/*
* $Id: XMLStreamEventReader.java,v 1.3 2004/07/12 15:38:06 cniles Exp $
*
* Copyright (c) 2004, Christian Niles, unit12.net
* All 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 Christian Niles, Unit12, 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 javanet.staxutils;
import javanet.staxutils.events.EventAllocator;
import javax.xml.stream.XMLEventReader;
import javax.xml.stream.XMLStreamException;
import javax.xml.stream.XMLStreamReader;
import javax.xml.stream.events.XMLEvent;
import javax.xml.stream.util.XMLEventAllocator;
/**
* {@link XMLEventReader} implementation based on a {@link XMLStreamReader} and
* an {@link XMLEventAllocator}.
*
* @author Christian Niles
* @version $Revision: 1.3 $
*/
public class XMLStreamEventReader implements XMLEventReader {
/** The underlying stream reader. */
private XMLStreamReader reader;
/** The event allocator used to create events. */
private XMLEventAllocator allocator;
/** Field used to cache peek()ed events. */
private XMLEvent nextEvent;
/** Whether the reader is closed or not. */
private boolean closed;
public XMLStreamEventReader(XMLStreamReader reader) {
this.reader = reader;
this.allocator = new EventAllocator();
}
public XMLStreamEventReader(XMLStreamReader reader,
XMLEventAllocator allocator) {
this.reader = reader;
this.allocator = (allocator == null ? new EventAllocator() : allocator);
}
/**
* No properties are supported, so this always throws
* {@link IllegalArgumentException}.
*/
public Object getProperty(String name) throws IllegalArgumentException {
throw new IllegalArgumentException("Unknown property: " + name);
}
public synchronized boolean hasNext() {
if (closed) {
return false;
}
try {
return reader.hasNext();
} catch (XMLStreamException e) {
// TODO how to handle inconsistency?
return false;
}
}
public synchronized XMLEvent nextTag() throws XMLStreamException {
if (closed) {
throw new XMLStreamException("Stream has been closed");
}
nextEvent = null;
reader.nextTag();
return nextEvent();
}
public synchronized String getElementText() throws XMLStreamException {
if (closed) {
throw new XMLStreamException("Stream has been closed");
}
// null the peeked event
this.nextEvent = null;
return reader.getElementText();
}
public synchronized XMLEvent nextEvent() throws XMLStreamException {
if (closed) {
throw new XMLStreamException("Stream has been closed");
}
XMLEvent event;
if (nextEvent != null) {
event = nextEvent;
nextEvent = null;
} else {
event = allocateEvent();
reader.next();
}
return event;
}
public synchronized XMLEvent peek() throws XMLStreamException {
if (closed) {
throw new XMLStreamException("Stream has been closed");
}
if (nextEvent == null) {
nextEvent = allocateEvent();
reader.next();
}
return nextEvent;
}
public Object next() {
try {
return nextEvent();
} catch (XMLStreamException e) {
// TODO throw a more descriptive exception?
throw new RuntimeException(e);
}
}
public void remove() {
throw new UnsupportedOperationException();
}
public synchronized void close() throws XMLStreamException {
if (!closed) {
reader.close();
closed = true;
nextEvent = null;
reader = null;
allocator = null;
}
}
/**
* Reads the next event from the underlying reader.
*
* @return The allocated {@link XMLEvent}.
* @throws XMLStreamException If an error occurs reading the underlying stream.
*/
protected XMLEvent allocateEvent() throws XMLStreamException {
return allocator.allocate(reader);
}
}