/**
* Licensed to Apereo under one or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information regarding copyright ownership. Apereo
* 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 the
* following location:
*
* <p>http://www.apache.org/licenses/LICENSE-2.0
*
* <p>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.apereo.portal.xml.stream;
import java.util.Deque;
import java.util.LinkedList;
import javax.xml.stream.XMLEventReader;
import javax.xml.stream.XMLStreamException;
import javax.xml.stream.events.XMLEvent;
/**
* Base class for {@link XMLEventReader}s for classes that want to inject additional events into the
* stream.
*
*/
public abstract class InjectingXMLEventReader extends BaseXMLEventReader {
private Deque<XMLEvent> additionalEvents;
public InjectingXMLEventReader(XMLEventReader reader) {
super(reader);
}
@Override
protected final XMLEvent internalNextEvent() throws XMLStreamException {
if (this.additionalEvents != null && !this.additionalEvents.isEmpty()) {
return this.additionalEvents.pop();
}
final XMLEvent event = this.getParent().nextEvent();
this.additionalEvents = this.getAdditionalEvents(event);
return event;
}
@Override
public final XMLEvent peek() throws XMLStreamException {
if (this.additionalEvents != null && !this.additionalEvents.isEmpty()) {
return this.additionalEvents.peek();
}
final XMLEvent event = this.getParent().peek();
final XMLEvent peekEvent = this.getPeekEvent(event);
if (peekEvent != null) {
return peekEvent;
}
return event;
}
@Override
public boolean hasNext() {
return super.hasNext()
|| (this.additionalEvents != null && !this.additionalEvents.isEmpty());
}
/**
* The Deque with the additional events WILL BE MODIFIED by the calling code.
*
* @param event The current event
* @return Any additional events that should be injected before the current event. If null the
* current event is returned
*/
protected Deque<XMLEvent> getAdditionalEvents(XMLEvent event) {
final XMLEvent additionalEvent = this.getAdditionalEvent(event);
if (additionalEvent == null) {
return null;
}
final Deque<XMLEvent> additionalEvents = new LinkedList<XMLEvent>();
additionalEvents.push(additionalEvent);
return additionalEvents;
}
/**
* Called by {@link #getAdditionalEvents(XMLEvent)} and then wrapped with a {@link Deque}. If
* there is a need to inject more than a single event override {@link
* #getAdditionalEvents(XMLEvent)}
*/
protected XMLEvent getAdditionalEvent(XMLEvent event) {
throw new UnsupportedOperationException(
"Either 'Deque<XMLEvent> getAdditionalEvents(XMLEvent event)' or 'XMLEvent getAdditionalEvent(XMLEvent event must be implemented");
}
/**
* @param event The peeked event
* @return An event to return in place of the peeked event, if null the peeked event is
* returned.
*/
protected abstract XMLEvent getPeekEvent(XMLEvent event);
}