/**
* 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.camel.component.hawtdb;
import org.apache.camel.Service;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.fusesource.hawtbuf.Buffer;
import org.fusesource.hawtbuf.codec.BufferCodec;
import org.fusesource.hawtbuf.codec.IntegerCodec;
import org.fusesource.hawtbuf.codec.StringCodec;
import org.fusesource.hawtdb.api.BTreeIndexFactory;
import org.fusesource.hawtdb.api.OptimisticUpdateException;
import org.fusesource.hawtdb.api.SortedIndex;
import org.fusesource.hawtdb.api.Transaction;
import org.fusesource.hawtdb.api.TxPageFile;
import org.fusesource.hawtdb.api.TxPageFileFactory;
/**
* Manages access to a shared <a href="http://hawtdb.fusesource.org/">HawtDB</a> file.
* <p/>
* Will by default not sync writes which allows it to be faster.
* You can force syncing by setting the sync option to <tt>true</tt>.
*/
public class HawtDBFile extends TxPageFileFactory implements Service {
private static final transient Log LOG = LogFactory.getLog(HawtDBFile.class);
// the root which contains an index with name -> page for the real indexes
private static final BTreeIndexFactory<String, Integer> ROOT_INDEXES_FACTORY = new BTreeIndexFactory<String, Integer>();
// the real indexes where we store persisted data in buffers
private static final BTreeIndexFactory<Buffer, Buffer> INDEX_FACTORY = new BTreeIndexFactory<Buffer, Buffer>();
private TxPageFile pageFile;
static {
ROOT_INDEXES_FACTORY.setKeyCodec(StringCodec.INSTANCE);
ROOT_INDEXES_FACTORY.setValueCodec(IntegerCodec.INSTANCE);
ROOT_INDEXES_FACTORY.setDeferredEncoding(true);
INDEX_FACTORY.setKeyCodec(BufferCodec.INSTANCE);
INDEX_FACTORY.setValueCodec(BufferCodec.INSTANCE);
INDEX_FACTORY.setDeferredEncoding(true);
}
public HawtDBFile() {
setSync(false);
}
public void start() {
if (getFile() == null) {
throw new IllegalArgumentException("A file must be configured");
}
if (LOG.isDebugEnabled()) {
LOG.debug("Starting HawtDB using file: " + getFile());
}
open();
pageFile = getTxPageFile();
execute(new Work<Boolean>() {
public Boolean execute(Transaction tx) {
int page = tx.allocator().alloc(1);
if (page == 0) {
// if we just created the file, first allocated page should be 0
ROOT_INDEXES_FACTORY.create(tx, 0);
LOG.info("Aggregation repository data store created using file: " + getFile());
} else {
// Was previously created.. so free up the test page
tx.allocator().free(page, 1);
SortedIndex<String, Integer> indexes = ROOT_INDEXES_FACTORY.open(tx, 0);
LOG.info("Aggregation repository data store loaded using file: " + getFile()
+ " containing " + indexes.size() + " repositories.");
}
return true;
}
});
}
public void stop() {
if (LOG.isDebugEnabled()) {
LOG.debug("Stopping HawtDB using file: " + getFile());
}
close();
pageFile = null;
}
public <T> T execute(Work<T> work) {
if (LOG.isTraceEnabled()) {
LOG.trace("Executing work +++ start +++ " + work);
}
Transaction tx = pageFile.tx();
T answer = doExecute(work, tx, pageFile);
if (LOG.isTraceEnabled()) {
LOG.trace("Executing work +++ done +++ " + work);
}
return answer;
}
public SortedIndex<Buffer, Buffer> getRepositoryIndex(Transaction tx, String name, boolean create) {
SortedIndex<Buffer, Buffer> answer = null;
SortedIndex<String, Integer> indexes = ROOT_INDEXES_FACTORY.open(tx, 0);
Integer location = indexes.get(name);
if (create && location == null) {
// create it..
int page = tx.allocator().alloc(1);
SortedIndex<Buffer, Buffer> created = INDEX_FACTORY.create(tx, page);
// add it to indexes so we can find it the next time
indexes.put(name, page);
if (LOG.isDebugEnabled()) {
LOG.debug("Created new repository index with name " + name + " at location " + page);
}
answer = created;
} else if (location != null) {
if (LOG.isTraceEnabled()) {
LOG.trace("Repository index with name " + name + " at location " + location);
}
answer = INDEX_FACTORY.open(tx, location);
}
if (LOG.isTraceEnabled()) {
LOG.trace("Repository index with name " + name + " -> " + answer);
}
return answer;
}
private static <T> T doExecute(Work<T> work, Transaction tx, TxPageFile page) {
T answer = null;
boolean done = false;
int attempt = 0;
while (!done) {
try {
// only log at DEBUG level if we are retrying
if (attempt > 0 && LOG.isDebugEnabled()) {
LOG.debug("Attempt " + attempt + " to execute work " + work);
}
attempt++;
answer = work.execute(tx);
// commit work
tx.commit();
// and flush so we ensure data is spooled to disk
page.flush();
// and we are done
done = true;
} catch (OptimisticUpdateException e) {
// retry as we hit an optimistic update error
LOG.warn("OptimisticUpdateException occurred at attempt " + attempt + " executing work " + work + " will do rollback and retry.");
// no harm doing rollback before retry and no wait is needed
tx.rollback();
} catch (RuntimeException e) {
LOG.warn("Error executing work " + work + " will do rollback.", e);
tx.rollback();
throw e;
}
}
return answer;
}
}