io.prestosql.sql.planner.iterative.rule.PruneOutputColumns.java Source code

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Here is the source code for io.prestosql.sql.planner.iterative.rule.PruneOutputColumns.java

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/*
 * 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.prestosql.sql.planner.iterative.rule;

import com.google.common.collect.ImmutableSet;
import io.prestosql.matching.Captures;
import io.prestosql.matching.Pattern;
import io.prestosql.sql.planner.iterative.Rule;
import io.prestosql.sql.planner.plan.OutputNode;

import static io.prestosql.sql.planner.iterative.rule.Util.restrictChildOutputs;
import static io.prestosql.sql.planner.plan.Patterns.output;

public class PruneOutputColumns implements Rule<OutputNode> {
    private static final Pattern<OutputNode> PATTERN = output();

    @Override
    public Pattern<OutputNode> getPattern() {
        return PATTERN;
    }

    @Override
    public Result apply(OutputNode outputNode, Captures captures, Context context) {
        return restrictChildOutputs(context.getIdAllocator(), outputNode,
                ImmutableSet.copyOf(outputNode.getOutputSymbols())).map(Result::ofPlanNode).orElse(Result.empty());
    }
}