Another update from ingydotnet^djgoku

Task/Range-expansion/Java/range-expansion.java

@@ -1,66 +1,65 @@
 import java.util.*;
-import java.util.regex.*;
 
-class Range implements Enumeration {
-  private int clower, cupper;
-  private int value;
-  private boolean inrange;
-  private Scanner ps = null;
-  private String ss;
+class RangeExpander implements Iterator<Integer>, Iterable<Integer> {
 
-  private static String del = "\\s*,\\s*";
+    private static final Pattern TOKEN_PATTERN = Pattern.compile("([+-]?\\d+)-([+-]?\\d+)");
 
-  public Range(String s) {
-    ss = s;
-    reset();
-  }
+    private final Iterator<String> tokensIterator;
 
-  public boolean hasMoreElements() {
-    return (inrange && (value >= clower && value <= cupper)) || ps.hasNext();
-  }
+    private boolean inRange;
+    private int upperRangeEndpoint;
+    private int nextRangeValue;
 
-  public Object nextElement() throws NoSuchElementException {
-    if (!hasMoreElements())
-      throw new NoSuchElementException();
-    if (inrange && (value >= clower && value <= cupper)) {
-      value++;
-      return value-1;
+    public RangeExpander(String range) {
+        String[] tokens = range.split("\\s*,\\s*");
+        this.tokensIterator = Arrays.asList(tokens).iterator();
     }
-    inrange = false;
-    String n = ps.next();
-    if (n.matches("[+-]?\\d+-[+-]?\\d+")) {
-      Scanner ls = new Scanner(n);
-      ls.findInLine("([+-]?\\d+)-([+-]?\\d+)");
-      MatchResult r = ls.match();
-      clower = Integer.parseInt(r.group(1));
-      cupper = Integer.parseInt(r.group(2));
-      value = clower+1;
-      inrange = true;
-      ls.close();
-      return clower;
+
+    @Override
+    public boolean hasNext() {
+        return hasNextRangeValue() || this.tokensIterator.hasNext();
     }
-    return Integer.parseInt(n);
-  }
 
-  public void reset() {
-    if (ps != null)
-      ps.close();
-    ps = new Scanner(ss).useDelimiter(del);
-    inrange = false;
-  }
+    private boolean hasNextRangeValue() {
+        return this.inRange && this.nextRangeValue <= this.upperRangeEndpoint;
+    }
+
+    @Override
+    public Integer next() {
+        if (!hasNext()) {
+            throw new NoSuchElementException();
+        }
+
+        if (hasNextRangeValue()) {
+            return this.nextRangeValue++;
+        }
+
+        String token = this.tokensIterator.next();
+
+        Matcher matcher = TOKEN_PATTERN.matcher(token);
+        if (matcher.find()) {
+            this.inRange = true;
+            this.upperRangeEndpoint = Integer.valueOf(matcher.group(2));
+            this.nextRangeValue = Integer.valueOf(matcher.group(1));
+            return this.nextRangeValue++;
+        }
+
+        this.inRange = false;
+        return Integer.valueOf(token);
+    }
+
+    @Override
+    public Iterator<Integer> iterator() {
+        return this;
+    }
 
-  protected void finalize() throws Throwable {
-    ps.close();
-    super.finalize();
-  }
 }
 
-class rangexp {
-  public static void main(String[] args) {
-    Range r = new Range("-6,-3--1,3-5,7-11,14,15,17-20");
-    while (r.hasMoreElements()) {
-      System.out.print(r.nextElement() + " ");
+class RangeExpanderTest {
+    public static void main(String[] args) {
+        RangeExpander re = new RangeExpander("-6,-3--1,3-5,7-11,14,15,17-20");
+        for (int i : re) {
+            System.out.print(i + " ");
+        }
     }
-    System.out.println();
-  }
 }