Java - StreamTokenizer quoteChar(int ch) method

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Description

The Java StreamTokenizer quoteChar(int ch) method specifies that matching pairs of this character delimit string constants in this tokenizer.

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.

If a string quote character is encountered, then a string is recognized, consisting of all characters after (but not including) the string quote character, up to (but not including) the next occurrence of that same string quote character, or a line terminator, or end of file. The usual escape sequences such as "\n" and "\t" are recognized and converted to single characters as the string is parsed.

Any other attribute settings for the specified character are cleared.

Declaration

Following is the declaration for java.io.StreamTokenizer.quoteChar(int ch) method.

public void quoteChar(int ch)

Parameters

ch − The character.

Return Value

This method does not return a value.

Exception

NA

Example - Usage of StreamTokenizer quoteChar(int ch) method

The following example shows the usage of StreamTokenizer quoteChar(int ch) method.

StreamTokenizerDemo.java

package com.tutorialspoint;

import java.io.BufferedReader;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.InputStreamReader;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.Reader;
import java.io.StreamTokenizer;

public class StreamTokenizerDemo {
   public static void main(String[] args) {
      String text = "Hello. This is a text \n that will be split "
         + "into tokens. 1 + 1 = 2";
         
      try {
         // create a new file with an ObjectOutputStream
         FileOutputStream out = new FileOutputStream("test.txt");
         ObjectOutputStream oout = new ObjectOutputStream(out);

         // write something in the file
         oout.writeUTF(text);
         oout.flush();

         // create an ObjectInputStream for the file we created before
         ObjectInputStream ois =  new ObjectInputStream(new FileInputStream("test.txt"));

         // create a new tokenizer
         Reader r = new BufferedReader(new InputStreamReader(ois));
         StreamTokenizer st = new StreamTokenizer(r);

         // specify o as a quote char
         st.quoteChar('o');

         // print the stream tokens
         boolean eof = false;
         
         do {
            int token = st.nextToken();

            switch (token) {
               case StreamTokenizer.TT_EOF:
                  System.out.println("End of File encountered.");
                  eof = true;
                  break;
                  
               case StreamTokenizer.TT_EOL:
                  System.out.println("End of Line encountered.");
                  break;
                  
               case StreamTokenizer.TT_WORD:
                  System.out.println("Word: " + st.sval);
                  break;
                  
               case StreamTokenizer.TT_NUMBER:
                  System.out.println("Number: " + st.nval);
                  break;
                  
               default:
                  System.out.println((char) token + " encountered.");
                  
                  if (token == '!') {
                     eof = true;
                  }
            }
         } while (!eof);

      } catch (Exception ex) {
         ex.printStackTrace();
      }
   }
}

Output

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

Word: AHell
o encountered.
Word: that
Word: will
Word: be
Word: split
Word: int
o encountered.
Word: kens.
Number: 1.0
+ encountered.
Number: 1.0
= encountered.
Number: 2.0
End of File encountered.

Example - Use double quotes (") to treat quoted text as one token

The following example shows the usage of StreamTokenizer quoteChar(int ch) method.

StreamTokenizerDemo.java

package com.tutorialspoint;

import java.io.IOException;
import java.io.Reader;
import java.io.StreamTokenizer;
import java.io.StringReader;

public class StreamTokenizerDemo {
   public static void main(String[] args) throws IOException {
      String input = "\"Hello World\" test";

      Reader reader = new StringReader(input);
      StreamTokenizer tokenizer = new StreamTokenizer(reader);

      tokenizer.quoteChar('"'); // Set " as the quote character

      System.out.println("Tokens:");
      while (tokenizer.nextToken() != StreamTokenizer.TT_EOF) {
         if (tokenizer.ttype == '"') {
            System.out.println("Quoted string: " + tokenizer.sval);
         } else if (tokenizer.ttype == StreamTokenizer.TT_WORD) {
            System.out.println("Word: " + tokenizer.sval);
         }
      }
   }
}

Output

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

Tokens:
Quoted string: Hello World
Word: test

Explanation

• The quoted string "Hello World" is returned as one token.

• sval contains Hello World (without quotes).

• ttype is the quote character (").

Example - Use single quote (') as quote character

The following example shows the usage of StreamTokenizer quoteChar(int ch) method.

StreamTokenizerDemo.java

package com.tutorialspoint;

import java.io.IOException;
import java.io.Reader;
import java.io.StreamTokenizer;
import java.io.StringReader;

public class StreamTokenizerDemo {
   public static void main(String[] args) throws IOException {
      String input = "'data set' is loaded";

      Reader reader = new StringReader(input);
      StreamTokenizer tokenizer = new StreamTokenizer(reader);

      tokenizer.quoteChar('\''); // Set single quote as quote character

      System.out.println("Tokens:");
      while (tokenizer.nextToken() != StreamTokenizer.TT_EOF) {
         if (tokenizer.ttype == '\'') {
            System.out.println("Quoted string: " + tokenizer.sval);
         } else if (tokenizer.ttype == StreamTokenizer.TT_WORD) {
            System.out.println("Word: " + tokenizer.sval);
         }
      }
   }
}

Output

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

Tokens:
Quoted string: data set
Word: is
Word: loaded

Explanation

• The tokenizer treats 'data set' as one token.

• The surrounding single quotes are not included in sval.