Push your development furtherusing J2EE Best Practices Real-life Examples. Sridhar Reddy Technology Evangelist
[email protected]
Sun™ Tech Days
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Sun Tech Days
Push yourIs development further What Needed…
Sun Tech Days
Learning the technology is
not enough Industry best practices Proven solutions How to avoid bad practices?
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Push yourArchitecture: development further How eBay
From there…
to Go…
… to here?
Microsoft IIS
J2EE™ Container
EJB™ Container Business Tier
MSXML
Integration Tier
Monolithic Proprietary
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Layered Loosely coupled Modular Standards based
Security
eBayISAPI.dll
Logging
Presentation Tier
Services Configuration
Web Container
Sun Tech Days
™ development further
Push yourJ2EE Core
Patterns
Sun Tech Days
Collection of best practices and Patterns for
for J2EE™ architecture Also J2EE™ architecture bad practices and
refactorings Based on Sun Java Center Services
experience Proven solutions Reuse design Robust and scalable architecture Improve quality Flexibility and maintainability
Create a common vocabulary
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Push your BluePrints development further Java Program TM
http://java.sun.com/blueprints JavaTM Technology Series
books
Designing Enterprise Applications with the J2EE Platform, 2nd Edition
Covers J2EE 1.3 platform features TM
Designing Web Services with the J2EE Platform (available fall 2003)
Sample applications
Java Pet Store Demo Java Adventure Builder Demo Concrete code for the BluePrints guidelines Starting points for your applications
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Sun Tech Days
Push your development further Agenda
Sun Tech Days
Web Tier best practices EJB Tier best practices Persistence Options Container Managed Persistence J2EE Performance JMS Best Practices (depending on the time)
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Push your development further
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Some Web Tier Best Practices and Patterns 7
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Push your development further Layering
Web Tier or Client
Network
Data Transfer Objects i.e. Business Data Values
EJB Session Beans
Business Logic Layer Service Layer
Entity EJBs
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Presentation Layer
Domain Layer Persistent Entities
Push your development further Rationale for Layers
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More flexible, extensible: Presentation Layers Frequent changes, design to be flexible
Business Services Implement “use-cases” Public Service interface Interface should remain valid for changes in
presentation and data store
Data Layers Fewer changes, designed to optimize data access
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Push your development further Model View Controller
Model = business data and rules, shared by all clients Controller defines the application behaviour, interprets user
actions and maps them into actions performed on the model View = renders the contents of the Model Client
Thin Browser HTTP Request
Presentation Layer
Model Layer
Persistence Layer
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Controller
HTML Page
View
Problem Domain Services
Enterprise Resources
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Push your development further Model View Controller
Separate: Model data Control Presentation of view
Request
Response
Servlet
Controller
Business Event
Forward Event
Bean
JSP
View Client
Data
Web MVC Pattern
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Model
Model EJB Tier
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Push your development further Service to Worker
Command Factory
3. Parse Request 5. Create 1. Request Client
Front Controller
2. Common logic
4. Get cmd
6. Execute
Command Helper
8. Dispatch 10. Response
7. Business logic
View Dispatcher
Servlet JSP Java™ Objects
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9. Get Data
View Helper Data Bean
Push further Useyour andevelopment MVC Framework
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Faster, easier development of Request processing Response generation
Use Struts, JSF, Sun ONE ... application framework
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Push your development further Struts Framework
Form Bean
View 1
1
Action
2 4 ActionServlet (Controller)
Action Model
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Action View 2 Struts-config.xml ........ ........ ........
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3
Action
Push your development further Struts and Core J2EE Front Controller
Request Action Servlet
Action Mapping (xml)
Patterns Command
Action
Client Uses Response
JSP View
View 15
Action Forward
Dispatcher
Action Form
View Helper
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Model
Business Service
Push your development further Ebay.com: Presentation
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Tier
Request Handler
Request Intercepting Filter
Front Controller
Navigation
Command
?
Business Service
and Dispatch
Client Navigator
Dispatcher
XML
View Processor Intercepting Filter
Response
View Processor
Transformer Helper
XSL
Core J2EE Pattern Strategy
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Push your development further
Business Delegate Client
independent from ejb tier Ejb details
hidden Mock objects can
be used to test client w/o ejb tier
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Push your development further Ebay.com: Presentation
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Tier
Request Handler
Service Interface
Request Intercepting Filter
Front Controller
Navigation
Command
Service Locator
Dispatcher
XML
View Processor Intercepting Filter
Response
Business Service
and Dispatch
Client Navigator
Business Delegate
View Processor
Transformer Helper
XSL
Core J2EE Pattern Strategy
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Push your development further Cache for Performance
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Some things can be cached and shared, use a
singleton: InitialContext object Anything retrieved from JNDI, EJB Home interfaces Repeated lookups can be expensive! Use Service Locator
Pattern
Some things are user specific, cached in session: Cache search results when you are only displaying a few
at a time (static data) Value List Pattern
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Sun Tech Days
Push your development further Service Locator Pattern
DON'T EJB Client
EJB Client
DO JMS Client
JNDI
JDBC Client
EJB Client
JMS Client Service Locator JDBC Client
EJB Client JNDI
Repeated lookups can be expensive! Use the Service Locator Pattern to Cache references obtained by JNDI lookups (ejb references, datasources, jms connection) 20
Push your development further ServiceLocator code
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01 public class ServiceLocator { 02 private InitialContext ic; 03 private Map cache; 04 private static ServiceLocator me; 05 06 private ServiceLocator() { 07 ic = new InitialContext(); 08 cache = Collections.synchronizedMap(new HashMap()); 09 } 10 public static ServiceLocator getInstance() { 11 if (me == null) { 12 me = new ServiceLocator(); 13 } 14 return me; 15 }
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Push your development further ServiceLocator code
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01 public EJBHome getRemoteHome(String jndiHomeName, Class className){ 02
03 04 05 06 07 08 09 10 11 12 15
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EJBHome home = null; if (cache.containsKey(jndiHomeName)) { home = (EJBHome) cache.get(jndiHomeName); } else { Object objref = ic.lookup(jndiHomeName); Object obj = PortableRemoteObject.narrow(objref, className); home = (EJBHome)obj; cache.put(jndiHomeName, home); } return home; }
Push your development further Client code
01 ServiceLocator serviceLocator = 02
ServiceLocator.getInstance();
03 try { 04 05
...
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ProjectHome projectHome =(ProjectHome) serviceLocator.getHome(“ProjectHome.class”);
Sun Tech Days
Push development further Tipsyour for Servlets
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Servlets are Multithreaded Avoid use of shared modified class variables Synchronize only small blocks in code
Don't store a lot of data in the HTTP
Session Remove servlet sessions when they
are no longer needed: In logoff call session.invalidate()
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Push your development Servlet Tips further
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DO use high performance J2EE
design patterns MVC, Service Locator
DON’T hold resources – explicitly
free them
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Push development Tipsyour for JSPs further
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Avoid scriptlets in JSP Use JSTL (JSP 2.0 Standard Tag Libraries):
Pass data to JSP in Servlet request object not
session If JSP does not use the HTTP session Use to prevent
HTTP Sessions from being automatically created
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Push your development further
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Some EJB Tier Best Practices and Patterns 27
Push development further Do your you need EJBs?
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Do you need declarative
transactional support? Do you need to distribute your
business logic? Do you need JMS, JAX-RPC, RMI? Do you need to support multiple
client types? Do you need method-level security
on your objects? Do you need Clustering for Scalability? 28
Push your development further Architecting Applications
Sun Tech Days
ebay Case Study Functional requirements captured
via use-cases Use-cases implemented using MVC &
Command design patterns Implement Business Logic as Services
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Sun Tech Days
Push yourUse development ebay case further realization
ebay Case Study
View Items by category Any User
Any user can view auction items by category
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View Items
Push yourItems development further Requirements View Design
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ebay Case Study Centralize Request Hndlg
Convert to Biz Command Assemble Data Use case Biz logic Retrieve Data by category
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Push yourItems development further View Design
ebay Case Study Front Controller
Transfer Object Assembler
Action Command
Business Delegate
Service Locator
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Session Facade
Value List Handler
Data Access Object
Transfer Object
Push yourApplication development further Core Design Patterns
Ebay Case Study Presentation
Response
Request
FRONT CONTROLLER
Data Integration & Persistence
BUSINESS SERVICE FACADE
VIEW
MODEL
COMMAND object
DATA TRANSFER OBJECT
WEB Tier
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Business Logic & Messaging Fabric
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Servlet
Java™ Objects
JSP
Session EJB
Value List Handler
DATA TRANSFER OBJECT
SessionEJB
DATA ACCESS OBJECT
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Push yourTransfer developmentObject further Data Client Object
EJB Network boundary
GetCity() GetState()
Before
DON'T DO too much network traffic
GetZipCode()
Client Object
Item Info Data Transfer Object
EJB
A Da ta Tra ns fe r Obje ct e ncaps ula te s a s e t of da ta va lues to re turn to the clie nt in one ne twork tra ns fe r
GetItemInfo() Return DTO GetCity()
After
DO Reduce network traffic with Data Transfer Object
GetState() GetZipCode() Network boundary
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Push yourApplication development further Core Design Patterns Business Logic & Messaging Fabric
Presentation
Response
Request
FRONT CONTROLLER
Data Integration & Persistence
BUSINESS SERVICE FACADE
VIEW
MODEL
COMMAND object
DATA TRANSFER OBJECT
WEB Tier
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Servlet
Java™ Objects
JSP
Session EJB
Value List Handler
DATA TRANSFER OBJECT
SessionEJB
DATA ACCESS OBJECT
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Push yourAccess development further Data Object Use DAO for read-only tabular access to a large set of data, when query results are large and short-lived BusinessObject
Uses
DataAccessObject
creates/uses
obtains/modifies
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Encapsulates
DataSource
Use Data Access Objects to encapsulate data-access logic -provides a simplified interface for performing complex JDBC operations -allows decoupling of data-access optimizations
TransferObject
Push your development further EJB Tier patterns
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Data Access Object (DAO) public class FacadeEJB implements SessionBean { protected EbayDAO dao; public void ejbCreate() { try { dao = EbayDAOFactory.getDAO(); } catch (EbayDAOSysException se) { throw new EJBException(se.getMessage()); }} … public ListChunk getItems(String categoryId, int startIndex, int count, Locale locale) { try { return dao.getItems(categoryId, startIndex, count, locale); } catch (EbayDAOSysException se) { throw new EJBException(se.getMessage()); }} …. }
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DAOs as the app is designed for different databases The name of the particulary DAO class is lookup in the env. settings given in the deployment descriptor Reflection is used to instantiate a concrete instance of the class
Example: EbayDAOFactory
Push yourApplication development further Core Design Patterns Business Logic & Messaging Fabric
Presentation
Response
Request
FRONT CONTROLLER
Data Integration & Persistence
BUSINESS SERVICE FACADE
VIEW
MODEL
COMMAND object
DATA TRANSFER OBJECT
WEB Tier
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Servlet
Java™ Objects
JSP
Session EJB
Value List Handler
DATA TRANSFER OBJECT
SessionEJB
DATA ACCESS OBJECT
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Push your development further Value List Handler
For querying, filtering, and
Interface
ValueListIterator
+GetSize():int +getCurrentElement():Object +getPreviousElements(count:int):List +getNextElements(count:int):List +resetIndex():void
displaying large amounts of data:
Value List Handler handles the search, can cache results and provides a traversable result set
Client
ValueListHandler
ValueList
DataAccessObject
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TransferObject
Sun Tech Days
Push your development furtherResults Example Caching Stateful Session
Client
ValueListHandler
1: Create
ValueListiterator
2: Execute Search
DataAccessObject
ValueList
2.1: Execute Search 2.1.1: Create
Return Sub List
3: Get Next
Return Value List
3.1: Get Sub-list 3.2: Return Sub-list
4: Get Previous
4.1: Get Sub-list 4.2: Return Sub-list
5: Get Current
5.1: Get Current
5.2: Return Value Object 6: Get Size
6.1: Get Size 6.2: Return Size
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Push your development further Returning Search Results Options
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ValueList Handler as a Stateful Session
EJB caches search results, and returns sub list ValueList Handler as Stateless Session
EJB:
Select * FROM item WHERE id=? [count] OFFSET [startIndex]
LIMIT
Instead of Value list could use JDBC 2.0
scrollable ResultSet but keeps connection open ! (J2SE 1.5 will have disconnected scrollable ResultSet) 41
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Push your development further Stateless Example Stateless Session
Client
1: Create
ValueListHandler ValueListiterator
2: Execute Search (index, count)
Return Sub List
2: Execute Search (index+count, count)
Return Sub List
DataAccessObject
2.1: Execute Search (index, count) 2.1.1: Create
Return sub List
2.1: Execute Search (index+count, count) 2.1.1: Create
Return sub List
Select * FROM item WHERE id=? LIMIT [count]OFFSET [startIndex]
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ValueList
Push yourApplication development further Core Design Patterns Business Logic & Messaging Fabric
Presentation
Response
Request
FRONT CONTROLLER
Data Integration & Persistence
BUSINESS SERVICE FACADE
VIEW
MODEL
COMMAND object
DATA TRANSFER OBJECT
WEB Tier
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Sun Tech Days
Servlet
Java™ Objects
JSP
Session EJB
Value List Handler
DATA TRANSFER OBJECT
SessionEJB
DATA ACCESS OBJECT
Sun Tech Days
Push your development further Session Facade pattern Session Bean
Entity Bean 1
Entity Bean Plain Java™ Object
Client 1. doThis(...)
2. getData()
2. getData() Entity Bean 2
Data Access Object 1
Session Bean
Data Access Object 2
Session Facade
3. process
Use the Session Facade:
Java™ Object
provide a simple interface to a complex subsystem of
enterprise beans Enforce a clear and strict separation of business logic from
presentation and data logic 44
Push development further Useyour the Session Facade
Sun Tech Days
pattern
To Execute complex use cases in a single network call to reduce network overhead Direct Bean Access
Don’t:
EJB
Client
Network Direct Entity Bean access results in excessive network overhead and multiple transactions
Do: Network Client
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F a c a d e
EJB
Direct Entity Bean access results in excessive network overhead
Sun Tech Days
Push yourthe development furtherFacade Use Session To group finer grained calls to local entity beans
Local vs. Remote Interfaces Remote Interfaces EJB client
EJB Object
Local Interfaces EJB client
EJB Object
Network Pass by Value: Serialize/deserialize method parameters
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Pass by Reference: Better performance
Push your development further& Design your local
remote EJBs
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Use Session Facade to group finer grained calls to local EJBs in a Coarse Grained Interface Java Client Remote Facade
WebComp onent
WebComp onent
WebComp onent Business Delegate
Relationship Reference
Admin Remote Facade
Determine which EJBs will be collocated within same VM
LineItem CreditCard Purchase Order Address
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Sun Tech Days
Push development further Useyour the Session Facade
To group related updates into container managed transactions Application Server TX_REQUIRED
Check Out
Client
Facade
TX_REQUIRED
DataBase Server or JMS Provider
Update Inventory Inventory
Order
Resource
createOrder Commit or Start Prepare rollback
Transaction Create context x Manager Add to context x
Transaction context
Add to context x Check context x to see if updates will work
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Push your development further eBay.com: Business
Sun Tech Days
Tier
ebay Case Study Dispatch Application Controller
Command
Context Object
Persistence Domain Store
DAO
Data Source
Business Logic/Data Application Service Facade
Business Object
Transfer Object Assembler
Value List Handler
Transfer Object
Core J2EE Pattern Strategy
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Session EJB tips
Push your development further
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Remove stateful session beans when
finished (user logs out)
Bean.remove()
Limit size of objects stored in session
beans due to memory cost and I/O for passivation
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Push your development further Stateless or Stateful
Session EJB?
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Stateless session beans are pooled and
can service multiple clients give best performance
Stateful store conversational state=1 per
client (are activated and passivated) For Performance Strive for Statelessness
when application has a high number of users convert Stateful to stateless by adding parameters
to the bean methods that hold the extra state 51
Push your development further Service Tier DON'T
s
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DO NOT store large amount of data
in Stateful SessionEJB DO NOT access of Entity EJBs remotely DO NOT implement fine-grained
components as remote EJBs
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Push your development further Design Patterns Summary Mediate business processing Locate services
Session Facade Obtain composite value objects
Encapsulate data
Access data sources
Message Driven Bean
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Access business list
Value List handler Encapsulate data
Transactional Data Business Components
Entity
Service Locator
Encapsulate data
Value Object Assembler Invoke business methods
Locate services
Transfer Object Encapsulate data
Data Access Object
Access data sources
Push your development further Design Patterns Summary
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Data Transfer Object
Exchanges data J2EE tiers
Service Locator
Holds results of JNDI lookups
Value List Handler
Handles larger result sets from database queries
Business Delegate
Simplifies the coupling between the J2EE Web &
EJB tiers
Session Facade
Provide business logic functionality
Data Access Object
Isolation layer for interfaces to a systems
resources
Etc.
www.sun.com/developer/blueprints/
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Push your development further
Persistence Best Practices 55
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Push yourAccess development further Data Options
in J2EE:
Sun Tech Days
Object-oriented (transactional) data model EJB container managed persistence Great choice for ease and performance
JDO
Tabular access EJBs should not be simple wrappers on
database data rows; they should have business logic. To simply access data, use Plain JDBC JDBC RowSets (disconnected J2SE 1.5)
Non-relational, non-object data access Use J2EE Connectors
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Sun Tech Days
Push yourvs. development BMP CMP further
BMP Bean
JDBC SQLJ
JDBC Driver
SQL
Bean State Database
EJB Container 1) Bean provider manages State and Data consistency 2) Bean provider handles relationships and OR Mapping
CMP Bean EJB Container
JDBC SQLJ
Persistence Manager
JDBC Driver
SQL
Bean State Database
1) Container manages State and Data consistency 2) Container/PM provides concurrency, relationships and OR Mapping
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Push your of development Effect Good further CMP Optimizations
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28 24 20 16 12
Simple BMP Optimized BMP CMP
8 4 0
Benchmark Score
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# of Database Calls
Push your2.0 development CMP Entity further Beans
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Entity Bean is now an abstract class, container extends it java.io.Serializable
javax.ejb.EnterpriseBean
javax.ejb.EntityBean
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CMP Entity Bean abstract class (Contains data handling logic)
You (bean provider) write this code.
CMP Entity Bean subclass (Contains persistence logic)
Container provides this class.
Push your development further and Accessors for CMP
CMR
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public abstract class OrderBean implements EntityBean { private EntityContext context; //access methods for cmp fields public abstract String getOrderID(); //primary key public abstract void setOrderID(String id); . . . //access methods for cmr fields public abstract Collection getLineItems(); public abstract void setLineItems(Collection lineItems);
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Push your development further Container Managed
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Relationships
Address Order
1
Local Entity
Shipping Address Local Entity
1 Client
Product
OrderBean
1
1 LineItems
ProductOrdered
M OrderHome
LineItem Local Entity
EJB Tier 61
M
Push your2.0 development further CMP Relationship
Handling
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In CMP 2.0, you declare fields and
relationships in deployment descriptor Container generates all the necessary code ... define your enterprise beans ... elements represent container-managed persistent fields ... define EJB relationships ...
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Push your development further Example CMP Wizard
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Sun Tech Days
Push your development Advantages of further CMP 2.0 for developer
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container manages the persistence and
the relationships, not you! Freedom from maintaining interactions
with the data store EJB™ Query Language (EJB QL) Portable code
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Push your development Advantages of further CMP 2.0 for Container
Sun Tech Days
Optimization is possible in query
operation Because Query is defined in deployment
descriptor via EJB QL
Optimization is possible because
persistent fields are only accessible via get and set methods Lazy loading,Dirty writes,Optimistic locking
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Push yourOptimizations development further CMP
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Aggressive Loading Loading fields relationships and fields of
children in the same query
Lazy Loading Deferring loading of any data until it is accessed
Dirty Writes Only update data which has been changed
in the database
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Push yourStandard development further CMP: Vs. Vendor Specific Features
Sun Tech Days
***HIDDEN SLIDE*** Standard features Declarative specification of: Persistent attributes, abstract schema, relationships,
queries for finder/select methods(via EJBQL), transactional attributes
Vendor specific Tools for O/R mapping, concurrency and
consistency semantics, caching semantics, performance and usability
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Push your development further Modes Database Isolation
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Choose the lowest cost transaction
isolation level that avoids corrupting the data. Transaction levels in order of
increasing consistency and cost are: Read Uncommitted Read Committed Repeatable Read Serializable
consider READ COMMITTED with
optimistic locking 68
Push your development further Entity Bean Tips
Sun Tech Days
Do not use EJB entity beans for batch
loading or queries that return large result sets. Use Data Access Objets encapsulating JDBC Use CMP rather than BMP entity bean
when possible Do not call EJB entity bean get & set
methods from client Wrap with session beans to provide course
grain access and single transaction context
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Push your development further EJB Summary
Sun Tech Days
EJB Container Services – use appropriately for: Distributed transaction management Robust security service Resource management (threads, sockets, database connections) Container persistence Remote accessibility Dispatch and life-cycle management.
Use EJB 2.0 local interfaces for performance
improvements When running in same JVM.
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Push your development further
J2EE Performance Tips 71
Sun Tech Days
Push your development further Application Resources
Standard application resources:
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CPU
Memory
I/O
Network
Database
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Push yourApp development further Tune Server
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# Execute threads that requests run on JDBC connection pools Prepared statement cache size JVM Heap size (go to Performance code camp) EJB Bean Cache and Pools Correct settings depend on application,
test to determine sizes 73
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Push your development further The EJB Container
Pooling and Caching of EJB Instances
Allow for reuse of bean instances Pooling
Caching
creation +
activation /
initialization
passivation
for message-driven
yes
no
for stateless session
yes
no
for stateful session
no
yes
for entity beans
yes
yes
objective: minimize
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Push yourKey development further Tune Container
Parameters
Sun Tech Days
Stateful session bean and entity bean
cache Cache = EJB instances with state Session timeouts
Stateless session and entity bean pools Pool = EJB instances with no assigned state
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Sun Tech Days
Push your development Entity Bean further Bean pool size Bean cache size
EjbActivate()
Does not exist NewInstance() setEntityContext()
unsetEntityContext()
pooled
ejbFind() EJB Instance
ejbCreate() ejbPostCreate()
ejbRemove() ejbActivate()
ejbPassivate()
ready
ejbLoad()
EJB Object
EJB Instance
business method
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ejbStore()
Push your development further Entity Bean Caching
Sun Tech Days
Commit Option A At the end of the transaction, the instance stays ready (cached) and the instance state is valid Commit Option B At the end of the transaction, the instance stays ready (cached) but the instance state is NOT valid ( ejbLoad will be called ) Commit Option C At the end of the transaction, neither the instance nor its state is valid (passivated) Best Option: do profiling with your application on your app server 77
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Push your development further Stateful Session Bean Bean cache size Session time out does not exist
ejbRemove()
1) newInstance() 2) setSessioncontext() 3)ejbCreate()
ejbPassivate()
Method-ready EJB Object
business method
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passive
EJB Instance
EjbActivate()
Push your development further Bean Stateless Session and Message Driven Bean
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Bean pool size does not exist 1) newInstance() 2) setSessioncontext()
EjbRemove()
3)ejbCreate()
method-ready pool Business method EJB Instance
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The Sun's EJB Container
Push your development further
Sun Tech Days
Cache Tunables
commit-option (B|C) (entity beans) Max-cache-size (0 = unbounded) cache-idle-timeout-in-seconds
(0 = indefinitely) removal-timeout-in-seconds
(stateful session)
Adjust cache size:
Increase until a good cache hit
rate is reached
For fine tuning, understand a beans usage pattern (reads, updates, creates, removes ...)
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Push development Theyour Sun's EJBfurther Container
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Pool Tunables steady-pool-size (not for message-
driven) max-pool-size (0 = unbounded) pool-idle-timeout-in-seconds
(0 = indefinitely) Adjust a bean’s pool size:
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Increase when observing excessive creation and deletion of bean instances
Decrease when accumulating a large number of instances in pool
Push development Theyour Sun's EJBfurther Container
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Configuring Pool and Cache
Per bean: in ejb module’s sun-ejb-
jar.xml
and
Global defaults: in server instance’s
server.xml
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and
Push your development further JDBC Tips
Sun Tech Days
Select a certified, high performance
type 2 (Thin) JDBC driver Tune connection pool size Close resources as soon as you’re done
with them (in finally) E.g. Statements, Connections, ResultSets…
Use JDBC’s PreparedStatement instead
of Statement when possible Tune statement caching
Turn off Auto-Commit 83
Group updates into a transaction
Push your development further Database Performance
Sun Tech Days
Common performance bottleneck Typical problems: Use small primary keys (number) Inefficient queries - sending SQL data that asks the database to do more work than necessary run the SQL through the EXPLAIN SELECT command index the columns in your WHERE clauses
Large Data Sets - processing large sets
of data in ResultSets 84
Push your developmentTips furtherSummary Performance
Sun Tech Days
Tips for better performance Tune app server and infrastructure Container Caching and Pools Database access Use JDBC for: Batch loading: session bean or message bean Large result sets: value list handler
Use CMP rather than BMP Entity Beans Use right isolation level and database
transactional control (locking)
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Push your development further Manage Expensive
Resources
Sun Tech Days
Cache “EJB homes” Cache data sources Minimize use of HTTP sessions Release database connections Remove unused stateful session beans Use local Interfaces [Session Facade]
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Push your development further Design Patterns can Significantly Help Performance
Session Facade Service Locator Value List Handler Data Transfer Object
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Push your development further
Some JMS Messaging, J2EE Best Practices 88
Sun Tech Days
Sun Tech Days
Push your development further Point-to-Point
Example: Order and Fulfillment
Queue
JMS Java™ Pet Store
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JMS
Sun Tech Days
Push your development further Publish and Subscribe
Example: Stock Price Changes
Topic Price Change
Traders/Brokers
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Push your development further Message-Driven Bean
Concurrent Asynchronous Processing High Scalability, High Throughput MDB instances are pooled by the container Allow for asynchronous concurrent message consumption
from the same destination
Container
JMS Provider Desti Queue nation
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MDB Consume Consumer r
Container Msg-
MDB driven Instances Instances
Bean
Msg-Driven Bean Class
Sun Tech Days
Push yourFacade development further MDB Pattern
Mailer MDB Asynchronous Message Delivery
Order Approval MDB
EJB Tier
LineItem Entity
Card Entity
1:m Purchase Order Entity Address Entity
Use the MDB Facade: provide a simple asynchronous interface to a complex
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subsystem of enterprise beans
Push JMSyour development further
Sun Tech Days
Use JMS for loosely coupled
applications that need reliable, scalable document oriented message exchange Including Message-Driven
Beans and JMS in your J2EE™ application can greatly increase performance, robustness, and efficiency 93
Push your development further
Tools Summary Resources 94
Sun Tech Days
Push your development further Use Tools
Sun Tech Days
Use IDE or Xdoclet to keep EJB class,
home interfrace, remote interface consistent Use Junit for Unit testing Use Ant to automate deployment and
testing All of these are provided with
Sun Java Studio
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Push your development further Summary J2EE Patterns and Best Practices
are proven solutions Reuse design Robust and scalable architecture Improve quality, performance Flexibility and maintainability
JavaTM BluePrints Program http://java.sun.com/blueprints Designing Enterprise Applications
with the J2EE Platform, 2nd Edition
96
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Push your development further Resources:
http://java.sun.com/blueprints Java Performance Tuning
97
J2EE Performance Testing
Push your development further
Sridhar Reddy Technology Evangelist
[email protected]
Sun™ Tech Days
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