Review

finding-3

/mubench/checkouts/lucene/1918/build/src/java/org/apache/lucene/util/AttributeSource.java

getAttributeImplsIterator()

class AttributeSource {
  /** Returns a new iterator that iterates all unique Attribute implementations.
   * This iterator may contain less entries that {@link #getAttributeClassesIterator},
   * if one instance implements more than one Attribute interface.
   * <p>Signature for Java 1.5: <code>public Iterator&lt;AttributeImpl&gt; getAttributeImplsIterator()</code>
   */
  public Iterator getAttributeImplsIterator() {
    if (hasAttributes()) {
      if (currentState == null) {
        computeCurrentState();
      }
      final State initState = currentState;
      return new Iterator() {
        private State state = initState;
      
        public void remove() {
          throw new UnsupportedOperationException();
        }
        
        public Object next() {
          if (state == null)
            throw new NoSuchElementException();
          final AttributeImpl att = state.attribute;
          state = state.next;
          return att;
        }
        
        public boolean hasNext() {
          return state != null;
        }
      };
    } else {
      return Collections.EMPTY_SET.iterator();
    }
  }

}