Month.java

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// to you under the Apache License, Version 2.0 (the
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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.Monotonic;
import org.apache.doris.nereids.trees.expressions.functions.PropagateNullableOnDateOrTimeLikeV2Args;
import org.apache.doris.nereids.trees.expressions.literal.DateLiteral;
import org.apache.doris.nereids.trees.expressions.literal.Literal;
import org.apache.doris.nereids.trees.expressions.shape.UnaryExpression;
import org.apache.doris.nereids.trees.expressions.visitor.ExpressionVisitor;
import org.apache.doris.nereids.types.DateTimeType;
import org.apache.doris.nereids.types.DateTimeV2Type;
import org.apache.doris.nereids.types.DateV2Type;
import org.apache.doris.nereids.types.TinyIntType;

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

import java.util.List;

/**
 * ScalarFunction 'month'. This class is generated by GenerateFunction.
 */
public class Month extends ScalarFunction
        implements UnaryExpression, ExplicitlyCastableSignature, PropagateNullableOnDateOrTimeLikeV2Args, Monotonic {

    private static final List<FunctionSignature> SIGNATURES = ImmutableList.of(
            FunctionSignature.ret(TinyIntType.INSTANCE).args(DateV2Type.INSTANCE),
            FunctionSignature.ret(TinyIntType.INSTANCE).args(DateTimeV2Type.SYSTEM_DEFAULT),
            FunctionSignature.ret(TinyIntType.INSTANCE).args(DateTimeType.INSTANCE)
    );

    /**
     * constructor with 1 argument.
     */
    public Month(Expression arg) {
        super("month", arg);
    }

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

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

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

    @Override
    public boolean isPositive() {
        return true;
    }

    @Override
    public int getMonotonicFunctionChildIndex() {
        return 0;
    }

    @Override
    public Expression withConstantArgs(Expression literal) {
        return new Month(literal);
    }

    @Override
    public boolean isMonotonic(Literal lower, Literal upper) {
        if (lower instanceof DateLiteral && upper instanceof DateLiteral) {
            return ((DateLiteral) lower).getYear() == ((DateLiteral) upper).getYear();
        }
        return false;
    }
}