things: Port to Java.

10-things/tf_10.java

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+import java.io.*;
+import java.util.*;
+
+public class tf_10 {
+    /*
+     * The main function
+     */
+    public static void main(String[] args) throws IOException {
+        new WordFrequencyController(args[0]).run();
+    }
+}
+
+/*
+ * The classes
+ */
+
+abstract class TFExercise {
+    public String getInfo() {
+        return this.getClass().getName();
+    }
+}
+
+class WordFrequencyController extends TFExercise {
+    private DataStorageManager storageManager;
+    private StopWordManager stopWordManager;
+    private WordFrequencyManager wordFreqManager;
+    
+    public WordFrequencyController(String pathToFile) throws IOException {
+        this.storageManager = new DataStorageManager(pathToFile);
+        this.stopWordManager = new StopWordManager();
+        this.wordFreqManager = new WordFrequencyManager();
+    }
+    
+    public void run() {
+        for (String word : this.storageManager.calculateWords()) {
+            if (!this.stopWordManager.isStopWord(word)) {
+                this.wordFreqManager.incrementCount(word);
+            }
+        }
+        
+        int numWordsPrinted = 0;
+        for (WordFrequencyPair pair : this.wordFreqManager.sorted()) {
+            System.out.println(pair.getWord() + " - " + pair.getFrequency());
+            
+            numWordsPrinted++;
+            if (numWordsPrinted >= 25) {
+                break;
+            }
+        }
+    }
+}
+
+/** Models the contents of the file. */
+class DataStorageManager extends TFExercise {
+    private String data;
+    
+    public DataStorageManager(String pathToFile) throws IOException {
+        byte[] dataBytes;
+        RandomAccessFile f = new RandomAccessFile(new File(pathToFile), "r");
+        try {
+            dataBytes = new byte[(int) f.length()];
+            f.readFully(dataBytes);
+        } finally {
+            f.close();
+        }
+        
+        this.data = new String(dataBytes, "UTF-8").replaceAll("[\\W_]+", " ").toLowerCase();
+    }
+    
+    public String[] calculateWords() {
+        return this.data.split("\\s+");
+    }
+    
+    public String getInfo() {
+        return super.getInfo() + ": My major data structure is a " + this.data.getClass().getName();
+    }
+}
+
+/** Models the stop word filter. */
+class StopWordManager extends TFExercise {
+    private Set<String> stopWords;
+    
+    public StopWordManager() throws IOException {
+        this.stopWords = new HashSet<String>();
+        
+        Scanner f = new Scanner(new File("../stop_words.txt"), "UTF-8");
+        try {
+            f.useDelimiter(",");
+            while (f.hasNext()) {
+                this.stopWords.add(f.next());
+            }
+        } finally {
+            f.close();
+        }
+        
+        // Add single-letter words
+        for (char c = 'a'; c <= 'z'; c++) {
+            this.stopWords.add("" + c);
+        }
+    }
+    
+    public boolean isStopWord(String word) {
+        return this.stopWords.contains(word);
+    }
+    
+    public String getInfo() {
+        return super.getInfo() + ": My major data structure is a " + this.stopWords.getClass().getName();
+    }
+}
+
+/** Keeps the word frequency data. */
+class WordFrequencyManager extends TFExercise {
+    private Map<String, MutableInteger> wordFreqs;
+    
+    public WordFrequencyManager() {
+        this.wordFreqs = new HashMap<String, MutableInteger>();
+    }
+    
+    public void incrementCount(String word) {
+        MutableInteger count = this.wordFreqs.get(word);
+        if (count == null) {
+            this.wordFreqs.put(word, new MutableInteger(1));
+        } else {
+            count.setValue(count.getValue() + 1);
+        }
+    }
+    
+    public List<WordFrequencyPair> sorted() {
+        List<WordFrequencyPair> pairs = new ArrayList<WordFrequencyPair>();
+        for (Map.Entry<String, MutableInteger> entry : wordFreqs.entrySet()) {
+            pairs.add(new WordFrequencyPair(entry.getKey(), entry.getValue().getValue()));
+        }
+        Collections.sort(pairs);
+        Collections.reverse(pairs);
+        return pairs;
+    }
+    
+    public String getInfo() {
+        return super.getInfo() + ": My major data structure is a " + this.wordFreqs.getClass().getName();
+    }
+}
+
+class MutableInteger {
+    private int value;
+    
+    public MutableInteger(int value) {
+        this.value = value;
+    }
+    
+    public int getValue() {
+        return value;
+    }
+    
+    public void setValue(int value) {
+        this.value = value;
+    }
+}
+
+class WordFrequencyPair implements Comparable<WordFrequencyPair> {
+    private String word;
+    private int frequency;
+    
+    public WordFrequencyPair(String word, int frequency) {
+        this.word = word;
+        this.frequency = frequency;
+    }
+    
+    public String getWord() {
+        return word;
+    }
+    
+    public int getFrequency() {
+        return frequency;
+    }
+    
+    public int compareTo(WordFrequencyPair other) {
+        return this.frequency - other.frequency;
+    }
+}