Transcript System Integration - 國立交通大學資訊工程學系NCTU Department of

Java 2 Platform, Enterprise Edition
(J2EE)
An Overview
蔡文能
交通大學資訊工程學系
[email protected]
1
What Is J2EE ?
• Java 2 Enterprise Edition
• There are 3 different specifications within
the Java framework (J2SE, J2ME, J2EE)
• Created to provide a simple, unified
standard for distributed applications through
a component based application model
• Specification is managed by a consortium
of industry leaders
2
Some useful online references
• http://java.sun.com
• http://java.sun.com/j2ee
• http://java.sun.com/j2ee/tutorial/index.html
3
J2EE and Other Java 2 Platform Editions
Source: Computer, August 2000
J2EE, J2SE, J2ME
4
J2EE and Other Java 2 Platform Editions
J2EE, J2SE, J2ME
Source: Sun Microsystems, Inc.
5
Java Development and Runtime Environment
Source: P.J. Perrone and V.S.R.R. Chaganti, Building Java Enterprise Systems with J2EE6
Java 2 Platform Runtime Architecture
Source: P.J. Perrone and V.S.R.R. Chaganti, Building Java Enterprise Systems with J2EE7
Java 2 Platform, Standard Edition (J2SE 1.3)
Source: Sun Microsystems, Inc., http://java.sun.com/j2se/1.3/
8
Java 2 Platform, Standard Edition (J2SE 1.4)
Source: Sun Microsystems, Inc., http://java.sun.com/j2se/1.4/
9
Why J2EE ?
• A stand alone program
• Client/Server (2-Tier)
– BBS, News, FTP, Telnet, …
• Traditional (non-component) N-Tier Systems
– 3-tier application: Browser – WEB Server – DBMS
• New trend:
– Component N-Tier Systems
(J2EE Architecture)
See figures on
next slides
10
2-Tier Database Access
• Client Tier – Presentation, Business Logic
• Data Tier – Database Management Services
Source: Sun Microsystems, Inc., JDBC 3.0 Specification
11
Traditional(non-component) N-Tier Systems
• Client Tier – Presentation Logic
• Application Tier – Business Logic
• Data Tier – Database Management Services
Source: Sun Microsystems, Inc., JDBC 3.0 Specification
12
Component N-Tier Systems
J2EE Architecture
Client Tier
Fireware
Applet
Container
Web Tier
Web Container
Connector
EJB Container
JSP
Standalone
Client
Client
Machine
EIS Tier
Business Tier
Enterprise
Information
Services
EJB
Servlet
J2EE Server
Machine
Database Server
Machine
13
J2EE Architecture (1/2)
J2EE Component and Container
Source: Sun Microsystems, Inc., J2EE Specification v1.3
14
J2EE Architecture (2/2)
• J2EE consists of three major parts:
– Components
Hold presentation and business logic
– Containers
Provide context for components
– Connectors
Provide access to legacy enterprise systems
15
J2EE Components
• Application clients
• Applets
• Web components
– Servelets, Java Server Pages (JSP)
– Portlet (see JSR168)
• Business components
– Enterprise Java Beans (EJB)
16
J2EE Component
Applet Component
• An applet is a program written in the JavaTM
programming language that can be included in an
HTML page, much in the same way an image is
included. When you use a Java technologyenabled browser to view a page that contains an
applet, the applet's code is transferred to your
system and executed by the browser's Java Virtual
Machine (JVM).
• An applet is a small program that is intended not
to be run on its own, but rather to be embedded
inside another application.
17
Applet pro vs. con
• Applets: Java code that runs inside browser
• Advantages:
–
–
–
–
Extends functionality on the client side
More complicated GUIs than w/ HTML or JavaScript
Computation can be off-loaded from server
Users don’t have to build, install, and configure
• Disadvantages:
– Download time
– “Sandbox” limits functionality (unless signed)
– Window management by browser
18
J2EE Component
Web Component
• Servlets
– A servlet is a program that extends the functionality of a Web
server. Servlets receive a request from a client, dynamically
generate the response (possibly querying databases to fulfill the
request), and then send the response containing an HTML or XML
document to the client
• JSP
– The JavaServer Pages (JSP) technology provides an extensible way
to generate dynamic content for a Web client. A JSP page is a textbased document that describes how to process a request to create a
response
19
Java Servlet
Servlet Class wasn’t
loaded into System
Class Loader
HTTP Request
Servlet Class
was loaded
Web
Services
Browser
Load Servlet class
Into System
Invoker
HTTP Response
Services
20
Java Servlet
• Java Servlet is the bridge for user to use Java
solution in Web Server.
• Java Servlet has better performance than
CGI(Common Gateway Interface).
• Java Servlet can use session to replace cookie and
enhance security.
• J2EE Server maintains the session for Java
Servlets.
21
JavaServer Pages (JSP)
Java
Source
Code
Compiler
Java
Bytecode
Load Servlet class
Into System
New JSP Page
JSP was modified
Class Loader
JSP isn’t loaded yet.
HTTP Request (.jsp)
Web
Services
Browser
Invoker
HTTP Response
jspServices
22
JavaServer Pages (JSP)
•
•
•
•
•
JSP has all features of Servlet.
JSP is a HTML like document.
JSP is designed for Web Page Developer.
JSP will change to Java Servlet source.
JSP is ran via Servlet mode.
23
JavaServer Pages
Objects
• JSP has 9 objects which developer can use
directly without new it.
JSP Object
java class
scope
request
response
pageContext
session
application
out
config
page
exception
javax.servlet.ServletRequest
javax.servlet.ServletResponse
javax.servlet.jsp. PageContext
javax.servlet.http.HttpSession
javax.servlet.ServletContext
javax.servlet.jsp.JspWriter
javax.servlet.ServletConfig
java.lang.Object
java.lang.Throwable
request
pag
page
session
application
page
page
page
page
24
Portlet and Portal
• JSR168
Browser
Portal
Server
HTTP
– Java portlet
standard
• WSRP (Web Services for Remote Portlets） WSRP
– Remote portlet
JSR168 Portlet Container
communication
protocol
JSR168
JSR168
– Portals aggregate
Portlet
Portlet
remote portlets
25
The Reason For JDBC
• Despite almost all databases supporting SQL, database vendors
(Microsoft Access, Oracle etc.) provide proprietary (no standard)
Application Programming Interfaces for sending SQL to the
server and receiving results from it!
• Languages such as C/C++ can make use of these proprietary
APIs directly
– High performance
– Can make use of non standard features of the database
– All the database code needs to be rewritten if you change
database vendor or product
• JDBC (Java DataBase Connectivity) is a vendor independent
API for accessing relational data from different database vendors
in a consistent way
26
CCTM: Course material developed by James King ([email protected])
JDBC
• JDBC provides an API that hides the vendor specific APIs by
inserting a driver between the Java application and the database API
• JDBC requires a vendor-specific driver
• The driver converts calls from JDBC API to vendor’s API =>
performance penalty
• The driver does not provide access to vendor specific functionality
• The same Java application can be used with a different vendor’s
database by simply switching JDBC driver and changing one line
of Java code.
• JDBC 1.0 is included inside JDK 1.1 or higher in a package java.sql
• JDBC 2.0 and 3.0 require updated drivers and an additional package
javax.sql
27
CCTM: Course material developed by James King ([email protected])
Rollback and Commit
• By default connections to the database commit each update as
soon as it is completed.
• If you want to make a set of changes and only commit the
aggregate result if nothing goes wrong auto commit needs to be
switched off
connection.setAutoCommit(false)
You can then use
connection.commit() to apply the changes
connection.rollback() to undo changes since the last commit
• You can switch auto commit back on using
connection.setAutoCommit(true)
28
CCTM: Course material developed by James King ([email protected])
J2EE Compoent (1/2)
EJB Component
• Enterprise JavaBean (EJB)
– The Enterprise JavaBeans (EJB) architecture is a
server-side technology for developing and deploying
components containing the business logic of an
enterprise application.
– Enterprise JavaBeans components, termed enterprise
beans, are scalable, transactional, and multi-user secure.
• EJB is an architecture for component-based
transactional distributed computing.
29
EJB Component (2/2)
• An enterprise bean contains business logic
that operates on the enterprise’s data.
• Client access is mediated by a Container.
• There are three kinds of enterprise beans:
session beans, entity beans, and messagedriven beans.
30
Enterprise Bean Objects
• Session objects: for a single client, shortlived, …Stateful, Stateless
• Entity objects: object view of data in the
database, shared by multiple clients, longlived, …
• Message-driven objects: triggered by a
single client message, short-lived,
stateless, …
31
Stateful vs. Stateless Session
Beans
• Stateful
– Possess Internal State
– One per client
– Need to handle
activation/ passivation
• Stateless
– Do not possess state
– Can be pooled to
handle multiple clients
– Do not need to be
passivated
32
Entity Beans: CMP vs. BMP
• Container Manager
Persistence
– Container responsible
for database accesses/
controls
– Developer focuses on
data use
• Bean Managed
Persistence
– Developer must write
code to handle
database accesses/
controls
– Used for more
specialized data
mapping strategies
33
Entity Bean Characteristics
• Provides an object view of data in the
underlying database
• Shared across multiple users
• Long-lived
• Survives container crash
34
To Implement an Enterprise Bean (1/2)
• Any enterprise bean must define two interfaces
and one or two classes
– Remote interface
• defines a bean’s external interface
• must extend javax.ejb.EJBObject (which in turn extends
java.rmi.Remote)
– Home interface
• The home interface defines a bean’s “life cycle” methods, eg.
create bean, remove bean, find bean, etc.
• must extend javax.ejb.EJBHome which also extends
java.rmi.Remote
35
To Implement an EJB (2/2)
• Bean Class
– The java class that actually implements the bean’s external
interface, e.g. the bean class provides implementations for the
bean’s “business methods”
– An entity bean must implement the javax.ejb.EntityBean interface,
while a session bean must implement the (you guessed it)
javax.ejb.SessionBean. Both of these interfaces extend
javax.ejb.EnterpriseBean
• Primary Key
– The primary key is a very simple class that provides a pointer into
a database; Only entity beans need a primary key. This class must
implment java.io.Serializable (so the entity bean can automatically
be sent to persistent storage)
36
EJB Container
• A container is provided by the Application Server
vendor to provide basic services that are required
by J2EE specification.
• An EJB programmer places their code here, and is
assured a variety of basic services are available
• This means the developer doesn’t have to code
these services from scratch
• Specification states which services must be
supported but not how
37
Basic Services Supplied by the
EJB Container
•
•
•
•
•
Security
Transaction management
Remote Client Connectivity
Life Cycle Management
Database Connection Pooling
38
More Services provided by container
• The following basic services will be supported by
all J2EE compliant products
–
–
–
–
–
–
–
RMI/RMI-IIOP
Resource Pooling
Thread Control
Presentation Logic
Persistence
Messaging
And more…
IIOP: Internet Inter-ORB Protocol
ORB: Object Request Broker
39
Can’t Do in an EJB
•
•
•
•
•
•
Can’t use threads
Can’t use the AWT
Can’t act as network server
Can’t use java.io package
Can’t load native libray
Can’t use this as an argument or return
value
40
EJB Benefits Summary
• Developing distributed applications in Java
– Application developer is spared from following details
•
•
•
•
Transaction management
State management
Multi-threading
Connection pooling
• Write once, run anywhere
• Interoperability with other languages
• Compatible with CORBA protocols
41
J2EE Containers (1/2)
Web Containers
• Web Component Containers
– 1. Servlet Containers
• A servlet container provides network services (by which requests and
responses are sent), decodes requests, and formats responses. All
servlet containers must support HTTP as a protocol for requests and
responses, but may also support additional request-response protocols
such as HTTPS.
– 2. JSP Containers
• A JSP container provides the same services as a servlet container and
an engine that interprets and processes a JSP page into a servlet.
– 3. Web Containers
• A Web container provides the same services as a JSP container and
access to the J2EE service and communication APIs.
42
J2EE Containers (2/2)
EJB Containers
• EJB Container
– Enterprise beans are hosted by an EJB
container. In addition to standard container
services, an EJB container provides a range of
transaction and persistence services and access
to the J2EE service and communication APIs.
43
Tomcat
• Tomcat: Java-based web server + servlet
container w/ JSP environment
• Execution modes:
– Standalone: default mode for Tomcat
– Out-of-process add-on: web server plugin
opens JVM outside web server; plugin and
JVM communicate using IPC mechanism
(TCP/IP sockets and special protocol)
44
Tomcat and Apache
• Communication mechanism between
Tomcat and Apache: web server adapter” or
named as “connector”
• Implemented as shared library (e.g.,
mod_jserv.so, mod_jk.so)
• Uses/manages TCP connections
• Uses the AJPV12/AJPV13 communication
protocol
45
J2EE Connectors
• Contract between container and Enterprise
Information Systems (EIS)
• Proprietary and under the hood
• Implementation is available with J2EE
specification version 1.3 / 1.4
46
J2EE Standard Services
• HTTP/HTTPS
• Java Transaction API (JTA)
• Java Database Connection (JDBC)
•
•
•
•
Java Message Service (JMS)
Java Authentication and Authorization Service (JAAS)
J2EE Connector Architecture (JCA)
Others: RMI-IIOP, JavaIDL, JavaMail, JavaBeans
Activation Framework (JAF), Java API for XML Parsing
(JAXP)
IIOP: Internet Inter-ORB Protocol
47
The Solution: J2EE Application Model
• J2EE application model partitions the work
needed to implement a multi-tier service into two
parts
– the business and presentation logic (implemented by the
application developer)
– the standard system services provided by the J2EE
platform.
• The developer can rely on the platform to provide
the solutions for the hard systems level problems
of developing a middle-tier service.
48
J2EE Application Model
Source: Sun Microsystems, Inc., http://java.sun.com/j2ee/overview2.html
49
Benefits of J2EE Application Model
• The J2EE application model provides the
benefits of Write Once, Run Anywhere™
portability and scalability for multi-tier
applications.
• This standard model minimizes the cost of
developer training while providing the
enterprise with a broad choice of J2EE
servers and development tools.
50
J2EE Platform Roles
•
•
•
•
•
•
J2EE Product Provider
Application Component Provider
Application Assembler
Deployer
System Administrator
Tool Provider
51
The Connector Architecture
• Integration of J2EE servers with Enterprise
Information Systems (EIS)
• EIS vendor-provided resource adaptors
• Resource adaptor-permitting application
servers
52
J2EE Connector
• J2EE Connector
– The J2EE Connector architecture defines a standard
architecture for connecting the J2EE platform to
heterogeneous EISs. Examples of EISs include ERP,
mainframe transaction processing, database systems,
and legacy applications not written in the Java
programming language. By defining a a set of scalable,
secure, and transactional mechanisms, the J2EE
Connector architecture enables the integration of EISs
with application servers and enterprise applications.
53
System Level Pluggability
Source: Sun Microsystems, Inc., J2EE Connector Architecture Specification
54
Connector Architecture Overview
Source: Sun Microsystems, Inc., J2EE Connector Architecture Specification
55
Connector Architecture Overview (cont.)
56
Source: Sun Microsystems, Inc., J2EE Connector Architecture Specification
Connector Architecture in B2B Scenario
Source: Sun Microsystems, Inc., J2EE Connector Architecture Specification
57
Client View of an Enterprise Bean
• Home Interface: methods for creating,
removing, and finding bean instances
• Remote Interface: methods callable by the
client
• Object Identity
• Metadata Interface: mainly for dynamic
invocation
• Handle
58
Client View of Session Beans
Source: Sun Microsystems, Inc., Enterprise JavaBeans 2.0
59
Accessing Enterprise Beans from Servlets/JavaServer Pages
Source: Sun Microsystems, Inc., J2EE Specification, v1.3
60
J2EE Deployment
61
Source: Sun Microsystems, Inc., J2EE Specification, v1.3
J2EE Application Life Cycle
Source: Sun Microsystems, Inc., J2EE Connector Architecture Specification
62
Overview of Enterprise Applications Integration (EAI)
Source: P.J. Perrone and V.S.R.R. Chaganti, Building Java Enterprise Systems with J2EE
63
Overview of Enterprise Applications Integration (EAI)
Source: P.J. Perrone and V.S.R.R. Chaganti, Building Java Enterprise Systems with J2EE
64
EAI with XML
Source: P.J. Perrone and V.S.R.R. Chaganti, Building Java Enterprise Systems with J2EE
65
Enterprise Beans of the Example Design
Source: Sun Microsystems, Inc., The J2EE Tutorial
66
J2EE Platform Technologies 1/3
• Servlets and JSP
– Java technology servlets and JavaServer Pages are server components that
run in a web server that supports dynamic HTML generation and session
management for browser clients.
• EJB
– Enterprise JavaBeans is a server component model that provides
protability across application servers and implements automatic services
on behalf of the application components.
• JTA
– Java Transaction API provides a transaction demarcation API.
• JTS
– Java transaction Service defines a distributed transaction management
service based on the CORBA Object Transaction Service.
67
J2EE Platform Technologies 2/3
• JNDI
– Java Naming and Directory Interface provides access to naming and
directory services, such as DNS, LDAP, NDS, and CORBA Naming.
• RMI-IIOP
– Remote Method Invocation(RMI) creates remote interfaces for Java-toJava communication. This extension uses the CORBA standard IIOP
communication protocol.
• Java IDL
– Java Interface Definition Language creates remote interfaces to support
java-to-CORBA communications.
68
J2EE Platform Technologies 3/3
• JDBC
– JDBC database access API provides uniform access to relational databases.
• JMS
– Java Messaging Service supports asynchronous communication using
either a reliable queuing or publish/subscribe model.
• JavaMail
– JavaMail provides a protocol-independent framework to build mail and
messaging applications.
• JAF
– JavaBeans Activation Framework provides standard services to determine
the type of an arbitrary piece of data and activate an appropriate
JavaBeans component to manipulate the data.
69
History of J2EE Technologies
• Distributed Objects
– CORBA, DCOM, etc.
– Three-tier scenario: presentation, business logic, and
backend databases
• Hard to “get right” without the proper infrastructure
• Server-Side Components
– Focuses on encapsulating “business rules” into objects
in the middle tier
• Component Transaction Monitors
– Descendant of CORBA’s Object Request Broker
• provides discovery, persistence, event notification, transactions,
etc. for three-tier or n-tier applications
70
J2EE Platform Services
• Naming Services
– Provide application clients, EJB and Web components with access to a
JNDI naming environment.
• Deployment Services
– Allow components and applications to be customized at the time they are
packaged and deployed.
• Transaction Services
– Devide an application into a series of indivisible or atomic units of work.
• Security Services
– Designed to ensure that resources are accessed only by users authorized to
use them.
72
J2EE Platform Benefits
•
•
•
•
•
Simplified architecture and development
Scalability to meet demand variations
Integration with existing information systems
Choices of servers, tools, components
Flexible security model
• The J2EE reduces the cost and complexity of developing
these multi-tier services, resulting in services that can be
rapidly deployed and easily enhanced as the enterprise
responds to competitive pressures.
73
J2EE Platform
• The J2EE platform is the standard environment for running J2EE
applications. The J2EE platform is composed of the following
elements:
– J2EE deployment specification - a standard that defines a
common way of packaging applications for deployment on any
J2EE compatible platform.
– Java technology standards for the J2EE platform - a set of
standards that all J2EE platform products must support (JMS ,
JNDI etc)
– IETF standards for the J2EE platform - a set of standards
defined by the Internet Engineering Task Force that all J2EE
platform products must support.(eg XML, HTTP, HTML)
– CORBA standards for the J2EE platform - a set of CORBA
standards upon which the J2EE platform bases its middle-tier
interoperability.
74
J2EE Application Assembly
• A J2EE application is packaged into one or more
standard units for deployment to any J2EE platformcompliant system.
• Each unit contains a functional component or
components (enterprise bean, JSP page, servlet, applet,
etc.), a standard deployment descriptor that describes
its content, and the J2EE declarations which have
been specified by the application developer and
assembler.
• Once deployed, theses components can then be run.
75
J2EE Reference Implementation
• Its primary role is as an operational definition of
the J2EE platform.
• Most importantly, it is used as the standard
platform for running the J2EE Compatibility Test
Suite.
• A secondary role for the reference implementation
is as a freely available platform for popularizing
Java 2 platform, Enterprise Edition.
76
J2EE Reference Implementation
• Latest version available for download
– JavaTM 2 SDK, Enterprise Edition
Version 1.3
– Downloadable at
http://java.sun.com/j2ee/
• NOTE :
– This version will require Java 2 SDK, Standard Edition
(J2SE) Version 1.3.1 or higher.
77
Application Servers
• Consists of
– EJB server
– Web server (HTTP)
– Secured web server (HTTPS) …
• J2EE Compliance Test
– Brings vendor neutrality to your applications
– Consists of more than 5000 tests
– Currently 9 application servers have been certified
• BEA WebLogic (BEA)
• iPlanet (Sun + Netscape)
• Websphere (IBM)
• (check out www.javasoft.com/j2ee for latest update)
78
The BEA WebLogic Server
• All Java, clean-room implementation of the J2EE
• Shipping basic APIs since 1997
• One of the most widely-used Application Servers
on the market
– Over 12,000 customers
• Associated BEA product: TUXEDO
– Distributed TP Monitor
– Originally developed at Bell Labs in 1984
– Influenced the design of WebLogic
79
Sun ONE Application Server 7
• Provides a comprehensive overview of the Sun ONE
Application Server.
Please note - the tour may take up to 1 minute to
complete testing your system before starting to load.
• Sun is the first software vendor to deliver a fully J2EE[tm]
platform-certified, commercial application server, free of
charge, on all leading OS platforms.
• The new Sun ONE Application Server 7 includes the
world's fastest, secure http server, and new "Always On"
technology.
Sun ONE Application Server 7
80
J2SE Component Links
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
Assistive Technologies
Drag and Drop
Java Access Bridge
JavaBeansTM Technology
Javadoc Tool
Java Foundation Classes (JFC)/Swing
Java HotSpotTM Virtual Machine
Java Platform Debugger Architecture (JPDA)
Java Plug-in for Windows XP
Java 2DTM API product page
Java Web Start
JDBCTM Technology
Pluggable Look and Feel
Remote Method Invocation (RMI)
Security
81
List of J2ME Technologies
–
–
–
–
–
–
–
–
–
–
–
–
–
–
Personal Profile
Personal Basis Profile
Java CardTM Technology
Java Embedded ServerTM Technology
JavaPhoneTM API
Java Telematics Technology (JTT)
Java TVTM API
J2ME Wireless Toolkit
PersonalJavaTM Technology
Wireless Developer web site
Connected Limited Device Configuration (CLDC)
Mobile Information Device Profile (MIDP)
Connected Device Configuration (CDC)
Foundation Profile
82
JBoss Application Server
• JBoss is a simply powerful J2EE application server.
– JBoss Application Server is the #1 most widely used Java application
server on the market. A J2EE certified platform for developing and
deploying enterprise Java applications, Web applications, and Portals,
JBoss Application Server provides the full range of J2EE 1.4 features as
well as extended enterprise services including clustering, caching, and
persistence.
• EJB3.0
– JBoss Application Server includes support for Enterprise Java Beans (EJB)
3.0 which is designed to dramatically simplify the enterprise Java
programming model.
• Service Oriented Architecture
– JBoss AS is founded on a service oriented microkernel architecture with
an extremely small in footprint that ensures all services are accessed,
managed, and integrated in a unified and consistent manner.
83
Introduction to Apache Ant
• What is Ant?
– Java-based build tool
• Why use Ant?
–
–
–
–
Cross-platform
Java domain smart
Fast, extensible, integrated
Alternatives?
• Analogy
– Factory automation
84
Typical Things to Build
85
Designing a Build
• What are you building?
• What does it take to build it?
• How are the steps related?
86
High-level Model
Source Code
HTML /
Text
files
Index
Application
(EAR)
87
Examples of Commercially Used AOP Tools
• AspectWerkz
– Supported by BEA
• Spring AOP framework
• JBoss AOP
• CME (Concern Manipulation
Environment)
– Supported by IBM
88
Technical Architecture
Web Tier
View - JSP
Struts - SearchForm
Commons Validator
Struts - SearchAction
SearchSessionBean
EJB Container
content
Ant build
<index>
task
SearchUtil API
Lucene API
index
89
AOP – Aspect Oriented Programming
• Which tools are suitable for commercial dev?
– Over a dozen tools are listed on aosd.net
– Early adopters harden new technologies
– How active are the user communities of each?
project
posts
AspectJ
list (november’04 posts)
url
aspectj-users at eclipse.org
eclipse.org/aspectj
user at aspectwerkz.codehaus.org
aspectwerkz.codehaus.org
aspects/jboss forum
jboss.org/products/aop
Spring AOP
springframework-user
www.springframework.org
abc
abc-users at comlab.ox.ac.uk
abc.comlab.ox.ac.uk
aspectsharp-users
aspectsharp.sourceforge.net
aspectc-user at aspect.org
aspectc.org
jac-users at objectweb.org
jac.objectweb.org
AspectWerkz
JBoss AOP
aspect#
AspectC++
JAC
150..210
each
1..30
90
IDE support, libs, and docs
AspectJ
ide
editor
eclipse,
jdeveloper,
jbuilder,
netbeans
highlighting,
content
assist,
advice links
Aspect
Werkz
advice links
JBoss
AOP
advice links,
UI for
pointcut
creation
Spring
AOP
eclipse
views
debugger
outline,
visualizer,
cross
references
ajdoc,
ajbrowser
aspect
manager,
advised
members
-
other
plain
Java
dynamic
deployment
UI, jboss
framework
integration
spring
framework
integration
libs
docs
-
++++
-
++
++++
++
+++
+
91
Building AOP programs
• What’s it like to adopt AOP on an existing
project?
source
AspectJ
extended
.java,
or .aj
Aspect
Werkz
JBoss
AOP
Spring
AOP
compiler
checking
incremental
aspectj
compile
full static
checking
java compile,
post
processing
minor static
checking,
none of
pointcuts
plain .java
, .xml
java compile
-
weaving
compile and
load-time,
produce
bytecode
runtime
interception
and proxies
deployment
static
deployment
hot
deployable
run
plain Java
program
framework
invoked &
managed
92
AOP features
• AspectJ and AspectWerkz
– AspectJ 5 will feature support for generics in pointcuts. The
@AspectJ syntax will support the AspectWerkz annotation
style
• JBoss AOP
– Static typing for parameters, performance improvements,
libraries, and more IDE support features
• Spring AOP
– Performance improvements, interoperability with AspectJ's
pointcuts, and packaging of some Spring AOP services as
AspectJ aspects
93
JBoss AOP (1/2)
- Lack of static checking for pointcuts
- Advanced IDE features not yet supported
+ Rich set of enterprise aspects libraries are
available and integrated with JBoss and JEMS
+ IDE support lowers adoption and reduces need to
hand-code XML
+ Support for dynamic deployment of aspects
http://jboss.org/products/aop
94
JBoss AOP (2/2)
95
Web services in JBoss Overview: JBoss.net
• Specifies how JBoss server components are exposed as Web
service
– Stateless Session Beans
– Web components
– POJO as servlet
96
JBoss Hibernate
Hibernate IS EJB 3.0 CMP
CMP is an API and XML mappings
Hibernate is the actual persistence engine
Hibernate caches are being integrated with
JBossCache
Full distributed data with OR backend on one node
97
Hibernate
Part of JBoss full-time
Gavin King and Christian Bauer on board
Persistence for POJOs (JavaBeans)
• Flexible and intuitive mapping
• Support for fine-grained object models
• Powerful, high performance queries
• Dual-Layer Caching Architecture (HDLCA)
• Support for detached objects (no DTOs)
• Transparent Persistence
• Automatic dirty checking
• Transitive Persistence
• Smart fetching and caching
• Smooth migration to EJB3.0
• Consulting and support available as part of JBoss inc
98
Tomcat 5.0.x improvements
• Tomcat’s Remy Maucherat is on JBoss inc staff
• Performance optimizations and reduced garbage collection
• Optional standalone deployer (validation and precompilation of
webapps)
• Scalability and reliability enhancements
• Complete server monitoring using JMX
• Improved Taglibs handling, including advanced pooling and tag plugins
• Embedding of Tomcat using JMX
• Enhanced Security Manager support (now allows very restrictive
policies)
• Expanded documentation
• Consulting and support available as part of JBoss inc
99
Tomcat standalone or Tomcat inside JBoss ?
• Better JBoss deployer
–
–
–
–
Hot deployment
Deployment of nested archives (EARs, SARs)
Redeployment
Automatic undeployment
• Advanced clustering
• Integrated J2EE stack within one VM
– Deployment descriptor
– Optimized local calls
– Integrated security
• AOP in JBoss 4.0 available in Tomcat components and
webapps
• Easy to use classloader
• Nukes
100
JBoss IDE
• JBoss IDE is based on Eclipse.
– Series of plugins for Eclipse
• The debugging and monitoring of JBoss servers and the control of
their life cycle (start/stop).
• A very comfortable and sophisticated support for XDoclet
– Support completion and generation
– Support for AOP (completion and generation).
• An easy way to configure and deploy the packaging layout of archives
(packed or exploded)
101
What Is JBossCache?
• What is JBossCache?
– A transactional replicated cache for JBoss with and without AOP
(aspect-oriented programming)
• A cache for frequently accessed elements
– Stateful Session Beans, HTTPSession
– Caches are used in a number of places in JBoss
• This one provides a central cache service (MBean interface)
• All access goes through the cache
–
–
–
–
Write-through (lazy or eager)
Reads only access the cache (very fast on cache hits)
Items not in the cache are loaded (e.g. from database)
Bounded size; old items are removed by eviction policy
• Local (=non-replicated) and replicated caches
– Replicated caches are the interesting part
102
Feature
• Transactions
– All modifications done within TX, replication at TX commit. No
replication on rollback
• Locking
– Access to nodes serialized by locks
– Lock acquisition timeouts used for deadlock prevention
• Replication
– local: in-VM, no replication
– repl-async: replication done on separate thread
– repl-sync: replication done on user's thread, wait for all acks
• All combinations supported
– From local/no-tx/no-locking to repl/tx/locking
– Ex: repl-async/no-locking/TX
103
Nukes on JBoss ™
• Nukes on JBoss is a port of PHP postnukes
– Scalability problems with Zend engine
– Full port to EJB/J2EE.
– Leverage the vast library of nukes modules
• Most of PN modules are ported
• Core : offers the core functionalities to other modules
– Security, lifecycle management, parameterization
• User : enables user management
• Html : stores files, filesystem is abstracted, stored in DB
• Sections : edit/publish articles
• FORUMS!!!!
104
CMS: ease of update for
non-techies
105
Nukes components
106
How to Deploy on JBoss (1/3)
1. Write your beans and package them in an ejb-jar
file.
2. Write your servlets/JSPs and package them in a
war file.
3. Add a Class-Path attribute to your war files
MANIFEST.MF file to reference your beans
package. for detailed information on that see
J2EE Deployment specification.
http://www.jboss.org
http://www.jboss.com
107
How to Deploy in JBoss (2/3)
4. Package your application in an ear file.
An ear file is a jar archive which contains:
• Your jar files
• Your war files
• A deployment descriptor for your
application.
This file must be named "application.xml", and must be
located in the META-INF directory in the ear archive. This
file tells JBoss which modules are EJBs, which ones are
web modules, and the context paths for the web-modules.
108
Sample Application.xml file
<?xml version="1.0" encoding="ISO-8859-1"?>
<application> <display-name>My application</display-name>
<module>
<web>
<web-uri>webmodule.war</web-uri> <context
root>/servlets</context-root>
</web>
</module>
<module>
<ejb>beans.jar</ejb>
</module>
</application>
109
How to Deploy in JBoss (3/3)
5. Deploy your ear file.
Option 1: Copy your ear file to
JBOSS_HOME/deploy (wow!)
Write once Deploy AnyWhere!!
110
Thank you!
謝謝捧場
http://www.csie.nctu.edu.tw/~tsaiwn/java/
蔡文能
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