Rubén Mondéjar

Enabling Wide-Area Service Oriented Architecture through the p2pWeb Model

In this paper we present the p2pWeb service oriented architecture (SOA). The p2pWeb model offers decentralized solutions for service description, publication, discovery and availability, following the Web services standards. The three innovative contributions in p2pWeb SOA are: easy integration of Web services into a p2pWeb network, secure and decentralized Web services deployment, and transparent location, load balancing and fault-tolerance peer-to-peer mechanisms. We believe that all the features our p2pWeb model offers can be of special interest for the creation of communities, and for the development of future collaborative decentralized applications

CloudSNAP: A transparent infrastructure for decentralized web deployment using distributed interception

Abstract Over the last years we have seen the proliferation of many new popular web applications, which are commonly used on a daily basis by most of us. The challenges that have to be overcome by web application designers include how to make these applications support as much concurrent users as possible, without degrading application’s performance, and without single points of failure. Such complex task would be much easier to achieve if designers could concentrate on the application functionalities without worrying about its wide-area scope and derived problems. In this article, we introduce CloudSNAP, a decentralized web deployment platform. CloudSNAP allows transforming any actual web application into a globally-enabled and scalable one. By using a distributed Peer-to-Peer (P2P) Cloud interception middleware, all necessary functionalities are injected into existent web infrastructures in a transparent way. Therefore, CloudSNAP provides many benefits from P2P Cloud computing, like a decentralized deployment environment as well as a set of distributed mechanisms, like load balancing, fault tolerance, dynamic activation, persistence and replication. Moreover, our solution offers important advantages: (i) a high degree of transparency and decoupling in all provided services by means of distributed interception techniques, and (ii) the direct deployment of existent Java Enterprise Edition (Java EE) applications and services with practically no changes on them. In summary, CloudSNAP makes it easy to deploy any Java EE web application into a P2P Cloud infrastructure, and immediately benefit from all of its inherent services at a minimal development and infrastructure cost.

Building a distributed AOP middleware for large scale systems

Building large scale applications is nowadays a complex challenge. Such complexity is determined by several factors like distributed application development, deployment or management, to name a few. Adaptive middleware plays an important role in achieving such task, and abstracts developers from the underlying layer issues like persistence, fault tolerance, and load balancing, among others. Distributed Aspect Oriented Programming (AOP) is a promising paradigm that offers new ideas in the middleware arena. Several models like remote pointcut or component-aspects for designing wide-area distributed systems exist in such setting, but none of them completely fulfill the scalability requirement. In this paper we present a distributed aspect middleware for large-scale systems mainly offering three contributions. Firstly we introduce a complete aspect remoting service with one-to-one and one-to-many abstractions. Secondly, we outline the construction of a distributed aspect meta-model that provides a novel distributed meta-pointcut mechanism to intercept remote services. Finally, the distributed aspect composition model that allows connection mechanisms in design, activation, and runtime phases. The last part of the paper includes a proof-of-concept, consisting of an adaptive Distributed Hash Table (DHT), which is a clear example of how a wide variety of distributed aspects on large-scale scenarios can be implemented by using our model.

Designing a distributed AOP runtime composition model

In this paper we present Damon, a new distributed aspect-oriented composition model. Our model mimics the CCM and is based on computational reflection, component-based design, and separation of concerns. Moreover, we benefit from the peer-to-peer substrate to implement these services in a decentralized and efficient way. Damon aims to provide new distributed concerns (i.e. replication) to existent or new applications transparently. It reduces the complexity of application development and allows runtime reconfiguring. The innovative contributions of our approach are composition capabilities in design, load-time and runtime phases, including the definition of distributed aspects and meta-aspects.

Damon: a decentralized aspect middleware built on top of a peer-to-peer overlay network

In this paper we present Damon, a decentralized wide-area runtime aspect middleware built on top of a structured peer-to-peer (p2p) substrate and a dynamic Aspect Oriented Programming (AOP) framework. By using this methodology, we provide innovative benefits like aspect persistence and discovery, a high performance one-to-one/one-to-many messaging system, reflective skills, and a decentralized aspect container. Furthermore, new pointcut abstractions (anypointcut, manypointcut and multipointcut) are introduced, which allow development of shared aspect functionalities in a transparent way. We believe that such middleware is a novel solution for allowing decentralized crosscutting concerns like fault-tolerance or load-balancing for distributed systems. This paper describes these ideas and it presents a use case of our middleware implementation.

Building wide-area collaborative applications on top of structured peer-to-peer overlays

In this paper we present p2pCM, a new distributed component-oriented model aimed to wide-area environments. Our model offers traditional component services like naming, activation, event notifications, and persistence on top of a structured peer-to-peer overlay. We benefit from the peer-to-peer substrate to implement these services in a decentralized and efficient way. The innovative contributions of our approach are a lightweight distributed container model, an adaptive component activation mechanism, which takes into account network locality, and a decentralized component location and deployment service. We focus on how the services provided by p2pCM can be used to implement essential computer-supported cooperative work (CSCW) services, like shared session management, awareness and coordination policies, and show a sample application which uses them. We believe that all of the features our component-oriented model provides can be very promising for the development of future wide-area distributed CSCW applications.

p2pCM: a structured peer-to-peer grid component model

In this paper we present p2pCM, a new distributed component-oriented model aimed to structured peer-to-peer grid environments. Our model offers innovative contributions like a lightweight distributed container model, an adaptive component activation mechanism, which takes into account network proximity, and a decentralized component location and deployment service. We believe that all of the features our component-oriented model provides can be very promising for the development of future wide-area distributed applications.

TaKo: Providing transparent collaboration on single-user applications

The conversion of legacy single-user applications into collaborative multi-user tools is a recurrent topic in groupware scenarios. Many recent literature works have tried to achieve transparent collaboration, which consists of enabling collaborative features without modifying the original application source code. In this paper, we define the available whitebox and blackbox models of transparent collaboration. Each of them differs on which degree the developer must have of the target application inner knowledge, in order to convert it into a multi-user tool. Moreover, we propose and define a novel blackbox model and its implementation (TaKo). Our proposal achieves complete transparency by intercepting user interface libraries and input events. This is the first blackbox solution constructed on top of interception technologies (Aspect Oriented Programming) and, unlike previous approaches, it provides support to both AWT and Swing applications. Our solution solves five important problems: simultaneous work, management of replicated resources (random number generators), collaborative services binding, detailed group awareness information, late joining, and unanticipated sharing support. We are also researching a prospective work on wide-area collaboration scenarios by using a peer-to-peer event substrate. Finally, this work provides validation of TaKo with several Swing-based and AWT-based tools, demonstrating that it is generic and imposes very low overhead.

Damon: A distributed AOP middleware for large-scale scenarios

Context: The development of distributed applications in large-scale environments has always been a complex task. In order to guarantee non-functional properties like scalability or availability, developers are usually faced with the same problems over and over again. These problems can be separated in distributed concerns, as for example, distribution, load-balancing or replication, just to name a few. Nevertheless, none of the current solutions in adaptive middleware area, like Aspect-Oriented Programming (AOP), is capable of implementing these distributed concerns transparently. Objective: In this article, we present a distributed AOP middleware for large-scale development, called Damon. Its main goal is to implement true distributed aspects, which enables the use of distributed concerns in applications that were not specifically designed for distributed or large-scale scenarios. Method: Our middleware comprises two main layers: a distributed composition model and a scalable deployment platform. The distributed composition model envisages separation of distributed aspects, taking the necessary features from component models, like distribution facilities and connectors, and from computational reflection, like introspection and meta-levels. This recursive and fully distributed model provides its own Architecture Description Language (ADL), and thus allows low dependency and high cohesion among distributed aspects. Additionally, our model is built on top of a deployment platform where distributed aspects are disseminated and activated in individual or grouped hosts. This platform benefits from peer-to-peer and dynamic AOP substrates to implement its services in a decentralized, decoupled, and efficient way. Results: Therefore, our middleware solution reduces the complexity of distributed application development, managing separated functionalities, and enabling necessary services like transparent reconfiguration and deployment at runtime. Finally, we have implemented a functional prototype and we conducted several experiments using the PlanetLab testbed. Conclusion: Our distributed AOP approach fulfills the large-scale scenarios requirements, and represents a solid building block for future distributed transparent infrastructures.