implement StringTokenizer

classpath/java/util/StringTokenizer.java

@@ -1,7 +1,94 @@
 package java.util;
 
-public class StringTokenizer implements Enumerator {
+public class StringTokenizer implements Enumeration {
   private final String in;
-  private String token;
-  private boolean includeDelimiters;
+  private String delimiters;
+  private final boolean includeDelimiters;
+  private int position;
+
+  public StringTokenizer(String in, String delimiters,
+                         boolean includeDelimiters)
+  {
+    this.in = in;
+    this.delimiters = delimiters;
+    this.includeDelimiters = includeDelimiters;
+  }
+
+  public StringTokenizer(String in, String delimiters) {
+    this(in, delimiters, false);
+  }
+
+  public StringTokenizer(String in) {
+    this(in, " \t\r\n\f");
+  }
+
+  private boolean isDelimiter(char c) {
+    return delimiters.indexOf(c) >= 0;
+  }
+
+  public int countTokens() {
+    int count = 0;
+    boolean sawNonDelimiter = false;
+    for (int i = position; i < in.length(); ++i) {
+      if (isDelimiter(in.charAt(i))) {
+        if (includeDelimiters || sawNonDelimiter) {
+          ++ count;
+        }
+        sawNonDelimiter = false;
+      } else {
+        sawNonDelimiter = true;
+      }
+    }
+
+    if (sawNonDelimiter) {
+      ++ count;
+    }
+
+    return count;
+  }
+
+  public boolean hasMoreTokens() {
+    for (int i = position; i < in.length(); ++i) {
+      if (isDelimiter(in.charAt(i))) {
+        if (includeDelimiters) {
+          return true;
+        }
+      } else {
+        position = i;
+        return true;
+      }
+    }
+    return false;
+  }
+
+  public String nextToken() {
+    for (int i = position; i < in.length(); ++i) {
+      if (isDelimiter(in.charAt(i))) {
+        if (includeDelimiters) {
+          return in.substring(i, i + 1);
+        }
+      } else {
+        position = i;
+        while (position < in.length() && ! isDelimiter(in.charAt(i))) {
+          ++ position;
+        }
+        return in.substring(i, position);
+      }
+    }
+    throw new NoSuchElementException();
+  }
+
+  public String nextToken(String delimiters) {
+    this.delimiters = delimiters;
+    return nextToken();
+  }
+
+  public boolean hasMoreElements() {
+    return hasMoreTokens();
+  }
+
+  public Object nextElement() {
+    return nextToken();
+  }
+
 }