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The Apache Cassandra Project develops a highly scalable second-generation distributed database, bringing together Dynamo's fully distributed design and Bigtable's ColumnFamily-based data model.
/*
* 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
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*/
package org.apache.cassandra.index.sasi.memory;
import java.nio.ByteBuffer;
import java.util.*;
import java.util.concurrent.ConcurrentSkipListMap;
import java.util.concurrent.ConcurrentSkipListSet;
import org.apache.cassandra.db.DecoratedKey;
import org.apache.cassandra.index.sasi.conf.ColumnIndex;
import org.apache.cassandra.index.sasi.disk.Token;
import org.apache.cassandra.index.sasi.plan.Expression;
import org.apache.cassandra.index.sasi.utils.RangeUnionIterator;
import org.apache.cassandra.index.sasi.utils.RangeIterator;
import org.apache.cassandra.db.marshal.AbstractType;
public class SkipListMemIndex extends MemIndex
{
public static final int CSLM_OVERHEAD = 128; // average overhead of CSLM
private final ConcurrentSkipListMap> index;
public SkipListMemIndex(AbstractType keyValidator, ColumnIndex columnIndex)
{
super(keyValidator, columnIndex);
index = new ConcurrentSkipListMap<>(columnIndex.getValidator());
}
public long add(DecoratedKey key, ByteBuffer value)
{
long overhead = CSLM_OVERHEAD; // DKs are shared
ConcurrentSkipListSet keys = index.get(value);
if (keys == null)
{
ConcurrentSkipListSet newKeys = new ConcurrentSkipListSet<>(DecoratedKey.comparator);
keys = index.putIfAbsent(value, newKeys);
if (keys == null)
{
overhead += CSLM_OVERHEAD + value.remaining();
keys = newKeys;
}
}
keys.add(key);
return overhead;
}
public RangeIterator search(Expression expression)
{
ByteBuffer min = expression.lower == null ? null : expression.lower.value;
ByteBuffer max = expression.upper == null ? null : expression.upper.value;
SortedMap> search;
if (min == null && max == null)
{
throw new IllegalArgumentException();
}
if (min != null && max != null)
{
search = index.subMap(min, expression.lower.inclusive, max, expression.upper.inclusive);
}
else if (min == null)
{
search = index.headMap(max, expression.upper.inclusive);
}
else
{
search = index.tailMap(min, expression.lower.inclusive);
}
RangeUnionIterator.Builder builder = RangeUnionIterator.builder();
search.values().stream()
.filter(keys -> !keys.isEmpty())
.forEach(keys -> builder.add(new KeyRangeIterator(keys)));
return builder.build();
}
}