/*
 * Copyright 2003-2011 JetBrains s.r.o.
 *
 * Licensed 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.jetbrains.mps.openapi.util;

import java.util.Iterator;

/**
 * Tree iterator traverses a n-ary tree in a way that a parent node is visited before its children and
 * children are returned left-to-right.
 */
public interface TreeIterator<T> extends Iterator<T> {

  /**
   * Skip children of the last element returned by the iterator.
   *
   * @throws IllegalStateException if the <tt>next</tt> method has not yet been called
   */
  void skipChildren();
}
