If.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.analyzer.Unbound;
import org.apache.doris.nereids.trees.expressions.Expression;
import org.apache.doris.nereids.trees.expressions.functions.CustomSignature;
import org.apache.doris.nereids.trees.expressions.functions.SearchSignature;
import org.apache.doris.nereids.trees.expressions.shape.TernaryExpression;
import org.apache.doris.nereids.trees.expressions.visitor.ExpressionVisitor;
import org.apache.doris.nereids.types.BooleanType;
import org.apache.doris.nereids.types.DataType;
import org.apache.doris.nereids.util.TypeCoercionUtils;

import com.google.common.base.Preconditions;

import java.util.List;
import java.util.Optional;

/**
 * ScalarFunction 'if'. This class is generated by GenerateFunction.
 */
public class If extends ScalarFunction
        implements TernaryExpression, CustomSignature {

    /**
     * constructor with 3 arguments.
     */
    public If(Expression arg0, Expression arg1, Expression arg2) {
        super("if", arg0 instanceof Unbound ? arg0 : TypeCoercionUtils.castIfNotSameType(arg0, BooleanType.INSTANCE),
                arg1, arg2);
    }

    /** constructor for withChildren and reuse signature */
    private If(ScalarFunctionParams functionParams) {
        super(functionParams);
    }

    /**
     * custom compute nullable.
     */
    @Override
    public boolean nullable() {
        for (int i = 1; i < arity(); i++) {
            if (child(i).nullable()) {
                return true;
            }
        }
        return false;
    }

    /**
     * withChildren.
     */
    @Override
    public If withChildren(List<Expression> children) {
        Preconditions.checkArgument(children.size() == 3);
        return new If(getFunctionParams(children));
    }

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

    @Override
    public FunctionSignature customSignature() {
        Optional<DataType> commonType;
        try {
            commonType = TypeCoercionUtils.findWiderTypeForTwo(
                    getArgumentType(1), getArgumentType(2), false);
        } catch (Exception e) {
            SearchSignature.throwCanNotFoundFunctionException(this.getName(), getArguments());
            return null;
        }
        if (commonType.isPresent()) {
            return FunctionSignature.ret(commonType.get())
                    .args(BooleanType.INSTANCE, commonType.get(), commonType.get());
        } else {
            SearchSignature.throwCanNotFoundFunctionException(this.getName(), getArguments());
            return null;
        }
    }
}