Hibernate + JodaTime mapping different types

Question

I am using hibernate reverse engineering and trying to get my Timestamps to map to a JodaTime type.

I have setup my hibernate.reveng.xml file properly

<sql-type jdbc-type="TIMESTAMP" hibernate-type="org.joda.time.contrib.hibernate.PersistentDateTime" not-null="true"></sql-type>

The issue is that when i run the rev-eng process my Java classes also get the members created as PersistentDateTime objects, but I don't want that because they are not usable. I need the java objects to be org.joda.time.DateTime

So I tried creating a custom engineering strategy

public class C3CustomRevEngStrategy extends DelegatingReverseEngineeringStrategy {

public C3CustomRevEngStrategy(ReverseEngineeringStrategy res) {
    super(res);
}

public String columnToHibernateTypeName(TableIdentifier table, String columnName, int sqlType, int length, int precision, int scale, boolean nullable, boolean generatedIdentifier) {
    if(sqlType==Types.TIMESTAMP) {
        return "org.joda.time.DateTime";
    }    else {
        return super.columnToHibernateTypeName(table, columnName, sqlType, length, precision, scale, nullable, generatedIdentifier);
    }
}

}

My thought was that the hibernate mapping files would get the hibernate.reveng.xml file settings and the java objects would get the settings from the custom strategy file...but that was not the case. Both the mapping file and Object are of type "org.joda.time.DateTime" which is not what I want.

How can I achieve my goal? Also, I am NOT using annotations.

• Hibernate 3.6
• JodaTime 2.3
• JodaTime-Hibernate 1.3

Thanks

EDIT: To clarify exactly what the issue is

After reverse engineering this is what I get in my mapping file and POJO class

<property name="timestamp" type="org.joda.time.contrib.hibernate.PersistentDateTime">
private PersistentDateTime timestamp;

As a POJO property, PersistentDateTime is useless to me as I cannot do anything with it such as time manipulations or anything. So this is what I want after my reverse engineering

<property name="timestamp" type="org.joda.time.contrib.hibernate.PersistentDateTime">
private org.joda.time.DateTime timestamp;

Using the Jidira library as suggested below gives me the same result, a POJO that I cannot use.

Answer 1

The JodaTime-Hibernate library is deprecated, and is probably the source of your problem. Don't dispair however as there is a (better) alternative.

You will need to use the JadiraTypes library to create the correct JodaTime objects from Hibernate. Add the library which can be found here to your project classpath and then change your type to org.jadira.usertype.dateandtime.joda.PersistantDateTime. All of the JodaTime objects have a corresponding mapping in that package, so if you decide to change to another object then just update your type.

This should ensure that your objects get created correctly.

I should add a caveat to my answer, which is that I have never used the JadiraTypes library with Hibernate 3. If it only supports Hibernate 4 (I don't see why it would, but...) let me know and I'll delete my answer.

Answer 2

The Hibernate Tools don't seem to separate Hibernate Types from the Java types. If you would be using annotations, this would be more clear as in that case you'd need an @Type annotation, which Hibernate will not generate at all. So using the exposed APIs won't help here.

Fortunately, Hibernate lets you plug into the actual code (or XML) generation after it does its processing. You can do that by replacing the Freemarker templates it uses to generate both XML and Java code. You'll need to use Ant for reverse engineering, however.

To start using Ant for this purpose (if you're not doing so already), you can either pull Hibernate Tools in as a build-time dependency using your dependency manager or download a JAR. Put the jar in Ant's classpath, but also extract the template files from it: since you're using XML configuration, you'll be interested in the /hbm directory. Then add the task using <taskdef> and, assuming that you extracted the templates to TPL_PATH/hbm/*.ftl, call it using <hibernatetool templatepath="TPL_PATH" ...>. (For more info, see below for a link to the docs). Using Ant also helps with automation, for example on CI servers where you won't have Eclipse.

You'll want to keep hibernate-type="org.joda.time.DateTime" in your hibernate.reveng.xml so that the Java files get generated correctly, but replace it with org.joda.time.contrib.hibernate.PersistentDateTime in the generated XML. To do that, edit TPL_PATH/hbm/property.hbm.ftl, replace ${property.value.typeName} with ${javaType}, and assign javaType to the right value before it's used:

<#assign javaType=property.value.typeName>
<#if javaType.equals("DateTime")>
<#assign javaType="org.jadira.usertype.dateandtime.joda.PersistentDateTime">
</#if>
<property
    name="${property.name}"
    type="${javaType}"
...

You might want to remove newlines to keep the generated XML clean.

This is all described in the Hibernate Tools documentation at http://docs.jboss.org/tools/archive/3.2.1.GA/en/hibernatetools/html/codegen.html#d0e6349 - except that the documentation doesn't tell you exactly which templates you need to modify, you need to figure that out by reading the templates.