ADVANCED POGRAMMING (JAVA) COURSE

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ADVANCED POGRAMMING (JAVA) COURSE

• Topics
• Java Database Connectivity (JDBC)
• Graphics Programming with Java 2D and Java 3D
• Security
• Servlets
• Java Server Pages
• Java-Based Wireless Applications

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Part I

• Java Database Connectivity
• (JDBC)

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Java Database Connectivity (JDBC)

• A common programming interface writing programs
• that access information stored in
• databases,
• spreadsheets, and
• other data sources
• either directly or
  through
• middleware

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JDBC contd

• By using the JDBC interface,
• Java programmers can request a connection with a
  database,
• Send query statements using SQL
• Receive the results for processing.
• Java runs on many different hardware platforms
  and operating systems,
• Developers can use JDBC to write applications
• access data across incompatible database
  management systems running on varied platforms.

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Internet Resources for JDBC

• http//java.sun.com/docs/books/tutorial/jdbc/index
  .html
• www.sql.org
• industry.java.sun.com/products/jdbc/drivers
• http//servlet.java.sun.com/products/jdbc/drivers
• java.sun.com/products/jdbc/faq.html
• http//java.sun.com/products/jdbc/articles/package
  2.html
• http//java.sun.com/developer/Books/JDBCTutorial/c
  hapter5.html
• www.jguru.com/jguru/faq/faqpage.jsp?nameJDBC

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What is the JDBC API?

• A set of classes and interfaces written in the
  Java
• a standard API for tool/database developers
• makes possible to write database applications
  using an Java API.
• Obtaining a variety of different data sources is
  possible for Java applications
• Makes possible to publish a web page containing
  an applet that uses information obtained from a
  remote data source. For example
• To connect all employees (even if they are using
  Windows, Macintosh, and UNIX machines) is
  possible as one or more internal databases via an
  intranet

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The JDBC 3.0 API

• Includes two packages
• java.sql package
• javax.sql package (adds server-side
  capabilities)
• While downloading the Java 2 Platform
• Standard Edition, Version 1.4 (J2SE), we can
• automatically get both packages
• The JDBC-ODBC Bridge provides a limited subset of
  the JDBC 3.0 API.
• Summary of new features has to be read at
• http//www-106.ibm.com/developerworks/java/library
  /j-jdbcnew/
• .

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The java.sql Package
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The java.sql Package

• Contains the entire JDBC API that sends SQL
  statements to relational databases and retrieves
  the results of executing those SQL statements.
• The Driver interface represents a specific JDBC
  implementation for a particular database system.
• Connection represents a connection to a database.
  
• The Statement, PreparedStatement, and
  CallableStatement interfaces support the
  execution of various kinds of SQL statements.
• ResultSet is a set of results returned by the
  database in response to a SQL query.
• The ResultSetMetaData interface provides metadata
  about a result set
• DatabaseMetaData provides metadata about the
  database as a whole.

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Array

• Provides an interface to SQL ARRAY objects.
• getArray() method returns a standard Java array
  of objects of the type returned by getBaseType().
  
• The contents of the array can also be returned as
  a ResultSet using the various getResultSet()
  methods.
• public abstract interface Array
• // Public Instance Methods
• public abstract Object getArray () throws
  SQLException
• public abstract int getBaseType () throws
  SQLException
• public abstract String getBaseTypeName () throws
  
• 
  SQLException
• public abstract ResultSet getResultSet () throws
  
• 
  SQLException

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• import java.sql. Connection
• import java.sql. DriverManager
• import java.sql. SQLException
• public class JdbcExam
• public static void main (String args)
• Connection con null
• try
• Class.forName ("com.mysql.jdbc.Driver").
  newInstance()
• con DriverManager. getConnection
  ("jdbcmysql///test", "root",
• 
  
  "secret")
• if (!con.isClosed())
• System.out.println ("Successfully
  connected to MySQL server
• 
  
  using TCP/IP...")
• catch(Exception e)
• System.err.println ("Exception "
  e.getMessage())
• finally
• try
• if(con ! null)
• con.close()

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• import java.sql. Connection
• import java.sql. DriverManager
• import java.sql. SQLException
• we imported 3 classes from java.sql package.
• Connection represents a connection to a database
  
• DriverManager manages JDBC drivers
• used to create connections to databases
• SQLException is an exception class
• which gets thrown in case any error occurs in the
  program

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• We declare a local variable to hold our
• java.sql. Connection object that we'll retrieve
• from java.sql. DriverManager later on.
• Connection con null
• We encapsulate our JDBC code in a
• try/catch/finally block.
• This is to ensure that if any runtime error gets
• thrown we catch it and display it to the user.
• try ...
• catch(Exception e)
• System.err.println("Exception "
  e.getMessage())
• finally ... .

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• We take the first step in establishing a
  connection to our MySQL database by loading the
  driver explicitly using Class.forName() method
• Class.forName("com.mysql.jdbc.Driver").newInstance
  ()
• Once the JDBC driver has been loaded in the JVM,
  we retrieve a connection to our MySQL database
  running on the local system using
  DriverManager.getConnection() method
• .The first argument to this method is complete
  database URL, next parameter is the user name and
  last parameter is the password.
• conDriverManager.getConnection("jdbcmysql///
• 
  test", "root", "secret")

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• After these steps are completed, it is required
  to obtain a connection to the MySQL database.
• We check to make sure we are properly connected
  and display a success message if we are.
• if(!con.isClosed())
• System.out.println("Successfully connected to "
  
• "MySQL server using
  TCP/IP...")
• To close the connection, we execute the
• Connection.close() method in the finally block of
  our
• try/catch/finally statement.
• try
• if(con ! null)
• con.close()
• catch (SQLException e)
• The Connection.close() method can also throw
  SQLException
• so that is why we encapsulate this close() method
  in a separate try/catch block.

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• http//www.mysql.com/get/Downloads/MySQL-4.0/mysql
  -4.0.18-win.zip/from/pickmirrors
• is the website which you can download the mysql
• http//www.mysql.com/doc/en/Windows_installation.h
  tml
• is the website which you can install the mysql

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• javax.sql package

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The javax.sql package

• Contains the JDBC 2.0 Standard Extension API.
• The classes and interfaces in this package
  provide new functionality,
• connection pooling, that do not fall under the
  scope of the original JDBC API and can therefore
  be safely packaged separately.
• The DataSource interface serves as a factory for
  Connection objects
• DataSource objects can be registered with a JNDI
  ( Java Naming and Directory Interface )server,
  making it possible to get the name of a database
  from a name service.
• PooledConnection supports connection pooling,
  which allows an application to handle multiple
  database connections in a fairly transparent
  manner.
• RowSet extends the ResultSet interface to a
  JavaBeans component that can be manipulated at
  design time and used with non-SQL data sources

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What Is the JDBC-ODBC Bridge?

• A JDBC driver
• implements JDBC operations which translate them
  into ODBC operations.
• ODBC acts as a normal application program.
• The bridge implements JDBC for any database for
  which an ODBC driver is available.
• contains a native library used to access ODBC.
• The Bridge is installed automatically with the
  Java 2 SDK, Standard Edition, as package
  sun.jdbc.odbc
• .

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A Base for Other APIs

• Java APIs are implemented as Java classes.
• The following are just a few of the available
  APIs except JDBC
• Java Real Time
• Java Foundation Classes (JFC)
• Swinguser interface
• Remote Method Invocation (RMI)
• Java for XML (JAXP)
• Java for XML Messaging (JAXM)
• Java Sound
• Java Media Framework
• Java 2D and 3D graphics
• Java Naming and Directory Interface (JNDI)
• http//www.alumni.caltech.edu/croft/research/java
  /snapshot/

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What Does the JDBC API Do?

• Establish a connection with a data source
• Send queries and update statements to the data
  source
• Process the results
• Connection con DriverManager.getConnection(
  
• "jdbcmyDriverwombat",
  "myLogin", "myPassword")
• Statement stmt con.createStatement()
• ResultSet rs stmt.executeQuery ("SELECT a, b, c
  FROM
• 
  Table1")
• while (rs. next())
• int x rs.getInt ("a")
• String s rs.getString ("b")
• float f rs.getFloat ("c")

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Why not Use ODBC from Java?

• Before the development of the JDBC API
• The most widely used programming interface
  Microsoft's ODBC (Open DataBase Connectivity) API
  
• To access relational databases
• ODBC can be used with Java, but
• The best application is JDBC API
• Applied as the form of the JDBC-ODBC Bridge
• ODBC is not appropriate for direct use from the
  Java programming language
• Uses C interface.
• Occurs a number of drawbacks in the security,
  implementation, robustness, automatic
  portability
• during the calls from Java to native C code
• QUESTION
• What are other important differences between
  JDBC API and ODBC API?
• Once ODBC (as native code) is called, Java
  programming language can't guarantee that a
  security violation won't occur (untrusted).

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The Bridges usage

• A JDBC connection is opened
• using a URL with the odbc subprotocol.
• Loading is done as follows
• Class.forName ("sun.jdbc.odbc.JdbcOdbcDriver"
  )
• Before any connection, the bridge driver class,
  sun.jdbc.odbc.JdbcOdbcDriver
• added to the java.lang.System property named
  jdbc.drivers OR
• explicitly loaded using the Java class loader.
• After loaded, the ODBC driver creates an instance
  of itself and registers this with the JDBC driver
  manager.

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What Is the JDBC URL Supported by the Bridge?

• uses the odbc subprotocol
• jdbcodbcltdata-source-namegtltattribute-namegtltat
  tribute-valuegt
• jdbcodbcsybase
• jdbcodbcmydbUIDme PWDsecret
• jdbcodbcora123 Cachesize 300

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JDBC Drivers

• Provides JDBC access via one or more Open
  Database Connectivity (ODBC) drivers.
• ODBC, which predates JDBC, is widely used by
  developers to connect to databases in a non-Java
  environment.
• JDBC supports four categories of drivers
• JDBC- to ODBC driver (Type 1)
• Native-API, partly driver (Type 2)
• JDBC- Net pure driver (Part 3)
• Native-Protocol pure Java driver (Type 4)

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JDBC- to ODBC driver (Type 1)

• A good approach for learning JDBC. May be useful
  for companies that already have ODBC drivers
  installed on each client machine
• The case for Windows-based machines running
  productivity applications.
• May be the only way to gain access to some
  low-end desktop databases.
• Not for large-scale applications. Performance
  suffers because there's some overhead associated
  with the translation work to go from JDBC to
  ODBC. Doesn't support all the features of Java.
  User is limited by the functionality of the
  underlying ODBC driver

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Native-API, partly driver (Type 2)

• Converts the calls that a developer writes to the
  JDBC application programming interface into calls
  that connect to the client machine's application
  programming interface for a specific database,
  such as IBM, Informix, Oracle or Sybase.
• Performance is better than that of Type 1, in
  part because the Type 2 driver contains compiled
  code that's optimized for the back-end database
  server's operating system.
• User needs to make sure the JDBC driver of the
  database vendor is loaded onto each client
  machine. Must have compiled code for every
  operating system that the application will run
  on. Best use is for controlled environments, such
  as an intranet.

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JDBC- Net pure driver (Type 3)

• Pure Java driver for database middleware, which
  provides connectivity to many different
  databases.
• Translates JDBC calls into the middleware
  vendor's protocol, which is then converted to a
  database-specific protocol by the middleware
  server software.
• Better performance than Types 1 and 2. Can be
  used when a company has multiple databases and
  wants to use a single JDBC driver to connect to
  all of them.
• Server-based, so no need for JDBC driver code on
  client machine.
• For performance reasons, the back-end server
  component is optimized for the operating system
  that the database is running on.
• Needs some database-specific code on the
  middleware server. If the middleware must run on
  different platforms, a Type 4 driver might be
  more effective.

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Native-Protocol pure (all) Java driver (Type 4)

• Written entirely in Java
• Converts JDBC calls into packets
• that are sent over the network in the proprietary
  format
• used by the specific database.
• Allows a direct call from the client machine to
  the database.
• Better performance than Types 1 and 2.
• No need to install special software on client or
  server. Can be downloaded dynamically.
• .

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Type 4 Java Driver contd

• Not optimized for server operating system, so the
  driver can't take advantage of operating system
  features.
• The driver is optimized for the database and can
  take advantage of the database vendor's
  functionality.
• User needs a different driver for each different
  database
• These drivers are also well suited for applet
  programming, provided that the Java security
  manager allows TCP/IP connections to the database
  server.

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Driver Types Results

• Type 1 and Type 2 drivers were provided
  primarily to allow Java programmers to create
  data-driven solutions before database vendors
  created pure java drivers
• Type 3 and Type 4 drivers are preferred, because
  they are pure Java solutions
• The cloudscape driver
• COM.cloudscape.core. RMiJdbcDriver
• is a Type 4 driver

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New APIs from Microsoft

• OLE (Object Linking and Embedding) DB
• ADO (ActiveX Data Objects)
• RDS (Remote Data Service)
• UDA (Universal Data Access)
• an umbrella term that covers OLE DB, ADO, RDS,
  and ODBC
• The JDBC 2.0 API contains all of the important
  functionality of UDA plus features not found in
  UDA, such as SQL3 support.

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OLE DB

• Microsoft's strategic low-level application
  program interface
• for access to different data sources.
• Includes the SQL capabilities of the
  Microsoft-sponsored standard data interface Open
  Database Connectivity
• Includes access to data other than SQL data.
• As a design from Microsoft's Component Object
  Model (COM), OLE DB is a set of methods, for
  reading and writing data.
• The objects in OLE DB consist mainly of a data
  source object, a session object, a command
  object, and a row set object.

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An application using OLE DB

• Initialize OLE
• Connect to a data source
• Issue a command
• Process the results
• Release the data source object
• Uninitialize OLE
• As a result
• A general-purpose set of interfaces designed to
  let
• developers build data access tools as components
• using the Component Object Model (COM).
• OLE DB enables applications to have uniform
  access to data stored in DBMS and non-DBMS
  information containers
• OLE DB takes advantage of the benefits of
  database
• technology without having to transfer data from
  its place of
• origin to a DBMS

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ActiveX Data Objects (ADO)

• A language-independent object model
• Expose data by an OLE DB Provider.
• The most commonly used OLE DB Provider
• the OLE DB Provider for ODBC Drivers,
• Exposes ODBC Data sources to ADO.
• ADO is newer and more like the JDBC API
• it is not pure Java
• http//msdn.microsoft.com/library/default.asp?url
  /downloads/list/dataaccess.asp

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Remote Data Service (RDS)

• The part of Microsoft's ActiveX Data Objects
  (ADO) programming model designed for remote data
  access in internet client/server applications. 
• On both client and server computers it depends
  upon the installation of the Microsoft Data
  Access Components (MDAC). 
• RDS has three core objects that are used to
  retrieve, manipulate, and update data in
  applications. 

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Remote Data Service (RDS) cont

• The RDS.DataControl and RDS.DataSpace objects
• installed on client computers and are directly
  accessed within applications to retrieve data
  from servers
• The RDSServer.DataFactory object, a server
  component
• can be accessed directly to communicate with
  data sources
• operates behind the scenes with the other RDS
  objects in handling database maintenance

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Cloudscape

• Cloudscape is a DBMS, a database management
  system, accessed by applications through the JDBC
  API.
• IBM Cloudscape provides developers a small
  footprint, standards- based Java database that
  can be tightly embedded into any Java based
  solution.
• Supports complex SQL, transactions and JDBC so
  that your applications can be migrated to DB2 UDB
  when they need to grow.
•  Supports data encryption on disk via JCE for
  secure operation in hostile environments.
• http//www.deitel.com/books/advjHTP1/advjHTP1_Clou
  dscapeInst
• allation.html

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Cloudscape cont

• Some standard Java tools and utilities that make
  it easier to use Cloudscape and to develop
  Cloudscape applications
• ij is Cloudscape's interactive JDBC scripting
  tool. It is a simple utility for running scripts
  against a Cloudscape database. You can also use
  it interactively to run ad hoc queries. ij
  provides several commands for ease in accessing a
  variety of JDBC features.
• ij can be used in an embedded or a client/server
  environment.
• Cloudview is a graphical user interface for
  creating and managing Cloudscape databases. It
  can be used in an embedded or a client/server
  environment.

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Cloudscape Database

• Consists of platform-independent files stored in
  a directory that has the same name as the
  database.
• Most of the Cloudscape tools are JDBC
  applications.
• A JDBC application is one that uses the classes
  in the java.sql package to interact with a DBMS.
• When we work with JDBC applications, we need to
  know about the following two JDBC concepts
• Drivers
• Database connection URLs

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Drivers

• Before a JDBC application interacts with a
  database, it must cause the appropriate JDBC
  driver to be loaded in the Java session.
  Cloudscape provides three JDBC drivers for use
  with the Cloudscape database engine. When you use
  the Cloudscape tools that are JDBC applications,
  you will need to know which driver to load.
• COM.cloudscape.core.JDBCDriver For embedded
  environments, when Cloudscape runs in the same
  JVM as the application
• COM.cloudscape.core.WebLogicDriver For
  client/server environments in which Cloudscape
  runs in the Cloudconnector framework and
  applications connect via the network
• COM.cloudscape.core.RmiJdbcDriver For
  client/server environments in which Cloudscape
  runs in the RmiJdbc Server framework and
  applications connect via the network

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Run as two different frameworks

• Embedded The simplest Cloudscape
  environment.
• Enables Cloudscape
  as part of a Java application
• Database accession
  as only one application at a time
• No network access
• Starting of an
  Cloudscape instance within the current JVM
• and shutting
  down before completing
• Client/Server The connection to Cloudscape over
  the network.
• Running embedded in a
  connectivity or server framework
• allows
  multiple network connections.
• The RmiJdbc framework
  enables the Cloudscape to execute
• as a
  stand-alone database server
• (a
  lightweight JDBC server and client)
• Each frame work directory has a bin subdirectory
  containing batch files

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A JDBC URL

• Provides a way of identifying a database so that
  the appropriate driver recognizes it and connects
  to it. .
• After the driver is loaded, an application must
  specify the correct database connection URL to
  connect to a specific database.
• The Cloudscape database connection URL allows us
  to accomplish more tasks than simply connecting.
• Some of them
• jdbccloudscape databaseName
  CloudscapeURLAttributes For embedded environments
  
• jdbccloudscapeweblogic databaseName
  CloudscapeURLAttributes
• For connecting to Cloudscape running inside the
  Cloudconnector framework, when the server is
  running on the default host localhost and is
  using the default port number 7001

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RmiJdbc Framework

• Change directories to bin directory in RmiJdbc
• Set the environment variables for the server
• Execution of the batch file setServerCloudscapeC
  P
• Launch the Cloudspace database server
• Execution of the batch file startCS
• Shut down the server
• Executiong stopCS

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Cloudview

• Graphical user interface for creating and
  managing Cloudscape databases.

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Connecting to a Server

• You can use Cloudview as a client application
  that interacts with Cloudscape running in a
  server framework.
• To do that, simply load the appropriate driver
  and use the appropriate protocol for the server
  framework, either RmiJdbc or Cloudconnector.

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CLOUDSPACE ORDBMS

• A Java and SQL based object-relational database
  management system

Description Founded in 1996, cloudspace is an
Internet services company specializing in
open-source Website and online software
development for the entertainment, technology and
professional services industries. Url
http//www.cloudspace.com