Tuesday, 1 January 2013

web architecture ???

what ?

  • approach of the design and planning the web sites which involves technical, aesthetic, and functional criteria
web pages ?
  • document or information resources that is suitable for the WWW and can be accessed through a web browser and can be displayed by  monitor or mobile
  • types :
    • static
      • does not change content or layout with every request to the web server
      • change when web author manually updates them with text editor or web editing tools
      • simple, secure, less prone to the technology errors and data breakdown, and easily visibe by search engines
    • dynamic
      • can adapt their content or appearence depending on user's interaction, changes in data supplies by and application, or as an evolution over timeason new web sites.
      • using client-side scripting techniques (content can be changes quickly on the user's computer without new web request to the web server.
      • client-server interaction
      • offers flexibility
    • active
  • when stored in common directory of a web server, they become websites
  • contain a group of web pages that linked together or have some coherent method or navigation

web essential !

lets learn about web essential !

the Internet

  • global system of interconnected network that use Internet Protocol Suite (TCP/IP) to serve billions of user worldwide
  • short form of internetwork, (interconnecting network with special gateways or routers)
  • operates without central governing body
  • networks of networks
  • linked by the broad array of electronic , wireless and optical networking technologies
  • carries a vast range of information resources and services
basic internet protocols
  • the IP is the principal communications protocols used for relaying datagram across the internetwork using the TCP/IP
  • responsible for routing packets across network boundaries has the task of delivering datagram from source host to destination host based on their address
  • the Internet defines addressing system that has two function ( addresses identify host and provide logical location service)
  • each packet is tagged with the header that contains meta-data for the purpose of delivery
  • addressing refer how end hosts become assigned IP address and how subnetworks of IP host address are divided and group together
  • routing performed by all host but most importantly by internetwork routers, IGPs and EGPs to help make IP datagram forwarding decisions across IP connected network
  • IP takes care of address and make sure routing know what to do with your data when arrives
  • data is transmit in small chunk (packets, approximately 1200 characters length)
  • IP address consistof four fields number which each of them less than 256
the WWW
  • global set of documents, images and other resources, logically interrelated by hyperlinks and referenced by URIs
  • www is a system of interlinked hypertext document access via the Internet
  • global information medium which users can write and read via compuers connected to the Internet
uniform resources identifiers
  • allow providers to identify services and clients to locate address web servers, file server and other database that store document and provide resources and access them using the HTTP
hypertext transfer protocol (HTTP)
  • networking protocol for distributive, collaborative and hypermedia information systems
  • foundation of data communication for the www
  • primary protocol of the web
  • web services may used HTTP to allow software system to communicate in order to share and exchanges data and business logic
  • functions as response-request in client-server computing model
web clients and servers
  • client-servers describes the realationships of cooperating system running in the application
  • primary function of web servers is to deliver web pages on the request to the client
  • a client initiates the communication by making request for a specific resources using HTTP and server responds with the content of the resources or error messages if unable to do so

web browser ?

nowadays, so many web broser we can use for browsing the internet such as Google Chrome, Mozzila Firefox, Opera, Safari, Internet Explorer, and many more.

however the one i enjoy using for browsing is GOOGLE CHROME! i think it is because google chrome is much more faster than the other.  but well, i don't really know using other browser aside from Mozzilla Firefox and Internet Explorer. heehe. about Mozzilla Firefox, i do using it sometimes and for Internet Explorer, i just using it when it is needed..hehe..

so everyone, what is your preferences for web browser ? care to tell me? ;)

java web technologies...

communication of java EE :

  1. web tier 
    • better support for web service
    • modern way for developing dynamic web pages
  2. business tier
    • easier way to writing Enterprise Java Bean
    • more to declaration than code-oriented
  3. servlet
    • server-side programming written in java
    • runs inside servlet container
    • advantages
      • multithreaded
      • stable environment and easy to deploy
      • inherits all good features of java programming language
    • lifecycle
      • 3 phases :
        • initialization
        • service client request
        • destruction
  4. java server pages (JSP)
    • offer layer of abstraction on top of the server
    • easier to code than servlet but less control
    • just like high programming language and machine language
    • element :
      • directives - instruction to JSP container
        • 3 main destructives : page, include and taglib
      • comments 
        • HTML comment - content visible to end user in the web browser
        • JSP comment - not visible to end user
      • scripting element - the area where the main java code reside
        • 3 categories
          • expression - accessing the value of java variables
          • scriptlet - one or more java statement in a JSP page
          • declaration 
      • action
      • templates
    • java bean
      • self-contained java class
      • provide set and get methods for accessing and updating its attributes from other classes
    • jsp implicit object
      • request
        • read the values of the HTML form in JSP, received as part of HTTP request sent by the client to the server
      • response
        • sent necessary information from the server to the client
      • pageContext
        • to get any attributes from any scopes
      • session
      • application 
        • put load on JSP container
      • out
        • send HTML content to web browser
  5. session
    • small and temporarily unique connection between server and a user enabling it to identify that user across multiple pages request or visit that site
    • session management
      • what ?
        • to use API provided by application server to identify the user across multiple page request
      • why ?
        • hundreds and thousand simultaneous user can be visiting your site and if you can identify each of them separately then it can provides tremendous benefits
        • uses
          • customization
            • to show different view of your websites
            • to show differnt content depending on user preferences
          • security
            • allow membership based access to the site
            • after log in, you can identify member from non-member by setting an attributes on the user session to some value
          • user behaviour
            • log user view like how many ad views have been show to user
            • no response shown in the lot, then its time to change the ad
        • techniques
          • url rewriting
            • another way of to support anonymous session tracking
          • cookies
    • JSP and JDBC
      • built in support for databases processing
      • provides set of clasess and interfaces that allow java application to work with RDBMS
  6. MVC
    • model - manages the behavior and data of the application domain, responses to request for information about its state ( from view ), and response to instruction to change state ( from controller )
    • view - renders the model into a form suitable for interaction
    • controller - receives user input and initiates a response by making calls on model objects
    • MVC Architecture 
      • dividing application component into three different categories : Model , View , Controller
      • its component has unique responsibility and each of them independent to other component
      • changes in one component has no or less impact on other component
    • Model
      • responsible for providing the data from the database and saving the data into the data store
      • all business logic are implement in the Model
      • sata access, data validating and data saving logic are part of the model
    • View 
      • represent user view of the application
    • Controller
      • intermediary between model and view
      • responsible receiving request from client
      • one request is received from client executes appropriate business logic from the model and produces output to the user using view component
  7. apache struts
    • struts frame work is the implementing MVC design pattern for the JSP
    • provide three key component :
      • request - provide by the application developer that is use to mapped to a particular URI 
      • response - used to transfer control to other resource which will be responsible for completing the response
      • tag library - helps the developer to creates interactive form based applications with server pages
    • struts workflow

  8. JSF
    • easy to build user interfaces for java web application by assembling reusable component in a page
    • is a vent driven
    • based on MVC design pattern
    • benefits :
      • provides many tag library for accessing and manipulating the components
      • automatically saves the form data and repopulates the form when it is display at client side
      • is a specification and vendors can develop the implementation for JSF
      • encapsulate the event handling and component rendering logic from programmer

semantic web?

what ?
  • to add meaning to the data
component ?
  • XML (eXtensible Markup Language)
    • to decribes the data and to focus what the data is
  • RDF ( Resource Description Framework )
    • framework for describing resource on the web
    • describes resources with properties and properties values which forms the Statement ( subject, predicate and object )
      • Statement : "The author of http://www.w3schools.com/RDF is Jan Egil Refsnes". 
      • resources ( subject ) : http://www.w3schools.com/RDF
      • properties ( predicate ) : author
      • properties value (object) : Jan Egil Refsnes
  • OWL (Web Ontology Language
    • represent the meaning of terms in vocabularies and the relationships between those terms
    • has three sublanguages :
      • OWL Lite
        • supports users primarily needing a classification hierachy and simple constraints
      • OWL DL
        • supports user who wants the maximum expressiveness while retainning computational completeness
      • OWL Full
        • supports user who want the maximum expressiveness and the syntactic freedom of RDF with no computational guarantees