au.net.causal.maven.plugins.boxdb.SqlDivider Maven / Gradle / Ivy

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package au.net.causal.maven.plugins.boxdb;

import org.codehaus.mojo.sql.SqlSplitter;

import java.io.BufferedReader;
import java.io.IOException;
import java.util.Arrays;
import java.util.Collections;
import java.util.List;

/**
 * Split SQL read from reader into statements that can be executed with JDBC connection.
 * 
 *
 * SQL statements are split semi-intelligently according to ';' and line breaks.  SQL comments are ignored.
 *
 * @see SqlSplitter
 */
public class SqlDivider
{
    private static final List SQL_COMMENT_STARTS = Collections.unmodifiableList(Arrays.asList("--", "//"));

    /**
     * Splits SQL statements read from a reader and processes them in a consumer.
     *
     * @param reader the reader to read SQL from.
     * @param sqlProcessor a consumer that accepts SQL statements.  Each SQL statement read from the reader
     *                     will be passed to this consumer one-at-a-time.
     *
     * @param  type of exceptions thrown from the consumer.
     *
     * @throws IOException if an I/O error occurs reading from the reader.
     * @throws E if an exception is thrown from the consumer.
     */
    public  void splitAndProcessSql(BufferedReader reader, ExceptionalConsumer sqlProcessor)
    throws IOException, E
    {
        int overflow = SqlSplitter.NO_END;

        StringBuilder sql = new StringBuilder();
        String line;
        while ((line = reader.readLine() ) != null)
        {
            line = line.trim();

            if (!line.isEmpty() && !SQL_COMMENT_STARTS.stream().anyMatch(line::startsWith))
            {
                if (sql.length() > 0)
                    sql.append(' ');

                sql.append(line);

                overflow = SqlSplitter.containsSqlEnd(line, ";", overflow);

                if (overflow > 0)
                {
                    String sqlToExecute = sql.substring(0, sql.length() - 1);
                    sqlProcessor.accept(sqlToExecute);
                    sql.setLength(0);
                    overflow = SqlSplitter.NO_END;
                }
            }
        }

        if (sql.length() > 0)
            sqlProcessor.accept(sql.toString());
    }
}