Formal specifications describe the behaviour of object-oriented systems precisely, with the intent to capture all properties necessary for correctness. Relationships between objects, and in a broader sense the relationship between whole components, may not be adequately captured by specifications. One critical component of specifications having a role in relationships are invariants which define a constraint between multiple objects. If an object's invariant relies on external objects for its conditions, correct operations which abide by their specifications modifying these external objects may violate the constraint. Such an invariant defines a relationship between multiple objects which is unsound since it does not adequately describe the responsibilities which the objects in the relationship have to each other. The root cause of this correctness loophole is the failure of specifications to capture such relationships adequately as well as their correctness requirements. This thesis addresses this shortcoming in a number of ways, both for individual objects in a sequential environment, and between concurrent components which are defined as specialized object types. The proposed Colleague Technique [29] defines sound invariants between two object types using classical Design-by-Contract [35] methodologies. Additional invariant conditions introduced through the technique ensure that no correct operation may produce a post-state which does not satisfy all invariants satisfied by the pre-state. Relationships between objects, as well as their correct specification and management, are the subjects of this thesis. Those relationships between objects which can be described by invariants are made sound with the Colleague Technique, or the lightweight ownership type system that accompanies it. Behavioural correctness beyond these can be addressed with specifications in a similar manner to sequential systems without concurrency, in particular with the use of runtime assertion checking [11].

Submitted by Johnny Rodrigues (johnnyrodrigues@ufcg.edu.br) on 2018-08-22T19:52:23Z No. of bitstreams: 1 ANA EMÍLIA VICTOR BARBOSA - DISSERTAÇÃO PPGCC 2007..pdf: 1669761 bytes, checksum: f47054507fe9200c8d1d56d2848ae276 (MD5) / Made available in DSpace on 2018-08-22T19:52:23Z (GMT). No. of bitstreams: 1 ANA EMÍLIA VICTOR BARBOSA - DISSERTAÇÃO PPGCC 2007..pdf: 1669761 bytes, checksum: f47054507fe9200c8d1d56d2848ae276 (MD5) Previous issue date: 2007-04-20 / Capes / Neste trabalho propomos uma técnica que visa detectar violações de propriedades comportamentais automaticamente durante a execução de sistema de software concorrentes. A técnica foi inspirada na metodologia de desenvolvimento Design by Contract (DbC). DbC permite que os desenvolvedores adicionem aos programas asserções para que sejam verificadas em tempo de execução. O uso de asserções para expressar propriedades de programas concorrentes (multithreaded)eparalelos, entretanto,não ésuficiente. Nesses sistemas,muitas das propriedades comportamentais de interesse, como vivacidade e segurança, não podem ser expressas apenas com asserções. Essas propriedades requerem o uso de operadores temporais. Neste trabalho, utilizamos Lógica Linear Temporal (Linear Time Logic - LTL) para expressar o comportamento desejado. Para dar suporte a checagem do comportamento dos programas em tempo de execução, propomos uma técnica baseada em Programação Orientada a Aspectos, que permite que o programa seja continuamente monitorado (o comportamento é checado através do uso de autômatos que permite a deteção de comportamentos inesperados). Associada a cada propriedade comportamental existe um conjunto de pontos de interesse do código-fonte que devem obedece-la. Esses pontos são então monitorados durante a execução do sistema através do uso de aspectos. Entre outros benefícios, a técnica permite que o sistema de software alvo seja instrumentado de maneira não intrusiva, sem alterar o código-fonte — particulamente, nenhum código do software alvo deve ser modificado para execução da monitoração. Para validar este trabalho, desenvolvemos como prova de conceitos um protótipo que implementa a técnica e permite a monitoração de programas Java multi-threaded, chamado DesignMonitor. Essa ferramenta é apresentada e discutida através de um estudo de caso para demonstrar a aplicação da técnica / In this work we propose and develop a technique that allows to detect the violation of behavior properties of concurrent systems. The technique was inspired by the Design by Contract (DbC) programming methodology, which proposes the use of assertions and their evaluation at runtime to check programs behavior. The use of simple assertions to express properties of concurrent and parallel programs, however, is not sufficient. Many of the relevant properties of those systems,s uch as liveness and security, can not be expressed with simple assertions. Thesepropertiesrequiretheuseof temporal operators. In our work, we used Linear Time Logic (LTL) to specify the expected behavior. To support the runtime checking of the program against the expected behavior, we propose a technique, based on Aspect-Oriented Programming, that allows the program to be continuously monitored (behavior is checked against automata that allows the detection of unexpected behaviors). Each property is mapped to a set of points of interest in the target program. Those points are then monitored during the system execution through aspects. Among other benefits, the technique allows the instrumentation of the target software to be performed automatically and in a non-intrusive way — in particular, no code must be changed toturn monitoring on or off. To validate the work, we developed a proof of concept prototype tool that implements the technique and allows the monitoring of multi-threaded Java programs, called DesignMonitor. The tool was used in case study that has allowed the evaluation and the discussion of practical issues related with the technique.