Visual Component Composition Environments

Transcription

1 Visual Component Composition Environments Based on Comparing Visual Component Composition Environments written by Alejandra Cechich and Manuel Prieto in 00. Presented by Yuxi Bai on March 8, 006 Agenda Visual Component Composition (VCC) and VCC Environments (VCCEs) Motivation for Comparing VCCEs Feature Analysis Proposed Framework Example 1: Visual Composition Using Patterns Example : Component Architecture Toolkit (CAT) Example : WREN Example : ITHACA Conclusion of the Authors Challenges of VCCs and VCCEs Criticism March, 006 Visual Component Composition Environments

2 VCC Traditional component composition process + GUI Search Select Configure (Connect & Adapt) Design Missing Functionality Implement Missing Functionality March, 006 Visual Component Composition Environments Motivations A common framework is necessary for comparative evaluation of methods and tools. No other motives are explicitly or implicitly stated by the authors. Perhaps there are a large number of VCC environments from which to choose... March, 006 Visual Component Composition Environments

3 Feature Analysis (DESMET) Proposed framework is based on the DESMET approach for Feature Analysis. Feature Analysis process: 1. Select set of candidate methods/tools to evaluate.. Determine the required features of these methods/tools.. Prioritize these features with respect to the users.. Determine the required confidence level, and thus, the level of rigor required in the analysis.. Formulate a scoring/ranking system for all features. 6. Allocate responsibilities for carrying out the analysis. 7. Perform the analysis using the above criteria. 8. Analyze and interpret the results. 9. Present the results to decision makers. March, 006 Visual Component Composition Environments Proposed Framework Features are classified as either simple or compound. Simple features are accessed by a nominal scale (Y, N). Compound (specific) features are accessed by a ordinal scale. The ordinal judgment scale ranges from -1 (makes things worse) to (full support). Degree of importance (optional for simple features): M, HD, D, N. It is possible for methods/tools to have the same aggregate score, and one of the methods/tools is missing mandatory features (but has many highly desirable features). Solution: Divide compound features into groups and compute the average score of the features in each group. A framework is an eligible candidate if and only if it obtains a score of at least in every feature group. March, 006 Visual Component Composition Environments 6

4 Visual Composition Using Patterns Composition pattern specifies the interactions between roles. Extended MSCs are used to specify composition patterns. GUI provides a palette of components, palette of composition patterns. The Universe contains a single composition model: the Java Bean component model. Extended MSCs assist in automatic compatibility checking: 1. Component and role compatibility, and. Component set and composition pattern compatibility. Resulting automaton is used as glue code. Illegal events are ignored for a given state. Real-time mismatch feedback provided to the user. Composition checking and glue code generation occurs after all roles have been filled. March, 006 Visual Component Composition Environments 7 Composition Using Patterns - Prototype March, 006 Visual Component Composition Environments 8

5 CAT, CCAT, XCAT Based on the standard grid computing model. Application (physical processes, mathematical models, etc.) Composition Tool Resource Discovery, Location, and Management Hardware and Software Resources Interface programming: input and output ports. Uses COTS in lower-level infrastructure layers (e.g. Globus). GUI: graphical workspace manager and InfoBrowser. Instantiate, connect, and disconnect components. XCAT supports scripting and web services. Globus (resource) Creation Service Component X A B Y Connection Service Component March, 006 Visual Component Composition Environments 9 CCAT Demo March, 006 Visual Component Composition Environments 10

6 WREN Assumes and exploits component self-description/metainformation that is self-contained. Minimum self-description of a specific format (a Java description class) is required. Diagrammatic representation is optional. WREN interfaces are self-description wrappers for Java interfaces. GUI provides component repository search and selection views, and a design editor for composition. March, 006 Visual Component Composition Environments 11 WREN Prototype... March, 006 Visual Component Composition Environments 1

7 ITHACA SIB: Software Information Base (common component repository) RECAST: Requirement Collection and Specification Tool Vista: Visual Scripting Tool Component Presentation Behaviour Ports Name Type polarity Composition Interface March, 006 Visual Component Composition Environments 1 ITHACA Prototypes... March, 006 Visual Component Composition Environments 1

8 Conclusion Magic numbers: S1: Component searching procedure S: Analysis of component compatibility S: Analysis of resulting composition compatibility S: Explicitly defined composition rules S: GUI S6: Automatic glue-code generation S7: Formal specification of composition rules S8: Composition models previously defined S9: Multiple-view support S10: Component reusability HD M M M M HD HD D D D Patterns 1 CAT 0 1 WREN 1 1 ITHACA More numbers (no magic here): Patterns CAT WREN G1: S1, S, S, S8... G: S, S... G: S6, S9. G: S7, S ITHACA.. Non-numerical conclusion... March, 006 Visual Component Composition Environments 1 Challenges of VCC Convince component developers to provide sufficient and correct meta-information about the components. Convince component developers and users to follow a single standard for describing components. Develop VCCEs that support heterogeneous component models. Represent components graphically in VCCEs. Base compositions on specific software architectures. Support components with non-deterministic behavior. March, 006 Visual Component Composition Environments 16

9 Criticism Subjectivity. Failure to justify the necessity of the framework. Invalid basis for comparison. Failure to provide adequate basis for assigning the particular scores in the Feature Analysis. Obvious errors and inconsistencies in the writing. Failure to address the challenges of VCCs/VCCEs. March, 006 Visual Component Composition Environments 17