Hibernate + Dynamic Groovy Class (Is this even possible)

[Caden Whitaker]

Hey all,

Having a mental exercise right now.

I've got a file on my computer called User.groovy

 
package com.test;

import javax.persistence.*;
import java.util.HashSet;
import java.util.Set;
import com.test.DataUtils;

@Entity
@Table(name = "user")
public class User {

	public test() {
		def manager = DataUtils.getInstance().createEntityManager()
		manager.getTransaction().begin()
		manager.persist new User(name: "Peter")
		manager.getTransaction().commit()
	}
	
	@Id
	@GeneratedValue(strategy = GenerationType.AUTO)
	@Column(name = "ID", nullable = false)
	Long id;

	@Basic
	@Column(name = "Name", nullable = true, unique = false)
	String name;
}

Then I wrote a JSP that does this:

        File file = new File("C:\\User.groovy");
        StringBuffer contents = new StringBuffer();
        BufferedReader reader = null;

        reader = new BufferedReader(new FileReader(file));
        String text = null;

        // repeat until all lines is read
        while ((text = reader.readLine()) != null)
        {
            contents.append(text)
                .append(System.getProperty(
                    "line.separator"));
        }

        // show file contents here
        System.out.println(contents.toString());

        GroovyClassLoader gcl = new GroovyClassLoader();
        Object[] args = {};
       ((GroovyObject)gcl.parseClass(contents.toString()).newInstance()).invokeMethod("test", args);

In a nutshell, the JSP is compiling the groovy file and then invoking the "test" method that tries to put test data through hibernate. The file compiles, but it bombs at the test call with the error Unknown entity: com.test.User

I get the error, do you get what I'm trying to do? Basically I'm trying to dynamically load a class into hibernate and have it create the tables and the content. Is this even possible?

Not sure if it matters but here's my persistence xml

<persistence version="1.0"
	xmlns="http://java.sun.com/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_1_0.xsd">
	<persistence-unit name="db-manager">

		<properties>
			<property name="hibernate.hbm2ddl.auto" value="create" />
            <property name="hibernate.archive.autodetection" value="class"/>
            <property name="hibernate.show_sql" value="true"/>
            <property name="hibernate.format_sql" value="true"/>
 	        
		</properties>
	</persistence-unit>
</persistence>

and here's how I create the entity manager factory

		    Map properties = new HashMap();
		    properties.put("hibernate.connection.driver_class", "org.h2.Driver");
		    properties.put("hibernate.connection.url", "jdbc:h2:test");
		    properties.put("hibernate.connection.username", "sa");
		    properties.put("hibernate.connection.password", "");
		    properties.put("hibernate.connection.pool_size", "1");
		    properties.put("hibernate.dialect", "org.hibernate.dialect.H2Dialect");
		    properties.put("hibernate.hbm2ddl.auto", "create");
		    this.entityManagerFactory = Persistence.createEntityManagerFactory("db-manager", properties);

That part should work, it's a copy from an existing hibernate app that I've been working with for awhile. And if I comment out the code inside User.test() the whole thing compiles with no errors. I understand the error, I'm just not sure if what I'm trying to do is even possible. Any ideas?