/*
* 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.PageBuilder;
import com.facebook.presto.spi.block.Block;
import com.facebook.presto.spi.block.BlockBuilder;
import com.facebook.presto.spi.type.Type;
import com.facebook.presto.type.MapType;
import javax.annotation.Nullable;
import static java.util.Objects.requireNonNull;
public class MapUnnester
implements Unnester
{
private final Type keyType;
private final Type valueType;
private Block block;
private final int channelCount;
private int position;
private int positionCount;
public MapUnnester(MapType mapType, @Nullable Block mapBlock)
{
this.channelCount = 2;
requireNonNull(mapType, "mapType is null");
this.keyType = mapType.getKeyType();
this.valueType = mapType.getValueType();
this.block = mapBlock;
this.positionCount = mapBlock == null ? 0 : mapBlock.getPositionCount();
}
protected void appendTo(PageBuilder pageBuilder, int outputChannelOffset)
{
BlockBuilder keyBlockBuilder = pageBuilder.getBlockBuilder(outputChannelOffset);
BlockBuilder valueBlockBuilder = pageBuilder.getBlockBuilder(outputChannelOffset + 1);
keyType.appendTo(block, position++, keyBlockBuilder);
valueType.appendTo(block, position++, valueBlockBuilder);
}
@Override
public boolean hasNext()
{
return position < positionCount;
}
@Override
public final int getChannelCount()
{
return channelCount;
}
@Override
public final void appendNext(PageBuilder pageBuilder, int outputChannelOffset)
{
appendTo(pageBuilder, outputChannelOffset);
}
@Override
public void setBlock(@Nullable Block mapBlock)
{
this.block = mapBlock;
this.position = 0;
this.positionCount = mapBlock == null ? 0 : mapBlock.getPositionCount();
}
}