Agile web development Groovy Grails with Netbeans
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- Groovy is a dynamic language that runs on the Java Virtual Machine and has seamless integration with Java. - Grails is an open source web application framework built on Groovy that follows conventions over configuration (CoC) and don't repeat yourself (DRY) principles. - Grails uses conventions to define a model-view-controller (MVC) structure and provides dynamic scaffolding to generate basic CRUD operations for domain classes.
![A Valid Java Program import java.util.*; public class Erase { private List<String> filterLongerThan(List<String> strings, int length) { List<String> result = new ArrayList<String>(); for (String n: strings) if (n.length() <= length) result.add(n); return (result); } public static void main(String[] args) { List<String> names = new ArrayList<String>(); names.add("Ted"); names.add("Fred"); names.add("Jed"); names.add("Ned"); System.out.println(names); Erase e = new Erase(); List shortNames = e.filterLongerThan(names, 3); System.out.println(shortNames); } }](https://image.slidesharecdn.com/groovygrailsnetbeans-12517452668498-phpapp03/85/Agile-web-development-Groovy-Grails-with-Netbeans-5-320.jpg)
![A Valid Groovy Program import java.util.*; public class Erase { private List<String> filterLongerThan(List<String> strings, int length) { List<String> result = new ArrayList<String>(); for (String n: strings) if (n.length() <= length) result.add(n); return (result); } public static void main(String[] args) { List<String> names = new ArrayList<String>(); names.add("Ted"); names.add("Fred"); names.add("Jed"); names.add("Ned"); System.out.println(names); Erase e = new Erase(); List shortNames = e.filterLongerThan(names, 3); System.out.println(shortNames); } }](https://image.slidesharecdn.com/groovygrailsnetbeans-12517452668498-phpapp03/85/Agile-web-development-Groovy-Grails-with-Netbeans-6-320.jpg)
![The Groovy Way def names = ["Ted", "Fred", "Jed", "Ned"] println names def shortNames = names.findAll{ it.size() <= 3 } print shortNames](https://image.slidesharecdn.com/groovygrailsnetbeans-12517452668498-phpapp03/85/Agile-web-development-Groovy-Grails-with-Netbeans-7-320.jpg)
![grails domain class Define relation between objects with attributes hasMany , belongsTo static hasMany = [ item: Item ] Groovy hashmap Address String street String zip static hasMany = [item:Item] 1 M Item String name String description Address address](https://image.slidesharecdn.com/groovygrailsnetbeans-12517452668498-phpapp03/85/Agile-web-development-Groovy-Grails-with-Netbeans-23-320.jpg)
![grails create-controller Controller made up of action methods Grails routes requests to the action corresponding to URL mapping Default action is index class Item Controller { def index = { redirect(action:list,params:params) } def list = { if(!params.max) params.max = 10 [ itemList: Item.list( params ) ] } def show = {... Actions http://host/catalog/item/list](https://image.slidesharecdn.com/groovygrailsnetbeans-12517452668498-phpapp03/85/Agile-web-development-Groovy-Grails-with-Netbeans-27-320.jpg)
![grails controller class Item Controller { def index = { redirect(action:list,params:params) } def list = { if(!params.max) params.max = 10 [ itemInstanceList: Item.list ( params ) ] } def show = {... returns an ArrayList of item objects retrieved from the item database table itemInstanceList variable is made available to the view](https://image.slidesharecdn.com/groovygrailsnetbeans-12517452668498-phpapp03/85/Agile-web-development-Groovy-Grails-with-Netbeans-29-320.jpg)
![Presenter’s Name [email_address] Carol McDonald Java Architect Tech Days 2009](https://image.slidesharecdn.com/groovygrailsnetbeans-12517452668498-phpapp03/85/Agile-web-development-Groovy-Grails-with-Netbeans-36-320.jpg)
Agile web development Groovy Grails with Netbeans
- 1. Agile Web Development with Groovy and Grails Carol McDonald, Java Architect
- 2. Objective Overview of the Grails Web Platform
- 4. What is Groovy? A dynamic language written for the JVM Generates byte code Java like syntax Easy learning curve for Java developers Seamless integration with Java A Groovy object is a Java Object Groovy application can create Java objects Java objects can create Groovy objects
- 5. A Valid Java Program import java.util.*; public class Erase { private List<String> filterLongerThan(List<String> strings, int length) { List<String> result = new ArrayList<String>(); for (String n: strings) if (n.length() <= length) result.add(n); return (result); } public static void main(String[] args) { List<String> names = new ArrayList<String>(); names.add("Ted"); names.add("Fred"); names.add("Jed"); names.add("Ned"); System.out.println(names); Erase e = new Erase(); List shortNames = e.filterLongerThan(names, 3); System.out.println(shortNames); } }
- 6. A Valid Groovy Program import java.util.*; public class Erase { private List<String> filterLongerThan(List<String> strings, int length) { List<String> result = new ArrayList<String>(); for (String n: strings) if (n.length() <= length) result.add(n); return (result); } public static void main(String[] args) { List<String> names = new ArrayList<String>(); names.add("Ted"); names.add("Fred"); names.add("Jed"); names.add("Ned"); System.out.println(names); Erase e = new Erase(); List shortNames = e.filterLongerThan(names, 3); System.out.println(shortNames); } }
- 7. The Groovy Way def names = ["Ted", "Fred", "Jed", "Ned"] println names def shortNames = names.findAll{ it.size() <= 3 } print shortNames
- 9. What is Grails? An Open Source Groovy MVC framework for web applications Principles CoC – Convention over configuration DRY – Don't repeat yourself Similar to RoR but with tighter integration to the Java platform
- 10. Why Grails? ORM layer can be overly difficult to master and get right A return to POJO and annotations in JPA but still lots of stuff to learn Numerous layers and configuration files lead to chaos Adoption of frameworks a good thing, but too often lead to configuration file hell Ugly JSPs with scriptlets and complexity of JSP custom tags Grails addresses these without compromising their benefits
- 12. How To Get Started Download Grails http://grails.org Configure Netbeans 6.5 Download Groovy http://groovy.codehaus.org Set GROOVY_HOME , GRAILS_HOME Add bin to your PATH $GROOVY_HOME/bin:$GRAILS_HOME/bin For command line
- 13. Using Grails
- 14. grails create-app Will be prompted for the name of the application Generate a directory structure for Grails source Additional libraries Configurations web-app IDE runs the "grails create-app" command Demo
- 15. Grails Directory Structure Application name Additional JARs Web application Grail source
- 16. Netbeans Grails Project Structure Project name Grail source Additional JARs Web application
- 17. Configure for MySQL copy the mysql-connector-java-5.1.6-bin.jar to the lib directory Edit DataSource.groovy dataSource { pooled = true driverClassName = "com.mysql.jdbc.Driver" username = "root" password = "" dialect = "org.hibernate.dialect.MySQL5InnoDBDialect" } environments { development { dataSource { dbCreate = "update" // one of 'create', 'create-drop','update' url = "jdbc:mysql://localhost/petcatalog" } }
- 18. MVC and Grails Models, or domain classes, represent the problem domain
- 19. grails create-domain-class The Model is your application's persistent business domain objects.
- 20. add the domain class attributes class Item { Long id String name String description String imageurl String imagethumburl BigDecimal price } Groovy with Grails dynamically generates getters and setters and the dynamic methods Item.save(), Item.delete(), Item.list(), Item.get() to retrieve/update data from/to the db table.
- 21. Persistence Methods GORM automatically provides persistence methods to your object save() , get() , delete() Automatically generates addTo * () for object relationships Where * is the name of the property def item = new Item(name:'Fred') def order = new Order(orderDate: new Date(), item: 'PSP') item. addToOrders (order) item. save ()
- 22. Queries Dynamically generated queries list , findBy Manual queries (not discussed here) HibernateQL Examples Item.list() Item.findBy Name ('nice cat')
- 23. grails domain class Define relation between objects with attributes hasMany , belongsTo static hasMany = [ item: Item ] Groovy hashmap Address String street String zip static hasMany = [item:Item] 1 M Item String name String description Address address
- 24. Scaffolding Generates CRUD actions and views for the corresponding domain class Dynamic: Enable the scaffold property in the controller class def scaffold = true Static grails generate-all Generates a controller and views for a domain class Useful to get up and running quickly
- 25. Scaffolding Generates a controller and views for the domain class Demo
- 26. MVC and Grails Controllers control request flow, interact with models, and delegate to views.
- 27. grails create-controller Controller made up of action methods Grails routes requests to the action corresponding to URL mapping Default action is index class Item Controller { def index = { redirect(action:list,params:params) } def list = { if(!params.max) params.max = 10 [ itemList: Item.list( params ) ] } def show = {... Actions http://host/catalog/item/list
- 28. URL Mappings Default mapping from URL to action method http://host/catalog/item/list Defined in grails-app/conf/UrlMappings.groovy static mappings = { "/$controller/$action ? /$id ? " Application Controller Action
- 29. grails controller class Item Controller { def index = { redirect(action:list,params:params) } def list = { if(!params.max) params.max = 10 [ itemInstanceList: Item.list ( params ) ] } def show = {... returns an ArrayList of item objects retrieved from the item database table itemInstanceList variable is made available to the view
- 30. MVC and Grails Views are defined in Groovy Server Pages (GSP) and render the model
- 31. grails view actions usually render a Groovy Server Page in the views directory corresponding to the name of the controller and action. list.gsp <html> <table> <tbody> < g:each in="${ itemInstanceList }" status="i" var=" itemInstance "> <td> ${fieldValue (bean: itemInstance , field:' price ')}</td> </tr> </g:each> </tbody> </table> g:each Groovy Tag loops through each object in the itemInstanceList variable displays the value of the item 's price attribute
- 32. grails run-app Will start the embedded web server and run the application Defaults to http://localhost:8080/<app_name> Demo
- 33. Summary Groovy is a powerful dynamic language for the JVM Grails is a full featured web platform
- 35. Acknowldegement Thanks to Guilaume Laforge of G2One for allowing me to use and adapt some of his slides
- 36. Presenter’s Name [email_address] Carol McDonald Java Architect Tech Days 2009
- 37. Lots of Books and Online Tutorials