/*
    * Licensed to the Apache Software Foundation (ASF) under one
    * or more contributor license agreements.  See the NOTICE file
    * distributed with this work for additional information
    * regarding copyright ownership.  The ASF 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.apache.giraph.io.iterables;
  
  import java.util.Iterator;
  
  /**
   * Wraps {@link Iterator} into object which provides iteration like in
   * {@link org.apache.giraph.io.VertexReader} or
   * {@link org.apache.giraph.io.EdgeReader}
   *
   * @param <T>
   */
  public class IteratorToReaderWrapper<T> {
    /** Wrapped iterator */
    private Iterator<T> iterator;
    /** Current object */
    private T currentObject = null;
  
    /**
     * Constructor
     *
     * @param iterator Iterator to wrap
     */
    public IteratorToReaderWrapper(Iterator<T> iterator) {
      this.iterator = iterator;
    }
  
    /**
     * Read next object
     *
     * @return False iff there are no more objects
     */
    public boolean nextObject() {
      boolean hasNext = iterator.hasNext();
      if (hasNext) {
        currentObject = iterator.next();
      } else {
        currentObject = null;
      }
      return hasNext;
    }
  
    /**
     * Get the current object
     *
     * @return Current object
     */
    public T getCurrentObject() {
      return currentObject;
    }
  }