Developer Libraries and Services

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Developer Libraries and Services
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Learning Objectives

• This module will help you...
• Learn about optional JXTA libraries and services
• Understand the goals of the JXTA Easy Entry
  Library (EZEL) project
• Understand the benefits of the JXTA Abstraction
  Library (JAL) API
• Gain familiarity with the JAL API
• Learn about other JXTA services

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Overview

• Optional Libraries
• EZEL
• JAL
• JXTA Services
• JAAS
• JNLP
• RMI, SOAP, etc.

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EZEL Overview

• EZEL Easy Entry Library for JXTA
• Goal
• Enable a client-server developer with no JXTA
  or P2P experience to create a JXTA service in
  a single afternoon
• Provides client/server-like API
• Hides implementation details
• Provides reasonable defaults

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Benefits

• Simplifies JXTA application development
• Reduces the learning curve
• Provides best practices for handling common
  JXTA programming tasks
• Complete isolation from API changes
• Can learn as you go and supplement API with
  direct JXTA programming

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JAL JXTA Abstraction Library

• Extension to EZEL
• API for commonly used JXTA primitives
• Discover peers (and allow to be discovered)
• Search for peers and peergroups
• Create and manage peergroups
• Communicate with other peers
• Get information about peers and peergroups

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JAL Architecture
Application
EZEL
Peer interface
JXTA Abstraction Layer
JXTA
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EZEL Classes

• class net.pkg.jal.EZAdvertisement
• class net.pkg.jal.EZCommunication
• class net.pkg.jal.EZDiscovery
• class net.pkg.jal.EZDisplay
• class net.pkg.jal.EZGroups
• class net.pkg.jal.EZMinimalPeer
• Implements net.pkg.jal.Peer, net.jxta.pipe.PipeMsg
  Listener
• class net.pkg.jal.EZUtilities

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JAL API

• void boot(String name)void boot(String name,
  String group)
• Boot the peer every peer must call it
• void publish()
• Publish peer so other can discover it
• String getName()
• Get the name of this peer
• String getPeers()
• Get peers associated with this peer in current
  peergroup

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JAL API Message Functions

• boolean sendMessage(String name, Message
  msg)Message receiveMessage()
• Send or receive a message
• boolean broadcast(Message msg)
• Broadcast a message to everyone in the group
• Message newMessage()
• Create a new, blank message
• void pushObject(Message msg, String tag,
  Object obj)Object popObject(Message msg,
  String tag)
• Push/pop an object to the Message

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JAL API Group Functions

• String getGroups()
• Get peergroups associated with this peer
• void createGroup(String name)
• Create a new group
• void createAndOrJoinGroup(String name)
• Create and/or join group
• void joinGroup(String name)
• Join a group
• void leaveGroup(String name)

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JAL API Search Display Functions

• boolean searchGroupWithName(String name)
• Search for a peergroup
• boolean searchPeerWithName(String name)
• Search for a peer
• void displayPeers()void displayGroups()void
  displayServices()
• Display all peers, peergroups, or services in the
  current peergroup
• String getPeerStatistics()
• Display some useful statistics

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JAL Example

• import net.jxta.endpoint.Messageimport
  net.pkg.jal.import java.io.public class
  TestApp private static Peer me public static
  void main (String args) me new
  EZMinimalPeer() try me.boot("MDE"
  args0) me.displayPeers() me.displayGroups(
  ) me.createGroup("MDE") me.displayGroups()
  me.joinGroup("MDE") me.displayPeers() me.d
  isplayGroups() //finally try out
  getJoinedGroups String a me.getJoinedGroups(
  ) System.out.println("getJoinedGroups") for
  (int i 0 i lt a.length i) System.out.prin
  tln(ai) System.exit(0) catch
  (Exception e) e.printStackTrace() System.ex
  it(0) System.exit(0)

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JAAS Overview

• Java Authentication and Authorization Service
  (JAAS)
• Enables services to authenticate and enforce
  access controls upon users
• Supports user-based authorization
• Releases
• Integrated into the Java 2 SDK, Standard Edition,
  v 1.4
• Optional package to the Java 2 SDK, v 1.3.x

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JAAS Membership Service Project

• JAAS MemberShip Service
• JXTA MembershipService implementation
• Uses JAAS for authentication
• Leverage existing authentication services
• (JNDI, LDAP, NIS, WinNT, and Unix)
• Provides a framework for integrating new
  authentication services
• (Liberty, SAML, Passport)
• Status
• A functional implementation of JaasMembershipServi
  ce is in place
• http//jaas-membership.jxta.org

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Code Example
try MembershipService membership
jaasGroup.getMembershipService()
AuthenticationCredential authCred
new AuthenticationCredential(jaasGroup,
"JAAS",

null) membership.join(membership.apply(authCred)
) Enumeration enum membership.getCurrentCreden
tials() if(enum.hasMoreElements())
JaasCredential subjCred (JaasCredential)enum
.nextElement() Subject subject
subjCred.getSubject() else System.out.prin
tln("No Credentials!") catch (Exception e)

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JXTA JnlpLoader Project

• Goals
• An implementation of JxtaLoader
• Utilizes Java Network Launching (JNLP) to load
  modules, and resources
• JnlpLoader is based on OpenJNLP
• http//openjnlp.nanode.org/
• Status
• Basic functionality is complete
• http//jnlploader.jxta.org/

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JXTA Community Services

• http//services.jxta.org
• SOAP
• JXTA SOAP bindings
• JXTA-RMI
• RMI API on top of JXTA
• Validation Service
• A ValidationService for JXTA Advertisements
• Many more ...

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Developer Libraries and Services