server/src/main/java/org/apache/druid/server/NoopQuerySegmentWalker.java

/*
 * 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.server;

import org.apache.druid.query.Query;
import org.apache.druid.query.QueryRunner;
import org.apache.druid.query.QuerySegmentWalker;
import org.apache.druid.query.SegmentDescriptor;
import org.joda.time.Interval;

/**
 * An empty implementation of {@link QuerySegmentWalker}.
 *
 * Some extentions need implementation of QuerySegmentWalker, but this class will not be used in
 * router. Bind {@link NoopQuerySegmentWalker} in router to allow router load some extentions, which
 * makes query can run through router.
 */
public class NoopQuerySegmentWalker implements QuerySegmentWalker
{
  @Override
  public <T> QueryRunner<T> getQueryRunnerForIntervals(Query<T> query, Iterable<Interval> intervals)
  {
    return null;
  }

  @Override
  public <T> QueryRunner<T> getQueryRunnerForSegments(Query<T> query, Iterable<SegmentDescriptor> specs)
  {
    return null;
  }
}