MonthsBetween.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.ExplicitlyCastableSignature;
import org.apache.doris.nereids.trees.expressions.functions.PropagateNullableOnDateOrTimeLikeV2Args;
import org.apache.doris.nereids.trees.expressions.literal.Literal;
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.DateV2Type;
import org.apache.doris.nereids.types.DoubleType;

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

import java.util.List;

/**
 * ScalarFunction 'months_between'.
 */
public class MonthsBetween extends ScalarFunction
        implements TernaryExpression, ExplicitlyCastableSignature, PropagateNullableOnDateOrTimeLikeV2Args {

    private static final List<FunctionSignature> SIGNATURES = ImmutableList.of(
            FunctionSignature.ret(DoubleType.INSTANCE).args(DateV2Type.INSTANCE, DateV2Type.INSTANCE,
                    BooleanType.INSTANCE),
            FunctionSignature.ret(DoubleType.INSTANCE).args(DateV2Type.INSTANCE, DateV2Type.INSTANCE));

    /**
     * constructor with 2 arguments.
     */
    public MonthsBetween(Expression arg0, Expression arg1) {
        super("months_between", arg0, arg1, Literal.of(true));
    }

    /**
     * constructor with 3 arguments.
     */
    public MonthsBetween(Expression arg0, Expression arg1, Expression arg2) {
        super("months_between", arg0, arg1, arg2);
    }

    /**
     * withChildren.
     */
    @Override
    public MonthsBetween withChildren(List<Expression> children) {
        Preconditions.checkArgument(children.size() == 2 || children.size() == 3);
        if (children.size() == 2) {
            return new MonthsBetween(children.get(0), children.get(1));
        } else {
            return new MonthsBetween(children.get(0), children.get(1), children.get(2));
        }
    }

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

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