FURTHER_EXAMPLES.md

Further Examples

This document showcases some further examples of reading data from alternate data sources. To successfully set up and customize additional database import tools, the DataReader, ImportConfig and CommandLineParser classes must be implemented.

MySQL Data Source

MySqlDataReader Implementation

The following libraries are required for the DataReader.

import com.graphaware.importer.data.access.QueueDbDataReader;
import org.apache.commons.dbcp2.BasicDataSource;
import org.springframework.jdbc.core.JdbcTemplate;
import javax.sql.DataSource;

The class itself is similar to that of the Oracle example in README.md. QueueDbDataReader is still extended although the MySQL JDBC driver is alternatively used. Note that variable db is added to represent the name of the database. The variable prefetchsize found in the OracleDataReader example is defunct in a MySQL environment and is therefore not included.

public class MySqlDataReader extends QueueDbDataReader {

    private final String db;
    private final int fetchSize;

    public MySqlDataReader(String dbHost, String dbPort, String user, String password, String db, int fetchSize) {
        super (dbHost, dbPort, user, password);
        this.db = db;
        this.fetchSize = fetchSize;
        try {
            Class.forName("com.mysql.jdbc.Driver");
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        }
    }

    @Override
    protected String getDriverClassName() {
        return "com.mysql.jdbc.Driver";
    }

    @Override
    protected String getUrl(String host, String port) {
        return "jdbc:mysql://" + host + ":" + port + "/" + db;
}

    @Override
    protected void additionalConfig(JdbcTemplate template) {
        template.setFetchSize(fetchSize);
    }

    @Override
    protected void additionalConfig(DataSource dataSource) {
        ((BasicDataSource) dataSource).setInitialSize(1000);
    }
}

MySqlImportConfig Implementation

The following libraries are required for the ImportConfig.

import com.graphaware.importer.config.DbImportConfig;
import com.graphaware.importer.data.access.DataReader;

Again, the class dismissed the prefetchsize variable found in the OracleDataReader example. The db database name variable is added in a similar way.

public class MySqlImportConfig extends DbImportConfig {

    private final String db;
    private final int fetchSize;

    public MySqlImportConfig(String graphDir, String outputDir, String props, String dbHost, String dbPort, String user, String password, String db, int fetchSize) {
        super(graphDir, outputDir, props, dbHost, dbPort, user, password);
        this.db = db;
        this.fetchSize = fetchSize;
    }

    @Override
    public DataReader createReader() {
        return new MySqlDataReader(getDbHost(), getDbPort(), getUser(), getPassword(), getDb(), fetchSize);
    }

    public String getDb() {
        return this.db;
    }
}

MySqlCommandLineParser Implementation

The following libraries are required for the CommandLineParser.

import com.graphaware.importer.cli.DbCommandLineParser;
import org.apache.commons.cli.CommandLine;
import org.apache.commons.cli.Option;
import org.apache.commons.cli.Options;
import org.apache.commons.cli.ParseException;

The CommandLineParser is the first point of interaction between user input and the program. It therefore has been slightly modified to idiomatically interpret a MySQL data source.

public class MySqlCommandLineParser extends DbCommandLineParser {

    @Override
    protected MySqlImportConfig doProduceConfig(CommandLine line, String graphDir, String outputDir, String props, String host, String port, String user, String password) throws ParseException {
        String db = String.valueOf(getOptionalValue(line, "db", ""));
        int fetchSize = Integer.valueOf(getOptionalValue(line, "fs", "10000"));

        return new MySqlImportConfig(graphDir, outputDir, props, host, port, user, password, db, fetchSize);
    }

    @Override
    protected void addOptions(Options options) {
        super.addOptions(options);
        options.addOption(new Option("db", "db", true, "database name"));
        options.addOption(new Option("fs", "fetchSize", true, "JDBC driver row fetch size (default 10000)"));
    }
}