/**
* 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.cassandra.service;
import java.io.IOException;
import java.net.InetAddress;
import java.util.*;
import java.util.concurrent.LinkedBlockingQueue;
import com.google.common.collect.AbstractIterator;
import com.google.common.collect.Iterables;
import com.google.common.collect.Iterators;
import org.apache.commons.collections.iterators.CollatingIterator;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.apache.cassandra.db.ColumnFamily;
import org.apache.cassandra.db.DecoratedKey;
import org.apache.cassandra.db.RangeSliceReply;
import org.apache.cassandra.db.Row;
import org.apache.cassandra.net.Message;
import org.apache.cassandra.utils.Pair;
import org.apache.cassandra.utils.ReducingIterator;
/**
* Turns RangeSliceReply objects into row (string -> CF) maps, resolving
* to the most recent ColumnFamily and setting up read repairs as necessary.
*/
public class RangeSliceResponseResolver implements IResponseResolver<Iterable<Row>>
{
private static final Logger logger_ = LoggerFactory.getLogger(RangeSliceResponseResolver.class);
private final String table;
private final List<InetAddress> sources;
protected final Collection<Message> responses = new LinkedBlockingQueue<Message>();;
public RangeSliceResponseResolver(String table, List<InetAddress> sources)
{
this.sources = sources;
this.table = table;
}
public List<Row> getData() throws IOException
{
Message response = responses.iterator().next();
RangeSliceReply reply = RangeSliceReply.read(response.getMessageBody());
return reply.rows;
}
// Note: this deserializes the response a 2nd time if getData was called first
// (this is not currently an issue since we don't do read repair for range queries.)
public Iterable<Row> resolve() throws IOException
{
CollatingIterator collator = new CollatingIterator(new Comparator<Pair<Row,InetAddress>>()
{
public int compare(Pair<Row,InetAddress> o1, Pair<Row,InetAddress> o2)
{
return o1.left.key.compareTo(o2.left.key);
}
});
int n = 0;
for (Message response : responses)
{
RangeSliceReply reply = RangeSliceReply.read(response.getMessageBody());
n = Math.max(n, reply.rows.size());
collator.addIterator(new RowIterator(reply.rows.iterator(), response.getFrom()));
}
// for each row, compute the combination of all different versions seen, and repair incomplete versions
return new ReducingIterator<Pair<Row,InetAddress>, Row>(collator)
{
List<ColumnFamily> versions = new ArrayList<ColumnFamily>(sources.size());
List<InetAddress> versionSources = new ArrayList<InetAddress>(sources.size());
DecoratedKey key;
@Override
protected boolean isEqual(Pair<Row, InetAddress> o1, Pair<Row, InetAddress> o2)
{
return o1.left.key.equals(o2.left.key);
}
public void reduce(Pair<Row,InetAddress> current)
{
key = current.left.key;
versions.add(current.left.cf);
versionSources.add(current.right);
}
protected Row getReduced()
{
ColumnFamily resolved = RowRepairResolver.resolveSuperset(versions);
RowRepairResolver.maybeScheduleRepairs(resolved, table, key, versions, versionSources);
versions.clear();
versionSources.clear();
return new Row(key, resolved);
}
};
}
public void preprocess(Message message)
{
responses.add(message);
}
public boolean isDataPresent()
{
return !responses.isEmpty();
}
private static class RowIterator extends AbstractIterator<Pair<Row,InetAddress>>
{
private final Iterator<Row> iter;
private final InetAddress source;
private RowIterator(Iterator<Row> iter, InetAddress source)
{
this.iter = iter;
this.source = source;
}
@Override
protected Pair<Row,InetAddress> computeNext()
{
return iter.hasNext() ? new Pair<Row, InetAddress>(iter.next(), source) : endOfData();
}
}
public Iterable<Message> getMessages()
{
return responses;
}
public int getMessageCount()
{
return responses.size();
}
}