/*
    * Copyright 2012 The Netty Project
    *
    * The Netty Project licenses this file to you under the Apache License,
    * version 2.0 (the "License"); you may not use this file except in compliance
    * with the License. You may obtain a copy of the License at:
    *
    *   http://www.apache.org/licenses/LICENSE-2.0
    *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
   * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
   * License for the specific language governing permissions and limitations
   * under the License.
   */
  package org.jboss.netty.channel.group;
  
  import java.util.Iterator;
  import java.util.NoSuchElementException;
  
  /**
   */
  final class CombinedIterator<E> implements Iterator<E> {
  
      private final Iterator<E> i1;
      private final Iterator<E> i2;
      private Iterator<E> currentIterator;
  
      CombinedIterator(Iterator<E> i1, Iterator<E> i2) {
          if (i1 == null) {
              throw new NullPointerException("i1");
          }
          if (i2 == null) {
              throw new NullPointerException("i2");
          }
          this.i1 = i1;
          this.i2 = i2;
          currentIterator = i1;
      }
  
      public boolean hasNext() {
          boolean hasNext = currentIterator.hasNext();
          if (hasNext) {
              return true;
          }
  
          if (currentIterator == i1) {
              currentIterator = i2;
              return hasNext();
          } else {
              return false;
          }
      }
  
      public E next() {
          try {
              E e = currentIterator.next();
              return e;
          } catch (NoSuchElementException e) {
              if (currentIterator == i1) {
                  currentIterator = i2;
                  return next();
              } else {
                  throw e;
              }
          }
      }
  
      public void remove() {
          currentIterator.remove();
      }
  
  }