content: /*
   * Copyright (c) 2010, Zepheira LLC, Some rights reserved.
   * 
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions are met:
   * 
   * - Redistributions of source code must retain the above copyright notice, this
   *   list of conditions and the following disclaimer.
   * - Redistributions in binary form must reproduce the above copyright notice,
   *   this list of conditions and the following disclaimer in the documentation
   *   and/or other materials provided with the distribution. 
   * - Neither the name of the openrdf.org nor the names of its contributors may
   *   be used to endorse or promote products derived from this software without
   *   specific prior written permission.
   * 
   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
   * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
   * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
   * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
   * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
   * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
   * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
   * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
   * POSSIBILITY OF SUCH DAMAGE.
   * 
   */
  package org.callimachusproject.xml;
  
  import javax.xml.stream.XMLEventFactory;
  import javax.xml.stream.XMLEventReader;
  import javax.xml.stream.XMLStreamException;
  import javax.xml.stream.events.EndDocument;
  import javax.xml.stream.events.StartDocument;
  import javax.xml.stream.events.XMLEvent;
  import javax.xml.stream.util.EventReaderDelegate;
  
  /**
   * Wraps an {@link XMLEventReader} and every stream starts with
   * {@link javax.xml.stream.events.StartDocument} and ends with
   * {@link javax.xml.stream.events.EndDocument}.
   * 
   * @author James Leigh
   * 
   */
  public class DocumentXMLEventReader extends EventReaderDelegate {
  	private final XMLEventFactory ef = XMLEventFactory.newInstance();
  	private boolean started;
  	private Object next;
  	private boolean ended;
  
  	public DocumentXMLEventReader(XMLEventReader reader) {
  		super(reader);
  	}
  
  	public void close() throws XMLStreamException {
  		super.close();
  	}
  
  	@Override
  	public XMLEvent nextEvent() throws XMLStreamException {
  		if (next != null) {
  			try {
  				if (next instanceof XMLEvent)
  					return (XMLEvent) next;
  			} finally {
  				next = null;
  			}
  		}
  		if (!started && !super.hasNext()) {
  			started = true;
  			return ef.createStartDocument();
  		}
  		if (!ended && !super.hasNext()) {
  			ended = true;
  			return ef.createEndDocument();
  		}
  		XMLEvent ret = super.nextEvent();
  		if (ret != null && ret.isStartDocument()) {
  			started = true;
  		}
  		if (ret != null && ret.isEndDocument()) {
  			ended = true;
  		}
  		if (!started) {
  			next = ret;
  			started = true;
  			return ef.createStartDocument();
  		}
  		return ret;
  	}
  
  	@Override
  	public Object next() {
  		if (next != null) {
  			try {
  				if (next instanceof XMLEvent)
  					return (XMLEvent) next;
  			} finally {
  				next = null;
  			}
  		}
  		if (!started && !super.hasNext()) {
  			started = true;
  			return ef.createStartDocument();
  		}
  		if (!ended && !super.hasNext()) {
  			ended = true;
  			return ef.createEndDocument();
  		}
  		Object ret = super.next();
  		if (ret != null && ret instanceof StartDocument) {
  			started = true;
  		}
  		if (ret != null && ret instanceof EndDocument) {
  			ended = true;
  		}
  		if (!started) {
  			next = ret;
  			started = true;
  			return ef.createStartDocument();
  		}
  		return ret;
  	}
  
  	@Override
  	public boolean hasNext() {
  		if (!ended)
  			return true;
  		return super.hasNext();
  	}
  
  	@Override
  	public XMLEvent peek() throws XMLStreamException {
  		if (next != null && next instanceof XMLEvent)
  			return (XMLEvent) next;
  		XMLEvent peek = super.peek();
  		if (!started && !peek.isStartDocument())
  			return ef.createStartDocument();
  		if (!ended && peek == null)
  			return ef.createEndDocument();
  		return peek;
  	}
  
  	@Override
  	public XMLEvent nextTag() throws XMLStreamException {
  		if (!started) {
  			started = true;
  		}
  		return super.nextTag();
  	}
  
  }
  