Usage examples are helpful for programmers learning to use APIs from third-party frameworks or libraries. There are lots of usage examples scattered in web pages on the Web, such as tutorials, blogs, and forums. A few researches have proposed approaches to leveraging these usage examples to improve programming. However, due to the lack of comprehensive understanding on the current situation of usage examples on the web, the work is still at the very beginning. Many concerns are reserved, for instance, how many usage examples can be found on the Web? how well do such examples support programmers on earth? what factors have impact on these examples' usability? In this paper, we conducted an exploratory study of usage examples on the web, including their distribution, characteristics like content style, correctness, and complexity, as well as their correlations. Through the study, we obtain some insight of how to facilitate utilization of usage examples on the web and what mechanisms could be provided. Possible research directions and problems are proposed at the end.

Programmers often learn how to use an API by studying its usage examples. There are many usage examples scattered in web pages on the Internet. However, it often takes programmers much effort to find out the desired examples from a large number of web pages by web search. This paper proposes a tool named APIExample that can extract usage examples for java APIs from web pages on the Internet and recommend them to programmers. Given a java API, the tool collects its related web pages from the Internet, extracts java code snippets and their surrounding descriptive texts embedded in the pages, then assembles them into usage examples for programmers. Furthermore, in order to help programmers capture more kinds of usages of the target API by browsing fewer examples, our tool clusters and ranks the listed examples based on the target API's usage. Besides, as a practical tool, APIExample provides multiple aspects of frequently-used information about using the target API in a concise user interface with friendly user experience. Two kinds of user-interaction style, a web search portal and an Eclipse plug-in, are now both publicly available.

In the past 40 years, software engineering has emerged as an important sub-field of computer science. The quality and productivity of software have been improved and the cost and risk of software development been decreased due to the contributions made in this sub-field. The software engineering community needs to invest much more efforts to cope with the drastically increasing demands on the information technology as well as the extremely open and dynamic nature of the Internet. The history of software engineering is reviewed with emphasis on the driving forces of software and the milestones of software engineering development. The history of software engineering in China is reviewed with emphasis on the relationship between software engineering and the software industry. Based on the above reviews, we argue that software engineering should become an independent discipline along with computer science and co-operative efforts from academia, governments and industries should be needed for the harmonious development of software engineering. Some results are presented based on China's experience of developing software engineering under this model.

To facilitate software maintenance and evolution, a helpful step is to locate features concerned in a particular maintenance task. In the literature, both dynamic and interactive approaches have been proposed for feature location. In this article, we present a static and noninteractive method for achieving this objective. The main idea of our approach is to use information retrieval (IR) technology to reveal the basic connections between features and computational units in the source code. Due to the imprecision of retrieved connections, we use a static representation of the source code named BRCG (branch-reserving call graph) to further recover both relevant and specific computational units for each feature. A premise of our approach is that programmers should use meaningful names as identifiers. We also performed an experimental study based on two real-world software systems to evaluate our approach. According to experimental results, our approach is quite effective in acquiring the relevant and specific computational units for most features.

Software reuse is widely believed as a feasible way to improve both the productivity and quality of software development. The developers must be capable to acquire enough desired components before developing with reuse. Many Internet-enabled reuse repositories exist to provide access to reusable resources. It is necessary to eliminate the semantic gaps of the repositories to enable users to access resources from multiple repositories via a single representation view. In some sense, the only usable information to mine the semantics of the terms representing the resources is the mutual components stored in the repositories. In this paper, the extended improved relevancy matching and ranking (EIRMR) method is proposed to enhance the semantic interoperability of reuse repositories, based on our previous work (IRMR) and the mutual components in the third-party repositories. Experimental results on the data sets from the real repositories demonstrated an improvement in terms of searching effectiveness.

To facilitate software maintenance and evolution, a helpful step is to locate features concerned in a particular maintenance task. In the literature, both dynamic and interactive approaches have been proposed for feature location. In this paper, we present a static and non-interactive method for achieving this objective. The main idea of our approach is to use the information retrieval (IR) technology to reveal the basic connections between features and computational units in source code. Due to the characteristics of the retrieved connections, we use a static representation of the source code named BRCG to further recover both the relevant and the specific computational units for each feature. Furthermore, we recover the relationships among the relevant units for each feature. A premise of our approach is that programmers should use meaningful names as identifiers. We perform an experimental study based on a GNU system to evaluate our approach. In the experimental study, we present the detailed quantitative experimental data and give the qualitative analytical results.

Software reuse is a promising solution to the software crisis. Reuse repositories are the basic infrastructure for software reuse. During the past decade, various academic, commercial, governmental, and industrial organizations have developed many Internet-enabled reuse repositories to provide access to software components and related resources. It has necessitated semantic interoperation to allow distributed maintenance and management of these repositories while enabling users to efficiently and conveniently access resources from multiple reuse repositories via a single representation view. In this paper, we have proposed an approach to enhancing the semantic interoperability of reuse repositories, called the improved relevancy matching and ranking (IRMR) method, based on analyzing the correlation of terms in representation methods of the repositories. A prototype system, the Virtual Repository supporting Semantic Interoperation (VRSI), is presented to illustrate the application of this approach to support the semantic interoperation of reuse repositories. Experimental results on real world reuse repositories demonstrated significant improvement in terms of searching effectiveness.

Runtime environment of software are becoming more and more dynamic and changeful, while pervasive computing and Web services further this situation. Software systems are not only becoming larger, more complex, and also more rigid, which make it difficult to evolve software. This paper focuses on online evolution, more exactly, how to make online evolution process convenient and smart, with help of runtime software architecture (RSA). Following issues are discussed in this paper: types of software environment changes, the incarnation of RSA, retrieval and manipulation of RSA, the relation between RSA and the runtime system, and a visual tool to show RSA, and make evolution process more easy and intuitionist.

Component-based reuse is a hopeful solution to the software crisis. Research on software architecture (SA) has revealed a component-based vision of the gross structure of software and provides a top-down approach to direct the component-oriented development process. But the gap between SA design and final implementation prevents it from playing a fundamental role in the process. On the other hand, the component-based software development (CBSD) technology such as Java 2 platform enterprise edition (J2EE) and Common Object Request Broker Architecture (CORBA) provides a feasible bottom-up way to construct systems from standard components, forming an implementation basis for an integrated component-oriented development process. In this paper we propose an architecture-based component composition (ABC) approach, which uses SA model as the blueprint of development and COTS middleware as the run-time platform to support an automated component-oriented development process.

Most online evolution of an application depends on its runtime environment. This paper addresses how to support online evolution by an application server, which is considered as a third kind of system software, besides OS and DBMS. From the view of requirements, evolutions of software can be divided into four categories: evolutions that do not alter requirements, evolutions that alter functional requirements, evolutions that alter local constraint requirements, and evolutions that alter global constraint requirements. All changes at the requirement level should be mapped to changes at the implementation level. In our approach implementation level entities, such as components and interceptors are responsible for online evolution. Evolutions in implementation level include adding, removing, updating, and reconfiguring the entities. One of the keys to our approach is to carefully distinguish states of components and interceptors, that is, whether they are in a ready, active, executing or evolving state. A well-designed architecture and feasible mechanisms for runtime instance loading are also keys to the solution. Based on this approach, an application server prototype, named PKUAS, has been implemented and is introduced in our paper.

Reuse is viewed as a realistically effective approach to solving software crisis. For an organization that wants to build a reuse program, technical and non-technical issues must be considered in parallel. In this paper, a model-based approach to building systematic reuse program is presented. Component-based reuse is currently a dominant approach to software reuse. In this approach, building the right reusable component model is the first important step. In order to achieve systematic reuse, a set of component models should be built from different perspectives. Each of these models will give a specific view of the components so as to satisfy different needs of different persons involved in the enterprise reuse program. There already exist some component models for reuse from technical perspectives. But less attention is paid to the reusable components from a non-technical view, especially from the view of process and management. In our approach, a reusable component model—FLP model for reusable component—is introduced. This model describes components from three dimensions (Form, Level, and Presentation) and views components and their relationships from the perspective of process and management. It determines the sphere of reusable components, the time points of reusing components in the development process, and the needed means to present components in terms of the abstraction level, logic granularity and presentation media. Being the basis on which the management and technical decisions are made, our model will be used as the kernel model to initialize and normalize a systematic enterprise reuse program.

As the size and complexity of software systems increase, the design and specification of overall system structure become more significant issues than the choice of algorithms and data structures of computation. An appropriate architecture for a system is a key element of its success. Based on the practice of Jadebird software production line, this paper proposes a software architectural style based on hierarchical message buses, named JB/HMB. In this style, the component model consists of external interfaces, static structure and dynamic behavior, which depicts a component from different aspects. Supported by message buses, components interact with one another by messages, which can be used to describe distributed and concurrent systems well. JB/HMB style supports stepwise decomposition and refinement, and runtime system evolution. Finally, characteristics of JB/HMB style are summarized as a conclusion, and future research directions are specified.

This paper introduces a reverse engineering tool, JBOORET (Jade Bird Object-Oriented Reverse Engineering Tool). This tool is developed by adopting a parser-based approach to assist the activity of extracting the higher-level design and source models from system artifacts. A conceptual model is formulated as the knowledge representation. Multi-perspective design and source models are recovered by JBOORET based on the comprehensive program information extracted from source code. Its flexible user interface can assist users to browse the detailed information of design and source models by using the selection and compaction mechanism. This paper discusses the design principles and decisions of JBOORET and describes its implementation.