/*
* 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.db;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.util.*;
import org.apache.cassandra.db.marshal.AbstractType;
import org.apache.cassandra.io.util.DataInputPlus;
import org.apache.cassandra.io.util.DataOutputPlus;
/**
* A slice represents the selection of a range of rows.
* <p>
* A slice has a start and an end bound that are both (potentially full) clustering prefixes.
* A slice selects every rows whose clustering is bigger than the slice start prefix but smaller
* than the end prefix. Both start and end can be either inclusive or exclusive.
*/
public class Slice
{
public static final Serializer serializer = new Serializer();
/** The slice selecting all rows (of a given partition) */
public static final Slice ALL = new Slice(ClusteringBound.BOTTOM, ClusteringBound.TOP)
{
@Override
public boolean includes(ClusteringComparator comparator, ClusteringPrefix clustering)
{
return true;
}
@Override
public boolean intersects(ClusteringComparator comparator, List<ByteBuffer> minClusteringValues, List<ByteBuffer> maxClusteringValues)
{
return true;
}
@Override
public String toString(ClusteringComparator comparator)
{
return "ALL";
}
};
private final ClusteringBound start;
private final ClusteringBound end;
private Slice(ClusteringBound start, ClusteringBound end)
{
assert start.isStart() && end.isEnd();
this.start = start;
this.end = end;
}
public static Slice make(ClusteringBound start, ClusteringBound end)
{
if (start == ClusteringBound.BOTTOM && end == ClusteringBound.TOP)
return ALL;
return new Slice(start, end);
}
public static Slice make(ClusteringComparator comparator, Object... values)
{
CBuilder builder = CBuilder.create(comparator);
for (Object val : values)
{
if (val instanceof ByteBuffer)
builder.add((ByteBuffer) val);
else
builder.add(val);
}
return new Slice(builder.buildBound(true, true), builder.buildBound(false, true));
}
public static Slice make(Clustering clustering)
{
// This doesn't give us what we want with the clustering prefix
assert clustering != Clustering.STATIC_CLUSTERING;
ByteBuffer[] values = extractValues(clustering);
return new Slice(ClusteringBound.inclusiveStartOf(values), ClusteringBound.inclusiveEndOf(values));
}
public static Slice make(Clustering start, Clustering end)
{
// This doesn't give us what we want with the clustering prefix
assert start != Clustering.STATIC_CLUSTERING && end != Clustering.STATIC_CLUSTERING;
ByteBuffer[] startValues = extractValues(start);
ByteBuffer[] endValues = extractValues(end);
return new Slice(ClusteringBound.inclusiveStartOf(startValues), ClusteringBound.inclusiveEndOf(endValues));
}
private static ByteBuffer[] extractValues(ClusteringPrefix clustering)
{
ByteBuffer[] values = new ByteBuffer[clustering.size()];
for (int i = 0; i < clustering.size(); i++)
values[i] = clustering.get(i);
return values;
}
public ClusteringBound start()
{
return start;
}
public ClusteringBound end()
{
return end;
}
public ClusteringBound open(boolean reversed)
{
return reversed ? end : start;
}
public ClusteringBound close(boolean reversed)
{
return reversed ? start : end;
}
/**
* Return whether the slice is empty.
*
* @param comparator the comparator to compare the bounds.
* @return whether the slice formed is empty or not.
*/
public boolean isEmpty(ClusteringComparator comparator)
{
return isEmpty(comparator, start(), end());
}
/**
* Return whether the slice formed by the two provided bound is empty or not.
*
* @param comparator the comparator to compare the bounds.
* @param start the start for the slice to consider. This must be a start bound.
* @param end the end for the slice to consider. This must be an end bound.
* @return whether the slice formed by {@code start} and {@code end} is
* empty or not.
*/
public static boolean isEmpty(ClusteringComparator comparator, ClusteringBound start, ClusteringBound end)
{
assert start.isStart() && end.isEnd();
return comparator.compare(end, start) <= 0;
}
/**
* Returns whether a given clustering or bound is included in this slice.
*
* @param comparator the comparator for the table this is a slice of.
* @param bound the bound to test inclusion of.
*
* @return whether {@code bound} is within the bounds of this slice.
*/
public boolean includes(ClusteringComparator comparator, ClusteringPrefix bound)
{
return comparator.compare(start, bound) <= 0 && comparator.compare(bound, end) <= 0;
}
/**
* Returns a slice for continuing paging from the last returned clustering prefix.
*
* @param comparator the comparator for the table this is a filter for.
* @param lastReturned the last clustering that was returned for the query we are paging for. The
* resulting slices will be such that only results coming stricly after {@code lastReturned} are returned
* (where coming after means "greater than" if {@code !reversed} and "lesser than" otherwise).
* @param inclusive whether or not we want to include the {@code lastReturned} in the newly returned page of results.
* @param reversed whether the query we're paging for is reversed or not.
*
* @return a new slice that selects results coming after {@code lastReturned}, or {@code null} if paging
* the resulting slice selects nothing (i.e. if it originally selects nothing coming after {@code lastReturned}).
*/
public Slice forPaging(ClusteringComparator comparator, Clustering lastReturned, boolean inclusive, boolean reversed)
{
if (lastReturned == null)
return this;
if (reversed)
{
int cmp = comparator.compare(lastReturned, start);
if (cmp < 0 || (!inclusive && cmp == 0))
return null;
cmp = comparator.compare(end, lastReturned);
if (cmp < 0 || (inclusive && cmp == 0))
return this;
ByteBuffer[] values = extractValues(lastReturned);
return new Slice(start, inclusive ? ClusteringBound.inclusiveEndOf(values) : ClusteringBound.exclusiveEndOf(values));
}
else
{
int cmp = comparator.compare(end, lastReturned);
if (cmp < 0 || (!inclusive && cmp == 0))
return null;
cmp = comparator.compare(lastReturned, start);
if (cmp < 0 || (inclusive && cmp == 0))
return this;
ByteBuffer[] values = extractValues(lastReturned);
return new Slice(inclusive ? ClusteringBound.inclusiveStartOf(values) : ClusteringBound.exclusiveStartOf(values), end);
}
}
/**
* Given the per-clustering column minimum and maximum value a sstable contains, whether or not this slice potentially
* intersects that sstable or not.
*
* @param comparator the comparator for the table this is a slice of.
* @param minClusteringValues the smallest values for each clustering column that a sstable contains.
* @param maxClusteringValues the biggest values for each clustering column that a sstable contains.
*
* @return whether the slice might intersects with the sstable having {@code minClusteringValues} and
* {@code maxClusteringValues}.
*/
public boolean intersects(ClusteringComparator comparator, List<ByteBuffer> minClusteringValues, List<ByteBuffer> maxClusteringValues)
{
// If this slice start after max or end before min, it can't intersect
if (start.compareTo(comparator, maxClusteringValues) > 0 || end.compareTo(comparator, minClusteringValues) < 0)
return false;
// We could safely return true here, but there's a minor optimization: if the first component
// of the slice is restricted to a single value (typically the slice is [4:5, 4:7]), we can
// check that the second component falls within the min/max for that component (and repeat for
// all components).
for (int j = 0; j < minClusteringValues.size() && j < maxClusteringValues.size(); j++)
{
ByteBuffer s = j < start.size() ? start.get(j) : null;
ByteBuffer f = j < end.size() ? end.get(j) : null;
// we already know the first component falls within its min/max range (otherwise we wouldn't get here)
if (j > 0 && (j < end.size() && comparator.compareComponent(j, f, minClusteringValues.get(j)) < 0 ||
j < start.size() && comparator.compareComponent(j, s, maxClusteringValues.get(j)) > 0))
return false;
// if this component isn't equal in the start and finish, we don't need to check any more
if (j >= start.size() || j >= end.size() || comparator.compareComponent(j, s, f) != 0)
break;
}
return true;
}
public String toString(ClusteringComparator comparator)
{
StringBuilder sb = new StringBuilder();
sb.append(start.isInclusive() ? "[" : "(");
for (int i = 0; i < start.size(); i++)
{
if (i > 0)
sb.append(':');
sb.append(comparator.subtype(i).getString(start.get(i)));
}
sb.append(", ");
for (int i = 0; i < end.size(); i++)
{
if (i > 0)
sb.append(':');
sb.append(comparator.subtype(i).getString(end.get(i)));
}
sb.append(end.isInclusive() ? "]" : ")");
return sb.toString();
}
@Override
public boolean equals(Object other)
{
if(!(other instanceof Slice))
return false;
Slice that = (Slice)other;
return this.start().equals(that.start())
&& this.end().equals(that.end());
}
@Override
public int hashCode()
{
return Objects.hash(start(), end());
}
public static class Serializer
{
public void serialize(Slice slice, DataOutputPlus out, int version, List<AbstractType<?>> types) throws IOException
{
ClusteringBound.serializer.serialize(slice.start, out, version, types);
ClusteringBound.serializer.serialize(slice.end, out, version, types);
}
public long serializedSize(Slice slice, int version, List<AbstractType<?>> types)
{
return ClusteringBound.serializer.serializedSize(slice.start, version, types)
+ ClusteringBound.serializer.serializedSize(slice.end, version, types);
}
public Slice deserialize(DataInputPlus in, int version, List<AbstractType<?>> types) throws IOException
{
ClusteringBound start = (ClusteringBound) ClusteringBound.serializer.deserialize(in, version, types);
ClusteringBound end = (ClusteringBound) ClusteringBound.serializer.deserialize(in, version, types);
return new Slice(start, end);
}
}
}