io.questdb.cairo.sql.DataFrameCursorFactory 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.cairo.sql;

import io.questdb.griffin.SqlException;
import io.questdb.griffin.SqlExecutionContext;
import io.questdb.std.Sinkable;
import io.questdb.std.str.CharSink;

import java.io.Closeable;

/**
 * A factory interface for dataframe cursors
 */
public interface DataFrameCursorFactory extends Sinkable, Closeable {

    DataFrameCursor getCursor(SqlExecutionContext executionContext, int order) throws SqlException;

    /**
     * @param sink to print data frame cursor to
     */
    default void toSink(CharSink sink) {
        throw new UnsupportedOperationException();
    }

    boolean supportTableRowId(CharSequence tableName);

    /**
     * Order of records in the data frame in regard to timestamp.
     *
     * @return 0 for ascending and 1 for descending
     */
    int getOrder();

    int ORDER_ASC = 0;
    int ORDER_DESC = 1;
    // Any order means that algorithm is able to work with frames in any order.
    // In this case frame order will be driven by the optimiser.
    // Any order is not returned by the factory
    int ORDER_ANY = 2;
}