io.questdb.griffin.engine.functions.conditional.NullIfStrFunctionFactory Maven / Gradle / Ivy

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 *  Copyright (c) 2014-2019 Appsicle
 *  Copyright (c) 2019-2022 QuestDB
 *
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *  http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
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package io.questdb.griffin.engine.functions.conditional;

import io.questdb.cairo.CairoConfiguration;
import io.questdb.cairo.sql.Function;
import io.questdb.cairo.sql.Record;
import io.questdb.griffin.FunctionFactory;
import io.questdb.griffin.SqlExecutionContext;
import io.questdb.griffin.engine.functions.BinaryFunction;
import io.questdb.griffin.engine.functions.StrFunction;
import io.questdb.std.Chars;
import io.questdb.std.IntList;
import io.questdb.std.ObjList;

public class NullIfStrFunctionFactory implements FunctionFactory {
    @Override
    public String getSignature() {
        return "nullif(SS)";
    }

    @Override
    public Function newInstance(
            int position,
            ObjList args,
            IntList argPositions,
            CairoConfiguration configuration,
            SqlExecutionContext sqlExecutionContext
    ) {
        Function strFunc1 = args.getQuick(0);
        Function strFunc2 = args.getQuick(1);
        return new Func(strFunc1, strFunc2);
    }

    private static class Func extends StrFunction implements BinaryFunction {
        private final Function strFunc1;
        private final Function strFunc2;

        public Func(Function strFunc1, Function strFunc2) {
            this.strFunc1 = strFunc1;
            this.strFunc2 = strFunc2;
        }

        @Override
        public Function getLeft() {
            return strFunc1;
        }

        @Override
        public Function getRight() {
            return strFunc2;
        }

        @Override
        public CharSequence getStr(Record rec) {
            CharSequence cs1 = strFunc1.getStr(rec);
            if (cs1 == null) {
                return null;
            }
            CharSequence cs2 = strFunc2.getStr(rec);
            if (cs2 == null) {
                return null;
            }
            return Chars.equals(cs1, cs2) ? null : cs1;
        }

        @Override
        public CharSequence getStrB(Record rec) {
            CharSequence cs1 = strFunc1.getStrB(rec);
            if (cs1 == null) {
                return null;
            }
            CharSequence cs2 = strFunc2.getStrB(rec);
            if (cs2 == null) {
                return null;
            }
            return Chars.equals(cs1, cs2) ? null : cs1;
        }
    }
}