cc.blynk.clickhouse.response.ClickHouseScrollableResultSet Maven / Gradle / Ivy

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Light and fast JDBC driver for ClickHouse
There is a newer version: 1.4.4
package cc.blynk.clickhouse.response;

import cc.blynk.clickhouse.ClickHouseStatement;
import cc.blynk.clickhouse.settings.ClickHouseProperties;

import java.io.IOException;
import java.io.InputStream;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;
import java.util.TimeZone;


public class ClickHouseScrollableResultSet extends ClickHouseResultSet {

    private List lines;

    public ClickHouseScrollableResultSet(InputStream is,
                                         int bufferSize,
                                         String db,
                                         String table,
                                         boolean usesWithTotals,
                                         ClickHouseStatement statement,
                                         TimeZone timezone,
                                         ClickHouseProperties properties) throws IOException {
        super(is, bufferSize, db, table, usesWithTotals, statement, timezone, properties);
        lines = new ArrayList<>();
    }

    public boolean hasNext() throws SQLException {
        if (rowNumber < lines.size()) {
            return true;
        }
        return super.hasNext();
    }

    @Override
    public boolean next() throws SQLException {
        if (rowNumber < lines.size()) {
            values = lines.get(rowNumber);
            nextLine = null;
            rowNumber += 1;
            return true;
        }
        if (hasNext()) {
            super.next();
            lines.add(values);
            return true;
        } else {
            rowNumber += 1;
            values = null;
            nextLine = null;
            return false;
        }
    }

    //////

    @Override
    public int getType() throws SQLException {
        return TYPE_SCROLL_INSENSITIVE;
    }

    @Override
    public int getRow() throws SQLException {
        return rowNumber;
    }

    @Override
    public boolean isBeforeFirst() throws SQLException {
        return getRow() == 0;
    }

    @Override
    public boolean isAfterLast() throws SQLException {
        return getRow() > lines.size();
    }

    @Override
    public boolean isFirst() throws SQLException {
        return getRow() == 1;
    }

    @Override
    public void beforeFirst() throws SQLException {
        absolute(0);
    }

    @Override
    public void afterLast() throws SQLException {
        absolute(-1);
        next();
    }

    @Override
    public boolean first() throws SQLException {
        return absolute(1);
    }


    @Override
    public boolean last() throws SQLException {
        return absolute(-1);
    }

    @Override
    public boolean absolute(int row) throws SQLException {
        if (row == 0) {
            rowNumber = 0;
            values = null;
            return false;
        } else if (row > 0) {
            if (row <= lines.size()) {
                rowNumber = row;
                values = lines.get(row - 1);
                return true;
            }
            absolute(lines.size());
            while (getRow() < row && hasNext()) {
                next();
            }
            if (row == getRow()) {
                return true;
            } else {
                next();
                return false;
            }
        } else {
            // We have to check the number of total rows
            while (hasNext()) {
                next();
            }
            if (-row > lines.size()) {
                // there is not so many rows
                // Put the cursor before the first row
                return absolute(0);
            }
            return absolute(lines.size() + 1 + row);
        }
    }

    @Override
    public boolean relative(int rows) throws SQLException {
        int r = getRow() + rows;
        if (r < 0) {
            r = 0;
        }
        return absolute(r);
    }

    @Override
    public boolean previous() throws SQLException {
        return relative(-1);
    }
}