/*
    * Copyright (C) 2007-2012 Argeo GmbH
    *
    * 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.argeo.jcr;
  
  import java.util.Collection;
  import java.util.Iterator;
  import java.util.NoSuchElementException;
  
  import javax.jcr.Node;
  import javax.jcr.NodeIterator;
  
  /** Wraps a collection of nodes in order to read it as a {@link NodeIterator} */
  public class CollectionNodeIterator implements NodeIterator {
  	private final Long collectionSize;
  	private final Iterator<Node> iterator;
  	private Integer position = 0;
  
  	public CollectionNodeIterator(Collection<Node> nodes) {
  		super();
  		this.collectionSize = (long) nodes.size();
  		this.iterator = nodes.iterator();
  	}
  
  	public void skip(long skipNum) {
  		if (skipNum < 0)
  			throw new IllegalArgumentException(
  					"Skip count has to be positive: " + skipNum);
  
  		for (long i = 0; i < skipNum; i++) {
  			if (!hasNext())
  				throw new NoSuchElementException("Last element past (position="
  						+ getPosition() + ")");
  			nextNode();
  		}
  	}
  
  	public long getSize() {
  		return collectionSize;
  	}
  
  	public long getPosition() {
  		return position;
  	}
  
  	public boolean hasNext() {
  		return iterator.hasNext();
  	}
  
  	public Object next() {
  		return nextNode();
  	}
  
  	public void remove() {
  		iterator.remove();
  	}
  
  	public Node nextNode() {
  		Node node = iterator.next();
  		position++;
  		return node;
  	}
  
  }