JarCastingReststop - friction-free web development
About
Reststop is a system for plugin based development on the Java Servlet API. The core of Reststop is a servlet filter that loads and reload plugins in separate class loaders. Using Reststop, you will develop your application as plugins, making it highly modular.
A Reststop plugin is simply a Maven module, in which your provide a collection of Servlet Filters, and methods to start and stop (init and destroy) your plugin. You also have a simple dependency injection system for exporting services from one plugin, and injecting them by type in another.
Reststop already provide a set of very useful plugins. We recommend you start looking at the following:
- reststop-development-plugin This plugin is monitoring your files, and automatically compiles and reloads java source code on changes.
- reststop-development-console This plugin gives you handy information about your application, exposed on the path /dev.
- jaxrs-api This plugin makes it a breeze to wire up Jax-RS Resources.
Reststop requires you to write your application as plugins, but what you do inside a plugin is entirely up to you. Inside a plugin you can introduce whatever framework you prefer.
Getting Started
The easiest way to understand Reststop, is to see it in action. Either take the intro tutorial or just follow the simple instructions below:
In this section we will be using a Maven plugin to create a small project, and make some small changes to understand how things work. Let's start:
Create Reststop project:
mvn -U org.kantega.reststop:reststop-maven-plugin:RELEASE:create
Open a browser to http://localhost:8080/helloworld/
This will show a page with the simple message:
{"message":"Hello world"}
Now add som politeness to the return statement in plugins/helloworld/src/main/java/YOUR.PACKAGE.NAME/HelloworldResource.java:
return new Hello(greeting + " dear world");
Then hit the reload button, and while you did that Reststop notified the change, recompiled and hot-deployed it:
{"message":"Hello dear world"}
Next Level
Try to change the word "world" into something different, and reload again:
return new Hello(greeting + " dear friend");
Reststop just discovered that a Test failed, showing test code and stack trace. Now update the HelloworldResourceTest.java to match and reload again.
Next try to remove the following line in HelloworldResource.java:
return new Hello(greeting + " dear friend");
Reststop now shows you an compilation error, with location and error message from the compiler. Wasn't that friction-free like a dynamic language?
Under the hood
To get a little more insight into Reststop, point your browser to http://localhost:8080/dev
This Development Console shows you all the plugins, classes and source dirs that Reststop is currently tracking for you.
Creating a new plugin
Go to root of your Reststop project and run:
mvn reststop:create-plugin -Dname=myplugin -Dpackage=org.company.helloworld.myplugin
This automatically creates a new plugin, with maven module and Reststops configuration.
Automatic recompile and hot-deploy
While writing code it is very convenient to have automatic recompile and hot-deploy. To experience this while developing, do the following:
mvn clean install
cd webapp
mvn jetty:run.
Add debugging
For a fully debugging enabled environment do the following:
mvn clean install
cd webapp
mvnDebug jetty:run.
Then attach your debugger. Using this combination of automatic recompile, hot-deploy and debugging enables a friction-free web development with the feedback loop of a dynamic language.
Maven Goals
reststop:create Creates Reststop project
reststop:create-plugin Creates Reststop plugin
reststop:run Run application and open project and browser
reststop:start Starts application
reststop:stop Stops application
reststop:package-plugins Packages plugins and plugin configuration
reststop:resolve-plugins Resolves plugin configuration
reststop:dist Build Zip based distribution packages
reststop:dist-rpm Build RPM based distribution packages
Plugin Consoles
reststop-development-console /dev
reststop-metrics-plugin /healthchecks/
reststop-metrics-plugin /assets/metrics
