Easy Database Migrations using Flyway, Java EE 6 and GlassFish

<properties>
	[..]
	<flyway.version>2.1.1</flyway.version>
</properties>
<dependencies>
	<dependency>
		<groupId>org.glassfish.main.extras</groupId>
		<artifactId>glassfish-embedded-all</artifactId>
		<version>3.1.2.2</version>
		<scope>provided</scope>
	</dependency>
	<dependency>
		<groupId>org.hibernate</groupId>
		<artifactId>hibernate-entitymanager</artifactId>
		<version>4.2.0.Final</version>
	</dependency>
	<dependency>
		<groupId>com.googlecode.flyway</groupId>
		<artifactId>flyway-core</artifactId>
		<version>${flyway.version}</version>
	</dependency>
</dependencies>

<properties>
	<derby.version>10.9.1.0</derby.version>
</properties>

<build>
    <defaultGoal>clean package org.glassfish.embedded:maven-embedded-glassfish-plugin:3.1.2:run</defaultGoal>
	<plugins>
		<plugin>
			<groupId>org.apache.maven.plugins</groupId>
			<artifactId>maven-war-plugin</artifactId>
			<version>2.1.1</version>
			<configuration>
				<failOnMissingWebXml>false</failOnMissingWebXml>
			</configuration>
		</plugin>
		<plugin>
			<groupId>org.glassfish.embedded</groupId>
			<artifactId>maven-embedded-glassfish-plugin</artifactId>
			<version>3.1.2</version>
			<dependencies>
				<dependency>
					<groupId>org.apache.derby</groupId>
					<artifactId>derbyclient</artifactId>
					<version>${derby.version}</version>
				</dependency>
				<dependency>
					<groupId>org.apache.derby</groupId>
					<artifactId>derby</artifactId>
					<version>${derby.version}</version>
				</dependency>
			</dependencies>
			<configuration>
				<goalPrefix>embedded-glassfish</goalPrefix>
				<app>${basedir}/target/${project.artifactId}-${project.version}.war</app>
				<autoDelete>true</autoDelete>
				<port>8080</port>
				<name>flyway-tutorial</name>
			</configuration>
		</plugin>
	</plugins>
</build>

package com.hascode.entity;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;

@Entity
public class Book {
	@Id
	@GeneratedValue
	private Long id;

	private String title;

	private String author;

	// getter, setter, hashCode, equals ...
}

<?xml version="1.0" encoding="UTF-8"?>
<persistence xmlns="http://java.sun.com/xml/ns/persistence"
	version="1.0">
	<persistence-unit name="hascode-jta-unit"
		transaction-type="JTA">
		<provider>org.hibernate.ejb.HibernatePersistence</provider>
		<jta-data-source>jdbc/__default</jta-data-source>
		<class>com.hascode.entity.Book</class>
	</persistence-unit>
</persistence>

package com.hascode.ejb;

import java.util.List;
import com.hascode.entity.Book;

public interface BookService {
	public abstract List<Book> findAll();
}

package com.hascode.ejb;

import java.util.ArrayList;
import java.util.List;

import javax.ejb.Stateless;
import javax.persistence.EntityManager;
import javax.persistence.PersistenceContext;

import com.hascode.entity.Book;

@Stateless
public class BookEJB implements BookService {
	@PersistenceContext(unitName = "hascode-jta-unit")
	private EntityManager em;

	@Override
	public List<Book> findAll() {
		List<Book> books = em.createQuery("SELECT b FROM Book b", Book.class)
				.getResultList();
		if (books == null)
			books = new ArrayList<Book>();
		return books;
	}
}

package com.hascode.servlet;

import java.io.IOException;
import java.util.List;

import javax.inject.Inject;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.hascode.ejb.BookService;
import com.hascode.entity.Book;

@WebServlet(name = "bookServlet", urlPatterns = "/books", loadOnStartup = 1)
public class BookServlet extends HttpServlet {
	private static final long serialVersionUID = 1L;

	@Inject
	private BookService bookEJB;

	@Override
	protected void doGet(final HttpServletRequest req,
			final HttpServletResponse resp) throws ServletException,
			IOException {
		List<Book> books = bookEJB.findAll();
		if (books.isEmpty()) {
			resp.getWriter().append("no books");
			return;
		}

		resp.getWriter().append(
				books.size() + " books:\n---------------------------------\n");
		for (Book book : books) {
			resp.getWriter().append("- " + book.getTitle() + "\n");
		}
	}
}

package com.hascode.ejb;

import java.util.logging.Logger;

import javax.annotation.PostConstruct;
import javax.annotation.Resource;
import javax.ejb.EJBException;
import javax.ejb.Singleton;
import javax.ejb.Startup;
import javax.sql.DataSource;

import com.googlecode.flyway.core.Flyway;
import com.googlecode.flyway.core.api.MigrationInfo;

@Singleton
@Startup
public class JeeDbMigrator {
	private final Logger log = Logger.getLogger(JeeDbMigrator.class.getName());

	@Resource(lookup = "jdbc/__default")
	private DataSource dataSource;

	@PostConstruct
	private void onStartup() {
		if (dataSource == null) {
			log.severe("no datasource found to execute the db migrations!");
			throw new EJBException(
					"no datasource found to execute the db migrations!");
		}

		Flyway flyway = new Flyway();
		flyway.setInitOnMigrate(true);
		flyway.setDataSource(dataSource);
		for (MigrationInfo i : flyway.info().all()) {
			log.info("migrate task: " + i.getVersion() + " : "
					+ i.getDescription() + " from file: " + i.getScript());
		}
		flyway.migrate();
	}
}

package db.migration;

import java.sql.Connection;
import java.sql.PreparedStatement;

import com.googlecode.flyway.core.api.migration.jdbc.JdbcMigration;

public class V201305162030__Insert_additional_books implements JdbcMigration {

	@Override
	public void migrate(final Connection con) throws Exception {
		PreparedStatement statement = con
				.prepareStatement("INSERT INTO Book (id, title) VALUES (4, 'You wont believe it - the fourth book')");
		statement.execute();
	}

}

$ tree
.
├── pom.xml
└── src
 └── main
     ├── java
     │   ├── com
     │   │   └── hascode
     │   │       ├── ejb
     │   │       │   ├── BookEJB.java
     │   │       │   ├── BookService.java
     │   │       │   └── JeeDbMigrator.java
     │   │       ├── entity
     │   │       │   └── Book.java
     │   │       └── servlet
     │   │           └── BookServlet.java
     │   └── db
     │       └── migration
     │           └── V201305162030__Insert_additional_books.java
     ├── resources
     │   ├── db
     │   │   └── migration
     │   │       ├── V201304161230__Create_book_table.sql
     │   │       ├── V201304171620__Insert_books.sql
     │   │       └── V201305011700__Alter_book_table_add_author.sql
     │   └── META-INF
     │       └── persistence.xml
     └── webapp
         └── WEB-INF
             └── beans.xml