io.druid.query.datasourcemetadata.DataSourceMetadataQuery Maven / Gradle / Ivy

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A module that is everything required to understands Druid Segments
There is a newer version: 0.12.3
/*
 * Licensed to Metamarkets Group Inc. (Metamarkets) under one
 * or more contributor license agreements. See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership. Metamarkets 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 io.druid.query.datasourcemetadata;

import com.fasterxml.jackson.annotation.JsonCreator;
import com.fasterxml.jackson.annotation.JsonProperty;
import com.google.common.collect.Lists;
import io.druid.common.utils.JodaUtils;
import io.druid.query.BaseQuery;
import io.druid.query.DataSource;
import io.druid.query.Query;
import io.druid.query.Result;
import io.druid.query.spec.MultipleIntervalSegmentSpec;
import io.druid.query.spec.QuerySegmentSpec;
import org.joda.time.DateTime;
import org.joda.time.Interval;

import java.util.Arrays;
import java.util.List;
import java.util.Map;

/**
 */
public class DataSourceMetadataQuery extends BaseQuery>
{
  public static final Interval MY_Y2K_INTERVAL = new Interval(
      JodaUtils.MIN_INSTANT, JodaUtils.MAX_INSTANT
  );

  @JsonCreator
  public DataSourceMetadataQuery(
      @JsonProperty("dataSource") DataSource dataSource,
      @JsonProperty("intervals") QuerySegmentSpec querySegmentSpec,
      @JsonProperty("context") Map context
  )
  {
    super(
        dataSource,
        (querySegmentSpec == null) ? new MultipleIntervalSegmentSpec(Arrays.asList(MY_Y2K_INTERVAL))
                                   : querySegmentSpec,
        false,
        context
    );
  }

  @Override
  public boolean hasFilters()
  {
    return false;
  }

  @Override
  public String getType()
  {
    return Query.DATASOURCE_METADATA;
  }

  @Override
  public DataSourceMetadataQuery withOverriddenContext(Map contextOverrides)
  {
    return new DataSourceMetadataQuery(
        getDataSource(),
        getQuerySegmentSpec(),
        computeOverridenContext(contextOverrides)
    );
  }

  @Override
  public DataSourceMetadataQuery withQuerySegmentSpec(QuerySegmentSpec spec)
  {
    return new DataSourceMetadataQuery(
        getDataSource(),
        spec,
        getContext()
    );
  }

  @Override
  public Query> withDataSource(DataSource dataSource)
  {
    return new DataSourceMetadataQuery(
        dataSource,
        getQuerySegmentSpec(),
        getContext()
    );
  }

  public Iterable> buildResult(DateTime timestamp, DateTime maxIngestedEventTime)
  {
    return Arrays.asList(new Result<>(timestamp, new DataSourceMetadataResultValue(maxIngestedEventTime)));
  }

  public Iterable> mergeResults(List> results)
  {
    if (results == null || results.isEmpty()) {
      return Lists.newArrayList();
    }

    DateTime max = new DateTime(JodaUtils.MIN_INSTANT);
    for (Result result : results) {
      DateTime currMaxIngestedEventTime = result.getValue().getMaxIngestedEventTime();
      if (currMaxIngestedEventTime != null && currMaxIngestedEventTime.isAfter(max)) {
        max = currMaxIngestedEventTime;
      }
    }

    return buildResult(max, max);
  }

  @Override
  public String toString()
  {
    return "DataSourceMetadataQuery{" +
           "dataSource='" + getDataSource() + '\'' +
           ", querySegmentSpec=" + getQuerySegmentSpec() +
           ", duration=" + getDuration() +
           '}';
  }

}