MapAgg.java

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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.ExplicitlyCastableSignature;
import org.apache.doris.nereids.trees.expressions.literal.MapLiteral;
import org.apache.doris.nereids.trees.expressions.shape.BinaryExpression;
import org.apache.doris.nereids.types.MapType;
import org.apache.doris.nereids.types.coercion.AnyDataType;
import org.apache.doris.nereids.types.coercion.FollowToAnyDataType;

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

import java.util.ArrayList;
import java.util.List;

/**
 * AggregateFunction 'map_agg'. This class is generated by GenerateFunction.
 */
public class MapAgg extends NotNullableAggregateFunction
        implements BinaryExpression, ExplicitlyCastableSignature {

    public static final List<FunctionSignature> SIGNATURES = ImmutableList.of(
            FunctionSignature.ret(MapType.of(new FollowToAnyDataType(0), new FollowToAnyDataType(1)))
                .args(new AnyDataType(0), new AnyDataType(1))
    );

    /**FunctionSignature
     * constructor with 2 arguments.
     */
    public MapAgg(Expression arg0, Expression arg1) {
        this(false, arg0, arg1);
    }

    /**
     * constructor with 2 arguments.
     */
    private MapAgg(boolean distinct, Expression arg0, Expression arg1) {
        super("map_agg_v1", distinct, arg0, arg1);
    }

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

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

    @Override
    public Expression resultForEmptyInput() {
        return new MapLiteral(new ArrayList<>(), new ArrayList<>(), this.getDataType());
    }
}