L2Distance.java

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package org.apache.doris.nereids.trees.expressions.functions.scalar;

import org.apache.doris.catalog.FunctionSignature;
import org.apache.doris.nereids.trees.expressions.Expression;
import org.apache.doris.nereids.trees.expressions.functions.AlwaysNullable;
import org.apache.doris.nereids.trees.expressions.functions.ComputePrecisionForArrayItemAgg;
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.ArrayType;
import org.apache.doris.nereids.types.DoubleType;

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

import java.util.List;

/**
 * l2_distance function
 */
public class L2Distance extends ScalarFunction implements ExplicitlyCastableSignature,
        ComputePrecisionForArrayItemAgg, UnaryExpression, AlwaysNullable {

    public static final List<FunctionSignature> SIGNATURES = ImmutableList.of(
            FunctionSignature.ret(DoubleType.INSTANCE)
                    .args(ArrayType.of(DoubleType.INSTANCE), ArrayType.of(DoubleType.INSTANCE))
    );

    /**
     * constructor with 1 argument.
     */
    public L2Distance(Expression arg0, Expression arg1) {
        super("l2_distance", arg0, arg1);
    }

    /**
     * withChildren.
     */
    @Override
    public L2Distance withChildren(List<Expression> children) {
        Preconditions.checkArgument(children.size() == 2);
        return new L2Distance(children.get(0), children.get(1));
    }

    @Override
    public <R, C> R accept(ExpressionVisitor<R, C> visitor, C context) {
        return visitor.visitL2Distance(this, context);
    }

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