org.apache.druid.query.ResultGranularTimestampComparator.java Source code

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Here is the source code for org.apache.druid.query.ResultGranularTimestampComparator.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;

import com.google.common.collect.Ordering;
import com.google.common.primitives.Longs;
import org.apache.druid.guice.annotations.PublicApi;
import org.apache.druid.java.util.common.granularity.Granularity;

import java.util.Comparator;

/**
 */
@PublicApi
public class ResultGranularTimestampComparator<T> implements Comparator<Result<T>> {
    private final Granularity gran;

    public ResultGranularTimestampComparator(Granularity granularity) {
        this.gran = granularity;
    }

    @Override
    public int compare(Result<T> r1, Result<T> r2) {
        return Longs.compare(gran.bucketStart(r1.getTimestamp()).getMillis(),
                gran.bucketStart(r2.getTimestamp()).getMillis());
    }

    public static <T> Ordering<Result<T>> create(Granularity granularity, boolean descending) {
        Comparator<Result<T>> comparator = new ResultGranularTimestampComparator<>(granularity);
        return descending ? Ordering.from(comparator).reverse() : Ordering.from(comparator);
    }
}