Spring Transaction & Spring AOP ศิรส สุภาวิตา @siros_s

Agenda: Spring Transaction Why Spring Transaction Transaction Manager Declarative Transaction with Annotation @Transactional Propagation Exception Handling

Why Spring Transaction? Uniform API Transactional resource synchronization On and off server Declarative Transaction

What about JTA? Require J(2)EE container (server) Require EJB for declarative transaction Necessary for distributed transaction

Uniform API Application Spring Transaction JDBC ORM JCA JTA

Transactional Resource Sync Spring Transaction

On and Off Server Spring Spring Spring Servlet Container J(2)EE Java

Declarative Transaction B C Begin Commit D Begin Commit D B C

Declarative Transaction (cont.) Transaction Demarcation Transaction logic is NOT the main business logic Reuse business logic with different transaction logic Programmatic transaction demarcation is NOT the answer

Transactional Resource Transaction Manager Transactional Resource Transaction Manager

Transaction Annotation Use annotation to declare transaction scope Require just one line of config in XML

Example: MyService

Example: Transactional MyService

Example: Detailed MyService

Propagation Define how transaction manager handles transaction SUPPORTS NOT_SUPPORTED REQUIRED REQUIRES_NEW MANDATORY NEVER NESTED

Example: Propagation A B C D REQUIRED SUPPORTS REQUIRED MANDAROTY REQUIRES_NEW NEVER A B C D REQUIRES_NEW

Exception Handling Default behavior Rollback for unchecked exception No rollback for checked exception Can be changed with @Transactional properties rollbackFor rollbackForClassname noRollbackFor noRollbackForClassname

Example: Exception Handling

Wait!! There is a better way!! Q & A

Agenda: Spring AOP Problems of existing approach AOP Definition AOP Proxy Spring AOP Spring Transaction with AOP

Problems?? Transaction policy is still defined locally on each class rather than globally across all classes. Modularity & Reusability Scattering & Tangling Even a medium sized application has multiple “concerns”.

Example of Transaction Policy All top level service operations must begin a new transaction (REQUIRES_NEW). Lower level service operations must operate under an existing transaction (MANDATORY). Data access operation should operate under a transaction (REQUIRES). The problem is that policies or concerns are usually applied based on neither class nor class hierarchy. They are mostly random.

Scattering obj.lastModified = new Date(); Customer cust = new Customer(); … cust.lastModified = new Date(); saveCustomer(cust); Invoice inv = new Invoice(); … inv.lastModified = new Date(); saveInvoice(inv); Course crs = new Course(); … crs.lastModified = new Date(); saveCourse(crs);

Scattering: Modified obj.lastModifiedBy = currentUser(); obj.lastModified = new Date(); Customer cust = new Customer(); … cust.lastModifiedBy = currentUser(); cust.lastModified = new Date(); saveCustomer(cust); Invoice inv = new Invoice(); … inv.lastModifiedBy = currentUser(); inv.lastModified = new Date(); saveInvoice(inv); Course crs = new Course(); … crs.lastModifiedBy = currentUser(); crs.lastModified = new Date(); saveCourse(crs);

Tangling obj.lastModified = new Date(); Course crs = new Course(); … saveCourse(crs); logger.log(“Start operation”); logger.log(“Start operation”); tx = new Transaction(); tx.begin(); Course crs = new Course(); crs.id = generateUUID(); … crs.lastModified = new Date(); saveCourse(crs); tx.commit(); obj.id = generateUUID(); tx = new Transaction(); tx.begin(); … tx.commit();

Aspect-Oriented Programming Concerns are designed and implemented independently During build time or runtime, concerns are compiled into full functioned application. This process is called “weaving”.

AOP Definition Aspect Join Point Pointcut Advice

Join Point public void createCustomer() { x Customer cust = new Customer(); … saveCustomer(cust); }

Pointcut public void createCustomer() { x Customer cust = new Customer(); … saveCustomer(cust); }

Advice public void createCustomer() { logger.log(“Start create…”); Customer cust = new Customer(); cust.id = generateUUID(); … cust.lastModified = new Date(); saveCustomer(cust); }

AOP Proxy Caller Target Object Advice Proxy Advice Advice

Spring AOP

Supported Pointcuts execution within this target args

execution execution(<modifier> <return-type> <declaring-type> <method-name> (<param>) <throws>) execution(* *(..)) execution(public void set*(..)) execution(public * com.spring66.service.*.*(..)) execution(public * com.spring66.service..*.*(..))

within within(com.spring66.service.*) within(com.spring66.service..*)

Advice before after after-returning after-throwing around

Spring Transaction with AOP

Is that all? Q & A