625 research outputs found
Automating SLA-Driven API Development with SLA4OAI
The OpenAPI Specification (OAS) is the de facto standard
to describe RESTful APIs from a functional perspective. OAS has been
a success due to its simple model and the wide ecosystem of tools supporting the SLA-Driven API development lifecycle. Unfortunately, the
current OAS scope ignores crucial information for an API such as its
Service Level Agreement (SLA). Therefore, in terms of description and
management of non-functional information, the disadvantages of not having a standard include the vendor lock-in and prevent the ecosystem to
grow and handle extra functional aspects.
In this paper, we present SLA4OAI, pioneering in extending OAS not
only allowing the specification of SLAs, but also supporting some stages
of the SLA-Driven API lifecycle with an open-source ecosystem. Finally,
we validate our proposal having modeled 5488 limitations in 148 plans
of 35 real-world APIs and show an initial interest from the industry with
600 and 1900 downloads and installs of the SLA Instrumentation Library
and the SLA Engine.Ministerio de Economía y Competitividad TIN2015-70560-RMinisterio de Ciencia, Innovación y Universidades RTI2018-101204-B-C21Ministerio de Educación, Cultura y Deporte FPU15/0298
Fostering SLA-Driven API Specifications
Software architecture tendencies are shifting to a microservice paradigm. In this context, RESTful APIs are being established the standard of integration. API designer often identifies two key issues to be competitive in such growing market. On the one hand, the generation of accurate documentation of the behavior and capabilities of the API to promote its usage; on the other hand, the design of a pricing plan that fits into the potential API user’s needs. Besides the increasing number of API modeling alternatives is emerging, there is a lack of proposals on the definition of flexible pricing plans usually contained in the Service Level Agreements (SLAs). In this paper we propose two different modeling techniques for the description of SLA in a RESTful API context: iAgree and SLA4OAI.Ministerio de Economía y Competitividad TIN2015-70560-RJunta de Andalucía P12-TIC-1867Ministerio de Economía y Competitividad TIN2014-53986-RED
Multi-Party Coordination in the Context of MOWS
Separation of concerns has been presented as a promising tool to tackle the design of complex systems
in which cross-cutting properties that do not fit into the scope of a class must be satisfied. In this paper,
we show that interactions amongst a number of objects can also be described separately from functionality,
which enhances reusability of functional code and interaction patterns. We present our proposal in the context
of Multi-Qrganisational Web-Based Systems (MOWS) and also present a framework that provides the infrastructure
needed to implement multiparty coordination as an independent aspect
Aspect-oriented interaction in multi-organisational web-based systems
Separation of concerns has been presented as a promising tool to tackle the design of complex systems in which
cross-cutting properties that do not fit into the scope of a class must be satisfied. Unfortunately, current proposals
assume that objects interact by means of object-oriented method calls, which implies that they embed interactions with
others into their functional code. This makes them dependent on this interaction model, and makes it difficult to reuse
them in a context in which another interaction model is more suited, e.g., tuple spaces, multiparty meetings, ports, and
so forth. In this paper, we show that functionality can be described separately from the interaction model used, which
helps enhance reusability of functional code and coordination patterns. Our proposal is innovative in that it is the first
that achieves a clear separation between functionality and interaction in an aspect-oriented manner. In order to show
that it is feasible, we adapted the multiparty interaction model to the context of multiorganisational web-based systems
and developed a class framework to build business objects whose performance rates comparably to handmade implementations;
the development time, however, decreases significantly.Comisión Interministerial de Ciencia y Tecnología TIC2000-1106-C02-0
Improving Semantic Web Services Discovery Using SPARQL-Based Repository Filtering
Semantic Web Services discovery is commonly a heavyweight task, which has scalability issues when the number of
services or the ontology complexity increase, because most approaches are based on Description Logics reasoning. As
a higher number of services becomes available, there is a need for solutions that improve discovery performance. Our
proposal tackles this scalability problem by adding a preprocessing stage based on two SPARQL queries that filter service
repositories, discarding service descriptions that do not refer to any functionality or non-functional aspect requested by
the user before the actual discovery takes place. This approach fairly reduces the search space for discovery mechanisms,
consequently improving the overall performance of this task. Furthermore, this particular solution does not provide yet
another discovery mechanism, but it is easily applicable to any of the existing ones, as our prototype evaluation shows.
Moreover, proposed queries are automatically generated from service requests, transparently to the user. In order to
validate our proposal, this article showcases an application to the OWL-S ontology, in addition to a comprehensive
performance analysis that we carried out in order to test and compare the results obtained from proposed filters and
current discovery approaches, discussing the benefits of our proposal
SOA4 All Integrated Ranking: a Preference-Based, Holistic Implementation
There exist many available service ranking implementations, each one providing ad hoc preference models that offer different levels of expressiveness. Consequently, applying a single implementation to a particular scenario constrains the user to define preferences based on the underlying formalisms. Furthermore, preferences from different ranking implementation’s model cannot be combined in general, due to interoperability issues. in this article we present an integrated ranking implementation that enables the combination of three different ranking implementations developed within the EU FP7 SOA4All project. Our solution has been developed using PURI, a Preference-based Universal Ranking Integration framework that is based on a common, holistic preference model that allows to exploit synergies from the integrated ranking implementations, offering a single user interface to define preferences that acts as a façade to the integrated ranking implementation
On User Preferences and Utility Functions in Selection: A Semantic Approach
Discovery tasks in the context of Semantic Web Services are
generally performed using Description Logics. However, this formalism
is not suited when non-functional, numerical parameters are involved
in the discovery process. Furthermore, in selection tasks, where an optimization
algorithm is needed, DLs are not capable of computing the
optimum. Although there are DLs extensions that can handle numerical
parameters, they bring decidability problems. Other solutions, as hybrid
approaches which use DLs in functional discovery and other formalisms
in non-functional selection, do not provide a semantic framework to describe
user preferences based on non-functional properties. In this work,
we propose to semantically describe user preferences, so they can be used
to perform selection within a hybrid solution. By using semantically described
utility functions in order to define user preferences, our proposal
enables interoperability between service offers and demands, while providing
a high level of expressiveness in these preferences and including
them within SWS descriptions.Comisión Interministerial de Ciencia y Tecnología TIN2006-0047
QoS-Aware Semantic Service Selection: An Optimization Problem
In order to select the best suited service among a set
of discovered services, with respect to QOS parameters, a
user have to state his or her preferences, so services can
be ranked according to these QOS parameters. Current Se-
mantic Web Services ontologies do not support the defini-
tion of QOS-aware user preferences, though there are some
proposals that extend those ontologies to allow selection
based on those preferences. However, their selection algo-
rithms are very coupled with user preferences descriptions,
which are defined without semantics or at a different seman-
tic level than service functionality. In this work, we present
a service selection framework that transforms user prefer-
ences into an optimization problem where the best service
is selected. This framework is based on an ontology that
conceptualizes these user preferences. Thus, we use a very
expressive solution decoupled with the concrete selection
technique by using XSL transformations, while describing
QOS-aware user preferences at the same semantic level of
functional preferences.Comisión Interministerial de Ciencia y Tecnología TIN2006-00472Junta de Andalucía TIC-253
ELeCTRA: Induced Usage Limitations Calculation in RESTful APIs
As software architecture design is evolving to microservice paradigms, RESTful APIs become the building blocks of applications. In such a scenario, a growing market of APIs is proliferating and developers face the challenges to take advantage of this reality. For example, third-party APIs typically define different usage limitations depending on the purchased Service Level Agreement (SLA) and, consequently, performing a manual analysis of external APIs and their impact in a microservice architecture is a complex and tedious task. In this demonstration paper, we present ELeCTRA, a tool to automate the analysis of induced usage limitations in an API, derived from its usage of external APIs. This tool takes the structural, conversational and SLA specifications of the API, generates a visual dependency graph and translates the problem into a constraint satisfaction optimization problem (CSOP) to obtain the optimal usage limitations.Ministerio de Economía y Competitividad TIN2015-70560-RJunta de Andalucía P12–TIC–1867Ministerio de Economía y Competitividad TIN2014-53986-REDTMinisterio de Educación, Cultura y Deporte FPU15/0298
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