
        // Here 'arg' is set to true i.e. to recognise and ignore Cstyle Comments 
        boolean arg = true; 
        token.slashStarComments(true); 
  
        int t; 
        while ((t = token.nextToken()) != StreamTokenizer.TT_EOF) 
        { 
            switch (t) 
            { 
            case StreamTokenizer.TT_WORD: 
                System.out.println("Word : " + token.sval); 
                break; 
            case StreamTokenizer.TT_NUMBER: 
                System.out.println("Number : " + token.nval); 
                break; 
            } 
        } 
    } 
} 
 
  

This program is about slashStarComments /* method */ 123

This method considers ‘method’ in ABC.txt file as an comment and thus ignores it.
Output :

  Word : This  Word : program  Word : is  Word : about  Word : slashStarComments  Number : 123.0

whitespaceChars() : java.io.StreamTokenizer.whitespaceChars(int low, int high) specifies all the characters in the range of low to high as white space, which serves only to separate tokens in the InputStream.
Syntax :

  public void whitespaceChars(int low, int high)  Parameters :  low : lower range of character to be white spaced.  high : higher range of character to be white spaced   Return :  void

Implementation :

   // Java Program illustrating use of whitespaceChars() method 
  
import java.io.*; 
public class NewClass 
{ 
    public static void main(String[] args) throws InterruptedException, 
                                         FileNotFoundException, IOException 
    { 
        FileReader reader = new FileReader("ABC.txt"); 
        BufferedReader bufferread = new BufferedReader(reader); 
        StreamTokenizer token = new StreamTokenizer(bufferread); 
           
        // Use of whitespaceChars() method 
        // Here range is low = 'a' to high = 'c' 
        token.whitespaceChars('a','d'); 
  
        int t; 
        while ((t = token.nextToken()) != StreamTokenizer.TT_EOF) 
        { 
            switch (t) 
            { 
            case StreamTokenizer.TT_WORD: 
                System.out.println("Word : " + token.sval); 
                break; 
            case StreamTokenizer.TT_NUMBER: 
                System.out.println("Number : " + token.nval); 
                break; 
            } 
        } 
    } 
} 
 
  

This program is about whitespaceChars()

Output :

  Word : This  Word : progr  Word : m  Word : is  Word : out  Word : whitesp  Word : eCh  Word : rs

Java.io.Printstream Class in Java | Set 2

Mohit Gupta

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Java.io.StreamTokenizer Class in Java | Set 2

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