Transcript 16_EZEL_final

Developer Libraries and Services
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Learning Objectives:
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This module will help you...
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Learn about optional JXTA libraries and
services
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Understand the goals of the JXTA Easy
Entry Library (EZEL) project
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Understand the benefits of the JXTA
Abstraction Library (JAL) API
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Gain familiarity with the JAL API
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Learn about other JXTA services
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Overview
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Optional Libraries
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EZEL
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JAL
JXTA Services
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JAAS
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JNLP
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RMI, SOAP, etc.
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EZEL Overview
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EZEL = Easy Entry Library for JXTA
Goal:
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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
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Hides implementation details
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Provides reasonable defaults
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Benefits
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Simplifies JXTA application development
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Reduces the learning curve
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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
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Extension to EZEL
API for commonly used JXTA primitives
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Discover peers (and allow to be discovered)
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Search for peers and peergroups
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Create and manage peergroups
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Communicate with other peers
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Get information about peers and
peergroups
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JAL Architecture
Application
Peer interface
EZEL
JXTA Abstraction
Layer
JXTA
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EZEL Classes
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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.PipeMsgListener
class net.pkg.jal.EZUtilities
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JAL API
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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
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boolean sendMessage(String name, Message msg)
Message receiveMessage()
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boolean broadcast(Message msg)
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Broadcast a message to everyone in the group
Message newMessage()
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Send or receive a message
Create a new, blank message
void pushObject(Message msg, String tag,
Object obj)
Object popObject(Message msg, String tag)
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Push/pop an object to the Message
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JAL API
Group Functions
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String[] getGroups()
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void createGroup(String name)
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Create and/or join group
void joinGroup(String name)
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Create a new group
void createAndOrJoinGroup(String name)
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Get peergroups associated with this peer
Join a group
void leaveGroup(String name)
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JAL API
Search & Display Functions
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boolean searchGroupWithName(String name)
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boolean searchPeerWithName(String name)
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Search for a peer
void displayPeers()
void displayGroups()
void displayServices()
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Search for a peergroup
Display all peers, peergroups, or services in the current
peergroup
String getPeerStatistics()
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Display some useful statistics
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JAL Example
import net.jxta.endpoint.Message;
import 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" + args[0]);
me.displayPeers();
me.displayGroups();
me.createGroup("MDE");
me.displayGroups();
me.joinGroup("MDE");
me.displayPeers();
me.displayGroups();
//finally try out getJoinedGroups
String a[] = me.getJoinedGroups();
System.out.println("getJoinedGroups:");
for(int i = 0; i < a.length; i++){
System.out.println(a[i]);
}
System.exit(0);
}catch (Exception e) {
e.printStackTrace();
System.exit(0);
}
System.exit(0);
}
}
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JAAS Overview
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Java Authentication and Authorization
Service (JAAS)
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Enables services to authenticate and
enforce access controls upon users
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Supports user-based authorization
Releases
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Integrated into the Java 2 SDK, Standard
Edition, v 1.4
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Optional package to the Java 2 SDK, v
1.3.x
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JAAS Membership Service Project
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JAAS MemberShip Service
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JXTA MembershipService implementation
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Leverage existing authentication services
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(JNDI, LDAP, NIS, WinNT, and Unix)
Provides a framework for integrating new
authentication services
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Uses JAAS for authentication
(Liberty, SAML, Passport)
Status
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A functional implementation of
JaasMembershipService is in place
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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.getCurrentCredentials();
if(enum.hasMoreElements()) {
JaasCredential subjCred = (JaasCredential)enum.nextElement();
Subject subject = subjCred.getSubject();
} else {
System.out.println("No Credentials!");
}
} catch (Exception e) {
}
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JXTA JnlpLoader Project
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Goals:
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An implementation of JxtaLoader
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Utilizes Java Network Launching (JNLP) to load
modules, and resources
JnlpLoader is based on OpenJNLP
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http://openjnlp.nanode.org/
Status
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Basic functionality is complete
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http://jnlploader.jxta.org/
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JXTA Community Services
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http://services.jxta.org
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SOAP
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JXTA-RMI
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RMI API on top of JXTA
Validation Service
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JXTA SOAP bindings
A ValidationService for JXTA Advertisements
Many more ...
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Developer Libraries and Services
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