/*
* 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.jackrabbit.jcr2spi.observation;
import java.util.List;
import java.util.LinkedList;
import java.util.NoSuchElementException;
import javax.jcr.observation.EventJournal;
import javax.jcr.RepositoryException;
import org.apache.jackrabbit.spi.Event;
import org.apache.jackrabbit.spi.EventFilter;
import org.apache.jackrabbit.spi.EventBundle;
import org.apache.jackrabbit.spi.commons.conversion.NamePathResolver;
import org.apache.jackrabbit.jcr2spi.WorkspaceManager;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* <code>EventJournalImpl</code> implement the JSR 283 event journal over SPI.
*/
public class EventJournalImpl implements EventJournal {
/**
* The logger instance for this class.
*/
private static final Logger log = LoggerFactory.getLogger(EventJournalImpl.class);
private final WorkspaceManager wspMgr;
private final EventFilter filter;
private final NamePathResolver resolver;
private List<Event> buffer = new LinkedList<Event>();
private long lastTimestamp = 0;
/**
* Current position.
*/
private long position = 0;
public EventJournalImpl(WorkspaceManager wspMgr,
EventFilter filter,
NamePathResolver resolver) {
this.wspMgr = wspMgr;
this.filter = filter;
this.resolver = resolver;
}
/**
* {@inheritDoc}
*/
public void skipTo(long date) {
// first try to skip in buffer
while (!buffer.isEmpty()) {
long eDate;
try {
eDate = buffer.get(0).getDate();
} catch (RepositoryException e) {
eDate = 0;
}
if (eDate <= date) {
buffer.remove(0);
} else {
return;
}
}
// if we get here then we need to refill the buffer after
// the given date
lastTimestamp = date;
refill();
}
/**
* {@inheritDoc}
*/
public javax.jcr.observation.Event nextEvent() {
return (javax.jcr.observation.Event) next();
}
/**
* {@inheritDoc}
*/
public void skip(long skipNum) {
while (skipNum-- > 0) {
next();
}
}
/**
* {@inheritDoc}
*/
public long getSize() {
return -1;
}
/**
* {@inheritDoc}
*/
public long getPosition() {
return position;
}
/**
* {@inheritDoc}
*/
public boolean hasNext() {
if (buffer.isEmpty()) {
refill();
}
return !buffer.isEmpty();
}
/**
* {@inheritDoc}
*/
public Object next() {
if (hasNext()) {
position++;
return new EventImpl(buffer.remove(0),
resolver, wspMgr.getIdFactory());
} else {
throw new NoSuchElementException();
}
}
/**
* {@inheritDoc}
*/
public void remove() {
throw new UnsupportedOperationException();
}
//----------------------------< internal >----------------------------------
private void refill() {
try {
EventBundle bundle = wspMgr.getEvents(filter, lastTimestamp);
for (Event e : bundle) {
buffer.add(e);
lastTimestamp = e.getDate();
}
} catch (RepositoryException e) {
log.warn("Exception while refilling event journal buffer", e);
}
}
}