com.facebook.presto.jdbc.internal.spi.statistics.PlanStatistics Maven / Gradle / Ivy

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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 com.facebook.presto.jdbc.internal.spi.statistics;

import com.facebook.presto.jdbc.internal.drift.annotations.ThriftConstructor;
import com.facebook.presto.jdbc.internal.drift.annotations.ThriftField;
import com.facebook.presto.jdbc.internal.drift.annotations.ThriftStruct;
import com.facebook.presto.jdbc.internal.jackson.annotation.JsonCreator;
import com.facebook.presto.jdbc.internal.jackson.annotation.JsonProperty;

import java.util.Objects;

import static java.util.Objects.requireNonNull;

@ThriftStruct
public class PlanStatistics
{
    private static final PlanStatistics EMPTY = new PlanStatistics(Estimate.unknown(), Estimate.unknown(), 0);

    private final Estimate rowCount;
    private final Estimate outputSize;
    // A number ranging between 0 and 1, reflecting our confidence in the statistics
    private final double confidence;

    public static PlanStatistics empty()
    {
        return EMPTY;
    }

    @JsonCreator
    @ThriftConstructor
    public PlanStatistics(@JsonProperty("rowCount") Estimate rowCount, @JsonProperty("outputSize") Estimate outputSize, @JsonProperty("confidence") double confidence)
    {
        this.rowCount = requireNonNull(rowCount, "rowCount is null");
        this.outputSize = requireNonNull(outputSize, "outputSize is null");
        checkArgument(confidence >= 0 && confidence <= 1, "confidence should be between 0 and 1");
        this.confidence = confidence;
    }

    @JsonProperty
    @ThriftField(1)
    public Estimate getRowCount()
    {
        return rowCount;
    }

    @JsonProperty
    @ThriftField(2)
    public Estimate getOutputSize()
    {
        return outputSize;
    }

    @JsonProperty
    @ThriftField(3)
    public double getConfidence()
    {
        return confidence;
    }

    private static void checkArgument(boolean condition, String message)
    {
        if (!condition) {
            throw new IllegalArgumentException(message);
        }
    }

    @Override
    public boolean equals(Object o)
    {
        if (this == o) {
            return true;
        }
        if (o == null || getClass() != o.getClass()) {
            return false;
        }
        PlanStatistics that = (PlanStatistics) o;
        return Double.compare(that.confidence, confidence) == 0 && Objects.equals(rowCount, that.rowCount) && Objects.equals(outputSize, that.outputSize);
    }

    @Override
    public int hashCode()
    {
        return Objects.hash(rowCount, outputSize, confidence);
    }

    @Override
    public String toString()
    {
        return "PlanStatistics{" +
                "rowCount=" + rowCount +
                ", outputSize=" + outputSize +
                ", confidence=" + confidence +
                '}';
    }
}