1. Copyright 2007 SpringSource. Copying, publishing or distributing without express written permission is prohibited. Overview of the Spring Framework Introducing Spring in the context of enterprise application architecture

2. Copyright 2007 SpringSource. Copying, publishing or distributing without express written permission is prohibited. 2 Topics in this session Goal of the Spring Framework Spring’s role in enterprise application architecture –Core support –Web application development support –Enterprise application development support The Spring triangle

3. Copyright 2007 SpringSource. Copying, publishing or distributing without express written permission is prohibited. 3 Topics in this session Goal of the Spring Framework Spring’s role in enterprise application architecture –Core support –Web application development support –Enterprise application development support The Spring triangle

4. Copyright 2007 SpringSource. Copying, publishing or distributing without express written permission is prohibited. 4 Goal of the Spring Framework Provide comprehensive infrastructural support for developing enterprise Java™ applications –Spring deals with the plumbing –So you can focus on solving the domain problem

5. Copyright 2007 SpringSource. Copying, publishing or distributing without express written permission is prohibited. 5 Spring’s Support (1) Core support –Application Configuration –Enterprise Integration –Testing –Data Access

6. Copyright 2007 SpringSource. Copying, publishing or distributing without express written permission is prohibited. 6 Application Configuration A typical application system consists of several parts working together to carry out a use case Component A Component B Component C

7. Copyright 2007 SpringSource. Copying, publishing or distributing without express written permission is prohibited. 7 Example: A Money Transfer System TransferService transfer( “300.00”, “1”, “2”) Account 1 confirmation debit(“300.00”) AccountRepository loadAccount(“1”); credit(“300.00”) Account 2 loadAccount(“2”);

8. Copyright 2007 SpringSource. Copying, publishing or distributing without express written permission is prohibited. 8 Spring’s Configuration Support Spring provides support for assembling such an application system from its parts –Parts do not worry about finding each other –Any part can easily be swapped out

9. Copyright 2007 SpringSource. Copying, publishing or distributing without express written permission is prohibited. 9 Money Transfer System Assembly TransferServiceImplJdbcAccountRepository Spring (1) new JdbcAccountRepository(…); (2) new TransferServiceImpl(); (3) service.setAccountRepository(repository); (1) new JdbcAccountRepository(…); (2) new TransferServiceImpl(); (3) service.setAccountRepository(repository); Part 1 Part 2 Assembly

10. Copyright 2007 SpringSource. Copying, publishing or distributing without express written permission is prohibited. 10 Parts are Just Plain Java Objects public class TransferServiceImpl implements TransferService { private AccountRepository accountRepository; public void setAccountRepository(AccountRepository ar) { accountRepository = ar; } … } public class TransferServiceImpl implements TransferService { private AccountRepository accountRepository; public void setAccountRepository(AccountRepository ar) { accountRepository = ar; } … } public class JdbcAccountRepository implements AccountRepository { … } public class JdbcAccountRepository implements AccountRepository { … } Part 1 Depends on service interface; conceals complexity of implementation; allows for swapping out implementation Part 2 Implements a service interface

11. Copyright 2007 SpringSource. Copying, publishing or distributing without express written permission is prohibited. 11 For Jdbc Swapping Out Part Implementations TransferServiceImplJdbcAccountRepository Spring (1) new JdbcAccountRepository(…); (2) new TransferServiceImpl(); (3) service.setAccountRepository(repository); (1) new JdbcAccountRepository(…); (2) new TransferServiceImpl(); (3) service.setAccountRepository(repository); HibernateAccountRepository (1) new HibernateAccountRepository(…); (2) new TransferServiceImpl(); (3) service.setAccountRepository(repository); (1) new HibernateAccountRepository(…); (2) new TransferServiceImpl(); (3) service.setAccountRepository(repository); StubAccountRepository (1) new StubAccountRepository(); (2) new TransferServiceImpl(); (3) service.setAccountRepository(repository); (1) new StubAccountRepository(); (2) new TransferServiceImpl(); (3) service.setAccountRepository(repository); For HibernateFor Unit Testing

12. Copyright 2007 SpringSource. Copying, publishing or distributing without express written permission is prohibited. 12 Enterprise Integration Enterprise applications do not work in isolation They require enterprise services and resources –Database Connection Pool –Database Transactions –Security –Messaging –Remote Access –Caching

13. Copyright 2007 SpringSource. Copying, publishing or distributing without express written permission is prohibited. 13 Spring Enterprise Integration Spring helps you integrate powerful enterprise services into your application –While keeping your application code simple and testable Plugs into all Java EE™ application servers –While capable of standalone usage

14. Copyright 2007 SpringSource. Copying, publishing or distributing without express written permission is prohibited. 14 Enterprise Money Transfer with Spring TransferServiceImplJdbcAccountRepository Spring TransactionManagerDataSource SoapWebService Exporter For DB Connection Pooling For DB TransactionsFor Remote Access

15. Copyright 2007 SpringSource. Copying, publishing or distributing without express written permission is prohibited. 15 Simple Application Code public class TransferServiceImpl implements TransferService { @Transactional public void transfer(MonetaryAmount amount, String srcAccountId, String targetAccountId) { Account src = accountRepository.loadAccount(srcAccountId); Account target = accountRepository.loadAccount(targetAccountId); src.debit(amount); target.credit(amount); } public class TransferServiceImpl implements TransferService { @Transactional public void transfer(MonetaryAmount amount, String srcAccountId, String targetAccountId) { Account src = accountRepository.loadAccount(srcAccountId); Account target = accountRepository.loadAccount(targetAccountId); src.debit(amount); target.credit(amount); } } Tells Spring to run this method in a database transaction

16. Copyright 2007 SpringSource. Copying, publishing or distributing without express written permission is prohibited. 16 Powerful Enterprise Services TransferServiceImpl transfer(“$50”, “1”, 2”) Spring TransactionInterceptor TransactionManager begincommit Transaction management behavior is added around your code You can change transaction managers without affecting your application code Spring

17. Copyright 2007 SpringSource. Copying, publishing or distributing without express written permission is prohibited. 17 Testing Automated testing is essential Spring enables unit testability –Decouples objects from their environment –Making it easier to test each piece of your application in isolation Spring provides system testing support –Helps you test all the pieces together

18. Copyright 2007 SpringSource. Copying, publishing or distributing without express written permission is prohibited. 18 Enabling Unit Testing public class TransferServiceImplTests extends TestCase { private TransferServiceImpl transferService; protected void setUp() { AccountRepository repository = new StubAccountRepository(); transferService = new TransferServiceImpl(repository); } public void testTransferMoney() { TransferConfirmation confirmation = transferService.transfer(new MonetaryAmount(“50.00”), “1”, “2”); assertEquals(new MonetaryAmount(“100.00”), confirmation.getNewBalance()); } public class TransferServiceImplTests extends TestCase { private TransferServiceImpl transferService; protected void setUp() { AccountRepository repository = new StubAccountRepository(); transferService = new TransferServiceImpl(repository); } public void testTransferMoney() { TransferConfirmation confirmation = transferService.transfer(new MonetaryAmount(“50.00”), “1”, “2”); assertEquals(new MonetaryAmount(“100.00”), confirmation.getNewBalance()); } Minimizing Dependencies Increases Testability Testing logic in isolation measures unit design and implementation correctness

19. Copyright 2007 SpringSource. Copying, publishing or distributing without express written permission is prohibited. 19 Accessing Data Most enterprise applications access data stored in a relational database –To carry out business functions –To enforce business rules

20. Copyright 2007 SpringSource. Copying, publishing or distributing without express written permission is prohibited. 20 Spring Data Access Spring makes data access easier to do effectively –Manages resources for you –Provides API helpers –Supports all major data access technologies JDBC Hibernate JPA iBatis

21. Copyright 2007 SpringSource. Copying, publishing or distributing without express written permission is prohibited. 21 Spring JDBC in a Nutshell Acquisition of the connection Participation in the transaction Execution of the statement Processing of the result set Handling of any exception Release of the connection int count = jdbcHelper.queryForInt( "SELECT COUNT(*) FROM CUSTOMER"); int count = jdbcHelper.queryForInt( "SELECT COUNT(*) FROM CUSTOMER"); All handled by Spring

22. Copyright 2007 SpringSource. Copying, publishing or distributing without express written permission is prohibited. 22 Spring’s Support (2) Web application development support –Struts integration –JSF Integration –Spring MVC and Web Flow Handle user actions Validate input forms Enforce site navigation rules Manage conversational state Render responses (HTML, XML, etc)

23. Copyright 2007 SpringSource. Copying, publishing or distributing without express written permission is prohibited. 23 Spring’s Support (3) Enterprise application development support –Developing web services –Adding manageability –Integrating messaging infrastructures –Securing services and providing object access control –Scheduling jobs

24. Copyright 2007 SpringSource. Copying, publishing or distributing without express written permission is prohibited. 24 The Spring Triangle Simple Object Dependency Injection Aspect-Oriented Programming Enterprise Service Abstractions

25. Copyright 2007 SpringSource. Copying, publishing or distributing without express written permission is prohibited. LAB Developing an Application from Plain Java Objects