Variance.java

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// to you under the Apache License, Version 2.0 (the
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//
//   http://www.apache.org/licenses/LICENSE-2.0
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package org.apache.doris.nereids.trees.expressions.functions.agg;

import org.apache.doris.catalog.FunctionSignature;
import org.apache.doris.nereids.trees.expressions.Expression;
import org.apache.doris.nereids.trees.expressions.functions.DecimalStddevPrecision;
import org.apache.doris.nereids.trees.expressions.functions.ExplicitlyCastableSignature;
import org.apache.doris.nereids.trees.expressions.shape.UnaryExpression;
import org.apache.doris.nereids.trees.expressions.visitor.ExpressionVisitor;
import org.apache.doris.nereids.types.BigIntType;
import org.apache.doris.nereids.types.DoubleType;
import org.apache.doris.nereids.types.FloatType;
import org.apache.doris.nereids.types.IntegerType;
import org.apache.doris.nereids.types.SmallIntType;
import org.apache.doris.nereids.types.TinyIntType;

import com.google.common.base.Preconditions;
import com.google.common.collect.ImmutableList;

import java.util.List;

/**
 * AggregateFunction 'variance'. This class is generated by GenerateFunction.
 */
public class Variance extends NullableAggregateFunction
        implements UnaryExpression, ExplicitlyCastableSignature,
        StdDevOrVarianceFunction, DecimalStddevPrecision {

    public static final List<FunctionSignature> SIGNATURES = ImmutableList.of(
            FunctionSignature.ret(DoubleType.INSTANCE).args(DoubleType.INSTANCE),
            FunctionSignature.ret(DoubleType.INSTANCE).args(BigIntType.INSTANCE),
            FunctionSignature.ret(DoubleType.INSTANCE).args(IntegerType.INSTANCE),
            FunctionSignature.ret(DoubleType.INSTANCE).args(SmallIntType.INSTANCE),
            FunctionSignature.ret(DoubleType.INSTANCE).args(TinyIntType.INSTANCE),
            FunctionSignature.ret(DoubleType.INSTANCE).args(FloatType.INSTANCE));

    /**
     * constructor with 1 argument.
     */
    public Variance(Expression arg) {
        this(false, false, arg);
    }

    /**
     * constructor with 1 argument.
     */
    public Variance(boolean distinct, Expression arg) {
        this(distinct, false, arg);
    }

    private Variance(boolean distinct, boolean alwaysNullable, Expression child) {
        super("variance", distinct, alwaysNullable, child);
    }

    /**
     * withDistinctAndChildren.
     */
    @Override
    public Variance withDistinctAndChildren(boolean distinct, List<Expression> children) {
        Preconditions.checkArgument(children.size() == 1);
        return new Variance(distinct, alwaysNullable, children.get(0));
    }

    @Override
    public NullableAggregateFunction withAlwaysNullable(boolean alwaysNullable) {
        return new Variance(distinct, alwaysNullable, children.get(0));
    }

    @Override
    public <R, C> R accept(ExpressionVisitor<R, C> visitor, C context) {
        return visitor.visitVariance(this, context);
    }

    @Override
    public List<FunctionSignature> getSignatures() {
        return SIGNATURES;
    }
}