org.apache.druid.query.materializedview.MaterializedViewQueryRunner.java Source code

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Here is the source code for org.apache.druid.query.materializedview.MaterializedViewQueryRunner.java

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/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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 org.apache.druid.query.materializedview;

import com.google.common.base.Function;
import com.google.common.collect.Lists;
import org.apache.druid.java.util.common.guava.MergeSequence;
import org.apache.druid.java.util.common.guava.Sequence;
import org.apache.druid.java.util.common.guava.Sequences;
import org.apache.druid.query.Query;
import org.apache.druid.query.QueryPlus;
import org.apache.druid.query.QueryRunner;

import java.util.Map;

public class MaterializedViewQueryRunner<T> implements QueryRunner<T> {
    private final QueryRunner runner;
    private final DataSourceOptimizer optimizer;

    public MaterializedViewQueryRunner(QueryRunner queryRunner, DataSourceOptimizer optimizer) {
        this.runner = queryRunner;
        this.optimizer = optimizer;
    }

    @Override
    public Sequence<T> run(QueryPlus<T> queryPlus, Map<String, Object> responseContext) {
        Query query = queryPlus.getQuery();
        return new MergeSequence<>(query.getResultOrdering(),
                Sequences.simple(Lists.transform(optimizer.optimize(query), new Function<Query, Sequence<T>>() {
                    @Override
                    public Sequence<T> apply(Query query) {
                        return runner.run(queryPlus.withQuery(query), responseContext);
                    }
                })));
    }
}