src/de/j32/util/FilteredIterator.java

   1 package de.j32.util;
   2
   3 import java.util.Iterator;
   4 import java.util.NoSuchElementException;
   5
   6
   7 public class FilteredIterator<E>
   8         implements Iterator<E>
   9 {
  10         Iterator<E> base_;
  11         Filter<E> filter_;
  12         E next_;
  13         boolean hasNext_ = true;
  14
  15         public FilteredIterator(Iterator<E> base, Filter<E> filter)
  16         {
  17                 base_ = base;
  18                 filter_ = filter;
  19                 advance();
  20         }
  21
  22         public E next()
  23         {
  24                 if (hasNext_) {
  25                         E rv = next_;
  26                         advance();
  27                         return rv;
  28                 }
  29                 else
  30                         throw new NoSuchElementException();
  31         }
  32
  33         public boolean hasNext()
  34         {
  35                 return hasNext_;
  36         }
  37
  38         public void remove()
  39         {
  40                 throw new UnsupportedOperationException();
  41         }
  42
  43         void advance()
  44         {
  45                 while (base_.hasNext()) {
  46                         next_ = base_.next();
  47                         if (filter_.match(next_))
  48                                 return;
  49                 }
  50                 hasNext_ = false;
  51                 next_ = null;
  52         }
  53
  54 }