Using Infinispan as a Backend for CDI Contexts

Tato práce vede čtenáře od vývoje kontextově závislé injekce v Java EE, ukazuje základní přehled o JSR 299, které se vyvinulo do rámce této specifikace a analyzuje referenční implementace Weld. V pozdějších částech je vytvořeno CDI rozšíření, které vytváří cluster-wide scope pomocí Infinispanu jako skladem dat, kterého základní vlastnosti jsou také prozkoumána.This thesis guides the reader from the evolution of the Contextual Dependency Injection in Java EE, shows the basic overview of JSR 299, frameworks that evolved into this specification and analyses the reference implementation Weld. In the later parts a CDI extension that creates a cluster-wide scope is creating using Infinispan as a backend storage, of which elementary features are also explored.

Automatic performance optimisation of component-based enterprise systems via redundancy

Component technologies, such as J2EE and .NET have been extensively adopted for building complex enterprise applications. These technologies help address complex functionality and flexibility problems and reduce development and maintenance costs. Nonetheless, current component technologies provide little support for predicting and controlling the emerging performance of software systems that are assembled from distinct components. Static component testing and tuning procedures provide insufficient performance guarantees for components deployed and run in diverse assemblies, under unpredictable workloads and on different platforms. Often, there is no single component implementation or deployment configuration that can yield optimal performance in all possible conditions under which a component may run. Manually optimising and adapting complex applications to changes in their running environment is a costly and error-prone management task. The thesis presents a solution for automatically optimising the performance of component-based enterprise systems. The proposed approach is based on the alternate usage of multiple component variants with equivalent functional characteristics, each one optimized for a different execution environment. A management framework automatically administers the available redundant variants and adapts the system to external changes. The framework uses runtime monitoring data to detect performance anomalies and significant variations in the application's execution environment. It automatically adapts the application so as to use the optimal component configuration under the current running conditions. An automatic clustering mechanism analyses monitoring data and infers information on the components' performance characteristics. System administrators use decision policies to state high-level performance goals and configure system management processes. A framework prototype has been implemented and tested for automatically managing a J2EE application. Obtained results prove the framework's capability to successfully manage a software system without human intervention. The management overhead induced during normal system execution and through management operations indicate the framework's feasibility

Adaptive Caching of Distributed Components

Die Zugriffslokalität referenzierter Daten ist eine wichtige Eigenschaft verteilter Anwendungen. Lokales Zwischenspeichern abgefragter entfernter Daten (Caching) wird vielfach bei der Entwicklung solcher Anwendungen eingesetzt, um diese Eigenschaft auszunutzen. Anschliessende Zugriffe auf diese Daten können so beschleunigt werden, indem sie aus dem lokalen Zwischenspeicher bedient werden. Gegenwärtige Middleware-Architekturen bieten dem Anwendungsprogrammierer jedoch kaum Unterstützung für diesen nicht-funktionalen Aspekt. Die vorliegende Arbeit versucht deshalb, Caching als separaten, konfigurierbaren Middleware-Dienst auszulagern. Durch die Einbindung in den Softwareentwicklungsprozess wird die frühzeitige Modellierung und spätere Wiederverwendung caching-spezifischer Metadaten gewährleistet. Zur Laufzeit kann sich das entwickelte System außerdem bezüglich der Cachebarkeit von Daten adaptiv an geändertes Nutzungsverhalten anpassen.Locality of reference is an important property of distributed applications. Caching is typically employed during the development of such applications to exploit this property by locally storing queried data: Subsequent accesses can be accelerated by serving their results immediately form the local store. Current middleware architectures however hardly support this non-functional aspect. The thesis at hand thus tries outsource caching as a separate, configurable middleware service. Integration into the software development lifecycle provides for early capturing, modeling, and later reuse of cachingrelated metadata. At runtime, the implemented system can adapt to caching access characteristics with respect to data cacheability properties, thus healing misconfigurations and optimizing itself to an appropriate configuration. Speculative prefetching of data probably queried in the immediate future complements the presented approach

Attribute based component design: Supporting model driven development in CbSE

In analysing the evolution of Software Engineering, the scale of the components has increased, the requirements for different domains become complex and a variety of different component frameworks and their associated models have emerged. Many modern component frameworks provide enterprise level facilities and services, such as instance management, and component container support, that allow developers to apply if needed to manage scale and complexity. Although the services provided by these frameworks are common, they have different models and implementation. Accordingly, the main problem is, when developing a component based application using a component framework, the design of the components becomes tightly integrated with the framework implementation and the framework model is embedded in the component functionality, and hence reduces reusability. Another problem arose is, the designers must have in-depth knowledge of the implementation of a component framework to be able to model, design and implement the components and take advantages of the services provided. To address these problems, this research proposes the Attribute based Component Design (AbCD) approach which allows developers to model software using logical and abstract components at the specification level. The components encapsulate the provided functionality, as well as the required services, runtime requirements and interaction models using a set of attributes. These attributes are systemically derived by grouping common features and services from light weight component frameworks and heavy weight component frameworks that are available in the literature. The AbCD approach consists of the AbCD Meta-model, which is an extension of the บML meta-model, and the Component Design Guidelines (CDG) that includes core Component based Software Engineering principles to assist the modelling process for designers. To support the AbCD approach, an implementation has been developed as a set of plug-ins, called the AbCD tool suite, for Eclipse IDE. An evaluation of the AbCD approach is conducted by using the tool suite with two case studies. The first case study focuses on abstraction achieved by the AbCD approach and the second focuses on reusability of the components. The evaluation shows that the artefacts produced using the approach provide an alternative architectural view to the design and help to re-factor the design based on aspects. At the same time the evaluation process identified possible improvements in the AbCD meta-model and the tool suite constructed. This research provides a non-invasive approach for designing component based software using model driven development

Rethinking Consistency Management in Real-time Collaborative Editing Systems

Networked computer systems offer much to support collaborative editing of shared documents among users. Increasing concurrent access to shared documents by allowing multiple users to contribute to and/or track changes to these shared documents is the goal of real-time collaborative editing systems (RTCES); yet concurrent access is either limited in existing systems that employ exclusive locking or concurrency control algorithms such as operational transformation (OT) may be employed to enable concurrent access. Unfortunately, such OT based schemes are costly with respect to communication and computation. Further, existing systems are often specialized in their functionality and require users to adopt new, unfamiliar software to enable collaboration. This research discusses our work in improving consistency management in RTCES. We have developed a set of deadlock-free multi-granular dynamic locking algorithms and data structures that maximize concurrent access to shared documents while minimizing communication cost. These algorithms provide a high level of service for concurrent access to the shared document and integrate merge-based or OT-based consistency maintenance policies locally among a subset of the users within a subsection of the document – thus reducing the communication costs in maintaining consistency. Additionally, we have developed client-server and P2P implementations of our hierarchical document management algorithms. Simulations results indicate that our approach achieves significant communication and computation cost savings. We have also developed a hierarchical reduction algorithm that can minimize the space required of RTCES, and this algorithm may be pipelined through our document tree. Further, we have developed an architecture that allows for a heterogeneous set of client editing software to connect with a heterogeneous set of server document repositories via Web services. This architecture supports our algorithms and does not require client or server technologies to be modified – thus it is able to accommodate existing, favored editing and repository tools. Finally, we have developed a prototype benchmark system of our architecture that is responsive to users’ actions and minimizes communication costs

Distributed aop middleware for large-scale scenarios

En aquesta tesi doctoral presentem una proposta de middleware distribuït pel desenvolupament d'aplicacions de gran escala. La nostra motivació principal és permetre que les responsabilitats distribuïdes d'aquestes aplicacions, com per exemple la replicació, puguin integrar-se de forma transparent i independent. El nostre enfoc es basa en la implementació d'aquestes responsabilitats mitjançant el paradigma d'aspectes distribuïts i es beneficia dels substrats de les xarxes peer-to-peer (P2P) i de la programació orientada a aspectes (AOP) per realitzar-ho de forma descentralitzada, desacoblada, eficient i transparent. La nostra arquitectura middleware es divideix en dues capes: un model de composició i una plataforma escalable de desplegament d'aspectes distribuïts. Per últim, es demostra la viabilitat i aplicabilitat del nostre model mitjançant la implementació i experimentació de prototipus en xarxes de gran escala reals.In this PhD dissertation we present a distributed middleware proposal for large-scale application development. Our main aim is to separate the distributed concerns of these applications, like replication, which can be integrated independently and transparently. Our approach is based on the implementation of these concerns using the paradigm of distributed aspects. In addition, our proposal benefits from the peer-to-peer (P2P) networks and aspect-oriented programming (AOP) substrates to provide these concerns in a decentralized, decoupled, efficient, and transparent way. Our middleware architecture is divided into two layers: a composition model and a scalable deployment platform for distributed aspects. Finally, we demonstrate the viability and applicability of our model via implementation and experimentation of prototypes in real large-scale networks

Repetitive querying of large random heterogeneous datasets in RDBMS using materialized views

A methodology has been developed to increase time efficiency of querying large heterogeneous datasets repetitively by applying materialized views on repetitive complex queries. Additionally, a simple user interface is provided to demonstrate the utility of this research methodology. The programs demonstrate sufficiently that the core design can be used to deploy a complete system which could be used in different domains. The methodology as developed in this research is presented as an experimental proof-of-concept prototype based on an abstract design

OPC UA Java History Gateway with Inherent Database Integration

OPC Unified Automation on automaatioteollisuudessa käytetty määrittely tiedon mallintamiseen ja hallintaan. Määrittely kuvaa mm. kommunikoinnin, tiedon mallintamisen ja turvallisen tiedonsiirron automaatiolaitteiden välillä. Tiedonsiirto tapahtuu palvelimien ja näihin yhteydessä olevien asiakassovellusten välillä. Työssä toteutetaan eräänlainen välityspalvelin (gateway) tiedon kokoamiseen. Välityspalvelin on yhteydessä useisiin muihin palvelimiin, joiden tietoja voi käsitellä sen kautta. Työn toinen tärkeä osa-alue on prosessitiedon tallentaminen SQL tietokantaan. Tähän tarkoitukseen työssä esitellään tietokannan rakenne, joka mahdollistaa OPC UA:lla mallinnetun tiedon tallentamisen (ja palauttamisen). Työssä myös toteutetaan prosessitiedon tallennus ja luku tietokannasta Javaa ja OPC UA:ta käyttäen. Samalla ratkaistaan osittainen OPC UA tietomallin esittäminen SQL tietokannassa. Työn ratkaisuna on prototyyppi OPC UA historiavälityspalvelimesta. Palvelin kokoaa useiden OPC UA palvelimien tietoja yhteen palvelimeen ja kykenee näin yhdistämään laitetietoja laajalta alalta. Palvelin myös tarjoaa aikasarjoja (pysyvästi) tallennetusta prosessidatasta, mikä mahdollistaa kehittyneemmän tiedon analysoinnin.OPC Unified Automation is a highly-developed information modelling and managing framework in use in the automation industry. OPC UA takes into account the communication, data modelling and security aspects w.r.t information exchange between devices in the factory floor. In practice the information exchange is done between server and client instances. Of these, servers hold the process data, and clients access it. An intermediate gateway is developed, which accesses (and allows managing) several other servers from a single instance. The storing of process data within the OPC UA framework is another main topic of this thesis. The thesis presents an SQL data model to storing time series process data acquired from multiple servers. The data itself is modelled using the OPC UA semantics. Additionally, the connectivity and data mapping to few SQL implementations is solved. A solution addressing both the storing and integration aspects is introduced in the form of the OPC UA History Gateway. The OPC UA History Gateway illustrates capabilities of the OPC UA framework in the data acquisition and device integration in the modern automation environment. The implemented (prototype) solution is shown to aggregate and store plant floor device information. The OPC UA History Gateway also provides trend data to clients, making more refined data analysis possible

CazDataProvider: a solution to the object-relational mismatch

Dissertação de mestrado em Engenharia de InformáticaToday, most software applications require mechanisms to store information persistently. For decades, Relational Database Management Systems (RDBMSs) have been the most common technology to provide efficient and reliable persistence. Due to the object-relational paradigm mismatch, object oriented applications that store data in relational databases have to deal with Object Relational Mapping (ORM) problems. Since the emerging of new ORM frameworks, there has been an attempt to lure developers for a radical paradigm shift. However, they still often have troubles finding the best persistence mechanism for their applications, especially when they have to bear with legacy database systems. The aim of this dissertation is to discuss the persistence problem on object oriented applications and find the best solutions. The main focus lies on the ORM limitations, patterns, technologies and alternatives. The project supporting this dissertation was implemented at Cachapuz under the Project Global Weighting Solutions (GWS). Essentially, the objectives of GWS were centred on finding the optimal persistence layer for CazFramework, mostly providing database interoperability with close-to-Structured Query Language (SQL) querying. Therefore, this work provides analyses on ORM patterns, frameworks, alternatives to ORM like Object-Oriented Database Management Systems (OODBMSs). It also describes the implementation of CazDataProvider, a .NET library tool providing database interoperability and dynamic query features. In the end, there is a performance comparison of all the technologies debated in this dissertation. The result of this dissertation provides guidance for adopting the best persistence technology or implement the most suitable ORM architectures.Hoje, a maioria dos aplicações requerem mecanismos para armazenar informação persistentemente. Durante décadas, as RDBMSs têm sido a tecnologia mais comum para fornecer persistência eficiente e confiável. Devido à incompatibilidade dos paradigmas objetos-relacional, as aplicações orientadas a objetos que armazenam dados em bases de dados relacionais têm de lidar com os problemas do ORM. Desde o surgimento de novas frameworks ORM, houve uma tentativa de atrair programadores para uma mudança radical de paradigmas. No entanto, eles ainda têm muitas vezes dificuldade em encontrar o melhor mecanismo de persistência para as suas aplicações, especialmente quando eles têm de lidar com bases de dados legadss. O objetivo deste trabalho é discutir o problema de persistência em aplicações orientadas a objetos e encontrar as melhores soluções. O foco principal está nas limitações, padrões e tecnologias do ORM bem como suas alternativas. O projeto de apoio a esta dissertação foi implementado na Cachapuz no âmbito do Projeto GWS. Essencialmente, os objetivos do GWS foram centrados em encontrar a camada de persistência ideal para a CazFramework, principalmente fornecendo interoperabilidade de base de dados e consultas em SQL. Portanto, este trabalho fornece análises sobre padrões, frameworks e alternativas ao ORM como OODBMS. Além disso descreve a implementação do CazDataProvider, uma biblioteca .NET que fornece interoperabilidade de bases de dados e consultas dinâmicas. No final, há uma comparação de desempenho de todas as tecnologias discutidas nesta dissertação. O resultado deste trabalho fornece orientação para adotar a melhor tecnologia de persistência ou implementar as arquiteturas ORM mais adequadas