Object-Oriented Query Language Design and Processing

This thesis proposes an object-oriented query language that is more powerful than many existing query languages. The language is formally specified and its expressive power is demonstrated by giving four translation schemes from other prominent object-oriented query languages. Further, this query language can be supported by a query algebra and both the query language and query algebra can be optimised using meaning preserving transformation rules. Object-Oriented Query Languages. The functional requirements of high-level object-oriented query languages are identified and they combine as well as supplement features found in existing object-oriented query languages. Effectively they formulate a query model against which existing query languages can be evaluated and compared. An evaluation of four representative query languages chosen from research prototypes and commercial products shows that none satisfies all the requirements. On the basis of the requirements a new query language, object comprehensions, is developed to provide a concise, clear, powerful, and optimisable query language for object-oriented databases. Some optimisation opportunities for the novel features are identified. A set of translation schemes from the query languages studied to object comprehensions is presented. Such translations demonstrate that object comprehensions are at least as powerful as these query languages and a system supporting object comprehensions can potentially support multiple query languages by providing translations to object comprehensions. Algebraic Support. The canonical algebra provides an abstract execution engine with which object comprehension queries can be expressed using algebraic operations. The translation scheme from object comprehensions to the canonical algebra is very simple and is no for supporting queries involving mixed collection classes The canonical algebra shares many operations with other query algebras and is formally specified. A set of transformation rules that can be used for optimisation is presented whose validity can be verified given the formal specification. Formal Data Model. The data model which forms the basis of investigation is formally defined using the specification language Z. This reference data model captures all the essential features of existing object-oriented data models including multiple inheritance. However, unlike existing data models, it also supports a generalised form of method over-loading. Static type checking of such overloaded methods is studied in this thesis

Implementing PRISMA/DB in an OOPL

PRISMA/DB is implemented in a parallel object-oriented language to gain insight in the usage of parallelism. This environment allows us to experiment with parallelism by simply changing the allocation of objects to the processors of the PRISMA machine. These objects are obtained by a strictly modular design of PRISMA/DB. Communication between the objects is required to cooperatively handle the various tasks, but it limits the potential for parallelism. From this approach, we hope to gain a better understanding of parallelism, which can be used to enhance the performance of PRISMA/DB.\ud The work reported in this document was conducted as part of the PRISMA project, a joint effort with Philips Research Eindhoven, partially supported by the Dutch "Stimuleringsprojectteam Informaticaonderzoek (SPIN)

An overview of Mirjam and WeaveC

In this chapter, we elaborate on the design of an industrial-strength aspectoriented programming language and weaver for large-scale software development. First, we present an analysis on the requirements of a general purpose aspect-oriented language that can handle crosscutting concerns in ASML software. We also outline a strategy on working with aspects in large-scale software development processes. In our design, we both re-use existing aspect-oriented language abstractions and propose new ones to address the issues that we identified in our analysis. The quality of the code ensured by the realized language and weaver has a positive impact both on maintenance effort and lead-time in the first line software development process. As evidence, we present a short evaluation of the language and weaver as applied today in the software development process of ASML

Model-driven performance evaluation for service engineering

Service engineering and service-oriented architecture as an integration and platform technology is a recent approach to software systems integration. Software quality aspects such as performance are of central importance for the integration of heterogeneous, distributed service-based systems. Empirical performance evaluation is a process of measuring and calculating performance metrics of the implemented software. We present an approach for the empirical, model-based performance evaluation of services and service compositions in the context of model-driven service engineering. Temporal databases theory is utilised for the empirical performance evaluation of model-driven developed service systems

Flattening an object algebra to provide performance

Algebraic transformation and optimization techniques have been the method of choice in relational query execution, but applying them in object-oriented (OO) DBMSs is difficult due to the complexity of OO query languages. This paper demonstrates that the problem can be simplified by mapping an OO data model to the binary relational model implemented by Monet, a state-of-the-art database kernel. We present a generic mapping scheme to flatten data models and study the case of straightforward OO model. We show how flattening enabled us to implement a query algebra, using only a very limited set of simple operations. The required primitives and query execution strategies are discussed, and their performance is evaluated on the 1-GByte TPC-D (Transaction-processing Performance Council's Benchmark D), showing that our divide-and-conquer approach yields excellent result

Efficient and Reasonable Object-Oriented Concurrency

Making threaded programs safe and easy to reason about is one of the chief difficulties in modern programming. This work provides an efficient execution model for SCOOP, a concurrency approach that provides not only data race freedom but also pre/postcondition reasoning guarantees between threads. The extensions we propose influence both the underlying semantics to increase the amount of concurrent execution that is possible, exclude certain classes of deadlocks, and enable greater performance. These extensions are used as the basis an efficient runtime and optimization pass that improve performance 15x over a baseline implementation. This new implementation of SCOOP is also 2x faster than other well-known safe concurrent languages. The measurements are based on both coordination-intensive and data-manipulation-intensive benchmarks designed to offer a mixture of workloads.Comment: Proceedings of the 10th Joint Meeting of the European Software Engineering Conference and the ACM SIGSOFT Symposium on the Foundations of Software Engineering (ESEC/FSE '15). ACM, 201

Weaving aspects into web service orchestrations

Web Service orchestration engines need to be more open to enable the addition of new behaviours into service-based applications. In this paper, we illus- trate how, in a BPEL engine with aspect-weaving ca- pabilities, a process-driven application based on the Google Web Service can be dynamically adapted with new behaviours and hot-fixed to meet unforeseen post- deployment requirements. Business processes (the ap- plication skeletons) can be enriched with additional fea- tures such as debugging, execution monitoring, or an application-specific GUI. Dynamic aspects are also used on the processes themselves to tackle the problem of hot-fixes to long running processes. In this manner, composing a Web Service ’on-the-fly’ means weaving its choreography in- terface into the business process