/*
* 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.project;
import com.facebook.presto.spi.ConnectorSession;
import com.facebook.presto.spi.Page;
import com.facebook.presto.spi.block.Block;
import com.facebook.presto.spi.block.BlockBuilder;
import com.facebook.presto.spi.block.BlockBuilderStatus;
import com.facebook.presto.spi.block.RunLengthEncodedBlock;
import com.facebook.presto.spi.type.Type;
import com.google.common.collect.ImmutableList;
import static com.facebook.presto.spi.type.TypeUtils.writeNativeValue;
public class ConstantPageProjection
implements PageProjection
{
private static final InputChannels INPUT_PARAMETERS = new InputChannels(ImmutableList.of());
private final Type type;
private final Block value;
public ConstantPageProjection(Object value, Type type)
{
this.type = type;
BlockBuilder blockBuilder = type.createBlockBuilder(new BlockBuilderStatus(), 1);
writeNativeValue(type, blockBuilder, value);
this.value = blockBuilder.build();
}
@Override
public Type getType()
{
return type;
}
@Override
public boolean isDeterministic()
{
return true;
}
@Override
public InputChannels getInputChannels()
{
return INPUT_PARAMETERS;
}
@Override
public Block project(ConnectorSession session, Page page, SelectedPositions selectedPositions)
{
return new RunLengthEncodedBlock(value, selectedPositions.size());
}
}