1. An Survey of Spring Chris Roeder March, 2011 This talk summarizes a lot of what is available in: Spring In Action , Craig Walls, Manning 2008

2. Spring is a collection of frameworks:

IoC an Inversion of Control

AKA: Dependency Injection Framework

Data Access,Transaction Management, Security 3. Remote Access Framework 4. Spring Dynamic Modules 5. Aspects a way to deal with cross cutting concerns 6. MVC an alternative to web application frameworks like Struts 7. Spring does not re-invent the wheel

Uses existing logging frameworks

8. Uses existinganything:ORM, transactions, Aspects, Remoting, etc. 9. Spring is there to provide portability betweenframeworks that share a purpose and interface 10. Spring Frameworks are Abstractions

Frameworks are collections of Java interfaces

11. Implemented by a variety of solutions:

Hibernate, JPA, Toplink

Injected into your code by the config file using the Java Bean Interface (more) 12. Leaving your code simple and full of POJOs (more later) 13. When needs require a different implementation, very easy to change the config file with no code changes 14. Detail: Java Bean

A JavaBean is a Java Object that is serializable, has a nullary constructor, and allows access to properties using getter and setter methods.

http://en.wikipedia.org/wiki/JavaBean

Not anEntityJava Bean or EJB 15. Detail: POJO

The name is used to emphasize that a given object is an ordinary Java Object, not a special object, and in particular not an Enterprise JavaBean

http://en.wikipedia.org/wiki/Plain_Old_Java_Object

Meaning it's not tied to a particular framework. 16. Inversion of Control or Dependency Injection?

Inversion of Control is a general concept that relates to event-driven programming where the stream of events dictates execution.

17. Dependency Injection is a more specific concept that refers to setting values on objects (Java Beans) from an external source. 18. Spring calls the framework IoC. 19. I call the concept used here DI. 20. Detail: IoC

Dependency Injection (DI)involves abstracting out the introduction of a project's components.

21. Even with good modularity, you still hard-code them together with code like this: 22. public static void main(String args[]) { DataProvider dp = new DataProvider(); CorpMetrics metrics = new CorpMetrics(); metrics.calculate(dp); 23. Detail: IoC 2

In other situations, JDBC in EJB for example, collaborators aren't hard-coded, but find each other at runtime:

24. A JDBC setup finds its database connection by consulting JNDI, making environmental assumptions: Context initContext = new InitialContext(); Context envContext= (Context)initContext.lookup("java:/comp/env"); DataSource ds = (DataSource)envContext.lookup("jdbc/myoracle"); Connection conn = ds.getConnection(); ( http://tomcat.apache.org/tomcat-5.5-doc/jndi-datasource-examples-howto.html ) 25. Changes still involve changing the java code. 26. Detail: IoC 3

Separate classes allows flexibility

27. Hard-coded constructor calls limit it. 28. Unit Testing with different configurations is made easier. 29. IoC is used as a supporting technology throughout Spring 30. UIMA users, as described in a 2009 poster paper, would find this eerily familiar

A bit of programmer humor would involve using uimaFIT and Spring to define a pipeline in a Spring config file instead of a CPE.

31. Detail: IoC 4

Alternate implementations require interfaces:

32. Code to Interfaces 33. Create new implementations of Classes that implement them. 34. Easy to swap with a different implementation when both implement the same Java interface. 35. Also works to enable a kind of multiple inheritance in Java. 36. Survey: Data Access

POJO model entities can be stored in any ORM tool, just plain JDBC or others

37. Operations on entities built in Data Access Objects (DAO)

GetById(), GetListWhere(), Update(), etc.

Spring provides templates to make building DAOs easy 38. BTW, these are used in FLEX integration 39. Survey: Transaction Management

Abstracts on top of JDBC, Hibernate, JPA, JMS, EJB transaction.jta.* classes

40. Databases handle their own transactions:

START TRANSACTION, SAVE TRANSACTION

EJB containers allow transactions between multiple systems 41. Coding to Spring allows flexibility and growth 42. Survey: Remote Access

Compares to RMI, SOAP WS, Hessian, Burlap

43. Abstracts the concept of remoting and provides different implementations. 44. Client and service objects are POJOs. 45. Can make use of JSR-181 Web Services Metadata annotations 46. Survey: Dynamic Modules

Spring-DM is an implementation and integration of OSGI modules into Spring.

47. provide another layer of encapsulation over the concept of Class. Now you can have private and public classes as members of a module (jar). 48. allow for a lifecycle, so module can have a running state. 49. provide better naming, so versions can be included. 50. provide restricted class space, allowing for more than one version of a class at the same time. 51. More: Yuriy is working on this 52. Survey: Aspects

Cross-Cutting Concern: functions that span multiple points of an application

53. Logging, Transactions, Security 54. Makes use of a proxy facility in Java reflection.

Instead of creating and using a new object, you create the object and a proxy around it. Then use the proxy in it's place.

55. The proxy intercepts function calls and allows implementations of a Handler interface to intercept them. Other Implementations exist, but are intrusive. 56. Survey: MVC

Spring has a Model, View, Control (MVC) framework for web applications. It separates code into three types:

Model the data and functions to manipulate it

57. View the JSP pages to render a web page 58. Controller the plumbing or routing A kind of Model 2 architecture where a controller servlet controls creates beans and introduces them to JSPs

Model 1 architecture is js JSP and Bean, leaving much to the JSP and scriptlets.

59. Links

http://www.theserverside.com/news/1364527/Introduction-to-the-Spring-Framework