io.trino.operator.exchange.PageChannelSelector Maven / Gradle / Ivy
/*
* 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 io.trino.operator.exchange;
import io.trino.spi.Page;
import java.util.function.Function;
import java.util.stream.IntStream;
import static com.google.common.base.Preconditions.checkArgument;
public class PageChannelSelector
implements Function
{
// No channels need to be remapped, only ensure that all page blocks are loaded
private static final Function GET_LOADED_PAGE = Page::getLoadedPage;
private final int[] channels;
public PageChannelSelector(int... channels)
{
this.channels = channels.clone();
checkArgument(IntStream.of(channels).allMatch(channel -> channel >= 0), "channels must be positive");
}
@Override
public Page apply(Page page)
{
// Ensure the channels that are emitted are fully loaded and in the correct order
return page.getLoadedPage(channels);
}
public static Function identitySelection()
{
return GET_LOADED_PAGE;
}
}