Sunjay will be presenting proven techniques that can take your team from vision to requirements in hours, not weeks.

Presentation Abstract

Markets, customers, and industries are moving quickly. Rapid application development is a strategic necessity. But, rapid application development techniques require rapid estimation and planning techniques. Business demands for improved time-to-market means your teams must estimate, plan, and budget application development projects with greater speed and accuracy.

Project Plan Ninja provides modern cues, clues, and tools for turning application development requirements into actionable budgets & work plans.

• Estimate application development projects in hours, not weeks
• Quickly and confidently enter feature negotiation with customers
• Envision a consistent estimation and budgeting process for your teams
• Bridge the gap between Agile-oriented and plan-driven estimation
• Understand how to build practical, repeatable work plans

There is no charge for attending this event, but preregistration is required. Please visit www.pmiwdc.org/Fairview and click on “Register Online” on the April 21 event.

Features

• Generation of a terracotta configuration file
• Generation of terracotta enabled start up scripts for containers

Installation
grails install-plugin terracotta

Usage
Install the plugin
Run the start up script generation task
Run the terracotta configuration generation task
generate a war for the application and deploy in a container
start the terracotta server(s)
start the application servers

Components
Generate<ContainerName>Script: Generate the start up script for an application server
GenerateTcConfig: Generate the tc-config.xml file for terracotta

Generate<ContainerName>Script
Currently only 2 containers are supported: jboss and tomcat.

Edit TerracottaConfig.properties to set the parameters for the start up scripts:
The terracotta install directory on the target jboss or tomcat server:
terracotta.install.dir
The path place where the tc.config.xml will be made available to on the servers (this plugin does not remote copy it you have to do that):
terracotta.config.path

Run:
grails generate-jboss-scripts

Copy the generated scripts in the startup script folders of the containers. You will later start the containers using these scripts instead of standard ones.

GenerateTcConfig
Generates the tc-config.xml required to run a terracotta enabled container.
It enables the clustering of all the domain classes defined in the project and allows to add any additional classes to be made clusterable by including a user defined xml segment.
It also clusters the http sessions across the container instances for your application.

Edit TerracottaConfig.properties to set the host names and ports for the terracotta servers to be used by the application.

Edit CustomIncludes.xml to specify any additional terracotta include rules required by your application.

Run:
grails generate-tc-config

Copy the generated file on each container server, in the location specified when generating the container start up scripts.

Running the Clustered Application
Deploy your application on all the container instances.
Start the terracotta server(s)
Start the containers using the generated start up scripts. (Note that you will need a form of load balancing to witness the effects of the clustering, I used Apache with mod_jk)

Fun Note
Start one only one node of your cluster. Start a session (log in your app, …). Stop that server instance, then start another one. Continue using your application without losing your session!

Looking Ahead
Future enhancements include support for more containers (easy), and support for running terracotta in development mode (more complex).

Technorati Tags: Terracotta, Grails, Scalability, Java, Clustering

Drools is a business rule management system (BRMS) and an enhanced Rules Engine implementation, ReteOO, based on Charles Forgy’s Rete algorithm tailored for the Java language.

Features

• Easy implementation of Drools
• Rules can be stored in file or in database
• Rules can be dynamically changed without rebuilding or restarting application

Installation

grails install-plugin drools

Usage

• Install the plugin
• Verify example rules:

  http://localhost:8080/your_app/drools/example

• Create your own rules: http://localhost:8080/your_app/drools and use droolsService in your code

Components

• DroolsController: Provides CRUD functionality for Drools Rule
• DroolsService: Fires all rules

DroolsService
droolsService.fireRules(resource, ruleKey, objList)

• resource: specifies where the rules are stored. ‘file’ or ‘db’
• ruleKey: identifier for the rule. For ‘file’ resource, this would be the name of the file (eg:ticket_example.drl). For ‘db’ resource, this is the Drools Rule key
• objList: list of objects that need to be put in session

Example

A simple Ticket processing system is available in the plugin. This example shows how tickets are processed based on their subscription plan.

Run the example: http://localhost:8080/your_app/drools/example

Your console output should be:

Start processing Ticket # 3
Start processing Ticket # 2
Start processing Ticket # 1
Firing rule Bronze Priority for Ticket # 3
Firing rule Silver Priority for Ticket # 2
Firing rule Gold Priority for Ticket # 1
Firing rule Special Discount for Ticket # 1

Display on your browser should be:

Tickets due for processing:
Ticket #1: Customer[Name:Jack, Subscription:Gold, Discount:0%] Status[New]
Ticket #2: Customer[Name:Tom, Subscription:Silver, Discount:0%] Status[New]
Ticket #3: Customer[Name:Bill, Subscription:Bronze, Discount:0%] Status[New]
Firing rules now ...
Tickets after processing:
Ticket #1: Customer[Name:Jack, Subscription:Gold, Discount:5%] Status[Escalate]
Ticket #2: Customer[Name:Tom, Subscription:Silver, Discount:0%] Status[Escalate]
Ticket #3: Customer[Name:Bill, Subscription:Bronze, Discount:0%] Status[Pending]

Note: This post was originally posted in the author’s blog

Technorati Tags: Grails, Grail Plugin, Drools for Grails, Drools Plugin

1. Update hibernate-entitymanager.jar (3.3.2 GA) in project/lib

2. Add hibernate-validator.jar (3.0.0 GA) in project/lib. Grails 1.0.1 did not require this jar

3. Changes to g:render taglib.
<g:render template=”templates/my_template.gsp” /> used to work in Grails 1.0.1 with template file in _templates/my_template.gsp under grails-app/views/mycontroller/. Now, for Grails 1.0.3 you need to have the template in template/_my_template.gsp.

4. Issues with domain properties.
my_domain.properties = another_domain.properties. This doesn’t work anymore in Grails 1.0.3, at least in some cases. Had to manually copy properties.

5. There are definitely issues with complex hibernate mapping involving legacy system. A particular hibernate relationship was throwing javax.persistence.PersistenceException with Grails 1.0.3. We couldn’t figure out the actual reason, had to make the relationship transient and manually manage it.

6. Changes to taglib g:actionSubmitImage. The following works fine in Grails 1.0.1.
<g:form name="myForm" action="myAction">
<g:actionSubmitImage value="Show" xsrc=".." mce_src=".." />
</g:form>
In Grails 1.0.3, you will need to change to <g:actionSubmitImage value=”Show” xsrc=”..” mce_src=”..” action=”myAction” />

7. Issues with blank spaces in directories in Windows: This is the nasty one and can drive you crazy. You may have problems running the app or executing tests. Errors such as java.util.zip.ZipException: The system cannot find the path specified or error trying to scan etc could be noticed. These errors are due to blank spaces in JAVA_HOME(c:\Program Files\..) and user.home (c:\Documents and Settings\..). To fix this:

• Re-install Java in directory without blank spaces (c:\Java\..)
• By default, the project is built in ${user.home}/.grails. We can change this location by specifying the user.home property in command-line such as grails -Duser.home=c:\ run-app or grails -Duser.home=c:\ test-app

Grails 1.0.3 seems much faster than Grails 1.0.1 and is probably worth the trouble.

Note: This post was originally posted in the author’s blog.

Technorati Tags: Grails, Grails upgrade, Grails upgrade issues, Grails 1.0.3, hibernate, taglib