Code Generator: Ability to generate a Java package per database schema

[cowwoc]

I'd like the code generator to translate schema names to package names. Take for example the H2 database that contains two schema names: INFORMATION_SCHEMA and PUBLIC. If "packageName" is set to "foo.queries" then I expect the code generator to generate "foo.queries.information_schema" and "foo.queries.public".

I fear the current strategy of generating all classes into the same package will lead to name conflicts.

[Timo Westkämper (timo-westkamper)]

I am afraid this would become too complex, since the old use cases should be supported as well. The supported way to avoid name clashes is to use schemaPattern.

If you need contents of two schemas you need two schema generations, which is also not an issue.

[cowwoc (gili)]

Would it be possible to add a configuration flag that defaults to false?

[rrmckinley (rrmckinley)]

I consider this out of scope for the generator. It is very easy to solve your problem at the exporter level. I'll post what I use below. It uses a config file for the schema info. Run it many times for many config files. If you don't want to repeat your package name in the config file, then add a little "SCHEMA_NAME".toLowerCase().replace('_', '.') too my example.

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.sql.Connection;
import java.sql.DriverManager;
import java.util.Arrays;
import java.util.List;
import java.util.Properties;

import com.mysema.codegen.CodeWriter;
import com.mysema.query.codegen.BeanSerializer;
import com.mysema.query.codegen.EntityType;
import com.mysema.query.codegen.Property;
import com.mysema.query.codegen.SerializerConfig;
import com.mysema.query.sql.Configuration;
import com.mysema.query.sql.MetaDataExporter;
import com.mysema.query.sql.MetaDataSerializer;
import com.mysema.query.sql.NamingStrategy;

public class SqlExporter {
 Connection conn; // connection of database containing the schema to use
 MetaDataExporter exporter;

 public static void main(String args[]) throws Exception {
  SqlExporter e = new SqlExporter(args[0]);

  e.exporter.export(e.conn.getMetaData());
  System.out.println("Completed");
 }

 public SqlExporter(String conf) throws Exception {
  Properties p = new Properties();
  p.load(new FileInputStream(conf));

  String jdbcClass = p.getProperty("jdbcClass");
  String jdbcURL = p.getProperty("jdbcURL");
  String jdbcUser = p.getProperty("jdbcUser");
  String jdbcPwd = p.getProperty("jdbcPwd");

  System.out.println("Connecting to Database " + jdbcURL + " User "
    + jdbcUser);
  Class.forName(jdbcClass).newInstance();
  conn = DriverManager.getConnection(jdbcURL, jdbcUser, jdbcPwd);
  System.out.println("Connected successfully");

  String namePrefix = p.getProperty("namePrefix");
  String packageName = p.getProperty("packageName");
  String schemaPattern = p.getProperty("schemaPattern");
  String tableNamePattern = p.getProperty("tableNamePattern");
  File targetFolder = new File(p.getProperty("targetFolder"));
  String namingStrategyName = p.getProperty("namingStrategy");

  String databaseName = p.getProperty("databaseName");

  NamingStrategy namingStrategy = (NamingStrategy) Class
    .forName(namingStrategyName).newInstance();

  MetaDataSerializer serializer = new MetaDataSerializer(namePrefix, namingStrategy);
  BeanSerializer beanSerializer = new BeanSerializer();

  exporter = new MetaDataExporter();
  exporter.setSerializer(serializer);
  exporter.setBeanSerializer(beanSerializer);
  exporter.setNamePrefix(namePrefix);
  exporter.setPackageName(packageName);
  exporter.setTargetFolder(targetFolder);
  exporter.setNamingStrategy(namingStrategy);
  exporter.setSchemaPattern(schemaPattern);
  exporter.setTableNamePattern(tableNamePattern);
 }
}

[cowwoc (gili)]

Works for me. Your help is much appreciated!

[Timo Westkämper (timo-westkamper)]

Ok, so I guess we are ok with the current state of things.

 This feature request also clashes with different packages for bean types and Q-types. Supporting both would make things quite complicated.