Implementation of XML
Database and
Enhancement of Resource
and Sensor Agents
Cuong Ngo
CSS497
Summer 2006
Professor Munehiro Fukuda
Overview
Mobile agents and AgentTeamWork
XML Format and XML DOM object
New XML database and Applet GUI
Dynamic monitoring of resources
Future work
AgentTeamwork
AgentTeamWork Overview
User A’s
Process
User A’s
Process
User B’s
Process
TCP
Communication
Snapshot
Methods
Results
GridTCP
User program wrapper
snapshot
GridTCP
Snapshot
Methods
User program wrapper
snapshot
Results
snapshot
Sentinel
Agent
Resource
Agent
User
A
GridTCP
User program wrapper
Sentinel
Agent
Sentinel
Agent
Commander
Agent
Snapshot
Methods
Resource
Agent
XDB
XDB
FTP
Server
snapshots
Bookkeeper
Agent
snapshots
Bookkeeper
Agent
User
B
Commander
Agent
Project Objectives
Replace old database, eXist


XDBase
eXist
No documentation
Need to include cluster information
Dynamically monitor resources
Proper communication between agents
XML Format
XML File
<department>
<employee>
<name>John Doe</name>
<email>[email protected]</email>
</employee>
<employee>
<name>Bill Jones</name>
<email>[email protected]</email>
</employee>
</department>
DOM Object
Element
“department”
Element
“employee”
Element
“name”
Text
“John Doe”
Element
“email”
Text
“[email protected]”
Element
“name”
Text
“Bill Jones”
Element
“email”
Text
“[email protected]”
Element
“employee”
DOM: Document Object Model
Keeps XML structure in tact
DOM Structure




Node
Document
Element
Text
Ability to:




Add
Delete
Modify
Query
Element
“department”
Element
“employee”
Element
“name”
Text
“John Doe”
Element
“email”
Text
“[email protected]”
“[email protected]”
Element
“id”
Whole XML File
Text
“5561”
Xpath Expressions
Xpath is a query language used to find
information in an XML document
Java provides XPathAPI to use Xpath
expressions to perform tasks
Examples






/department/employee
/department/employee[name=‘John Doe’]/
//name
//employee[name = ‘Bill Jones’]/email/text()
//employee/*
//name | //email
Element
“department”
Element
“employee”
Element
“name”
Text
“John Doe”
Element
“email”
Text
“[email protected]”
Element
“name”
Text
“Bill Jones”
Element
“email”
Text
“[email protected]”
Element
“employee”
Database Overview
Parse XML document to DOM object and create a wrapper object called
Resource

Modification timestamp

Availability

Ping
Collection class contains Resources
Database contains Collections

Parse and process request
Services connect to database and demand a request


RetrievalService
QueryService
Applet-based GUI interacts with database
Database Services
Create a collection, synchronize by writing
database contents back to local disk, and
shutting down of the database
Store, retrieve and delete a collection or
resource
Update a single resource or an entire collection
Query a collection for specific items
Specifically query the database for resources
based on requirements
Resource Itinerary with Cluster
Information
Old format included only IP addresses

Assumed every IP was public
New format contains a cluster, its gateway
and its cluster nodes.


Use gateway to communicate between nodes
of different clusters
Even gateway must be running
AgentTeamWork platform
Applet-based GUI
Graphically interact with the new database
Ability to:




Look at database contents
Add files
Delete files
Connect to remotely located databases
Applet-based GUI 2
ResourceAgent Modifications
Create runtime file for each cluster node
Create itinerary for SensorAgent to
monitor nodes dynamically


Query the database for all nodes within a
domain, such as “UWB”
Itinerary includes cluster and public nodes
Proper communication with other agents
SensorAgent Modifications
Resource
id 1
XDBase
Sensor
Client Root
Id 4
Client 1
Id 16
Sensor
Server Root
Id 5
Client 2
Id 17
Server 1
Id 20
Server 2
Id 21
SensorAgent Modifications 2
Resource
id 1
XDBase
Sensor
Root
Id 4
Public Client
Root
Id 17
Gateway 1
Id 16
G1 Client
Root
Id 65
Gateway 2
Id 64
G2 Client
Root
Id 256
G2 Server
Root
Id 257
G2
Client 1
Id 1024
G2
Server 1
Id 1028
Cluster 2
G1 Server
Root
Id 66
Cluster 1
Client 1
Id 68
Client 2
Id 69
Public Server
Root
Id 18
Server 1
Id 72
Server 2
Id 73
Future Expansions of Database
Easy to add new functionality to database



Create a service to send a request to
database
Database parses and processes the request
Database send back results
Future AgentTeamWork Tasks
SensorAgent

Have 2 cluster gateways perform bandwidth
test to monitor inter-cluster bandwidth
Need communication to change
unavailable nodes to available when a job
is complete

CommanderAgent informs ResourceAgent
which in turns creates a service request to the
database
What I Learned
XML, DOM object, Xpath
Grid computing programming
Communication between team members
Understanding existing code and
modifying it without breaking it
Acknowledgements
Advisor Prof. Munehiro Fukuda
Sponsor Prof. Shinya Kobayashi
Emory Horvath
CSS301, CSS342, CSS343, CSS434,
CSS442, CSS360
XML and Java, 2nd Edition book
Questions ?