gt:         for (String s : st.keys())
context: package meka.classifiers.multilabel.neurofuzzy;
  /*************************************************************************
   *  Compilation:  javac ST.java
   *  Execution:    java ST
   *  
   *  Sorted symbol table implementation using a java.util.TreeMap.
   *  Does not allow duplicates.
   *
   *  % java ST
   *
   *************************************************************************/
  
  import java.util.Iterator;
  import java.util.NoSuchElementException;
  import java.util.SortedMap;
  import java.util.TreeMap;
  
  /**
   *  The <tt>ST</tt> class represents an ordered symbol table of generic
   *  key-value pairs.
   *  It supports the usual <em>put</em>, <em>get</em>, <em>contains</em>,
   *  <em>delete</em>, <em>size</em>, and <em>is-empty</em> methods.
   *  It also provides ordered methods for finding the <em>minimum</em>,
   *  <em>maximum</em>, <em>floor</em>, and <em>ceiling</em>.
   *  It also provides a <em>keys</em> method for iterating over all of the keys.
   *  A symbol table implements the <em>associative array</em> abstraction:
   *  when associating a value with a key that is already in the symbol table,
   *  the convention is to replace the old value with the new value.
   *  Unlike {@link java.util.Map}, this class uses the convention that
   *  values cannot be <tt>null</tt>&mdash;setting the
   *  value associated with a key to <tt>null</tt> is equivalent to deleting the key
   *  from the symbol table.
   *  <p>
   *  This implementation uses a balanced binary search tree. It requires that
   *  the key type implements the <tt>Comparable</tt> interface and calls the
   *  <tt>compareTo()</tt> and method to compare two keys. It does not call either
   *  <tt>equals()</tt> or <tt>hashCode()</tt>.
   *  The <em>put</em>, <em>contains</em>, <em>remove</em>, <em>minimum</em>,
   *  <em>maximum</em>, <em>ceiling</em>, and <em>floor</em> operations each take
   *  logarithmic time in the worst case.
   *  The <em>size</em>, and <em>is-empty</em> operations take constant time.
   *  Construction takes constant time.
   *  <p>
   *  For additional documentation, see <a href="http://introcs.cs.princeton.edu/44st">Section 4.4</a> of
   *  <i>Introduction to Programming in Java: An Interdisciplinary Approach</i> by Robert Sedgewick and Kevin Wayne. 
   */
  public class ST<Key extends Comparable<Key>, Value> implements Iterable<Key> {
  
      private TreeMap<Key, Value> st;
  
      /**
       * Initializes an empty symbol table.
       */
      public ST() {
          st = new TreeMap<Key, Value>();
      }
  
  
      /**
       * Returns the value associated with the given key.
       * @param key the key
       * @return the value associated with the given key if the key is in the symbol table
       *     and <tt>null</tt> if the key is not in the symbol table
       * @throws NullPointerException if <tt>key</tt> is <tt>null</tt>
       */
      public Value get(Key key) {
          if (key == null) throw new NullPointerException("called get() with null key");
          return st.get(key);
      }
  
      /**
       * Inserts the key-value pair into the symbol table, overwriting the old value
       * with the new value if the key is already in the symbol table.
       * If the value is <tt>null</tt>, this effectively deletes the key from the symbol table.
       * @param key the key
       * @param val the value
       * @throws NullPointerException if <tt>key</tt> is <tt>null</tt>
       */
      public void put(Key key, Value val) {
          if (key == null) throw new NullPointerException("called put() with null key");
          if (val == null) st.remove(key);
          else             st.put(key, val);
      }
  
      /**
       * Removes the key and associated value from the symbol table
       * (if the key is in the symbol table).
       * @param key the key
       * @throws NullPointerException if <tt>key</tt> is <tt>null</tt>
       */
      public void delete(Key key) {
          if (key == null) throw new NullPointerException("called delete() with null key");
          st.remove(key);
      }
  
      /**
       * Does this symbol table contain the given key?
       * @param key the key
       * @return <tt>true</tt> if this symbol table contains <tt>key</tt> and
       *     <tt>false</tt> otherwise
       * @throws NullPointerException if <tt>key</tt> is <tt>null</tt>
       */
      public boolean contains(Key key) {
          if (key == null) throw new NullPointerException("called contains() with null key");
          return st.containsKey(key);
      }
  
      /**
       * Returns the number of key-value pairs in this symbol table.
       * @return the number of key-value pairs in this symbol table
       */
      public int size() {
          return st.size();
      }
  
      /**
       * Is this symbol table empty?
       * @return <tt>true</tt> if this symbol table is empty and <tt>false</tt> otherwise
       */
      public boolean isEmpty() {
          return size() == 0;
      }
  
      /**
       * Returns all keys in the symbol table as an <tt>Iterable</tt>.
       * To iterate over all of the keys in the symbol table named <tt>st</tt>,
       * use the foreach notation: <tt>for (Key key : st.keys())</tt>.
       * @return all keys in the sybol table as an <tt>Iterable</tt>
       */
      public Iterable<Key> keys() {
          return st.keySet();
      }
  
      /**
       * Returns all of the keys in the symbol table as an iterator.
       * To iterate over all of the keys in a symbol table named <tt>st</tt>, use the
       * foreach notation: <tt>for (Key key : st)</tt>.
       * @return an iterator to all of the keys in the symbol table
       */
      public Iterator<Key> iterator() {
          return st.keySet().iterator();
      }
  
      /**
       * Returns the smallest key in the symbol table.
       * @return the smallest key in the symbol table
       * @throws NoSuchElementException if the symbol table is empty
       */
      public Key min() {
          if (isEmpty()) throw new NoSuchElementException("called min() with empty symbol table");
          return st.firstKey();
      }
  
      /**
       * Returns the largest key in the symbol table.
       * @return the largest key in the symbol table
       * @throws NoSuchElementException if the symbol table is empty
       */
      public Key max() {
          if (isEmpty()) throw new NoSuchElementException("called max() with empty symbol table");
          return st.lastKey();
      }
  
      /**
       * Returns the smallest key in the symbol table greater than or equal to <tt>key</tt>.
       * @return the smallest key in the symbol table greater than or equal to <tt>key</tt>
       * @param key the key
       * @throws NoSuchElementException if the symbol table is empty
       * @throws NullPointerException if <tt>key</tt> is <tt>null</tt>
       */
      public Key ceil(Key key) {
          if (key == null) throw new NullPointerException("called ceil() with null key");
          SortedMap<Key, Value> tail = st.tailMap(key);
          if (tail.isEmpty()) throw new NoSuchElementException();
          return tail.firstKey();
      }
  
      /**
       * Returns the largest key in the symbol table less than or equal to <tt>key</tt>.
       * @return the largest key in the symbol table less than or equal to <tt>key</tt>
       * @param key the key
       * @throws NoSuchElementException if the symbol table is empty
       * @throws NullPointerException if <tt>key</tt> is <tt>null</tt>
       */
      public Key floor(Key key) {
          if (key == null) throw new NullPointerException("called floor() with null key");
          // headMap does not include key if present (!)
          if (st.containsKey(key)) return key;
          SortedMap<Key, Value> head = st.headMap(key);
          if (head.isEmpty()) throw new NoSuchElementException();
          return head.lastKey();
      }
  
      /**
       * Unit tests the <tt>ST</tt> data type.
       */
      public static void main(String[] args) {
          ST<String, String> st = new ST<String, String>();
  
         // insert some key-value pairs
          st.put("www.cs.princeton.edu",   "128.112.136.11");
          st.put("www.cs.princeton.edu",   "128.112.136.35");    // overwrite old value
          st.put("www.princeton.edu",      "128.112.130.211");
          st.put("www.math.princeton.edu", "128.112.18.11");
          st.put("www.yale.edu",           "130.132.51.8");
          st.put("www.amazon.com",         "207.171.163.90");
          st.put("www.simpsons.com",       "209.123.16.34");
          st.put("www.stanford.edu",       "171.67.16.120");
          st.put("www.google.com",         "64.233.161.99");
          st.put("www.ibm.com",            "129.42.16.99");
          st.put("www.apple.com",          "17.254.0.91");
          st.put("www.slashdot.com",       "66.35.250.150");
          st.put("www.whitehouse.gov",     "204.153.49.136");
          st.put("www.espn.com",           "199.181.132.250");
          st.put("www.snopes.com",         "66.165.133.65");
          st.put("www.movies.com",         "199.181.132.250");
          st.put("www.cnn.com",            "64.236.16.20");
          st.put("www.iitb.ac.in",         "202.68.145.210");
  
  
          System.out.println(st.get("www.cs.princeton.edu"));
          System.out.println(st.get("www.harvardsucks.com"));
          System.out.println(st.get("www.simpsons.com"));
          System.out.println();
  
          System.out.println("ceil(www.simpsonr.com) = " + st.ceil("www.simpsonr.com"));
          System.out.println("ceil(www.simpsons.com) = " + st.ceil("www.simpsons.com"));
          System.out.println("ceil(www.simpsont.com) = " + st.ceil("www.simpsont.com"));
          System.out.println("floor(www.simpsonr.com) = " + st.floor("www.simpsonr.com"));
          System.out.println("floor(www.simpsons.com) = " + st.floor("www.simpsons.com"));
          System.out.println("floor(www.simpsont.com) = " + st.floor("www.simpsont.com"));
  
          System.out.println();
  
          System.out.println("min key: " + st.min());
          System.out.println("max key: " + st.max());
          System.out.println("size:    " + st.size());
          System.out.println();
  
          // print out all key-value pairs in lexicographic order
  