CDM Java Library¶

• Table of contents
• CDM Java Library
  • Release
    • Source Code
  • Layers
    • Spring 2.0 Framework
    • Domain Model w/ persistency
      • Property change support
      • Validation
      • XML binding
    • DAO
      • O/RM
    • Service layer
      • XML (Un)Marshalling
      • Validation
      • HowTo's
  • Background
    • Spring Resources
    • Hibernate Resources

The CDM Library is meant to be a shared library for the between several applications which can be of any kind, i.e. J2EE having an application container, simple command line tools or swing desktop applications.

The library defines a persistent domain model, EDITs CommonDataModel, that can be serialsed and read in XML. Business logic shared between applications should be part of this library as much as possible, while application specific logic has to stay out. We hope to develop this library in collaboration with the CATE project initially.

Release¶

We are currently debating whether OSGi bundles and/or JAR archives are our preferred form of a CDM library release.

Source Code¶

The source:trunk/cdm can be found in the EDIT subversion repository:

http://dev.e-taxonomy.eu/svn/trunk/cdm

For building Apache Ant must be installed as well Java JDK.

Layers¶

Spring 2.0 Framework¶

We use the Spring 2.0 framework to develop the library and keep the coupling of components low.

• Spring2.0 Documentation

• Introduction to the Spring Framework

• Die Rückkehr der POJOs. Das Spring-Framework: leichtgewichtiges Komponentenmodell als Alternative zu EJB

Domain Model w/ persistency¶

Domain objects (also called business objects sometimes) are directly taken as POJOs from the CommonDataModel. The logic inherent to the domain objects are restricted to their own object graph, i.e. their own properties and related objects. But not unrelated objects available through DAOs only. Typical logic includes validation and calculations.

• Business Object Pattern

• AnemicDomainModel Anti Pattern

Property change support¶

We plan to implement java.bean propertyChangeSupport methods to send change events to registered lissteners:

• http://www.onjava.com/pub/a/onjava/2004/06/02/desktop.html

• http://www.javalobby.org/java/forums/t19476.html

Validation¶

Validation primarily in setter methods. Implement separate Rule classes too?

XML binding¶

using JAXB

DAO¶

Every domain class has at least a DAO for CRUD operations.

O/RM¶

using JPA w/ Hibernate . Alternatively try TopLink

Service layer¶

The service layer defines the primary public exposed interface for other applications. Every DAO is also exposed as a service, but more complex services can be offered too. Complex validation is part of the service layer as well as import/export of XML files using the XML binding of the domain objects.

• ApplicationService Pattern

XML (Un)Marshalling¶

Services to read and write xml data into domain objects using the JAXB annotations in the domain model

Validation¶

Validation across unrelated domain objects needs to be implemented outside of the domain model. The service layer takes care of this. Validation rules could (should?) be implemented as separate Rule classes

HowTo's¶

Releases¶

• run ant:distAsZip from build.xml in project edit_cdm

• upack dist\zip\cdmLibrary.zip

• put cdmLibrary.jar and all jars from dist\zip\lib into project eu.etaxonomy.cdmLibrary

• refresh project and add all unknown libraries to the project classpath

• update classpath in plugin.xml\Runtime

• test with project eu.etaxonomy.taxeditor

Background¶

• Domain Models and Validation. An Architectural Discussion

• Avoiding anemic domain models with Hibernate

Spring Resources¶

• http://www.java2s.com/Code/Java/Hibernate/Spring-Hibernate.htm

• http://www.ibm.com/developerworks/web/library/wa-spring2/

• http://www.shoesobjects.com/blog/2004/11/21/1101083542880.html

Hibernate Resources¶

• Hibernate Mini Guide, ServerSide.com