io.prestosql.operator.aggregation.histogram.HistogramStateFactory 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 io.prestosql.operator.aggregation.histogram;

import io.prestosql.spi.function.AccumulatorStateFactory;
import io.prestosql.spi.type.Type;
import io.prestosql.type.BlockTypeOperators.BlockPositionEqual;
import io.prestosql.type.BlockTypeOperators.BlockPositionHashCode;

import static java.util.Objects.requireNonNull;

public class HistogramStateFactory
        implements AccumulatorStateFactory
{
    private final Type keyType;
    private final BlockPositionEqual equalOperator;
    private final BlockPositionHashCode hashCodeOperator;
    private final int expectedEntriesCount;

    public HistogramStateFactory(
            Type keyType,
            BlockPositionEqual equalOperator,
            BlockPositionHashCode hashCodeOperator,
            int expectedEntriesCount)
    {
        this.keyType = requireNonNull(keyType, "keyType is null");
        this.equalOperator = requireNonNull(equalOperator, "equalOperator is null");
        this.hashCodeOperator = requireNonNull(hashCodeOperator, "hashCodeOperator is null");
        this.expectedEntriesCount = expectedEntriesCount;
    }

    @Override
    public HistogramState createSingleState()
    {
        return new SingleHistogramState(keyType, equalOperator, hashCodeOperator, expectedEntriesCount);
    }

    @Override
    public Class getSingleStateClass()
    {
        return SingleHistogramState.class;
    }

    @Override
    public HistogramState createGroupedState()
    {
        return new GroupedHistogramState(keyType, equalOperator, hashCodeOperator, expectedEntriesCount);
    }

    @Override
    public Class getGroupedStateClass()
    {
        return GroupedHistogramState.class;
    }
}