Developer Libraries and Services

1. Developer Libraries and Services

2. 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

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

4. 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

5. 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

6. 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

7. JAL Architecture Application EZEL Peer interface JXTA Abstraction Layer JXTA

8. 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.PipeMsgListener • class net.pkg.jal.EZUtilities

9. 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

10. 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

11. 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)

12. 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

13. 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); }} JAL Example

14. 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

15. 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 JaasMembershipService is in place • http://jaas-membership.jxta.org

16. 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) { }

17. 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/

18. 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 ...

19. Developer Libraries and Services