Counts words in a file, outputs results in sorted form : File Commands « File Input Output « Java

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3. File Commands

Counts words in a file, outputs results in sorted form

    
// : c12:WordCount.java
// Counts words in a file, outputs results in sorted form.
// {Args: WordCount.java}
// From 'Thinking in Java, 3rd ed.' (c) Bruce Eckel 2002
// www.BruceEckel.com. See copyright notice in CopyRight.txt.

import java.io.BufferedReader;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import java.io.StreamTokenizer;
import java.util.Collection;
import java.util.Iterator;
import java.util.Set;
import java.util.TreeMap;

class Counter {
  private int i = 1;

  public int read() {
    return i;
  }

  public void increment() {
    i++;
  }
}

public class WordCount1 {
  private static final String usage = "Usage: \nWordCount file\n"
      + "Counts the words in the file and "
      + "outputs results in sorted form.";

  private FileReader file;

  private StreamTokenizer st;

  // A TreeMap keeps keys in sorted order:
  private TreeMap counts = new TreeMap();

  public WordCount1(String filename) throws FileNotFoundException {
    try {
      file = new FileReader(filename);
      st = new StreamTokenizer(new BufferedReader(file));
      st.ordinaryChar('.');
      st.ordinaryChar('-');
    } catch (FileNotFoundException e) {
      throw new RuntimeException(e);
    }
  }

  public void dispose() {
    try {
      file.close();
    } catch (IOException e) {
      throw new RuntimeException(e);
    }
  }

  public void countWords() {
    try {
      while (st.nextToken() != StreamTokenizer.TT_EOF) {
        String s;
        switch (st.ttype) {
        case StreamTokenizer.TT_EOL:
          s = new String("EOL");
          break;
        case StreamTokenizer.TT_NUMBER:
          s = Double.toString(st.nval);
          break;
        case StreamTokenizer.TT_WORD:
          s = st.sval; // Already a String
          break;
        default: // single character in ttype
          s = String.valueOf((char) st.ttype);
        }
        if (counts.containsKey(s))
          ((Counter) counts.get(s)).increment();
        else
          counts.put(s, new Counter());
      }
    } catch (IOException e) {
      throw new RuntimeException(e);
    }
  }

  public Collection values() {
    return counts.values();
  }

  public Set keySet() {
    return counts.keySet();
  }

  public Counter getCounter(String s) {
    return (Counter) counts.get(s);
  }

  public static void main(String[] args) throws FileNotFoundException {
    if (args.length == 0) {
      System.out.println(usage);
      System.exit(1);
    }
    WordCount1 wc = new WordCount1(args[0]);
    wc.countWords();
    Iterator keys = wc.keySet().iterator();
    while (keys.hasNext()) {
      String key = (String) keys.next();
      System.out.println(key + ": " + wc.getCounter(key).read());
    }
    wc.dispose();
  }
} ///:~



           
         
    
    
    
  

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