Reconstructing an Architecture

Why Lost documentation No documentation ever Architectural drift Prove conformance

Approaches Manual Methods Top down  For example, start with high-level diagrams Bottom up  For example, start with comments in code Opportunistic  Use whatever is available Tools

Tool-Based Reconstruction View Extraction DB Presentation Pattern Recogn. Visualization View Fusion Reconstruction Doc System

Data Source Types Static Dynamic

Tools Parsers Abstract Syntax Tree Analyzers Lexical Analyzer Profilers Code instrumentation tools Ad hoc Workbench

Extracted Data

Guidelines Use least-effort Validate the information extracted Extract dynamic information when needed For example, if the system uses a lot of late binding or runtime configuration

Tool-Based Reconstruction View Extraction DB Presentation Pattern Recogn. Visualization View Fusion Reconstruction Doc System

Database Structure Need a standard format or model Authors use Rigi Standard FormatRigi Standard Format RDF triples are very similar, and OWL reasoning might be useful RDFOWL Efficient queries Support fusion Checkpointing for intermediate results

DB tables Table of relation names Table of elements Table for each relation - triples RelationTable RelationTypeThing1Thing2 IncludesTable File1File2 ContainsTable FileFunction And/Or …

Tool-Based Reconstruction View Extraction DB Presentation Pattern Recogn. Visualization View Fusion Reconstruction Doc System

View Fusion Reconcile Augment Establish connections

Example: fusing static and dynamic views of the “calls” relation Static: calls extracted from source List::length PrimitiveOp::Compute Dynamic: calls detected by profiler List::length List::getnth ArithmeticOp::Compute StringOp::Compute Static analyzer missed this (no reason given) What about these?

Fusing static+dynamic, continued PrimitiveOp +Compute ArithmeticOp +Compute StringOp +Compute Static analyzer saw this Profiler saw these List::length List::getnth PrimitiveOp::Compute Fused list of calls: See examples 10-4, 10-5 p 240

Example: fusing calls from different processes main() { register(); } Server main() { launch(); } GUI Launcher Calls mainregister mainlaunch Calls Server.mainregister Launcher.mainlaunch UnfusedFused

Guidelines for Fusions Fuse when no single view shows needed information Fuse when a view is too ambiguous and ambiguity can be resolved by fusion Use multiple extraction techniques Different kinds of tools Different implementations of tools

Tool-Based Reconstruction View Extraction DB Presentation Pattern Recogn. Visualization View Fusion Reconstruction Doc System

Reconstructions SQL examples for Reconstructions See 10.9 – aggregate local variables Build SQL queries for reconstruction

Yet more guidelines Work with the architect if possible Code segments should be as re-usable as possible A “code segment” is a capability based on DB query + other code, that can identify patterns or create views Code segments can take advantage of Naming conventions Directory structure

Example in text Repeated view fusions and aggregations eventually produce a just- barely-usable view pp 248 – 257