Center for Open Middleware

Center for Open Middleware

Application integration with the W3C Linked Data standards

Nandana Mihindukulasooriya

Universidad Politécnica de Madrid

nmihindu@fi.upm.es

@nandanamihindu

Día W3C en EspañaDecember 18th, 2013

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Evolution of Application Integration

http://www.immortalhumans.com/wp-content/uploads/Evolution-11.jpg

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Linked Data

• Connecting data distributed across the Web• Similar to how documents are connected using hyperlinks to set up an

hypertext web

• Based on four rules defined by Tim Berners Lee [1]:1. Use URIs as names for things

2. Use HTTP URIs so that people can look up those names.

3. When someone looks up a URI, provide useful information, using the standards (RDF*, SPARQL)

4. Include links to other URIs, so that they can discover more things

[1] http://www.w3.org/DesignIssues/LinkedData.html

[2] Linking Open Data cloud diagram, by Richard Cyganiak

and Anja Jentzsch. http://lod-cloud.net/

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Why Linked Data ?

• Global identifiers that are dereferenceable • Easily accessible data using HTTP• Reconciliation of duplicate data• Avoid data silos

• Use of standards • Interoperability

• Flexible graph based RDF data model • Easy to merge data from different sources • Multiple schemas can live together • Easy to evolve

• Typed links between data from different sources • Ability to traverse through data to find more information and context

• Richer knowledge representation and modeling• Mappings without complex transformations

• By adding more information rather than converting data

No silver bullets

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Linked Data specifications

• Advanced modeling• OWL

Domain Specification

Protocol HTTP

Data model RDF(S)

Serializations RDF/XMLTurtleTriGRDFaJSON-LD

Query SPARQL

W3C Linked Data Platform

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Linked Data Platformhttp://www.w3.org/2012/ldp/

• RESTful protocol for Read / Write Linked Data

• Extensions to HTTP protocol • Pagination, ordering, partial updates, introspection, creation factories, collections

• Standardization focused of interoperability

• Developed by W3C Linked Data Platform Working Group• 54 participants from 32 organizations

• Industry: IBM, Oracle, EMC, Fujitsu, OpenLink Software, Base22, …• Academia: Universidad Politécnica de Madrid, University of Oxford, DERI, Université de Lyon, INRIA,

…

• Progress:• Several public working drafts are available • On its way to a Candidate Recommendation

• Current and potential implementations: • OpenLink Virtuoso, Eclipse Lyo, ALM iStack middleware, Apache Marmotta, Callimachus,

Tabulator, rdflib.js, RWW.IO, …

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An example: BugLinks An LDP-enabled bug tracker

OPTIONS

OPTIONS

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Looking up for the projectGET /bug-tracker/alm-istack HTTP/1.1

Host: example.org

Accept: text/turtle; charset=UTF-8

HTTP/1.1 200 OK

Content-Type: text/turtle; charset=UTF-8

Link: <http://www.w3.org/ns/ldp/Container>; rel="type"

ETag: W/"123456789"

@prefix dcterms: <http://purl.org/dc/terms/>.

@prefix ldp: <http://www.w3.org/ns/ldp#>.

@prefix bt: <http://www.example.org/vocab#>.

</bug-tracker/alm-istack> a ldp:SimpleContainer, bt:ProductDescription;

dcterms:title "A collection of bug reports on ALM iStack project";

bt:developer </user/johndoe>;

ldp:contains </bug-tracker/alm-istack/bug3>;

ldp:contains </bug-tracker/alm-istack/bug4> .

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Looking up for the project with many bugs (Paging)

GET /bug-tracker/buggy-product HTTP/1.1

Host: example.org

Accept: text/turtle; charset=UTF-8

HTTP/1.1 303 See Other

Location: /bug-tracker/buggy-product?firstpage

Link: <http://www.w3.org/ns/ldp/Container>; rel="type"

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HTTP/1.1 200 OK

Content-Type: text/turtle; charset=UTF-8

Link: <http://www.w3.org/ns/ldp/Resource>; rel="type“

Link: </bug-tracker/buggy-product?secondpage>; rel='next'

ETag: W/"123456789“

@prefix ldp: <http://www.w3.org/ns/ldp#>.

@prefix bt: <http://www.example.org/vocab#>.

<bug-tracker/buggy-product> a ldp:SimpleContainer,bt:ProductDescription;

ldp:contains </bug-tracker/alm-istack/bug1>;

…

ldp:contains </bug-tracker/alm-istack/bug200> .

Looking up for the project with many bugs (Paging) II

GET /bug-tracker/buggy-product?firstpage HTTP/1.1

Host: example.org

Accept: text/turtle; charset=UTF-8

Under discussion

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Creating a new bug reportPOST /bug-tracker/alm-istack HTTP/1.1

Host: example.org

Content-Type: text/turtle

@prefix dcterms: <http://purl.org/dc/terms/>.

@prefix bt: <http://www.example.org/vocab#>.

<> a bt:BugReport;

dcterms:title "Server crashed";

dcterms:creator </user/janedoe> .

HTTP/1.1 201 Created

Location: /bug-tracker/alm-istack/bug5

Link: <http://www.w3.org/ns/ldp/Resource>; rel="type"

ETag: W/"123456789"

Content-Length: 0

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Looking up for a project (again)GET /bug-tracker/alm-istack HTTP/1.1

Host: example.org

Accept: text/turtle; charset=UTF-8

HTTP/1.1 200 OK

Content-Type: text/turtle; charset=UTF-8

Link: <http://www.w3.org/ns/ldp/Container>; rel="type"

ETag: W/“223456789"

@prefix dcterms: <http://purl.org/dc/terms/>.

@prefix ldp: <http://www.w3.org/ns/ldp#>.

@prefix bt: <http://www.example.org/vocab#>.

</bug-tracker/alm-istack> a ldp:SimpleContainer, bt:ProductDescription;

dcterms:title "A collection of bug reports on ALM iStack project";

ldp:contains </bug-tracker/alm-istack/bug3> ;

ldp:contains </bug-tracker/alm-istack/bug4> ;

ldp:contains </bug-tracker/alm-istack/bug5> .

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Looking up for a bug reportGET /bug-tracker/alm-istack/bug5 HTTP/1.1

Host: example.org

Accept: text/turtle; charset=UTF-8

HTTP/1.1 200 OK

Content-Type: text/turtle; charset=UTF-8

Link: <http://www.w3.org/ns/ldp/Resource>; rel="type"

ETag: W/"123456789"

@prefix dcterms: <http://purl.org/dc/terms/>.

@prefix ldp: <http://www.w3.org/ns/ldp#>.

@prefix bt: <http://www.example.org/vocab#>.

</bug-tracker/alm-istack/bug5> a bt:BugReport;

dcterms:title "Server crashed";

dcterms:creator </user/janedoe>;

dcterms:created "2013-05-05T10:00"^^xsd:dateTime;

bt:state bt:New .

.

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ALM iStack Project

Objective:

To evaluate and foster the adoption of Linked Data technologies as the means for facilitating real-time Application Lifecycle Management tool integration in enterprise-grade environments.

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Architecture of the Proof-of-Concept

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Enterprise readiness

VALIDATION

TRANSACTIONS

SECURITY

DESIGN PATTERNS &

ANTI-PATTERNS

APPLICATION MODELS

DISCOVERY & INTROSPECTI

ON

VOCABULARY

MANAGEMENT

VERSIONING

PROVENANCE

IDENTITY MANAGEME

NT

PERFORMANCE

OPTIMIZATION

TESTING

PARTIAL RETRIEVALS & UPDATES

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Final remarks • Linked Data can be a good approach when the

integrations are data intensive• Service orientation vs. Data / Resource orientation

• Linked Data Platform as a standard RESTful protocol for read/write Linked Data

• Supported by the industry• OSLC / IBM Rational Jazz• EU projects (PPP/FP7): CESAR, iFEST, CRYSTAL

• Some work to be done on enterprise Quality of Service requirements

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Center for Open Middleware

Thank You !Application integration with

the W3C Linked Data standards

Raúl García Castro,

Miguel Esteban Gutiérrez,

Nandana Mihindukulasooriya