JNDI

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JNDI
Celsina Bignoli bignolic_at_smccd.net
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Naming Services

• Name reference to an entity
• A naming service
• Associates (binds) names with objects
• Provides mechanisms for finding an object based
  on a name
• Naming services are ubiquitous in computing
• DNS (name IP address)
• File system naming service

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Directory Services

• A directory object is a special object which has
  attributes associated with it.
• A directory service is a naming service with
  additional functionality for manipulating
  attributes
• A directory is a system of correlated directory
  objects

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Directory Structure
Employee1
Employees
Employee2
Company
Printers
Computer1
Hardware
Computers
Computer2
Fax Machines
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Existing Naming Directory Services

• Examples
• LDAP (Lightweight Directory Access Protocol)
• NIS (Network Information System)
• Novells NDS (Network Directory System)
• Each has its own proprietary set of services
• Makes it hard to switch between systems

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JNDI

• Provides a common interface to disparate
  directory services
• You can use behind the scene an heterogeneous set
  of Naming and Directory systems making it look
  like one, and not having to learn their specific
  APIs
• Use JNDI for resource factories, look up beans,
  acquire references

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JNDI Architecture
Client Code
JNDI Client API
Service Provider Interface
LDAP Service Provider
NIS Service Provider
File System Service Provider
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JNDI Concepts

• Atomic name indivisible name
• Ex usr, local
• Compound name zero or more atomic names put
  together according to a specific syntax
• Ex /usr/local
• Binding association of a name with an object
• run.exe associates to an executable file in the
  file system
• Context a set of 0 or more bindings, with its
  own distinct atomic name.

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JNDI Concepts (2)

• Naming system connected set of contexts that use
  the same name syntax
• Ex folder tree in a file system
• Namespace set of names in a name system
• Composite Name name that spans multiple naming
  systems

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Initial Context Factories

• Initial Context starting point from where to
  perform naming and directory operations
• Initial Context Factory used to acquire initial
  context. Implemented by the JNDI Driver
• To acquire an Initial Context you must provide
• IP address of the J2EE server
• Port number
• Starting location within the JNDI tree
• User name/ password combination to access J2EE
  server