/*
* Licensed 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 com.facebook.presto.operator;
import com.facebook.presto.spi.block.Block;
import com.facebook.presto.spi.block.SortOrder;
import com.facebook.presto.spi.type.Type;
import com.google.common.collect.ImmutableList;
import java.util.Comparator;
import java.util.List;
import static com.google.common.base.Preconditions.checkArgument;
import static com.google.common.base.Preconditions.checkNotNull;
public class RowComparator
implements Comparator<Block[]>
{
private final List<Type> sortTypes;
private final List<Integer> sortChannels;
private final List<SortOrder> sortOrders;
public RowComparator(List<Type> sortTypes, List<Integer> sortChannels, List<SortOrder> sortOrders)
{
this.sortTypes = ImmutableList.copyOf(checkNotNull(sortTypes, "sortTypes is null"));
this.sortChannels = ImmutableList.copyOf(checkNotNull(sortChannels, "sortChannels is null"));
this.sortOrders = ImmutableList.copyOf(checkNotNull(sortOrders, "sortOrders is null"));
checkArgument(sortTypes.size() == sortChannels.size(), "sortTypes size (%s) doesn't match sortChannels size (%s)", sortTypes.size(), sortChannels.size());
checkArgument(sortChannels.size() == sortOrders.size(), "sortFields size (%s) doesn't match sortOrders size (%s)", sortChannels.size(), sortOrders.size());
}
@Override
public int compare(Block[] leftRow, Block[] rightRow)
{
for (int index = 0; index < sortChannels.size(); index++) {
Type type = sortTypes.get(index);
int channel = sortChannels.get(index);
SortOrder sortOrder = sortOrders.get(index);
Block left = leftRow[channel];
Block right = rightRow[channel];
int comparison = sortOrder.compareBlockValue(type, left, 0, right, 0);
if (comparison != 0) {
return comparison;
}
}
return 0;
}
}