Death by Annotations

Every so often I read how 'we're all going to be drowning in annotations' or how someone's 'annotations are exploding' and consequently how 'OMG annotations suck'. I'd agree it's a problem. But, seeing as how Metawidget is probably going to make it worse, not better, I thought I should offer a balanced view.

Here's the basic problem. Here's a piece of Real Code, from one of my production systems, that uses JPA, JAXB, Hibernate extensions and Metawidget:

@OneToMany( cascade = CascadeType.ALL )
@JoinColumn( name = "survey_id" )
@IndexColumn( name = "number", base = 1 )
@Cascade( org.hibernate.annotations.CascadeType.DELETE_ORPHAN )
@UiComesAfter( "dateExtension" )
@XmlElementWrapper
@XmlElement( name = "question" )
public List getQuestions()
{
   return mQuestions;
}

A lot of people are going to look at that, think it looks really messy, and turn off. And I agree - it does look really messy. But it's important to consider what we've gained here, and what the alternative is:

• it's less code, and more typesafe, than 4 separate XML configuration files


• the metadata is closer to the thing the metadata is referring to


• whilst it may seem like a lot of annotations for little actual code (the bit in bold), that's backward thinking: annotations are code, albeit declarative code. And it's a lot less code to write something declaratively than procedurally

So whilst I don't necessarily think annotations are as good as life can get, I do think they're better than anything we ever had before. The challenge now is how do we make them better?