Re: Groovy and Grails vs. Java for Web Interface (see Java web application frameworks / architecture)

"Kenneth P. Turvey" <>
25 Sep 2009 19:18:38 GMT
On Tue, 22 Sep 2009 12:24:20 -0700, markspace wrote:

Kenneth P. Turvey wrote:

When compared to
technologies like JSF, grails really eases web development

I know almost nothing about Grails or Groovy. Could you justify this
statement for me? What's "easier" about G&G? Maybe with some code
examples you've written, since we're all about SSCCEs here.

There are a number of reasons that grails seems to require less code to
produce a similar product, but a few spring to mind:

1) Groovy is just more succinct. It often requires less code to do the
same thing for common tasks.

2) All the pieces are already assembled for you. You get hibernate,
springs, a web container for testing, basically everything you need to get
started out of the box.

3) The framework allows simple things to be simple. It is based on an MVC
architecture like many other frameworks. The model for a given web page
is represented as a list. The controller passes the list to a GSP script
(much like JSP, but with templating) and produces the view.

It also provides mocks for making unit testing easier.

An SSCCE is a bit difficult since there are many files to a given web
application. I'll provide a domain class as an example, but it probably
isn't the best example:

class User {

    String username;
    String passwordHash;
    String email;
    String firstName;
    String lastName;
    Date birthDate;
    Date memberSince;

    byte[] avatar;
    String penName;

    static hasMany = [ratings:Rating, mystuff:MyStuff]

    static constraints = {
        username(blank:false, size:4..15,
            nullable:false, unique:true)
        passwordHash(blank:false, nullable:false) email
        firstName(blank:false, nullable: false) lastName
(blank:false, nullable:
        false) birthDate(nullable:false)
        avatar(nullable: true, maxSize: 30000)

    String toString() {
        return username

This is all you need to do to create a domain object with methods to find
it based on criteria, to validate it before sending it to the database and
provide internationalized error messages when it fails. You don't have to
do any configuration of hibernate or anything else. You drop this file in
the right directory and you have a working domain class.

This is just one example. There are numerous other ways that grails makes
things simpler.

The view has always been my biggest headache in web development. I'm
afraid I have a poor sense of the aesthetic. So grails doesn't really
help me there, but in all the other aspects of web development it really

Its use of reasonable defaults really simplifies things.

While in development you can allow the system to generate pages for doing
CRUD operations on domain objects. So (without the associations of
course) one could generate an entire CRUD application with just the code
above. Now I admit that this would be of limited value for anything but
development, but it is helpful none the less.

Kenneth P. Turvey <>

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