io.questdb.griffin.engine.functions.groupby.FirstCharGroupByFunction Maven / Gradle / Ivy

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 *  Copyright (c) 2014-2019 Appsicle
 *  Copyright (c) 2019-2023 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,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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package io.questdb.griffin.engine.functions.groupby;

import io.questdb.cairo.ArrayColumnTypes;
import io.questdb.cairo.ColumnType;
import io.questdb.cairo.map.MapValue;
import io.questdb.cairo.sql.Function;
import io.questdb.cairo.sql.Record;
import io.questdb.griffin.engine.functions.CharFunction;
import io.questdb.griffin.engine.functions.GroupByFunction;
import io.questdb.griffin.engine.functions.UnaryFunction;
import org.jetbrains.annotations.NotNull;

public class FirstCharGroupByFunction extends CharFunction implements GroupByFunction, UnaryFunction {
    private final Function arg;
    private int valueIndex;

    public FirstCharGroupByFunction(@NotNull Function arg) {
        this.arg = arg;
    }

    @Override
    public void computeFirst(MapValue mapValue, Record record) {
        mapValue.putChar(this.valueIndex, this.arg.getChar(record));
    }

    @Override
    public void computeNext(MapValue mapValue, Record record) {
        // empty
    }

    @Override
    public Function getArg() {
        return this.arg;
    }

    @Override
    public char getChar(Record rec) {
        return rec.getChar(this.valueIndex);
    }

    @Override
    public String getName() {
        return "first";
    }

    @Override
    public void pushValueTypes(ArrayColumnTypes columnTypes) {
        this.valueIndex = columnTypes.getColumnCount();
        columnTypes.add(ColumnType.SHORT);
    }

    public void setChar(MapValue mapValue, char value) {
        mapValue.putChar(this.valueIndex, value);
    }

    @Override
    public void setNull(MapValue mapValue) {
        setChar(mapValue, (char) 0);
    }
}