Java KPI tutorial

Java KPI for Smart M3
Brief introduction
Fabio Viola
University of Bologna
Master Degrees in computer and electronic engineering
October 1, 2014
Introduction
Preliminary steps
Joining/Leaving a SS
Table of Contents
1
Introduction
Introduction
2
Preliminary steps
3
Joining/Leaving a SS
Join
Leave
4
CRUD operations
Defining triples
Insertion
Removal
Update
Query
5
Subscriptions
Introduction to subscriptions
Defining the handler
Subscription
Unsubscription
6
Reference Links
CRUD operations
Subscriptions
Reference Links
Introduction
Preliminary steps
Joining/Leaving a SS
CRUD operations
Subscriptions
Reference Links
Introduction
The present document is a brief introduction to the Java KPI, libraries needed
to access a Smart-M3 Smart Space.
In this tutorial Eclipse is the environment taken into account.
Introduction
Preliminary steps
Joining/Leaving a SS
Table of Contents
1
Introduction
Introduction
2
Preliminary steps
3
Joining/Leaving a SS
Join
Leave
4
CRUD operations
Defining triples
Insertion
Removal
Update
Query
5
Subscriptions
Introduction to subscriptions
Defining the handler
Subscription
Unsubscription
6
Reference Links
CRUD operations
Subscriptions
Reference Links
Introduction
Preliminary steps
Joining/Leaving a SS
CRUD operations
Subscriptions
Reference Links
Importing the libraries
Once a new Java project has been created, it must be configured to load the
required libraries. Right click on the project name and then click on Properties.
In the Java Build Path section, Libraries tab, a click on the Add External
JARs... button allows to load the files sofia kp.jar and jdom-2.0.5.jar.
Now the libraries must be imported into the classes in the following way:
import
import
import
import
import
import
import
java .
sofia
sofia
sofia
sofia
sofia
sofia
u t i l . Vector ;
k p . KPICore ;
k p . SIBResponse ;
k p . SSAP XMLTools ;
kp . SSAP sparql response ;
kp . iKPIC subscribeHandler ;
kp . iKPIC subscribeHandler2 ;
Introduction
Preliminary steps
Joining/Leaving a SS
CRUD operations
Subscriptions
Reference Links
Creating a KP
To create a new KP, a new object of class KPICore must be instantiated.
KPICore mykp = new KPICore ( s i b i p , s i b p o r t , s s n a m e ) ;
where:
sib ip is a String containing the IP address (or hostname) of the server
running the SIB;
sib port is an Integer containing the port number of the SIB;
ss name is a String representing the name of the smart space.
It is useful to declare a SIBResponse object to check the response of the SIB
to the future commands:
SIBResponse r e s p = n u l l ;
Introduction
Preliminary steps
Joining/Leaving a SS
Table of Contents
1
Introduction
Introduction
2
Preliminary steps
3
Joining/Leaving a SS
Join
Leave
4
CRUD operations
Defining triples
Insertion
Removal
Update
Query
5
Subscriptions
Introduction to subscriptions
Defining the handler
Subscription
Unsubscription
6
Reference Links
CRUD operations
Subscriptions
Reference Links
Introduction
Preliminary steps
Joining/Leaving a SS
CRUD operations
Subscriptions
Reference Links
Join
To join a smart space simply invoke the join method of the instantiated object:
r e s p = mykp . j o i n ( ) ;
i f (! resp . isConfirmed () ) {
System . e r r . p r i n t l n ( ” E r r o r j o i n i n g t h e SIB ” ) ;
System . e x i t ( 0 ) ;
}
Introduction
Preliminary steps
Joining/Leaving a SS
CRUD operations
Leave
Leaving a smart space is as easy as joining it:
r e s p = mykp . l e a v e ( ) ;
i f (! resp . isConfirmed () ) {
System . e r r . p r i n t l n ( ” E r r o r l e a v i n g t h e SIB ” ) ;
System . e x i t ( 0 ) ;
}
Subscriptions
Reference Links
Introduction
Preliminary steps
Joining/Leaving a SS
Table of Contents
1
Introduction
Introduction
2
Preliminary steps
3
Joining/Leaving a SS
Join
Leave
4
CRUD operations
Defining triples
Insertion
Removal
Update
Query
5
Subscriptions
Introduction to subscriptions
Defining the handler
Subscription
Unsubscription
6
Reference Links
CRUD operations
Subscriptions
Reference Links
Introduction
Preliminary steps
Joining/Leaving a SS
CRUD operations
Defining triples
// d e c l a r e a l i s t o f t r i p l e s
V e c t o r<V e c t o r<S t r i n g >> t r i p l e s = new V e c t o r<V e c t o r<S t r i n g >>() ;
// d e c l a r e a t r i p l e
V e c t o r<S t r i n g > t r i p l e = new V e c t o r<S t r i n g >() ;
// d e c l a r i n g t h e f i e l d s
S t r i n g s u b j e c t = ” h t t p : / / n s#s u b j e c t ” ;
S t r i n g p r e d i c a t e = ” h t t p : / / n s#p r e d i c a t e ” ;
S t r i n g o b j e c t = ” h t t p : / / n s#o b j e c t ” ;
// f i l l t h e t r i p l e
t r i p l e . add ( s u b j e c t ) ;
t r i p l e . add ( p r e d i c a t e ) ;
t r i p l e . add ( o b j e c t ) ;
t r i p l e . add ( ” u r i ” ) ;
t r i p l e . add ( ” u r i ” ) ;
// add t h e t r i p l e t o t h e
t r i p l e s . add ( t r i p l e ) ;
list
Subscriptions
Reference Links
Introduction
Preliminary steps
Joining/Leaving a SS
CRUD operations
Subscriptions
Reference Links
Insertion
Now that a list of triples has been defined, the insertion can be done invoking
the method insert of the mykp object.
r e s p = mykp . i n s e r t ( t r i p l e s ) ;
i f (! resp . isConfirmed () ) {
System . e r r . p r i n t l n ( ” I n s e r t f a i l e d ! ” ) ;
}
else {
System . o u t . p r i n t l n ( ” I n s e r t s u c c e s s f u l ! ” ) ;
}
The insert method can also be invoked with the following parameters:
subject (String);
predicate (String);
object (String);
subject type ("uri" or "literal");
object type ("uri" or "literal").
Introduction
Preliminary steps
Joining/Leaving a SS
CRUD operations
Subscriptions
Reference Links
Removal
In the same way of the insert:
r e s p = mykp . remove ( t r i p l e s ) ;
i f ( ! r e s p . i s C o n f i r m e d ( ) ){
System . o u t . p r i n t l n ( ”Remove e r r o r ! ” ) ;
}
else {
System . o u t . p r i n t l n ( ”Remove s u c c e s s f u l l ” ) ;
}
Even the remove method can be invoked specifying subject, predicate, object,
subject type and object type.
Introduction
Preliminary steps
Joining/Leaving a SS
CRUD operations
Subscriptions
Reference Links
Update
The update method accept a Vector of Vector of String to express the new
triples and another one for the old triples.
r e s p = mykp . u p d a t e ( n e w t r i p l e s ,
old triples );
Alternatively it takes ten arguments:
the new subject (String);
the new predicate (String);
the new object (String);
the type of the new subject (a String that can be "uri" or "literal");
the type of the new object (a String that can be "uri" or "literal");
the old subject (String);
the old predicate (String);
the old object (String);
the type of the old subject (a String that can be "uri" or "literal");
the type of the old object (a String that can be "uri" or "literal");
An example:
r e s p = mykp . u p d a t e ( s u b j e c t 2 , p r e d i c a t e 2 , o b j e c t 2 , ” u r i ” , ” u r i ” ,
subject1 , predicate1 , object1 , ” u r i ” , ” u r i ”) ;
And then the usual check on the resp variable can be done.
Introduction
Preliminary steps
Joining/Leaving a SS
CRUD operations
Subscriptions
RDF Query
In the following listing, the method queryRDF is used. Its arguments are:
the subject (String or null to match everything);
the predicate (String or null to match everything);
the object (String or null to match everything);
the type of the subject ("uri" or "literal");
the type of the object ("uri" or "literal");
// e x e c u t e t h e q u e r y
r e s p = mykp . queryRDF ( s u b j e c t , p r e d i c a t e , o b j e c t , ” u r i ” , ” u r i ” ) ;
// p r i n t t h e r e s u l t
V e c t o r<V e c t o r<S t r i n g >> q u e r y r e s p o n s e = r e s p . q u e r y r e s u l t s ;
f o r ( V e c t o r<S t r i n g > t : q u e r y r e s p o n s e ) {
System . o u t . p r i n t l n ( t ) ;
}
Reference Links
Introduction
Preliminary steps
Joining/Leaving a SS
CRUD operations
Subscriptions
Reference Links
SPARQL Query
The following listings shows how to query the SIB with the SPARQL language:
// D e f i n e t h e q u e r y
S t r i n g q u e r y = ”SELECT ? s ? p ? o WHERE { ? s ? p ? o }” ;
// E x e c u t e t h e q u e r y
r e s p = mykp . querySPARQL ( q u e r y ) ;
// Check t h e r e s u l t s
i f ( ! r e s p . i s C o n f i r m e d ( ) ){
System . o u t . p r i n t l n ( ”SPARQL Query e r r o r ! ” ) ;
}
else {
// Get t h e r e s u l t s
V e c t o r<S t r i n g [] > row = n u l l ;
SSAP sparql response sparql query response = resp . s p a r q l q u e r y r e s u l t s ;
// C y c l e t h r o u g h t h e r e s u l t s
w h i l e ( s p a r q l q u e r y r e s p o n s e . hasNext ( ) ){
s p a r q l q u e r y r e s p o n s e . next () ;
row = s p a r q l q u e r y r e s p o n s e . getRow ( ) ;
f o r ( S t r i n g [ ] r : row ) {
System . o u t . p r i n t l n ( r [ 0 ] + ” , ” + r [ 1 ] + ” , ” + r [ 2 ] ) ;
}
}
}
Introduction
Preliminary steps
Joining/Leaving a SS
Table of Contents
1
Introduction
Introduction
2
Preliminary steps
3
Joining/Leaving a SS
Join
Leave
4
CRUD operations
Defining triples
Insertion
Removal
Update
Query
5
Subscriptions
Introduction to subscriptions
Defining the handler
Subscription
Unsubscription
6
Reference Links
CRUD operations
Subscriptions
Reference Links
Introduction
Preliminary steps
Joining/Leaving a SS
CRUD operations
Subscriptions
Reference Links
Subscribe
With a subscription, a program receives a notification for each triple that
matches a pattern or a query. Once the notification is received, an handler is
triggered.
The definition of an handler class is shown in the following slide, before
introducing the activation of a subscription.
Introduction
Preliminary steps
Joining/Leaving a SS
CRUD operations
Subscriptions
Reference Links
Defining the handler class
The handler class is a class that implements the iKPIC subscribeHandler2
interface.
p u b l i c c l a s s MyHandler i m p l e m e n t s i K P I C s u b s c r i b e H a n d l e r 2 {
p u b l i c MyHandler ( ) {
// I n i t i a l i z a t i o n c o d e
}
@Override
p u b l i c v o i d k p i c R D F E v e n t H a n d l e r ( V e c t o r<V e c t o r<S t r i n g >> n e w T r i p l e s ,
V e c t o r<V e c t o r<S t r i n g >> o l d T r i p l e s ,
S t r i n g indSequence ,
S t r i n g subID ) {
// P r o c e s s added and removed t r i p l e s !
}
}
Introduction
Preliminary steps
Joining/Leaving a SS
CRUD operations
Subscriptions
Reference Links
RDF Subscription
Once that the handler class has been defined (and imported), a subscription
can be executed with:
r e s p = mykp . s u b s c r i b e R D F ( s u b j e c t , p r e d i c a t e , o b j e c t , o b j e c t t y p e , MyHandler ) ;
String sub id = resp . subscription id ;
where object type can be "uri" or "literal".
Introduction
Preliminary steps
Joining/Leaving a SS
CRUD operations
Subscriptions
SPARQL Subscription
In a SPARQL subscription, the pattern is expressed with a String variable:
S t r i n g p a t t e r n = ”SELECT ? s ? p ? o WHERE { ? s ? p ? o }” ;
r e s p = mykp . subscribeSPARQL ( p a t t e r n , MyHandler ) ;
String sub id = resp . subscription id ;
Reference Links
Introduction
Preliminary steps
Joining/Leaving a SS
CRUD operations
Subscriptions
Unsubscription
To close a subscription (nevermind if it is a RDF or a SPARQL one) the
required steps are:
mykp . u n s u b s c r i b e ( s u b i d ) ;
Reference Links
Introduction
Preliminary steps
Joining/Leaving a SS
Table of Contents
1
Introduction
Introduction
2
Preliminary steps
3
Joining/Leaving a SS
Join
Leave
4
CRUD operations
Defining triples
Insertion
Removal
Update
Query
5
Subscriptions
Introduction to subscriptions
Defining the handler
Subscription
Unsubscription
6
Reference Links
CRUD operations
Subscriptions
Reference Links
Introduction
Preliminary steps
Reference Links
Software
Smart-M3
Java KPI
Joining/Leaving a SS
CRUD operations
Subscriptions
Reference Links

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