Java.io.StreamTokenizer Class in Java | Set 2

Last Updated : 09 Jan, 2017

StringTokenizer Class in Java | Set 1

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

// 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

// 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.");

            }
        }
    }
}

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

// 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.");

            }
        }
    }
}

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

// 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;
            }
        }
    }
}

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 : 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

// 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;
            }
        }
    }
}

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 : 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

// 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;
            }
        }
    }
}

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 : This program is about whitespaceChars() Output :

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

kartik

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Practice Tags :

Java

Java.io.StreamTokenizer Class in Java | Set 2

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