JsonExtract.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.ExplicitlyCastableSignature;
import org.apache.doris.nereids.trees.expressions.visitor.ExpressionVisitor;
import org.apache.doris.nereids.types.VarcharType;
import org.apache.doris.nereids.util.ExpressionUtils;

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

import java.util.List;

/**
 * ScalarFunction 'json_object'. This class is generated by GenerateFunction.
 */
public class JsonExtract extends ScalarFunction
        implements ExplicitlyCastableSignature, AlwaysNullable {

    public static final List<FunctionSignature> SIGNATURES =
            ImmutableList.of(FunctionSignature.ret(VarcharType.SYSTEM_DEFAULT)
                    .varArgs(VarcharType.SYSTEM_DEFAULT, VarcharType.SYSTEM_DEFAULT));

    /**
     * constructor with 1 or more arguments.
     */
    public JsonExtract(Expression arg0, Expression arg1, Expression... varArgs) {
        super("json_extract", ExpressionUtils.mergeArguments(arg0, arg1, varArgs));
    }

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

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

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