Hloader is a pure
Java tool for loading Domain Objects represented as XML files into
Agile projects using Hibernate typically use JavaBeans to define their
Domain Objects. Domain Objects typically represent a table in a
relational database. A Hibenate mapping file is created (either
directly or automatically using hibernatedoclet) which provides the
additional information, such as table, column names, relationships with
other tables etc to allow Hibernate to read and write the Domain
Objects to and from a database. Hibernate generates schemas, permitting
new versions of schema objects to be readily created.
Having generated a schema, they are often populated with test data.
Until now this bootstrap data has had to be specified as
sql scripts. These sql scripts are then loaded into a database using
Changes to the Domain Objects then invalidate the sql scripts. Say a
column is added. The sql
insert statement must be changed
add a column in the correct position. Then the value for the column
added in the right position. This is a tedious and error prone
process. Each sql statement must honour referential integrity.
Rows in tables with foreign keys must exist first. As the sql setup
data gets larger the maintenance of the insert scripts gets harder and
Hloader remedies this situation by letting setup data be specified as
Domain Objects. They are specified in an XML file. Hloader instantiates
Java Domain Objects from the XML file and then uses Hibernate to
persist them to the specified database. Most changes to Domain Objects
require no change at all to the XML file.
In this way hloader takes the pain out of setup data.
Hloader has the following features:
- Simple and easy to use
- Fast to create setup data and maintain it
- Loads Domain Objects for Hibernate 3.1. Version 0.7 supports Hibernate 3.0 and version 0.6 works with
Hibernate 2 and 2.1.
- Replacement for the Ant
- Supports Oracle, MySQL, Sql Server and HSQLDB. Readily extensible
to other databases.
- Comes with an Ant taskdef for Ant script inclusion. Can also be
- Uses Jelly to create powerful macros.
- Minimal dependencies.
- Fully documented. See the online Documentation
and the online JavaDoc.
- Comprehensive Test Coverage.
- Available under the Apache 1.1
license. Hloader's copyright and licensing have had legal review,
making hloader suitable for
use in Apache projects.
- Tested. All versions of
hloader are tested for several weeks on a large and complex project
4 May 2006. hloader 0.8 released. Minor release to support Hibernate3.1
14 August 2005. hloader 0.7 released. Hloader now supports Hibernate3,
and works with Oracle, MySQL, SQLServer and HSQLDB. Extensive documentation has been created to allow new
users to get going.
9 August 2004. hloader 0.6 released. The team feels that hloader is now
ready for a wider audience. Enjoy!
hloader project gratefully acknowledges the contribution of wotif.com,
who granted a license to the authors to in respect of code developed at
wotif.com for the purpose of making it available to the community under
an Apache open source license.
Thanks to ThoughtWorks for free legal assistance in formalising the
granting of code from wotif.com to the open source community. Copies
of the executed deeds are available should anyone need to audit
hloader Name and Logo
hloader is a utility for Hibernate to load domain objects. While
not a formal part of the Hibernate project, hloader is only useful for
a project using Hibernate for persistence. Thus the name.
The logo is meant to look like an asphalt cutter/loader. The
balls are objects in unserialized form. The conveyor belt loads the
objects into the hopper.